nf OF

CALIFORNIA

EARTH

JCES

RY

[BRARY

UNIVERSITY OF CALIFORNIA

•Accession Clots

town

A MONOGRAPH

or THE

MOLLUSC A FROM THE GREAT OOLITE,

CHIEFLY FEOM

MINCHINHAMPTON

AND

THE COAST OF YORKSHIRE,

BY

J. MOEEIS, F.G.S. AND JOHN LYCETT.

PART I.

UNIVALVES.

LONDON :

PRINTED FOR THE PALuEONTOGRAPHICAL SOCIETY.

1850.

C. AND J. ADLARD, PR1HTKRS, BARTHOLOMEW CLO8B.

INTRODUCTION.

THE authors of the present Monograph, after due consideration of the materials at
their disposal, have thought fit to limit their illustrations to the Testacea of the Great
or Bath Oolite ; a term under which they would include the series of beds situated
between the Fullers-earth strata upon which they repose, and the Bradford clay to which
they are subjacent. To have enlarged the plan, so as to include the Testacea of the Corn-
brash and Forest marble, would doubtless have been more comprehensive ; but in the
present state of our knowledge, the advantage would have been rather apparent than
real. It will be found that the very few univalves which have been assigned to
those deposits are almost without exception contained likewise in the Great Oolite, and
will be found in the Monograph. It is, moreover, not impossible, that at some future
time a series of univalves may be obtained from the Cornbrash, or Forest marble, differing
specifically from those of the Great Oolite, in which case a separate Monograph, or an
appendix to the present one, might be given.

It is much to be regretted, that collections of shells should have been procured
from so few situations in the long course of the formation in this country; and when
it is remembered, that the Great Oolite constitutes a member of that series of secondary
rocks which first engaged the attention of geologists, some surprise will mingle with
our regret. The defect, however, would appear to be of easy explanation. The shells
do not lie upon the surface, or become separated from the matrix by the action of
the weather; they are to be procured only by carefully working away the investing
stone when practicable, which is not always the case : there are likewise large areas
constituting, probably, the greater portion of the formation, which are altogether des-
titute of organic remains, or contain only a finely comminuted shelly drift ; the areas
containing assemblages of well-preserved shells, would appear to be of small extent, and
the presence of several of these in the vicinity of the residence of one of the authors,
together with the great profusion of undescribed testacea which they have produced,
have constituted the principal inducement to the present attempt of describing them ;
these favorable circumstances have enabled them to ascertain the position and vertical
range of the species with a greater degree of accuracy than would otherwise have
been possible.

Beyond the limits of the Minchinhampton district, the number of species procured

87469

vi INTRODUCTION.

has been but inconsiderable ; these latter belong chiefly to Ancliff,1 and to the vicinity of
Scarborough. The parallelism of the deposits at the two former places would appear
to be well ascertained, but with respect to the rocks which are so extensively exposed
upon the coast of Yorkshire, although the evidence of geological position appears to
be satisfactorily determined, they possess but few mineral features which serve to connect
them with their supposed equivalents in Gloucestershire, Wiltshire, and Somersetshire ;
they constitute a great carboniferous deposit of the Oolitic period, abounding with land
plants, and containing intercalated bands or thin beds of dark gray argillaceous shales,
limestones, and sandstones, containing marine shells, of which only a minority of species
have been identified in other localities. The evidence afforded by the few species of
univalves which have been forwarded to the authors from Scarborough, through the
kindness of Mr. Bean, though not conclusive, tends rather to assimilate them with the
Inferior Oolite ; and it will be perceived on consulting the table of species at the end of
the Monograph, that of the twenty-one Yorkshire species, none have been identified with
Great Oolite shells of Minchinhampton or Ancliff, but that seven agree specifically with
Inferior Oolite shells of the Cotteswold hills. The Yorkshire deposits to which these
remarks refer constitute the entire series of plant-bearing beds numbered 11, 12, and 13
in Phillips's ' Geology of Yorkshire,' reposing on No. 14, or the Dogger, which is proved by
its fossils to be the equivalent of the Inferior Oolite, or at least to a portion of that
formation. Admitting, therefore, the parallelism of the deposits containing somewhat
distinct Faunas, in the north-eastern and south-western parts of the present area of
England, we are naturally led to infer, either that the physical conditions might be favor-
able to the continuance of species in one locality, or that species characteristic of an older
deposit, in a more distant region, may have migrated and lived on during the formation of
a newer deposit in another, the conditions having become unfavorable to the perpetuity
of their development in the latter deposit over the original region whence they had
migrated.3

For the above-mentioned reasons, it has been deemed desirable to separate the

1 The section at Ancliff, near Bradford, is as follows :

Rubble . 5 feet. . . Abounding with Polyparia.

Soft Oolite 15 „ . . This is the bed celebrated for the Ancliff fossils.

Clay . 1 „ . . Containing small sponges, and many fragments of shells.

Rag . 6J „ . . Very coarsely Oolitic.

Soft Oolite 5 „

From Mr. Lonsdale's interesting memoir, " On the Oolitic District of Bath," in the 'Geol. Trans.,' vol. iii,
p. -_';i2, in which many other sections of the Great Oolite are given, and the range of the deposit in that
neighbourhood is accurately traced.

2 Unfortunately the entire character of the fauna of the Great Oolite in the centre of England is not
well ascertained, nor is the range and extent, southerly, of the fluvio-marine conditions of the Yorkshire
Oolite accurately determined. As bearing on this point, the reader is referred to a paper by Captain
L. L. B. Ibbetson arid Mr. Morris, "On the Geology of Stamford" ('Brit. Assoc. Rep.,' 1847, p. 127).
The subject of migration of species, during the Oolitic epoch, is ably treated in a valuable memoir by
M. Gressly, 'Observations Geologiques sur la Jura Soleurois.'

INTRODUCTION. vii

Yorkshire shells from those of the West of England, and to have them figured on separate
plates, as by this arrangement it is trusted that confusion will be avoided, whatever may
ultimately be determined with regard to the position of these deposits.

It will be observed that several characteristic groups of shells have been arranged
into new genera and sub-genera, the knowledge of which, it is believed, will conduce
materially to the identification of the members of the lower Oolitic system of rocks ; of
these Ceritella, Brachytrema, Alaria, Cylindrites, and Trochotoma, are likewise represented
in the Inferior Oolite, but by other species ; in no instance has any species of these genera
been found common to the two formations. Other genera occur whose species are equally
characteristic of the two formations ; the table of comparison at the end of the memoir will
indeed serve to show how small a number of the spiral univalves are really common to both
formations ; with the Patelloidea the case is somewhat different, but the entire number,
excluding the Yorkshire species, is very small ; a fact the more worthy of notice as a much
larger number of the bivalves are common to both, or if capable of being separated, can
only be regarded as sub-species, or varieties of the same species. The literature of the
science has hitherto been singularly deficient in illustrations of English Great Oolite
univalves ; Lhwyd's ' Lithophylacii Britannici Ichnographia' contains a few ; Conybeare and
Phillips, in their ' Geology of England and Wales,' p. 210, enumerate three species.
Sowerby's ' Mineral Conchology ' contains thirteen, one only of which is from the Min-
chinhampton district. Mr. Lonsdale's paper on the ' Oolitic district of the neighbourhood
of Bath' has only three identified species. In Prof. Phillips's ' Geology of Yorkshire,' (part
I, p. 123,) fifteen species of univalves are enumerated, which are reproduced in Mr.
Williamson's paper on the ' Yorkshire Oolites,'1 but without descriptions. Dr. Fitton's notice
of the strata at Stonesfield2 gives an accurate enumeration of the different beds, but with few
organic remains. In the paper by Capt. L. L, B. Ibbetson and Mr. Morris, on the
'Geology of Stamford,'3 a few univalves are mentioned ; and, lastly, in the ' Geology of Chel-
tenham/ edited by Messrs. Strickland and Buckman, a list is given from the Stonesfield
slate of East Gloucestershire of six Echinoderniata, or at least fragments of them, and
nineteen gasteropoda, remains of which, however, are sometimes very imperfect.4 It may be

1 Geol. Trans., 2d Ser., vol. v, Part i, p. 240. 2Zool. Journal, vol. iii.

3 Brit. Assoc. Reports, 1847.

* The following is a section of the quarry on Sevenhampton Common, whence most of the fossils were
obtained :

Soil . . . . . . .2 feet.

A yellow clay, of a somewhat soapy feel, very rich in fossil shells . 6 ,,
Ragstone, similar to the Stonesfield slate . . . - „ 4 inches.

Thin seam of soft stone, with Ostrea acuminata, and small joints of

Apiocrinites . . . . . 3

Blue marl a

• • »

Ragstone . . . . 14 „

Stonesfield slate . . . . .4

Fullers-earth

viii INTRODUCTION.

gathered from these details, that in undertaking the present work, the authors have neces-
sarily, to a great extent, entered upon an unexplored field of study, — have been compelled
to investigate the relations of forms which, in very many instances, have only recently been
brought under their notice, and respecting whose analogues some doubt or difference of
opinion may occasionally exist : with a sincere desire to avoid error, they have in every
instance rejected species of which the examples were imperfect or doubtful.

It is with pleasure and gratitude they acknowledge the assistance which they have
received in the prosecution of their task, and their thanks are especially due to Professor
Edward Forbes, for his valuable memoir on the Echinodermata ; to D. Sharpe, Esq., for his
copious notes on the Nerinese, and other valuable suggestions ; to Wm. Bean, Esq., of Scar-
borough ; to M. Bouchard, of Boulogne ; to Professor Tennant, F.G.S. ; to S. V. Wood, Esq.,
F.G.S. ; to Professor Buckman ; to — Bravender, Esq., of Cirencester ; and to J. Bentley,
Esq., of Stamford, for the loan of specimens for comparison and figuring : to M. A.
Buvignier, of Verdun, for his little work on the ' Oolitic Fossils of the Ardennes ;' — also
for the opportunities afforded them in consulting the important collections of the Viscomte"
D'Archiac; J. Baber, Esq., F.G.S. ; J. S. Bowerbank, Esq., F.R.S. ; J. G. Lowe, Esq. of
Chippenham; Rev. P. B. Brodie, F.G.S.; E. H. Bunbury, Esq., M.P., F.G.S.; S. P.
Pratt, Esq., F.R.S. ; and to Professor E. Deslongchamps, of Caen, for his obliging kindness
in forwarding to them a suite of specimens typical of some of the species figured by him
in a series of memoirs, containing many valuable observations, published in the seventh and
eighth volumes of the ' Memoires de la Societe Linneenne de Normandie ;' as well as to
J. de Carle Sowerby, Esq., for the loan of many of the original specimens described in the
' Mineral Conchology ;' and to G. R. Waterhouse, Esq., and S. P. Woodward, Esq., for the
facilities afforded to the authors in their examination of the species contained in the National
Collection. To the artists, Messrs. Bailey and C. R. Bone, of the Ordnance Geological
Survey, the authors tender their acknowledgments for the pains they have taken in the
accuracy of the lithographs.

A MONOGRAPH

OP THE

MOLLUSCA FROM THE GREAT OOLITE.

GENERAL GEOLOGICAL REMARKS.

THE Minchinhampton district of the Great Oolite has produced by far the greater
number of our illustrative specimens ; and as the formation at that locality exhibits features
of a very varied as well as comprehensive character, we may be excused for entering
somewhat more into detail in our remarks upon it. The Great Oolite in this portion of
Gloucestershire constitutes the uppermost rock of the Cotteswold Hills ; it everywhere
overlies the Fullers-earth, which, in turn, reposes upon the uppermost beds of the Inferior
Oolite; — there is, therefore, a regular unbroken sequence of the Oolite rocks exposed on
the flanks of the various deep valleys of denudation which pervade the district. The
physical features of the district are strongly marked ; the larger valleys have a mean depth
of about 500 feet, and exhibit what can scarcely be met with in any other part of England ;
a single unbroken declivity comprising the Great Oolite, Fullers-earth, Inferior Oolite, and
upper portion of the Lias. The Inferior Oolite at these escarpments has a thickness of about
230 feet, the Fullers-earth of 70 feet, and the different beds of Great Oolite of 120 feet ; but
of these latter, only about the lower 40 feet anywhere approach to the brow of the escarp-
ments. The narrow and deep vale of Chalford, with its lateral branches, intersects the
strike of the Great Oolite, and divides the fossiliferous portion of the district into two parts ;
another and wider valley, further south, likewise intersects the strike of the formation. In
this are situated the villages of Woodchester, Hailsworth, and Avening ; but here the
amount of denudation, horizontally, has been more extensive ; and as the Great Oolite is
likewise much less fossiliferous, it need only be adverted to as supplying many additional
positions, where the rock can conveniently be quarried by open-work excavations. It will,
therefore, be perceived that the natural features of the district eminently conduce to the
study of its organic remains.

2 MOLLUSCA FROM THE GREAT OOLITE.

The mineral masses which constitute this series of beds are exclusively of marine origin,
the varying character of their organic contents being connected both with the mineral
character of the deposit spread upon the floor of the ancient sea, and with its depth.
These deposits may be conveniently divided into three groups :

1st. The Weatherstones ; 3d. The Sandstones ; and 3d. The Limestones.

The weatherstones, which are situated at the base of the formation, average about
40 feet in thickness. They consist of shelly sandstones, abounding with crystalline
carbonate of lime, and having Oolitic grains irregularly and sparingly distributed throughout
their mass. The variety of mineral character is so great, that no two quarries, or beds of
the same quarry, or even distant parts of the same bed, are alike in structure, aspect,
hardness, durability, or in the abundance of their included organic relics ; and they appear
to have constituted a deposit both littoral and formed in a shallow sea, exposed to the
influence of tides and currents. The beds, which are sometimes of considerable thickness,
consist of layers of testacea, in a fragmentary state, piled confusedly, but forming, obliquely,
laminated surfaces, often interrupted and crossed by others which proceed in different
directions. The shelly relics often constitute a considerable proportion of the whole mass ;
they are converted into crystalline carbonate of lime, which frequently fills the interior of
the univalves ; and it is to the abundance of this mineral, disseminated everywhere, that
the weatherstones owe their superior durability upon exposure to the atmosphere. As a
general rule, therefore, the beds which contain the greatest abundance of shells are those
which are most fitted to resist the action of frost ; water percolates their structure in much
smaller quantity, and more slowly, and, on escaping, carries away but little lime in
solution. The open joints of the Great Oolite, adjacent to the shelly beds, are therefore
nearly free from the large stalactitical masses which load the joints of the freestone in the
Inferior Oolite.1 With the testaceous fragments are associated shells in a perfect condition,
though frequently worn and abraded, the valves of the conchifera being rarely in apposition ;
also, palatal bones and teeth of fishes, portions of Crustacea, spines of cidaris, ossicula of
pentacrinites and asterias, rolled fragments of zoophytes, and dicotyledonous wood, the
partitions of the beds disclosing not unfrequently the ripple-marks of a beach. It might
be imagined that beds of such a littoral character would be unsuited to the propagation
and development of the Cephalopoda ; and it will occasion no surprise when we find that

1 For economic purposes, the weatherstones are valuable on account of their durability. In proof of
this, we may refer to the good state of preservation which the ancient part of the church at Minchinhampton
exhibits, and which shows a care and judgment in the selection of materials not always to be found in
modern edifices. It is rather a singular fact, that Caen and Minchinhampton, the two places which have
produced by far the most extensive series of Great Oolite shells, are connected historically as well as geologically.
Matilda, wife of William the Conqueror, founded the nuns of the Holy Trinity at Caen, of which body one
of her daughters became a member. William endowed them with the manor of Minchinhampton, at which
place they had a religious establishment. They built the church, and dedicated it to the Holy Trinity.
It would seem that William despoiled the Saxon Countess Goda of the manor, which she possessed in the
time of Edward the Confessor, and bestowed it upon the favorites of his wife.

MOLLUSCA FROM THE GREAT OOLITE. 3

examples of this class of carnivorous mollusks are here few, both as to number of species
and of individuals. This fact, together with the circumstance that they do not mark any
particular stratum, renders it highly probable that they were not associated, when living,
with the denizens of these shelly beds, but, like dead shells of the recent Spirulae,
individuals occasionally floated upon the surface, and were wafted to some coast or shelly
strand, often very distant from their real habitat. With the chambered shells such occur-
rences may have been common ; the air-tight little vessel, separated by decomposition from
the animal, would ride upon the wave, and only suffer injury upon striking the ground of
the beach. A consideration of the gregareous habits of the several families of recent, and
probably also of extinct Cephalopoda, would lead us to regard an occasional stray individual
as having travelled from some colony more or less distant ; but the beds of closely-packed
Ammonites, of every stage of growth, which occur in certain of the Jurassic rocks, would
appear to be the effect of occasional rapid earthy deposits, which took place during that
seasonal period when the Mollusks, lying torpid and contracted within their shells, were
at once entombed in that condition. We have also an explanation of the perfect condition
which the Ammonites of these beds usually exhibit ; the place of retirement would be
exempt from the turbulence of a shallow sea, and exposed only to the deposit of mud or
other fine sediment, which would protect the shells from injury. In the few Ammonites
and Nautili of the weatherstone beds, we see the reverse of these conditions ; — those large
and fragile shells, exposed in that detrital deposit to every kind of attrition and accident,
are very rarely perfect ; seldom more than two continuous chambers can be found Avhich
have not been invaded by earthy sediment, and often large portions of shell are wanting
altogether. The paucity of the Brachiopoda in these beds is also worthy of notice. Three
species of Terebratula are found associated with nearly 400 species of Mollusks; and
certain genera, which are peculiarly prominent in the Oolitic rocks generally, are mostly
absent ; of these genera, the Pholadomyaj, Homomyse, Cercomyae, Myopsides, Gresslyse or
Pleuromyse, the Arcomyee and Ceromya3, being exceedingly rare. The greater number of
these genera are not uncommon in the limestones or upper beds of the Great Oolite, and
occasionally, also, in the lower beds or sandstones, when they are separate from any shelly
deposit.

The section of the shelly beds, exhibited by the great quarry upon Minchinhampton
Common, affords a clear view of their distinctive characters and order of superposition.
The upper part consists of thinly-laminated stone, five or six feet in thickness ; to this
succeeds the beds usually termed planking, a designation implying a thin bedded stone,
out occasionally consisting of beds of great thickness : fourteen feet would appear to be
their utmost thickness. They mark the downward limit of our new genus Purpuroidea,
in the lowest bed of which it is very abundant.

An uncertain and variable stratum, of a few inches, of sandy marl next succeeds, in
which the few casts of bivalve shells hitherto found have the valves in apposition. To this
succeeds thin-bedded yellowish sandstones, nearly destitute of shells, and worthless for

4 MOLLUSCA FROM THE GREAT OOLITE.

economic purposes : their thickness is about twelve feet. A soft, shelly sandstone, called
oven-stone, next occurs : the shells increase in quantity downwards : about six feet will
represent its thickness. To this succeeds the weatherstones, consisting of several beds, the
aggregate thickness of which is about six feet. These lower beds are very shelly ; but, owing
to the greater hardness of the matrix, specimens cannot be extracted in any considerable
number. The blue or brown clays of the Fullers-earth support the weatherstones, without
any appearance of Stonesfield slate. It is also absent in several other limited shelly
deposits ; but, as a general rule, throughout the district, the Great Oolite, near to its base,
has one or more beds, which possess all the essential characters of Stonesfield slate. A little
higher in the series than the shelly beds, the limestones occur which cover continuously a
very considerable area upon both sides of the vale of Chalford, and continue upwards, with
various modifications of character, even to the Bradford clay. The lowest of this series is
a very compact cream-coloured semi-siliceous, but argillaceous limestone, four feet thick,
divided into two beds. It is usually destitute of organic remains ; but in some localities
contains casts of species of Purpuroidea, of several species of Natica ; and, also, at a single
locality, a dense colony of our new genus Pachyrisma, which has not hitherto been found
in any other stratum. This limestone extends even to the vicinity of Cirencester, and was
employed by the Romans to form tessarse for their pavements, as noticed by Messrs.
Buckman and Nevvmarch, in their new work on Corinium.1 The base line of the white
limestone is 60 feet above the Fullers-earth at Minchinhampton, and 45 feet, four miles to
the east of that place, near to the railway (Sapperton tunnel) ; the measurements have
been obtained by well-sinkings. Above this rock occurs a series of pale brown or
chocolate-coloured limestones, sometimes compact, sometimes sandy, having between them
an occasional uncertain band of marly clay. These clays are always fossiliferous, abounding
in casts of bivalve shells, which have both valves generally united. The uppermost 40 feet
of this series, owing to the worthless character of the stone, is very imperfectly exposed,
our knowledge of it being chiefly derived from pits of no great size, opened for the repair
of the roads. The eastern extremity of the railway tunnel (Sapperton) offers an extensive
section of these beds, but their position does not allow of their being studied, except at a
distance. The white limestone is exposed about the middle of the section. One of the
road-side excavations, two miles east of Minchinhampton, and 90 feet above the Fullers-
earth, has two beds of sandy limestone which is more than usually fossiliferous, they
expose sections of Nerinea, Pterocera, Natica, Cylindrites, Bulk, Purpuroidea, several of
the Echinodcrmata, &c. The bivalves, which are more numerous, comprise Pholadomya,
Homomya, Ceromya, Lucina, and Cercomya. The shell is preserved in the condition of
crystalline lime, but the interior mould only can be extracted entire. At three miles and
a half east of Minchinhampton, a large excavation has a band of brown clay, which abounds
with Terebratula maxillata, being almost the only fossil. This band is 115 feet above the

' Illustrations of the remains of Roman art in Cirencester, the site of Antient Corinium,' by Professor
Buckman, F.G.S., and W. C. Newmarch. London, 1850.

MOLLUSCA FROM THE GREAT OOLITE. 5

Fullers-earth. In another direction, one mile south-east of the town, is a marly band,
containing a dense colony of a species of Terebratula, which is likewise the sole fossil
observed. This isolation of the Terebratute is worthy of notice ; they occur but as a few
stray individuals in the shelly beds of the formation : in one instance, indeed, a shelly quarry
at Bussage, a little to the north of the vale of Chalford, contains a large assemblage of a
smooth, undescribed species, but at that place the other genera suddenly disappear, and the
TerebratulaB are either alone or accompanied only by a few small bivalve shells. The
Bradford clay, marked by the Terebratula digona, has not been discovered nearer than the
cuttings at the Tetbury road station, eight miles distant. The Great Oolite has now been
traced upwards throughout the Minchinhampton district, but there yet remains a sub-
division of the formation to be noticed ; this consists of sandstones, nearly worthless for
economic purposes, and of but little interest to the Palaeontologist; they constitute the entire
series of beds which underlie the limestones, and usually terminate downwards in Stones-
field slate, or have one or two beds which approach the slate in mineral character. These
sandstones must be regarded as merely continuations of the Weatherstone beds, but are nearly
or quite destitute of shelly detritus and crystalline structure ; for it is a curious but un-
doubted fact that the shelly weatherstones never have the limestones incumbent upon them.
All the quarrymen are aware of the fact from the experience which they have gained in the
numerous trials for weatherstone. At Bussage an instance may be seen of a weatherstone
quarry passing into a worthless sandstone on approaching the area covered by the lime-
stone ; occasionally, indeed, the sandstones disclose a cluster of Pholadomya3, and in the
vicinity of the Stonesfield slate contain some other bivalves which are never found in the
shelly beds. Occasionally over some small areas good serviceable quarries of weatherstone
are worked in situations where scarcely a single perfect shell can be procured ; there is then
a dense, finely comminuted, shelly detritus, and the rock abounds with calcareous spar, and
becomes thick bedded ; several quarries of this description have been worked in the parish
of Avening with good success ; in this condition the rock presents an exact counterpart to the
general aspect of the freestone beds in the middle portion of the Inferior Oolite in Gloucester-
shire, except that perhaps in the latter formation the oolitic grains are rather more abundant.
One of the most forcible impressions conveyed to the mind by a survey of the testacea
of this formation, when compared with that of the other members of the oolitic system, is
the great scarcity of the Cephalopoda, so few indeed are they, that the entire number procured
during the last twelve years may almost be counted. For this scarcity we think we can per-
ceive a compensation in the appearance of several genera of zoophagous gasteropods, in such
numbers as must effectually have checked any undue predominance which might have been
acquired by the phytiphagous mollusca, in the absence of the Cephalopoda. When the
Phasianella: and Natica3, which are now known to be zoophagous, are added to our species
of flesh-eating mollusca, it will at once be perceived how amply nature provided for the
maintenance of the balance of the testaceous animals during the deposition of the Great Oolite
of England. The great mass of the testacea are bivalves, and in species they exceed, by
about one fourth, the united number of the Gasteropoda, Cephalopoda, and Echinodermata.

2

MOLLfiSCA FROM THE GREAT OOLITE.

SUB-KINGKDOM-MOLLUSCA,

CLASS — CEPHALOPODA. Cumer.

CEPHALOPODES, Lamarck; Ffrussac.
CEPHALOPIIOIIES, De Blainville.

The remains of the Cephalopodous mollusca may generally be considered of extreme
rarity in the Great Oolite, in proportion to their abundance in the Inferior Oolite, and Lias
below, and the Kelloway rock and Oxford clay above that formation. Limited, however,
as the numbers were of the class at this particular period, the two principal orders into
which naturalists have divided the Cephalopoda, viz., the Dibranchiata and Tetrabranchiata,
were at that time fairly represented in the Nautilus, Ammonite, and Belemnite, the two
latter genera being well known as typical and characteristic of the secondary period of
geologic history.

Class.1 Order. Group. Family. Genus.

Dibranchiata. Oigopsidse. Belemnitidse. Belemnites.
Cephalopoda. ) (Acetabulifera, D'Orb.)

Tetrabranchiata. ' Nautilidee. Nautilus.

(Tentaculifera, D'Orb.) [Ammonitidse. Ammonites.

ORDER - DIBRANCHIATA. Owen.

Family — BELEMNITIDVE.

BELEMNITES, Ehrhart, 1727. Lam., Blainv., Voltz, D'Orb., &c.
NAUTILUS BELEMNITA, Gmelin.

ACAMAS, ACHELOIS, CALLIRHOB, CETOCIS, CHRYSAOK, HlBOLITHES, PACUTES,

PORODRAGUS, THALAMUS, De Montfort, 1808.
NOTOSIPHITES, GASTHOSIPHITES, Duval.
BELEMNITES, PSEUDOBELUS, Blainville, 1827.
BELEMNITA, Fleming, 1828.

An elongated, conical, or fusiform body, of a radiated fibrous structure (the osselet,
or guard), solid posteriorly, and more or less pointed (the rostrum) ; anteriorly pro-

1 For a concise and interesting account of the general characters and classification of the Cephalopoda,
the reader is referred to a previous Monograph, by Mr. F. Edwards, ' On the Eocene Mollusca,' Part I,
Cephalopoda.

CEPHALOPODA. 7

duced, truncated and furnished with a deep conical cavity (the alveolus), containing the
distal portion of a horny or fibro-calcareous chambered shell (the phragmacone], perforated
on the ventral part by a marginal siplumcle, and from the dorso-lateral margins of the
anterior extremity of which shell proceed two elongated, slender, testaceous processes ; the
whole body being invested with a thin, testaceous, or corneo-calcareous integument (the
capsule, or periostricum).1

1 On the subject of the Belemnite and allied forms, the reader is referred to the Memoir by Professor
Owen, in the 'Phil. Trans.,' 1844, p. 65 ; and the interesting papers in the same work, by G. A. Mantell,
Esq., LL.D., 'Phil. Trans.,' 1848, p. 171, and 1850, p. 393 ; also to the ' Paleontologie Francaise, Terrains
Jurassiques,' p. 40, by M. A. D'Orbigny.

In corroboration of the interesting facts cited by Dr. Mantell, respecting the continuation of the
phragmacone of the Belemnite, we quote the following graphic statement of a writer of the last century as
bearing on the subject. The remarks are contained in an account descriptive of the sinking of a well at
Montbard, in 1774.

" There were, moveover, great numbers of Belemnites, all conical, the largest being from 7 to 8 inches
long. They were pointed like an arrow at one end, and the other terminated irregularly, and was flattened,
as if they had been crushed. They were brown, both on the outside and inside, and were formed of a
material, arranged internally in transverse or radiating striae, which met at the axis of the Belemnite. This
axis was, in all, rather eccentric, and marked from one extremity to the other by a fine white line. When-
ever the Belemnite attained a certain size, the base contained a small cone, more or less long, made up of
cells, in the form of plates set one within the other (as in Nautili). The white line ended at the summit of
the cone. This small cone was invested along its whole length by a yellowish crustaceous pellicle, extremely
thin, although composed of several layers ; and the body of the Belemnite (with a radiating structure),
which enclosed the whole, became thin in proportion as the diameter of the cone increased. Such,
generally, was the character of the Belemnites which were found mingled with the soil thrown out of the
shaft, and which character is common to all those of this species. In order to ascertain the position which
the Belemnites occupied in the beds, several portions were softened carefully, and it was found that they all
laid flat, and parallel with the beds. What most astonished us, and what has not hitherto been noticed, was
this, that we then perceived, that to the extremity of the base of all the Belemnites, was attached an
appendage of a yellowish colour, composed of a substance like that of the shells, and which was shaped like
the widened part of a funnel which had been flattened. Many of these were two inches long, one inch
broad at the further end, and about six lines at the point where they were attached to the Belemnite. In
examining closely this shelly or crustaceous prolongation (which was so delicate that it could scarcely be
touched without breaking), I observed that this part of the Belemnite, which has not hitherto been recog-
nised, is nothing more than the continuation of the thin shell or crust which covers the little chambered
cone, of which I have already spoken ; so that it may be said, that all Belemnites which are at present to
be found in collections of Natural History are imperfect ; and that the portion we are acquainted with is
only, as it were, the case or covering of a portion of the shell which at one time enclosed the animal."

Buffon, 'Epochs de la Nature,' iii, Epoch 5, p. 143.

' Historic des Mineraux, des argiles et de glaises,' vi, p. 122.

The above passage is translated from the 'Explication de la Carte Geologique de France,' torn. 2,
p. 350.

s MOLLUSCA FROM THE GREAT OOLITE.

BELEMNITES FCSIFORMIS, Park. Plate I, figs. 6, 8.

BELEMNITES FUSIFOKMIS, Park. Org. Rem. iii, p. 127, t. 8, f. 13, 1811.

Miller. Geol. Trans., 2d Series, ii, p. 61, t. 8, f. 22, t. 9,

figs. 5, 7.

Brown. Illust. Foss. Conch., p. 41, t. 29, f. 14.
Flem. Brit. Anira., p. 240.

FLEURIAUSCS, D'Orb. Pal. Fran?. Terr. Jur., p. 11, t. 13, figs. 14-18.
— Buckman. Geol. of Chelt., t. 3, f. 9.

S. Testa clongatd, gradli, antice compressd, attenuatd, postice depressd, acutissimd
subtus lonyitiidinaliter sulcatd, sulco postice, anticeque non interrupto ; aperturd compressd.
(D'Orb.)

An elongated, smooth, somewhat fusiform Belemnite, somewhat compressed anteriorly
and depressed posteriorly, terminating in a rather sharp point ; marked throughout the
whole length by a deep single uninterrupted furrow, slightly enlarged towards the point of
the rostrum. Alveolar cavity occupying about a fourth of the length. There is some
slight confusion respecting this species, which is undoubtedly the shell alluded to by
Parkinson in the work above cited, and described by Miller as coming from the Stonesfield
slate, near Woodstock. The specimens figured (PI. I, figs. 6 — 8), are from that locality. It
appears also to be identical with the B. Flcuriausus, D'Orb., which is found in the Great
Oolite in the environs of Lucon (Vendee). We are further confirmed in this opinion by the
fact that Professor Buckman has identified and figured, in the work above referred to, a
Belemnite under the name of S. Flcuriausus, as occurring in the Stonesfield slate of Glou-
cestershire, which is identical with our shell from the same deposit in Oxfordshire, the
latter being the original locality from which the species was first obtained. The con-
fusion appears to have arisen from the English specimens having been confounded with the
B. hastatus, Blainville (Hibolithcs, Montfort), from the Oxford clay, at least it is so quoted
by M. D'Orbigny (' Pal. Franc. Terr. Jur.' p. 1 21), and also by Bronn (' Index Palaeon-
tolog.,' p. 156), an opinion that Mr. Miller may possibly have induced, inasmuch as he also
considered De Montfort's species to be synonymous with the B. fusiformis.

Locality. The Stonesfield slate of Stonesfield ; and Eyeford near Cheltenham.

BELEMNITES BESSINUS, D'Orb. Plate I, figs. 5, 7.

BELEMNITES BESSINUS, D'Orb. Pal. Fran?. Terr. Jur., p. Ill, t. 13, f. 14-18.
CANALICCLATUS, Buckman. Geol. of Chelt., p. 71, t. 3, fig. 8.

B. Testa elongatd, antice compressd, posticc depressd, subtus longitudinaliter sulcatd,
Hideo postice interrupto, aperturd compressd. (D'Orb.)

An elongated, smooth, very slightly fusiform shell anteriorly compressed, posteriorly
depressed, marked throughout the whole length by a furrow which is wider, and slightly
divided towards the point.

CEPHALOPODA. g

The specimen figured appears to be the same as the E. Bcssimts, D'Orb., from the Inferior
Oolite of Port-en-Bessin (Calvados) ; the general proportions are similar, about eight times
as long as wide, and the division of the furrow may be faintly traced in some specimens.
It is probably identical with the shell figured by Professor Buckman (loc. cit.) as S. cana-
licatus, Schlot., but that species is stated by M. D'Orbigny to have an equally impressed
furrow, whereas, in our specimens, it is always expanded towards the point of the rostrum.

Locality. The Stonesfield slate of Stonesfield, and Sevenhampton near Cheltenham.

ORDER — TETRABRANCHIATA. Owen.
Family — NAUTILID^E.

NAUTILUS, Linnaus.

BISIPHITES, OCEANUS, De Montfort.
OMPUALIA, De Haan.
NAUTILITES, Schlotheim.

A discoidal, convoluted, multilocular shell, compressed or ventricose, with contiguous
volutions, the last one generally concealing the others, septa transverse, concave, and some-
times sinuous, with entire margins, more or less centrally perforated in their disc.

»

NAUTILUS DISPANSUS. Plate II, figs. 5, 5«.

N. Testa subfflobosd, late umbilicatd, anfractibus rotundatis, lateraliter subcarinatix •,
aperturd dilatatd, subovali ; septis (?), siphunculo (?) .

A somewhat globose and smooth shell, with rapidly increasing volutions, and a large
and rather deep umbilicus, exposing the previous volutions ; umbilicus occupying about
one third of the diameter of the shell ; volutions rounded on the back, and slightly cari-
nated towards the base by the obliquely flattened form of the outer margin of the
umbilicus. Aperture expanded, arched, semi-ovate, wider than high.
Septa and Siphuncle not visible in the specimen described.

Diameter of the aperture . Clinches

Height of the „ 3£ „

Volutions increase in size (increasing about § in the

volution), from . 2^ to G£ in.

Height of re-entering volution 1 „

This species is closely related to N. excavatus, Sow., ' Min. Con.' tab. 529, f. 1, from th.
Inferior Oolite of Dorsetshire ; but it is readily distinguished from it by the more oval form
of the aperture j the width of the umbilical opening, in proportion to the diameter, is also

10 MOLLUSCA FROM THE GREAT OOLITE.

different, being in N. dispansus about one third, and in N. excavatus about the half of
the diameter of the shell ; the form also of the umbilical cavity varies in the two species ; in
N. excavatus, the sides of the cavity are regularly conical, as shown in Mr. Sowerby's figure,
above quoted, and in the 'Pal. Fran. Terrains Jurassiques,' t. 30 ; in N. dispansus the outer
margin of the umbilicus is obliquely flattened, or subconical, the inner side being
rather steep.

A single specimen only has been found of this species in the shelly beds of the Great
Oolite near Minchinhampton.

NAUTILUS BABERI. Plate I, figs. 1, la.

N. Testa discoided, compressd, l&vigatd, subumbilicatd ; anfractibus angulatis, com-
pressis ; aperturd compressd subquadrata ; septis vix sinuosis ; siphunculo (?)

A compressed, smooth shell, or only slightly marked by the lines of growth, with
angular embracing volutions, leaving but a faint trace of an umbilical cavity ; aperture
somewhat quadrilateral, narrowed above, and wider than it is long ; the septa are slightly
sinuous, curving towards the umbilicus and outer margin.

This species is allied to N. truncatus, Sow., from the Lias, but is distinguished by the
form of the mouth, and character of the septa.

Locality. Great Oolite near Minchinhampton.

We have much pleasure in dedicating this species to our friend, James Baber, Esq., of
Knightsbridge, whose interesting collection of fossil remains is always liberally opened to
public view.

NAUTILUS SUBTRUNCATUS. Plate I, figs. 2, 2«.

N. Testa discoided, inflatd, Icevigatd, sulcatd, subimperforatd ; anfractibus rotundatm
(jun.), subangulatis (adulta] ; aperturd depressd, subquadratd ; septis (?), siphunculo (?).

A smooth, or slightly furrowed, and somewhat inflated shell, with rounded and
embracing volutions in the young state, which become truncate, or subquadrate, in the adult,
and having a very shallow, or slightly impressed, umbilicus. Aperture about twice as
wide as it is high, flattened above, and somewhat compressed laterally.

This shell has the general form of the N. latidorsatus, D'Orb. ' Terr. Jur.' t. 24, but the
broad umbilicus and more quadrate form of the young shell in that species readily
distinguish them. This species belongs to the section of imperforate Nautili, of which
N. truncatus, Sow., N. clausus, D'Orb., are examples ; a group, the species of which were
not apparently very numerous during the Jurassic period.

Locality. Great Oolite near Minchinhampton.

CEPHALOPODA. 11

ORDER — TETRABRANCHIATA.
Family — AMMONITID^E.

AMMONITES, Brugiere. 1789.

OPHIOPOMORPHITES, Plott.

PLANORBITES, OKBULITES, GLOBITES, PLANULITES, Lam.

AMALTHEUS, PLANULITES, De Montfort.

PLANITES, GLOBITES, De Haan.

NAUTILUS, ARGONAUTA, Reinecke.

AMMONITA, ORBULITA (pars.), Fleming.

A more or less discoidal, multilocular shell, with contiguous volutions; volutions
generally visible, septa transverse, with sinuated edges, perforated by a single tube, situated
close to the outer margin.

AMMONITES SUB-CONTRACTUS. Plate II, figs. 1, la, jun., figs. 2, 2«.

A. Testa discoided, subglobosd, costatd, umbilicatd, anfractibus involutis, rotundatis
compressis, lateribus 16 — 18 costatis, costis obtusis bi-trifurcatis, in dorsum continuis ;
aperturd semiellipticd subcontractd ; umbilico magno, excavato, subconica,

A sub-globose, deeply umbilicated, and costated shell, with sixteen to eighteen obtuse
ridges (tubercles ?) surrounding the margin of the umbilical cavity, from each of which
three or four smaller costse pass over the somewhat depressed and rounded back.
Aperture, semi-elliptical.

Proportion of umbilicus to diameter, rather more than one-half. Diameter, 5 inches.
Thickness, 3 inches. Height of aperture, 1^ inches, twice as wide as it is high.

The specimen from which our figure is taken has been much worn by clearing it
from the original matrix, but a careful examination discloses the prominent marginal costae,
as well as the smaller ones which arise from them and pass over the back.

In the umbilicus, the marginal costse are well exhibited, which in the young state were
more compressed, and continued on the inner side of the cavity.

This species is distinguished from the Amman, coronatus, Brug., by its more globose
form, less conical umbilicus, and the more arched and less expanded aperture. It is closely
allied to Am. contractus, Sow., and in a young state might be mistaken for that species ;
but the ribs are larger and not so numerous or elevated ; the less embracing volutions, and
the more contracted form of the aperture in the adult shell, are also characters by which it
may be distinguished.

Unfortunately the determination of the species, and their varieties of the Ammonites in
the Great Oolite of Minchinhampton, is rendered extremely difficult, in consequence of tin
great rarity of specimens, and their state of preservation, rarely allowing the least trace of
the sinuated edges of the septa to be observed.

12 MOLLUSCA FROM THE GREAT OOLITE.

AMMONITES ARBUSTIGERUS, D'Orb. Plate II, figs. 4, 4a.

AMMONITES ABBUSTIGERUS, D'Orb. 1848. Pal. Fran?., Terr. Jur., p. 414, t. 143.

D'Orb. 1850. Prod. Paleont., p. 296.

A. Testa compressd, anfractibus rotundatis, latis, lateribus convexis transversim 22
costatis ; costis obtusis bi-trifurcatis vel intermcdiis, dorso sub-convexo ; aperturd oblongd,
compressd.

A discoidal, costated shell, with somewhat convex and gradually increasing volutions ;
umbilicus large : the principal costae are obtusely rounded, and about twenty-two in number,
bifurcating as they pass over the back, having occasionally an intermediate rib; back
convex ; aperture oblong.

Locality. In the Great Oolite of Minchinhampton, and described by M. D'Orbigny
as occurring both in the Great and Inferior Oolite of Normandy.

AMMONITES MACROCEPHALUS, Schloth., var. Plate II, figs. 3, 3 a.

AMMONITES MACEOCEPHALUS, Schloth. 1813. Min. Tasch. vii, p. 70.

Schloth. 1820. Petref., p. 70, No. 16.
Zieten. 1830. Pet. Wurtemberg, t. 5, f. 1, 4.
D'Orbigny. 1848. Pal. Fran?. Terr. Jur., p. 430, t. 151.
D'Orbigny. 1850. Prod. Pal<§ont., p. 127.

A. Testa discoided, sub-ylobosd, anfractibus involutis, rotundatis, costatis: costis
20 — 30 obtusis, media laterum bifurcatis; aperturd semi-ettipticd ; umbilico subcontract.

An inflated, or somewhat globose shell, with rather depressed volutions, and a narrow
and deep umbilicus, from the margin of which arise about twenty to thirty obtuse ribs,
which bifurcate in passing over the back. Back convex ; aperture semi-elliptical.

We have ventured to assign our specimens to the Ammonites macrocephalus of
Schlotheim, although their imperfect state of preservation renders this identification
somewhat doubtful. The specimens of this species hitherto obtained by us from the
Oolite, are always in the state of casts, and very much eroded, so that the principal ribs
which surround the umbilical cavity, are nearly obliterated, as shown in the figure,
tab. 2, fig. 3.

Locality. Great Oolite near Minchinhampton.

AMMONITES GRACILIS, Buckman. Plate I, figs. 3, 3a.

AMMONITES GRACILIS, Buckman. 1845. Geol. of Chelt., p. 104, t. 3, fig. 6.

A. Tcsld discoided, compressd, anfractibus ovatis lateribus sub-complanatis, transversim
30—40 costatis; costis bi-trifurcatis vel inter mediis, in dorsutn continuis, aperturd ovatd,
sub-sayittatd.

A discoidal, compressed, ribbed Ammonite, with six to eight oval, slowly increasing

CEPHALOPODA. 13

volutions, the last formed partly concealing the previous ones, with about thirty to forty
rounded or obtuse and nearly straight ribs on the inner margin, which generally become
bi- or trifurcate about the middle of the volution, and some pass over the back, giving it
a costated appearance ; the ribs, however, are not aways confluent, an intermediate one
frequently arising about the middle of the volution; from the manner in which each
volution is enveloped, the previous ones only exhibit the simple costae, as seen in the
specimen figured at Tab. I, fig. 3. The aperture is semi-ovate and compressed. The
sinuosities of the septa are not to be traced with any degree of accuracy, but they appear
generally to resemble those indicated by D'Orbigny. ' Terr. Jurass.,' t. 148. (Am. Bakeri®.}

Differing as our figure1 does from that given by Prof. Buckman in the ' Geology of
Cheltenham,' we have no doubt of the identity of the specimens, having been enabled,
through the kindness of that gentleman, to compare the original form. All the
specimens we have examined of this species are more or less compressed, and this cause
may have partly influenced the peculiar saggitate form of the aperture in the individual
shell selected by Prof. Buckman for illustration.

The costae which ornament this shell in the young state, and for a considerable period
of its growth, become partially obsolete in a more advanced stage. Perfect specimens of
this shell, showing the fact, are excessively rare, but we have collected large fragments of
this species on Sevenhampton common, in which the character is clearly exhibited

Locality. The specimen figured is in the collection of James Baber, Esq. F.G.S., and
was obtained from the Stonesfield slate of Stonesfield. It also occurs in the same
formation at Sevenhampton common.

AMMONITES WATERHOUSEI. Plate I, figs. 4, 40.

AMMONITES DISCUS, If Orb. Terr. Jurass., p. 394, t. 131.

— If Orb. Prod. Pal&mt., p. 296. 1850.

A. Testa compressd, sub-carinald, anfraetibus compressis, latis, externe angulatis;
l&vigatis ; dorso acuto ; umbilico angustato ; aperturd sagittatd.

A compressed, discoidal shell, formed of very compressed and nearly embracing
volutions ; the inner half of the shell flattened and smooth ; the outer, with obtuse, rather
distant and flexuous costse, terminating near the margin ; keel acute ; mouth sagittate.

This specimen, from the Great Oolite of Minchinhampton, agrees in all the characters
with the Am. discus, figured and described by M. D'Orbigny, 'Terr. Jurass.,' pi. 131, and

1 Unfortunately the specimen figured illustrates only the young state or inner volutions of this species,
not having received at that time the finer specimens helonging to Professor Buckman, and from which the
following description was drawn up : "A. gracilis. Keel crenated ; volutions six or seven, half concealed ;
ribs straight, passing over the back, and thus making the crenations of the keel ; sometimes two or three
ribs are confluent towards the front; diameter about 9 inches ; thickness 1£ inches; apertmv *:ii;itt;itc."
(Geol. ofChelt., p. 104.)

3

14 MOLLUSCA FROM THE GREAT OOLITE.

which is cited by that author as occurring both in the Great and Inferior Oolite of
Normandy. We also possess the same species from the Inferior Oolite of Briclport and
Gloucestershire. It differs, however, essentially from the original specimen of Am. discus,
Sow., described in the ' Min. Conch.,' tab. 12, which has a more regular, sagittate aperture,
and does not possess the central flattened space, so characteristic of our species.

Locality. Great Oolite of Minchinhampton, Lycett. In the same formation at
Ranville (Calvados), Niort (Deux Sevres), Mansigny (Vendee), D'Orbigny. In the Inferior
Oolite at Bridport, and near Stroud; Eterville and Moutiers (Calvados).

We have much pleasure in assigning to this species the name of G. R. Waterhouse,
Esq., whose arrangement and careful study of the Cephalopoda, contained in the National
Collection, have materially assisted this branch of Palaeontology.

CLASS — GASTEROPODA. Cuvier.
ORDER — PROSOBRANCHI ATA. M. Edwards.

CTENOBEANCHIATA, Schweigger.

Family — STROMBID^E.

PTEROCERA, Lamarck, 1801.

Shell turrited, ventricose, spire usually short, aperture oval, having a lengthened canal at
both extremities, outer lip expanded into hollow thickened spines, with an anterior sinus
separate from the caudal canal.

PTEROCERA IGNOBILIS. Plate III, fig. 14.

P. Testa parva turbinatd; spird breviusculd; anfractibus lcevigatis,planatis (3 — 4) ultimo
obsolete transversim bicarinato; carind superiori obsolete nodosd; caudd brevi.

Shell small, turbiuated, spire short, whorls smooth, flattened (3 — 4), the last whorl twice
carinated, the upper carina obscurely nodulous, canal short.

The great breadth of the whorls, and the obscurely bicarinated last whorl, are the leading
features. This shell approaches Alaria lavigata; but in that species the spire is much more
lengthened, and the volutions do not become angular, until at least five have been com-
pleted, it then produces small processes, which are deciduous, and the last whorl does not
attain any undue magnitude ; but, in the species before us, the fourth volution is large, has
considerable squareness, but with scarcely any distinct carina.

Locality. Rare in the planking of Minchinhampton Common.

GASTEROPODA. 15

PTEROCERA BENTLEYI. Plate III, figs. 15, 15a, var. fig. 16.

P. Testa turritd, anfractibus convexis, costis transversalibus (4) ; anfractu ultimo per-
magno, et costato; labio externo palmato digitis quinque divaricatis ; canali obliquo elongate.

Shell turrited, turbinated, whorls convex, costated, costae (4) transverse, last whorl very
large and costated, the costa3 terminate in an expanded palmated wing, digitations five in
number, beneath which are numerous diverging lines which connect the wing with the
caudal extremity.

The whorls are oblique in their upper and cylindrical in their lower portions ; their
encircling ribs are unequal and irregular ; no other markings are preserved ; but the con-
dition of the specimens is scarcely so good as could be wished. The wing is enormously
expanded ; the spines extend a little beyond the connecting portions of the wing.

Locality. The Stonesfield slate at Collyweston has furnished the present specimens.
The specific name in compliment to John F. Bentley, Esq., of Stamford, who has enriched
our knowledge of the fossils of that locality.

ALARIA. Nov. Gen.

A. Testa turritd, alatd et caudatd, aid Integra vel digitatd, interdum varicem formanti;
canali posteriori nutlo, labro sinistro tenui, nunquam calloso nee anfractum ultimum obti-
genti, labro dextro interdum ultra anfractum ultimum extenso, canali anteriori producto out
breviusculo.

Shell turrited, winged, and with a caudal extremity, wing entire or digitated, sometimes
produced into a thickening or varix, no posterior canal, left lip thin, never thickened, nor
extended upon the penultimate whorl, right lip sometimes extended slightly upon the
penultimate volution, anterior canal either produced and lengthened or short.

This genus is constituted to receive a numerous group of winged shells, which are
separated from the true Strombida?, Rostellaria?, and Pterocerse by a simple but important
distinctive character, viz. the absence of a posterior channel upon the spire. The greater
number of our Great Oolite species of Strombidse will be found to range themselves
under this division of the family ; the character of the wing is various, consisting either of
a simple, undivided, and thickened process, or divided into two or more digitations ; the
channel, likewise, may be either short and straight, or lengthened and curved ; the inner
lip is always thin — usually effuse and scarcely visible, but never produced into a thickened
posterior ridge, as in the true Rostellariae ; the wing, in some instances, is extended slightly
upon the penultimate volution, which is its utmost limit.

Another character of some importance, first noticed by Mons. Deslongchamps, and
which appears to characterise this group of shells, is this : the animal, after having
developed the right margin of the shell, continued to increase in growth, and (like the
species of Murex and Eanclla) reproduced a second dilated and digitated margin, similar

16 MOLLUSCA FROM THE GREAT OOLITE.

to the first, and generally opposite to it, a character rarely if ever found in the recent
Pterocerae or Rostellariae.1

ALARIA ARMATA. Plate III, fig. 1, la.

A. Testa turritd, anfractibns carinatis, et angulato-nodosis, nodis prominentibus 6 in ambitu.
Anfractu ultimo gibbo, bicarinato; carind superiori prominentiori spinis acutis ; in estate
juniori digitis tribus parvis ; in tstate adultd digitis superioribus duobus longissimus. Caudd
/mi //a curvatd. Striis tenuissimis confertis transversis, plerumque obsoletis.

Shell turrited, whorls carinated, angulated and carinated in their middle portion;
nodules 6 in a volution. The last whorl has three carinae, the last of which is nearly
obsolete. In the young state it has three small digitations; when adult, the two superior
carinae are extended into very long digitations ; the first carina having two angular pro-
minences or spines. The entire surface of the shell has numerous fine encircling striae,
which for the most part are indistinct.

The acute spine, number of whorls, their prominently angular figure, together with the
spine upon the middle of the superior carina of the last whorl, are characteristic features ;
from A. hamus and A. Phittipsii the character of the wing is sufficient to distinguish it.

Locality. The planking beds of Minchinhampton Common have furnished all our
specimens ; the coarse character of the deposit rarely allows the display of the fine stria?,
or other features of much delicacy. It is moderately rare.

ALARIA HAMUS, Desl. sp. Plate III, figs. 2, Za, 2t>.

ROSTELLARIA HAMDS, Deslonffchamps. 1842. Mem. Soc. Linn. Normandie, vol. vii,

p. 173, pi. 9, figs. 32, 33, 34, 35, 36.

Desk. Lam. An. sans Vert., 2d Edit., 1843, torn. 9, p. 666.
PTEROCERA HAMUS, D'Orb. 1850. Prod. Paleont, p. 270.

A. Testa turritd, anfractibus transverse strialis, media angulato-nodulosis, nodulis plus
minusve crebris, ultimo anfractu gibbo, bicarinato, carind superiori majori ; aperturd
Mffoiif!. Carind majore ultimo anfractu nodulosa, nodulis parvis, subobsoletis. (Des-
longchamps.)

Shell turrited, whorls transversely striated, having a circle of nodules somewhat angu-
lated in their middle part, the nodules being more or less closely arranged. The last whorl
is large; it has two carinae, the first of which is much the larger, and is indented or formed
into closely arranged nodules, which are sometimes nearly obsolete.

In some specimens, the larger carina is quite smooth, in others the indentations are
oblique; the canal is short and straight.

1 Mem. Soc. Linn, de Normandie, vii, p. 171, 176. Lam. Anim. sans Vert, 2d Edit., p. 671.

GASTEROPODA. 17

Locality. The planking of Minchinhampton Common and white stone of Bussage
contain it ; but at the latter place the more delicate features are usually best preserved. It
is rather rare. Inf. Oolite, Bayeux ; Great Oolite, Ranville, Normandy. (Desl.)

ALARIA L.EVIGATA. Plate III, fig. 3, 3 a.

A. Testa fusiformi, anfractibus convexis, Itevigatis, ultimo bicarinato, carind superiori
spinigera ; spino oblongo ori opposite; aid brevissimd in estate juniori monodactyld, dein
(eetate adultd) magnd didaclyld, digitis longis divaricatis, tenuibus, trigonis-, caudd longd,
recta, apice sub-incurvo; aperturd oblongd, labro sinistro subcalloso.

Shell fusiform, whorls convex, smooth, the last whorl with two carinse, the upper carina
spined ; the spine oblong, and placed opposite to the aperture ; the wing very small when
young, at first it has but one digitation, with advance of growth it acquires two large digi-
tations, which diverge in opposite directions, they are smooth and three-sided ; the caudal
extremity is long and curved towards the apex ; the aperture is oblong, the left lip being
slightly thickened.

In everything, excepting its smooth surface, this shell agrees with the Rostellaria
myurus of Deslongchamps ; but as we have seen about twelve specimens, which were well
preserved, it is impossible that they ever could have had the striae which distinguish the
shell from Normandy.

Locality. It is rare, and has been found only in the planking of Minchinhampton
Common and contemporaneous beds of white stone north of the Vale of Brimscombe.

ALARIA HAMULUS, Desl. sp. Plate III, figs. 4, 4a, 45.

ROSTELLARIA HAMULUs, Deslongchamps. Mem. Soc. Linn. Normandie, vol. vii, p. 175,

pi. 9, figs. 37—40.

— Desk. Lam. An. sans Vert., 1843, torn. 9, p. 666.
PTEROCERA HAMULUS, If Orb. Prod. Paldont., p. 302.

A. Testa parvd turritd, apice obtuso, anfractil>us(5—6) carinatis nodulosis ; ultimo anfractu
auhgibbo, transverse striato ; striis in&qualibus, majoribus alternatim minoribusqwe ; carind
nodulosd seu plicatd; labro externo incrassato variculam simidante; aid parvd unidiffitato,
apice acuto irigono, subtus canaliculate; caudd brevissimd, aperturd subellipticd.

Shell small, turrited, clavate, apex obtuse, whorls (5 — 6) convex, nodulated, nodules
six in a volution. The last whorl has a single nodulated carina terminating anteriorly in a
slight digitation. In the immature state the digitation is produced into a hook-shaped
process. The surface has numerous encircling striae, somewhat irregular, but which arc
alternately large and small. The upper margin of each whorl has a prominent line closely
tuberculated ; the aperture is narrow, being contracted on the right side by a thickened

18 MOLLUSCA FROM THE GREAT OOLITE.

fold or varix, of which there are two upon the last volution. The inner lip is broad and
distinct, the channel is short and straight. A small canal passes from the aperture to the
apex of the rudimentary digitation.

M. Deslongchamps has described this species from three small specimens, which are
very imperfect, having only the last volution. The name is scarcely appropriate to full-
grown individuals which nearly lose the hook-like digitation : in one instance only have
we noticed the hamulus of the dimensions figured by M. Deslongchamps, and this occurred
in the smallest of our specimens, which was but little larger than the Norman one. It
would, therefore, seem that this feature was of an uncertain character, and disappeared at a
later period of growth.

Locality. The beds of planking at Minchinhampton Common, and their equivalents,
the white stone of Bussage and Eastcombs, have supplied all the specimens which have
come to our knowledge. It is not very rare. In the Great Oolite (pierre blanche},
Langrune, Normandy. (Desl.)

ALARIA PHILLIPSII, If Orb. sp. Plate III, figs. 5, oa.

PTEROCERA PUILLIPSII, If Orb. 1850. Prod. Paleont, p. 270.

ROSTELLARIA COMPOSITA, Phil. 1835. Geol. Yorksh., i, t. 9, fig 28, (not Sow.)

A. Testa turritd ; spird elongatd ; anfractibus numerosis, convexis, vcl subangulatis,
transverse striatis, et costis obliquis numerosis approximatis ; anfractu ultimo bicarinato ;
old unidigito, caudd recta, breviusculd.

Shell turrited ; spire elongated ; whorls numerous, convex, or subangulated, trans-
versely striated, and ornamented with numerous closely-arranged oblique ribs upon the
lower half of each whorl ; the last whorl is striated and bicarinated, terminating in a simple
or undivided wing ; the caudal extremity is straight, smooth, and of moderate length.
A. hamus is the species which approximates most nearly to it ; but in that shell the
longitudinal costsB are less numerous, not oblique, and are visible throughout the length of
the whorl ; whereas in the A. Phillipsii they occupy the lower half only, and form an angle
at their upper termination. The upper and larger carina upon the last whorl is more
smooth and less prominent than in the A. hamus, and the entire form of the shell more
lengthened or slender.

Locality. Scarborough, in dark chocolate-coloured argillaceous shale. Great Oolite,
(Phillips.)

ALARIA PAGODA. Plate III, fig. 6.

Testa turritd; anfractibus numerosis, in media carinato-crenatis, ultimo bicarinato;
carinis tuberculatis ; anfractibus transverse striatis; striis duabus prominenlibus suturam

GASTEROPODA. 19

approximantibus. Aid magnd, expansd, in digitos duobus productd, digitis parvis, caudd
brevissimd.

Shell turrited ; whorls numerous, each with an acute mesial carina, the last whorl with
two carinse ; the edges of the carina undulate and are nodulated ; the whorls are trans-
versely striated above the carina ; beneath are two prominent striae, bordering the suture ;
wing large and expanded, extended into digitations ; the digitations are small, the caudal
termination very short.

This elegant shell possesses a certain family resemblance, which places it near to several
of our Great Oolite examples of the genus. The acute carina reminds us of A. trifida, the
nodules of A. hamus, and the general figure of the wing and caudal extremity of A.
paradoxa ; the whorls are comparatively numerous and narrow, the mesial carina very
prominent, and the junctions of the whorls strongly defined.

Locality. The white stone of Eastcombs has furnished our only example.

ALARIA ATRACTOIDES, Desl. sp. Plate III, figs. 7, la.

PTEHOCERA ATKACTOIDES, Deslong champs. Mem. Soc. Linn, de Norraandie, vol. vii,

p. 166, pi. 9, figs. 7, 8, 9.

Desk. Lam. An. sans Vert., 2d Edit., 1843, torn. 9, p. 681.
D'Orb. Prod. Paleont., p. 302.

A. " Testa fusiformi, transversim striatd; striis alter nis altioribus ; anfractibus bicarinatis
(carina superiore majore) longitudinaliter plicato-nodosis, plicis remotiusculis, nodis quadratis,
acutis, ultimo anfractu subgi bbo ; caudd longd, incurvd." (Deslongchamps.) Aid expansd
in digitis trigonis quatervis vcl quinque (diffito mperiori majori).

Shell fusiform, transversely striated ; striae alternately elevated ; whorls twice carinated
(the upper carina being the largest), longitudinally nodulated and plicated ; the plications
remote, the nodules square and acute. The last whorl is large, the canal long and curved,
the wing expanded, having four and perhaps five triangular digitations, of which the
upper one is the largest.

We have three specimens of this rare shell, in one of which the wing is well developed,
with the exception of the extremity of the lower digitation, which may be imperfect.

Locality. The planking beds of Minchinhampton Common. Great Oolite (caillasse),
Ranville, Normandy. (Desl.}

ALARIA HEXAGONA. Plate III, fig. 8.

A. Testa turritd ; anfractibus paucis (4), angulatis et nodulosis ; nodulis 6 liexagonix ;
ultimo anfractu unicarinato, nodulosa, varicem ori opposition gerente. Aldparvd, caudd
sublonga ; aperturd conlractd, ovatd ; labro sinistro tenui.

Shell turrited ; apex obtuse ; whorls few (4), prominently angulated and nodulated ;

20 MOLLUSCA FROM THE GREAT OOLITE.

nodules 6 in a volution, giving it a six-sided aspect. The last whorl has a single nodulated
carina, which has a prominence placed opposite to the aperture. The wing seems to be
but little produced, and is not divided into digitations. The canal is rather long and
straight ; the aperture ovate and contracted ; the left lip thin.

This is a rare species, of which we have only seen about six specimens : all of these
have been more or less imperfect, the wing being badly preserved, or wanting altogether.

Locality. The planking beds of Minchinhampton Common.

ALARIA PARADOXA, Desl. sp. Plate III, figs. 9, 10.

PTEROCEKA PARADOXA, Deslongchamps. 1842. M6m. Soc. Linn. Normandie, vol. vii,

p. 170, pi. 9, figs. 16 — 18, 20—22.

Desk. Lam. An. sans Vert., 2d Edit., 1843, torn. 9, p. 682.
D'Orb. 1850. Prod. Paleont., p. 302.

A. Testa parvd ovatd ; spird breviusculd obtusd ; anfractibus 7 angulato-nodosis, nodis
remotiusculis ; ultimo anfractu pluricostato, costis tran-sversis subtequidistantibus, et ineequa-
Jifjus; caudd brevi, recta ; aid angustd, varicem simulante, pluri-dentatd, dentibus inaequa-
libus subtiis canaliculatis, aperturd angustatd, varicemformante.

Shell small, ovate ; spire moderately elevated, obtuse ; whorls angulated and nodulated,
the nodules being distant, or about 7 in a volution. The last whorl has plain transverse
ribs, nearly equidistant, and slightly unequal in size. The canal is short and straight ;
the wing is thickened into a kind of varix at the aperture, which is contracted.

The spire bears a larger proportion to the last whorl than appears in M. Deslongchamps'
figures, which may be accounted for by his having restored the former' portion from another
specimen ; exactness in such a case is not to be expected.

This species is comparatively rare. We have scarcely seen one which is perfect.

Locality. Great Oolite of Minchinhampton. Bath Oolite (pierre blanche], Langrune,
Colleville, Normandy. (Deslongchamps.)

ALARIA PARADOXA, var. Plate III, fig. 9 a.

Shell ovate; spire moderately elevated; whorls (6) convex, rendered angular by pro-
minent tubercles, of which there are seven or eight in a volution ; the last whorl is large,
has numerous transverse ribs, of which two are more prominent ; the ribs terminate in
small digitations ; there is also a large bifid spine placed opposite to the wing,

As compared with A. paradoxa, the spire is more elevated, and bears a larger pro-
portion to the body whorl ; the encircling ribs upon the last whorl are much more elevated
and unequal, the two larger ones giving a kind of bicarinated aspect to it, and terminating
in digitations, which are much larger than in the former shell. The large bifid spine upon

GASTEROPODA. 21

the opposite side of the whorl is another distinctive character. The caudal extremity is
short and straight. Length, 10 lines; breadth, including digitations, 9 lines.
Locality. This species is found in all the shelly beds, but is far from common.

ALARIA TRIPIDA, Phil. sp. Plate III, figs. 11, lira, 115, lie.

ROSTELLAEIA TBIFIDA, Phillips. 1835. Geol. of Yorksh., i, t. 5, fig. 4.
BISPINOSA, Phillips. Geol. of Yorksh., i, t. 4, fig. 32.
BICAKINATA, Goldfuss. Petref, t. 170, fig. 1.
TRIFIDA, Deslongchamps. Mem. Soc. Linn. Normandie, vol. vii, pi. 9,

figs. 28, 29,30,31.
— — Desk. Lam. An. sans Vert., 2d Edit., t. 9, p. 665.

A. " Testa fusiformi, turritd, transverse striatd, anfractibus medio carinato-acutis ; ultimo
bicarinato, yibbo ; aid didactyld, digitis in estate adultd longissimis, recurvatis ; in juniore
modo unico, modo duobus inaequalibus digitis, seu inferiore, sen superiore longiore ; caudd
longissimd, recurvatd; aperturd anyustatd." (Deslongchamps.)

Shell fusiform turreted, transversely striated ; whorls acutely carinated about the middle
part ; the last whorl has two carinse, the upper of which is most prominent, and has a
prominence or spine opposite to the aperture. The wing is digitated ; when full grown
the digitations are very long and recurved, the larger being sometimes the upper, and at
other times the lower digitation. In the young state it has only one carina and digitation.
The canal is very long and recurved, the aperture small.

Having had the advantage of examining a large number of specimens, comprising every
variety both in form and stage of growth, we feel no hesitation in uniting the two species
here indicated. The whorls have every degree of angularity, specimens of A. bispinosa
having the lower half of each volution simply cylindrical, the carina not projecting beyond
it, and the first three or four whorls are smooth and simply convex, scarcely showing any
trace of angularity. The extreme of the other variety has the carina not only angulated
acutely, but spread out horizontally into a prominent tabular border.

The encircling striae are equally variable. In some instances the striae are regular and
equal, but more frequently they are alternately large and small ; at other times, however,
they are altogether irregular and unequal.

Locality. This species occurs throughout the whole of the Great Oolite near Minchin-
hampton ; even the upper beds, when shelly, not unfrequently contain it. Undoubtedly it
is the most common example of the genus. In the Calcareous grit; Oxford Clay; Kelloway
Rock, near Scarborough, Yorkshire (Phillips).

M. E. Deslongchamps describes this species as occurring throughout the Jurassic series
of Normandy, viz. the' Lias, Eontaine-Etoupefour ; Inferior Oolite, Bayeux ; Great Oolite,
Ranville ; Oxford Clay, Vaches-Noires ; Kimmcridge Clay, Villerville.

22 MOLLUSCA .FROM THE GREAT OOLITE.

ALARIA PARVULA. Plate III, fig. 12«, IZb.

A. Testdparvd, furritd; anfractibus quinque convexis, angmtatis, lavibits, ultimo planato,
striato; striis transversis, crebris, acutis, subcrenulatis ; caudd brevissimd ; aid — ?

Shell small, turreted, volutions (5) convex, narrow, smooth, the last volution flattened,
striated, striae transverse, closely arranged, acute, and slightly crenulated ; the canal nearly
obsolete ; wing unknown.

Locality. The planking of Minchinhampton Common has furnished only one well-
preserved specimen with which we are acquainted, — it does not exceed 6 lines in length ;
the whorls are very narrow and convex, the striae being visible only upon the body whorl.

ALARIA? CIRRUS, Desl. sp. Plate III, figs. 13, 13a.

ROSTELLARIA CIRRUS, Deslongchamps. 1842. M6m. Soc. Linn. Normandie, vol. vii,

p. 178, pi. 9, f. 26.

— Desk. Lam. An. sans Vert., 2d Edit., torn. 9, p. 668.
PTEROCERA CIRRUS, D'Orb. 1850. Prod. Pal6ont., p. 302.

A. Testa turritd, transversim striatd, qpice acuminate; anfractibus medio carinatis, ultimo
inflate, bicarinato ; carind superiori eminentiori, gibbum transverse ollongum ori oppositum
yerenti : aid brevissimd, in estate juniori monodactyld, deinde ((state progredienti) didactyld,
digitis longis, divaricatis, tenuibus, trigonis. Caudd longissimd, recta, apice incurvo.
(Deslongchamps.)

Shell turreted, apex pointed, transversely striated, whorls carinated in the middle, the
last whorl inflated, having two carinae ; the first carina being the most prominent. A
transverse prominence is placed opposite to the aperture ; the canal is long and straight,
except the extremity, which is curved.

A single specimen, in which the last whorl is imperfect, is all we have to refer to ; the
form, however, is unequivocal ; the spire is unusually short and ventricose, as compared
with other examples of the genus, and in the stage of growth which our specimen exhibits,
had not acquired the large digitations and caudal extremity proper to a later period.

Locality. Minchiuhampton Common ; it must be referred to some of the shelly beds
beneath the planking ; rare. Great Oolite, Ranville, Normandy. (Desl.}

Family — MURICID.E.
Fusus, Lam. 1801.

•

Shell fusiform or subfusiform, ventricose in the middle, with an elevated spire, volutions
convex, generally costated or striated ; aperture ovate, terminating anteriorly in a more or
less elongated canal, outer lip entire, sharp ; columella smooth.

GASTEROPODA. 23

Fusus MULTICOSTATUS. Plate V, fig. 6, 60.

F. Testa parvd, turritd, turbinatd, anfractibus convexis (5 — 6), suturisprofunde separatis;
costis lonffitudinalibus numerosis, obliquis, striis transversis, crebris; aperturd parvd, caudd
breviusculd.

Shell small, turreted, turbinated ; whorls very convex, 5 — 6 in number ; the sutures
being deeply impressed, the costse are longitudinal, rounded, and directed obliquely from
left to right; there are also numerous closely-arranged transverse striae; the aperture is
small, the canal short.

Locality. The planking bed of Minchinhampton Common has afforded this pretty
little species : it is moderately rare.

Fusus CORONATUS. Plate V, fig. 5.

F. Testa parvd, turritd, an/ractibus convexis, angustatis et nodulosis (nodulis 9), parts
superiori transverse trilineatis; anfractu ultimo ventricoso ; basi Itevi, caudd subrectd.

Shell small, turreted, whorls convex, narrow, and nodulated ; nodules about 9 in a
volution, with three encircling lines beneath the middle of each volution ; the last whorl is
veutricose, the caudal extremity nearly straight.

The general aspect of this little species has some resemblance to a Rostellaria; there
does not appear, however, to be any expanded wing or other characteristic features of that
genus.

Locality. It is very rare. We have obtained only three specimens, which occurred in
the planking of Minchinhampton Common.

Fusus? SUB NODULOSUS, D' Orb. Plate V, fig. 9, 9 a.

Fusus SUBNODULOSUS, D'Orb. 1850. Prod. Paleont., p. 303.
— NODULOSUS, Deslong champs. M£m. Soc. Linn. Normandie, vol. vii, pi. 10,
figs. 36, 37. (Not Sow., 1837.) (Not Lamarck.)

F. Testa minutd, ovato-turritd, acutd; anfractibtts rotundato-inflatis, transverse striatis,
nodulis (6) subobliquis, lonffitudinalibus; columelld marginatd, aperturd ovatd, caudd
breviusculd.

Shell minute, ovately turreted, acute; whorls rounded, tumid, transversely striated;
nodules 6 in a volution, longitudinal, and rather oblique ; columella marginated, aperture
ovate, caudal extremity short ; length,- 3 lines.

The transverse striae are not mentioned by M. Deslongchamps ; but in the specimen
which we have figured they are very distinct.

24 MOLLUSCA FROM THE GREAT OOLTTE.

Locality. It would appear to be very rare, and has been found only in the planking of
Minchinhampton Common ; but with this and other minute shells it is not easy to form an
accurate notion of their actual numbers. In the Bath Oolite of Langrune, Normandy.
(Desl.)

BRACHTTREMA. Nov. Gen.

Fusus. Species in part. Auct.

The Great Oolite shells, which we have placed under this generic designation, present
characters so much at variance with the received ideas of Fusus, that we have been induced
to erect them into a new genus, under the name Brachytrema ; the definition of this form,
whether it be regarded as subdivision of Fusus, or as a distinct genus, is as follows :—

B. Testa turritd, turbinatd; anfractibus convexis et costs fis, nodulosis, aut cancellatis;
labro dextro tenui ; columelld rotundatd, leevi, ad basin contortd; canali brevi, obliquo.

Shell small, turreted, turbinated ; whorls either costated, nodulated, or cancellated ;
the last whorl large and ventricose; right lip thin and smooth; columella smooth, rounded,
twisted near to the base, and reflecting outwards, forming a short oblique canal ; aperture
moderately large, subovate, its length being usually less than that of the spire.

The general figure of this genus is turbinated, and nearer to Buccinum than Fusus ; it
has, however, the base and channel of Cerithium ; the short oblique canal and twisted
columella separate it from Fusus, the genus to which the known species have most
frequently been referred. The following forms may possibly be assigned to this genus :—
Murex haccanensis of Phillips, the Fusus carinatus of Roemer, the Triton buccinoideum, the
Purpura Jilosa, the Murex versicostatus, and the Fusus corallensis of Buvignier, and, pro-
bably, the Fusus nassoides and the Fusus nodulosus of Deslongchamps. All the species are
small, the largest scarcely equalling 10 lines in length.

The Fusus Thorenti d'Archiac would appear at first sight to belong to this genus; but
having examined the original specimens in the collection of Viscomte d'Archiac, we are
inclined to believe that the figure in the 'Memoirs of the Geological Society of France'
(vol. v, plate 30, fig. 8), is taken from an imperfect shell, which is closely allied to, if not
identical with, the Turbo pyramidalis of the same author.

BRACHYTREMA BUVIGNIKB.I. Plate V, fig. 7.

B. Testa conicd, turbinatd, apice obtuso; anfractibus 5 planatis, et costulatis; costis (14)
longitudinalibus, clatis, lineas transversas numerosas, elatas, distantes gerentibus.

Shell conical, turbinated, apex obtuse, whorls 5, flattened and costated ; costac longi-
tudinal, elevated, about 14 in a volution, and impressed by transverse lines : the lines are

GASTEROPODA. 25

numerous, distant, and elevated — a single one more elevated, being placed at the base of
each whorl. The longitudinal ribs are occasionally unequal, one unusually large sometimes
appearing, but not extending beyond the whorl, forming a varix after the manner of
Triton ; the columella is twisted, turned outwards at the base, and forms, with the outer
lip, a short oblique channel, which is not perceptible upon the back of the shell ; the outer
lip is thin and dentated externally by the elevated transverse lines.

Locality. This species is moderately rare ; it occurs in the coarse bed of planking
at Minchinhampton Common, and is seldom well preserved.

BRACHYTREMA TURBINIFORMIS. Plate IX, fig. 35, 35a.

B. Testa turbinatd, vcntricosd, spird elevatd; anfractibus 4 anffustatis, convexis, nodulato-
carinatis; ultimo anfractu ventricoso, costulis longitudinalibus ; striis transversis numerosis,
impressis; aperturd subrotundd, canali subnullo, columella recta.

Shell turbinated, ventricose ; spire elevated ; whorls 4, narrow, convex, their sutures
deeply impressed, having a nodulated carina; the last whorl is large and ventricose, having
small longitudinal ribs crossed by numerous transverse striae; the aperture is nearly round,
the canal reduced to a mere notch ; the columella straight.

This species is chiefly distinguished from its congeners by a greater dilatation of the last
whorl, which is much expanded transversely. Unfortunately the beds of planking, which
contain this and various other small univalves with ornamented surfaces, is of so coarse a
structure, and adheres to the shells with such tenacity, that it is not often that their features
can be distinguished. Length 6 lines.

Locality. Minchinhampton Common.

Family— BUCCINID.E.

PURPUROIDEA, Lycett. 1848.

MUREX, sp., Sow. 1827.
PURPURA, sp., Buvignier. 1843.
PCRPURINA, sp., D'Orb. 1850.

P. Testa turbinatd, spird elevatd, aperturd non longiori, apice subacuto ; anfractibus
convexis, in media tuberculatis, anfractu ultimo ventricoso ; basi tmncatd, aperturd mb-
quadratd, superne acutd, inferne truncatd, latd ; canali lato, recurvato ; columella arcuatd,
rotundatd, Icevi, basi acuminatd, incurcatd; labio effuso, in medio subdepresso, labro tenui
et sinuato, umbilico obteclo.

Shell turbinated ; spire elevated, not longer than the aperture, with a somewhat acute
apex ; whorls convex, nodulated in their middle part, the last whorl ventricose, the base

2G MOLLUSCA FROM THE GREAT OOLITE.

truncated, the aperture subquadrate, acute above, widely notched at the base, but not
deeply nor recurved ; columella curved, and turning inwards at its base, which is pointed ;
it is rounded and smooth ; the inner lip is effuse, rather depressed in the middle, covering
an umbilicus; the outer lip is thin and somewhat sinuated.

This is one of the most remarkable of the Great Oolite genera of Univalves, and has
not as yet been found in any other than the oolitic rocks. It constitutes an addition to the
Purpurifera of Lamarck, or the Entomostomata of De Blainville. The following characters
in their combination will be found sufficiently to distinguish it from all other known genera :
the truncated base, the wide and shallow notch, the columella smooth, rounded, and curving
inwards, the concealed umbilicus, and the thin sinuated outer lip. The young shells are
delicately striated or grooved, the basal notch is scarcely formed, and they are perfectly free
from adherent shells. On the other hand, the full-grown shells are always more rugose ;
with advance of age their sulcations or other markings become irregular, or are nearly
obliterated, the basal notch becomes more important, and not unfrequently the whole-
external surface becomes covered with adherent shells. It would even seem that those
encrusting shells were carried about by the animal during life. They are never found upon
the young shells, or within the aperture, upon the left lip, about the basal notch, or, in
fact, upon any part which was in contact with the soft parts of the animal. As the
Purpuroidea are found lying in every possible position, the absence of adherent shells upon
the parts in question may be held conclusive as to their period of attachment.

It will be seen, then, that the generic characters above enumerated acquire importance
only upon their being viewed in combination. Owing, perhaps, to a want of attention to
this circumstance, it may be that an undue value has been assigned to one or two cha-
racters, or to the inspection of ill-preserved specimens, or the want of a sufficient number
to exhibit their several phases of form and markings ; — to one or all of these causes of error
we may ascribe the fact, that one of our species has already been thrice figured and
described under two generic and three specific designations.

The beds of planking upon Minchinhampton Common are the productive site of this
genus. The shells are clustered together over a small area. Originally the space was
about 100 yards in length and half that extent in breadth ; but from the rapid quarrying
of the stone, which there occurs in very large blocks, by far the greater portion is now
removed, and the genus has already become comparatively scarce. Two other localities,
near and upon the same geological position, have furnished it, but very rarely, and in a bad
state of preservation. In the upper division of the Great Oolite near Minchinhampton
(from the white limestone upwards), the genus is likewise found occasionally over small areas,
and in considerable numbers ; but, owing to the compactness of the investing limestone,
the shells can never be extricated except as casts. In this condition, with some small por-
tion of the shell preserved, they resemble the specimen figured in the ' Mineral Conchology,'
t. 578, fig. 4 ; but when entirely denuded of the crystalline shell, they have the aspect of
Natica, and without great care might be taken for that genus, the surface is smooth,

GASTEROPODA. 27

and retains only the faintest traces of tubercles ; the axial umbilicus is very conspicuous ;
and all trace of the wide basal notch being lost, the aperture resembles an entire-
mouthed shell. The hard limestone being much used for rough walls, it is upon these,
when partial disintegration has taken place, that the casts of Purpuroidea are to be found.
The genus has never been discovered lower than the planking.

PURPUROIDEA MOREAUSIA. Plate IV, figs. 1, la, 2, 3, 3a, 4.

PURPURA MOHEAUSIA, Buviffnier. Mem. Soc. Philomath. Verdun, 1843, pi. 6, fig. 19,

p. 26.
PUEPURINA D'Orb. Prod. Paleont., p. 357, 1850.

P. Testa turritd, ylobosd ; spirdbrevi, anfractibus 3 — 4, nodulosis vel spiniferis ; spinis
magnis, obtusis, in serie unicd 7, 8, aut 9 in ambitu ; anfractu ultimo striato, striis regu-
laribus transverse subundulatis (obsolctis in (state senior f) ; aperturd ampld, subquadratd ;
canali dilatato, leviter excavato,

Shell globose, spire prominent, whorls 3 — 4, angulated ; angles tuberculated ; tubercles
large, elevated, 8 or in others 7, upon a volution ; the last whorl ventricose ; the tubercles
increasing in size until they become large blunt spires ; beneath the tubercles the surface
has numerous undulating closely-arranged encircling costse; the aperture is large and
widely truncated at its base ; the inner lip is somewhat depressed in its middle part.

This is by much the most abundant, and at the same time typical species of the genus.
There may be considered to be two varieties, one having 8, the other only 7, spines in a
volution ; the latter variety has the spire more depressed, the aperture occupying three
fourths of the entire length of the shell. The elevated longitudinal swellings, produced by
the successive extensions of the outer lip in growth, sometimes interfere with the continuity
of the encircling ribs, — cause them to undulate, and occasionally obscure them altogether
hence, in the younger specimens, the ribs are more regular and distinctly marked. Very
rarely, indeed, individuals have been found which simulate P. nodulata, the lines of growth
being enlarged to imperfect ribs, which suddenly disappear, or are depressed at the place
where, in the species referred to, the second circle of nodules is situated ; the spire also
becomes more elevated, which adds to the resemblance. In the figure given by Buvignier,
the inner lip is more flattened, or Purpura like, than might have been expected ; but the
figure altogether is executed in a very indifferent manner.

Locality. The vicinity of Minchinhampton is the only locality in which this remarkable
shell is known to have been procured in England. Buvignier mentions that M. Moreau,
of St. Mihiel, has found it in the Coral rag of that place, and likewise in the ferruginous
Oolite of Launoy.

28 MOLLUSCA FROM THE GREAT OOLITE.

PURPUROIDEA GLABRA. Plate IV, figs. 5, 5«, 6, 6«.

P. Testa turbinatd, ovatd ; spird exsertd ; anfradibus^ — §angulatis, angulis tuber culos
10 gerentibus ; anfractu ultimo ventricoso, laevi, basi truncatd; aperturd magnd.

Shell turbinated, ovate ; spire elevated ; whorls 5 — 6 angulated ; angles tuberculated ;
tubercles 10 in a volution; the last whorl ventricose, smooth, the base truncated; the
aperture large.

In the young state the spire is simply convex, without tubercles, which are only faintly
visible upon the last whorl. In every stage of growth the tubercles are less conspicuous
than in either of the other two species, and the surface of the last whorl is entirely destitute
of ribs and of a second circle of tubercles ; the spire is smaller than in P. nodulata, but
more elevated than in P. Moreausia. The length of the aperture is three fifths of that of
the entire shell.

Locality. It accompanies the other congeneric forms in the Minchinhampton Great
Oolite, but is very much the most rare of them. The proportion of each species is probably
as follows : P. Moreausia, 50 ; P. nodulata, 5 ; P. glabra, 1.

PURPUROIDEA NODULATA. Plate V, figs. 1, la, 2, 3, 4.

MUEEX NODULATUS, Young and Bird. Geol. of Yorkshire Coast, p. 245, t. 11, fig. 3.
— TUBEROSUS, Sow. Min. Con., t. 578, fig. 4 ; but not t. 229, fig. 1, which is a

Tertiary shell.
PURPUKA LAPIEH.REA, Buvignier. Mem. Soc. Philomath. Verdun, 1843, p. 27,

pi. 6, fig. 21.

PURPUROIDEA NODULATA, Lycett. Annals of Nat. Hist., 1848, p. 250.
MUREX TUBEROSUS, Brown. Illust. Foss. Conch., p. 59, pi. 34, fig. 19.

P. Testa turbinatd, ovatd; spird escsertd ; anfractibusb — 6 angulatis; angulis tuberculos
(9 — 11) plerumque elatiores gerentibus ; anfractu ultimo subventricoso, tuberculis binis
cincto, props basin transverse carinato ; tuberculis inferioribus minoribus, approximatis et in
costulis lonffitudinalibus obliquis productis : aperturd magnd subquadratd, labro dextro
sinuato.

Shell turbinated, ovate ; spire elevated ; whorls 5 — 6 angulated ; the angles tubercu-
lated; the tubercles usually elevated, 9, 10, or 11 in a volution; the last whorl ventricose,
encircled with two rows of tubercles ; those on the second row are much the smaller, and are
more closely arranged, and prolonged into longitudinal oblique ribs, which are sometimes
nearly obsolete ; below the ribs is a transverse keel, placed near to the base of the shell.
The aperture is of moderate size, the outer lip being much sinuated.

The first two or three whorls are convex, and destitute of tubercles ; the tubercles
vary much in size in different specimens — when very much elevated they are com-
pressed laterally. In the young state, the apex of the spire is more acuminated, the surface

GASTEROPODA. 29

of the whorls has fine encircling striae, the second circle of tubercles is not formed, or is
merely rudimentary, and the longitudinal ribs beneath and basal carina are both absent ;
the last whorl has therefore a smooth aspect, which is in striking contrast with specimens of
advanced age. The length of the aperture in the adult shell somewhat exceeds that of the
spire ; but the latter portion varies much in altitude, and occasionally exceeds the aperture
in length. Upon the whole, the aspect of this species varies so considerably, independently
of the changes produced by the stages of growth, that a considerable number are requisite
for its full elucidation. It accompanies P. Moreausia, but is much more rare, probably in
the proportion of about 1 to 10.

The figures given by Young, Sowerby, and Buvignier, present but a remote resemblance
to each other and to our figures, but there cannot be much doubt of their identity. Young's
figure represents an individual with a spire rather depressed ; that in the ' Mineral Con-
chology' is from a mutilated specimen, little better than a cast. Buvignier's figure is
likewise imperfect, besides which, the artist appears to have represented the inner lip of a
true Purpura.

Locality. Minchinhampton Common.

This species has been found in Yorkshire only in the Coralline Oolite, where casts are
stated to be not unfrequent in the hard limestone. M. Buvignier's specimen is from the
ferruginous oolite of Vieil-St.-Remy.

Family — CERITHIAD.E.
CER.ITHIUM, Adamon, 1757. Brug., Lam.

Shell elongated, tuberculated or costated, seldom smooth; spire pyramidal or cylin
drical, composed of numerous volutions ; aperture subquadrate, terminated anteriorly by a
short canal, which is most frequently reflected outwards and backwards.

CERITHIUM QUADRICINCTUM, Gold/. Plate IX, fig. 8.

CERITHIDM QUADRICINCTUM, Goldfuss. Petref., p. 32, t. 173, fig. 11.

Bronn. Index Palaeont., p. 272.

C. Testa conicd, anfractibus (10 — 12) quadrigonis, cingidatis, tingulis swpcrficialibus
quarternis granulatis ; granulis longitudinalibus serialis.

Shell conical, spire obtuse, whorls (10 — 12) rather convex; encircled with four costae;
the costae are granulated, so as to form a longitudinal series. The whorls are narrow,
the height scarcely exceeding one third of the transverse diameter ; the largest specimens
do not exceed half an inch in length, and half of that length may be considered as the
average dimensions.

5

30 MOLLUSCA FROM THE GREAT OOLITE.

Locality. It is by far the most abundant of the Great Oolite Cerithia, and may usually
be seen sprinkled over the blocks of planking at Minchinhampton Common ; but occurs
indifferently in all the shelly beds.

CERITHIUM LIM^EFORME, Bom. Plate VII, fig. 2.

CERITHIUM LIMJEFORME, Roemer. 1836. Nordd. Oolith., p. 142, t. 11, f. 19.
Goldfuss. Petref., iii, p. 33, t. 173, f. 17.
Bronn. Index Palseont., p. 269.

C. Testa turritd, anfractibus (1 — 8) depressis, subplanis, cingillato-granulatis trilineatis,
granulis majusculis approximates costellas longitudinales formantibm, aperturd ovatd, canali
brevi truncato.

Shell turreted, apex pointed, whorls (7 — 8) depressed, nearly flat, having transversely
nodulated costse, three in number upon each whorl ; the nodules are nearly joined longi-
tudinally, presenting the appearance of longitudinal ribs in the young shell ; but in a more
adult state the upper row becomes more distinctly separated from the other two, which
latter have sometimes an additional row of smaller granules between them.

This shell, as compared with C. quadricinctum, would appeal1 to be much more rare ;
but as it requires a close inspection to distinguish them, some uncertainty must exist.

Locality. It accompanies the above-mentioned species in all the shelly beds. Its length
does not exceed 3 lines.

CERITHIUM SEXCOSTATUM. Plate VII, fig. 3, 30.

C. Testa turritd, lesvi, anfractibus convexiusculis, costatis ; costis (6 — 7) lonyitudi-
nalibus, l&vigatis, rotundatis, angustatis, rectis: aperturd ovatd; caudd obsoletd.

Shell turreted, smooth ; whorls rather convex, costated ; costa? (7 — C) longitudinal
smooth, rounded, narrow, and straight; aperture ovate. The ribs do not form a con-
tinuous line upon the volutions, a complete circle occupying more than 6, but less than 7
costae, whose upper extremities scarcely reach the sutures of the whorls ; the whorls are
rather high, their junctions are deeply impressed, the last whorl being equal in length to
two fifths of the entire shell. Axis 1\ lines.

Locality. The white stone of Bussage has furnished our only example.

CERITHIUM PEXTAGONUM, Arckiac. Plate IX, fig. 22.

CEKITIIIUM PENTAGONUM, Archiac. Me"m. Soc. G6ol. Fr., torn. 5, p. 384, t. 31, f. 6.

D'Orfj. Prod. Pal&mt., p. 303.
— Bronn. Index Palseont., p. 271.

GASTEROPODA. 31

C. Testa subulatd, apice acuto, anfractibus (10 — 11) planatis, pent'agonalis, longi-
tudinaliter costatis; costis 5 in ambitu, perpendiculariter continuis, elaiis, subacutis ; strii*
numerosis transversis impressis ; canali minima.

Shell subulate, apex acute, whorls (10 — 11) flattened, pentagonal, longitudinally
costated ; costae continuous, perpendicular, elevated, rather acute, 5 in a volution ; striae
numerous, transverse ; canal very small.

This elegant, symmetrical, and remarkable species has the junctions of the whorls strongly
marked ; it ranks among the choicest of our smaller shells. Axis 9 lines, transverse
diameter 2 lines.

Locality. It has been found only in the planking of Minchinhampton Common and
white stone of Bussage. We are not aware that more than four examples have been
discovered.

CERITHIUM STRANGULATUM, Archiac. Plate IX, fig. 18.

CEHITHTUM STRANGULATUM, Archiac. 1843. Mem. Geol. Soc. France, v, p. 382, t. 31,

figs. 1, a, b.

D'Orb. Prod. Paleont., p. 303.
Bronn. Index Palaeont., p. 274.

C. Testa minutd, subcylindricd, pupceformi, costatd ; anfractibus subplanatis 7, trans-
versim sulcatis; sulcis 4, penultimo 5; costis (6) rectis, elatis et longitudinaliter continuis
ab apice ad anfractum penultimum ; apertura constrictd, parvd, obliqud subrotundd ; canali
nullo.

Shell minute, subcylindrical, or pupaoform, costated ; whorls nearly flat (7), transversely
sulcated, sulci 4, and 5 upon the penultimate whorl; costa3 6, straight, elevated, and
longitudinally continuous from the apex to the penultimate whorl ; aperture contracted,
small, oblique and somewhat rounded ; no canal.

This little shell has prominent lines dividing the transverse sulcations ; the costal
elevations, although strongly marked upon the first three or four whorls, are not dis-
tinguishable upon the latter two; these whorls have also a greater proportional length than
the others, their breadth but little exceeding their height ; the junctions of the whorls are
not very strongly marked, the apex of the spire is obtuse, the aperture much contracted,
rounded, and oblique or pupseform.

The obtuse spire, flattened whorls, and fewness of the costae, will distinguish this from
C. bulimoides, Deslongchamps, and C. Rocmeri, Goldfuss ; to which in other respects it has
some resemblance. We have considered it a variety of C. strangulatum, Archiac, although
in that species the apex is pointed, the general breadth is greater, and the costae are
continued even to the base of the shell.

Locality. Ancliff, Wiltshire ; Eparcy, France.

32 MOLLUSCA FROM THE GREAT OOLITE.

CERITHIUM TENNANTI. Plate IX, fig. 20.

C. Testa turrit a, acutd, conicd, anfractibus numerosis, angustatis, tricinctis ; carinis
tribus, elalioribus, striis numerosis longitudinalibus impressis ; basi planatd, canali
brevissimd.

Shell turreted, acute, conical, whorls numerous, thrice cinctured ; the bands elevated,
and impressed with numerous longitudinal striae ; base flattened, canal obsolete.

The transverse keels are equal, narrow, and elevated, one being mesial, the others close
to the anterior margin of the whorls; the figure is perfectly regular, and the whorls
narrow ; the aperture and canal are very short.

Locality. Ancliff.

Named after Prof. J. Tennant, from whose interesting collection of Oolite Fossils this
species is figured.

CERITHIUM ROISSII, Arch. sp. Plate VII, fig. 14, 14a.

TUKKITELLA ROISSII, Archiac. 1843. Me"m. Soc. Geol. Fr., vol. v, p. 380, t. 30, f. 2.

Bronn. Index Palseont., p. 1336.
CHEMNITZIA ROISSTI, D'Orb. Prod. Paleont., p. 298.

C. Testa turritd subconicd, lavi, qpice acuto ; anfractibus panels, planatis; suturis via
tumidulis; caudd brevi subrectd.

Shell turreted, subcouical, smooth; apex acute; whorls few, flattened; the sutures slightly
tumid ; canal short, and nearly straight.

A very short or conical species, the diameter of which through the last whorl is upwards
of half the entire length of the shell ; a longitudinal section displays a columella of great
thickness, the internal cavity being small.

Locality. Rare in the Great Oolite of Minchinhampton Common. Eparcy, France.

NERIN^A, Def ranee. 1825.

Shell turreted, either conical or cylindrical, consisting of numerous whorls ; aperture
subquadrate, having an anterior and posterior short canal ; columella, with one or more
folds ; outer lip, with one or more folds, which are continued through the length of the
shell ; columella umbilicated in the conical, solid in the cylindrical species.

VOLTZII, Desl. Plate VII, figs. 11, l\a ; var? figs. 7, la.

VOLTZII, Dedongchamps. 1842. Mem. Soc. Linn. Normandie, vol. vii, pi. 8,

fig. 34.
— L'Orb. Prod. Pal6ont., p. 298. (Not N. Yoltzii, D'Arch.;

GASTEROPODA. 33

N. Testa turrito-conicd, spird angulo 18° — 22°, anfractibus subplanis inornatis; colu-
melld crassd, prius solidd denique perforatd, plicas duas parvas, remotas gerente; labro
dextro intus uniplicato, aperturd rhomboidcdi.

Shell elongated, conical, smooth ; in its young state there is usually a slight depression
round the lower part of each whorl, this is gradually lost in the larger whorls, which are
quite flat ; but specimens may be found in which all the whorls are slightly convex. The
columella is solid in the young shell ; but usually becomes perforated about an inch below
the apex ; there is great variety in this respect in different specimens, the perforation some-
times commencing within half an inch from the apex, while other shells, an inch and a half
long, may be found quite solid. The spiral angle also varies from 20° to 22° in different
specimens ; in some instances the sides of the shell are straight, in others the lower part is
more cylindrical than the upper ; in some few instances the lower part of the shell enlarges
more rapidly than the upper, in which case the perforation of the columella is unusually
large. Thus the species varies in its external form, from a neat, regular shell to a
very clumsy one. The aperture is rhomboidal, its height being half as much again as its
width, ending below in a short canal. There are three internal folds, viz.: one on the outer
lip, near to the base of the whorl, which is insignificant at the aperture, but long and strong
in the inner whorls; another, thick and blunt on the columella, a little below the preceding;
thirdly, one small and blunt on the top of the whorl. These folds are very constant in
form, and serve to distinguish the species readily.

Sutural angle 90° to 95°

Basal angle 125° to 130°

Length, 1 inch to 2J inches.

In the young state, or when the axis does not exceed 10 or 12 lines, the aspect is so
dissimilar of this protean shell, that a particular description of that condition is necessary: —
It is taper and pointed, the volutions are convex, very narrow, an individual of 9 lines
having as many whorls. The sutures are very deeply depressed, the shell is altogether
delicate and fragile, but perfectly regular. Specimens exceeding 10 lines increase dispro-
portionally in the height of their whorls ; they become more flattened, the sutures are less
strongly defined, the shell acquires a considerable increase of thickness, and the whole is
changed.

Locality. This specimen occurs in every stage of growth and throughout the entire
thickness of the formation in Gloucestershire; its habits were gregareous — the shelly
weatherstones more especially contain it in great numbers.

NERIN^EA (TROCHALIA) EUDESII. Plate VII, fig. 6, 60.

? CERITHIUM DEFRANCII, Deslongchamps. Mdm. Soc. Linn. Normaudie, vol. yii, pi. 8,

fig. 36.

N. Testa turritd, conicd, anfractibus (1 0) concavis, angustatis, lineis transversis cinctis

34 MOLLUSCA FROM THE GREAT OOLITE.

cum aliis minoribus alternates, suturis carinatis, carinis clatis et Icevigatis, basi planulatd,
canali brevissimo; aperturd subquadratd.

Shell turreted, conical, excavated; whorls (10) concave, narrow, with numerous trans-
verse very fine lines, alternating with others still more faintly impressed ; the sutures are
carinated, the carinse elevated and smooth, the base flattened, the canal short. Aperture
subquadrate.

The general aspect of our species approaches near to the Cerithium Defrancii of
M. Deslongchamps, whose figure however is less conical, and the concavity of the whorls
is much less. These differences, however, are only such as may pertain to varieties of the
same species. It is rare ; and the few examples which have occurred to us are composed
entirely of crystalline carbonate of lime, which does not allow of the internal characters
being fully determined ; as far as we can observe them, the outer lip is simple, and the
columella plicated with one fold, and the upper portion of the volution has a very slight
fold. This shell belongs to the subgenus Trochalia, Sharpe; but to the species having the
columella solid and not hollow.

Locality. The upper portion of the shelly beds near to Minchinhampton and
Chalford.

NERIN^A DUFRENOYI, Arch. sp. Plate VII, fig. 8, Sa — 8e.

CERTTHIUM DCFRENOYI, Archiac. 1843. Mem. Soc. Geol. Fr., vol. v, pi. 31, figs. 3, 4.
D'Orb. 1850. Prod. Paleont., p. 303.

N. Testa parvd, cylindrico-subulatd ; anfractibuslatis,planatis, costutts cinctis, etnodu-
lafis; cingulis 4 out 5, indsfUxKbnt dense-nodulatis, cingula infra suturam valdc elatd, et
Iceviyatd, sine nodulis. Anfractibus lineis perpendicwlaribus, interstitialibus dense et
tenuissime instructis. Aperturd elongatd, columella solidd, plicis duabus ? parvis; plied
caiernd unicd, magnd.

Shell small, cylindrical, or subulate ; the whorls wide, flattened, encircled with costse,
which are nodulated ; the encircling bands are 4 or 5, unequal and closely, but sometimes
imperfectly, nodulated ; the band nearest to the upper suture the largest and most elevated,
it is nearly smooth, and without nodules. The surface of the volutions has also very
closely-arranged fine perpendicular lines visible iipon the interstices of the cinctures. The
aperture is elongated and narrow ; the columella solid, with two small folds ; the outer lip
has a single, much larger fold.

The perpendicular length of the whorls is nearly equal to their transverse diameter ; the
sutures are strongly marked. The usual length of this species does not exceed an inch,
the number of volutions in large specimens not exceeding ten. The coarseness of the
Great Oolite rock is not favorable to the preservation of the more delicate features of this
pretty and fragile species, so that in the greater number of instances the surface of the

GASTEROPODA. 35

whorls is nearly smooth. It occurs in all the shelly beds of the formation in Minchin-
hampton district, and may be discovered in every quarry, sometimes in great numbers.

The smallness of the object, and the state of preservation, renders it difficult to obtain
a good section of the interior ; the folds upon the columella have been but imperfectly
disclosed, but there is little doubt that they are as above described ; the aperture is usually
more narrow than is represented at fig. 8a.

Locality. Minchinhampton Common ; Eparcy, France.

STRICKLANDI. Plate VII, fig. 9, 9a.

N. Testa cylindrico-subulatd, anfractibus latis, planatis, superne leviter convexis, suturis
profundis impressis ; cingulis scabris aut crenulatis, numerosis et approximatis, superne
evanesccntibus : aperturd, plicisque ignotis.

Shell cylindrical or subulate ; whorls wide, numerous, flattened, or very slightly convex
on their upper portions, their sutures strongly marked; the whorls are encircled with
numerous, closely-arranged, scabrous, or crenulated lines, which are nearly obsolete upon
their upper portions : aperture and plica3 unknown.

The character of the surface much resembles Cerithium tortile, Deslongchamps ; but the
whorls in that shell are much more convex and narrow ; in the present species the length
of the whorls perpendicularly is about equal to their transverse diameter.

Locality. The Stonesfield slate on the borders of Minchinhampton Common has
furnished our specimens ; they have occurred rarely, and only in fragments ; when perfect,
the length must be considerable.

NERIN^EA PUNCTATA, Volts. Plate VII, fig. 10, 10a, 6, c.

NEKIN.BA PHNCTATA, Volts, and Bronn. Jahrb., 1836, p. 559, t. 6, fig. 23.
Bronn. Index Palseont., p. 803.

N. Testa turrito-conicd, anfractibus sub-gradatis, cingulatis, cingulis binis ternisve nodu-
losis ; columella solidd, biplicatd, labro dextro uniplicato.

Shell elongated, conical, with a regular spiral angle of about 18°; whorls flat, pro-
jecting at the upper part beyond the whorl above, and thus giving a step-like outline to the
shell; ornamented with two or three transverse finely-knotted rings: columella solid.
Three internal folds, viz.: one strong sharp fold on the middle of the outer lip; one smaller
fold on the columella, a little lower than the former, and a blunt thick fold on the top of
the whorl near to the columella. Aperture rhoniboidal, rather higher than wide.

This is a more regular and elegant shell than N. Voltzii, to which it is so nearly allied,
that worn specimens of the two species may easily be confounded: in that case the
N.punctata may be distinguished by its step-like outline, flatter base, and longer and

36 MOLLUSCA FROM THE GREAT OOLITE.

sharper folds on the columella. With N. elegans (Thurm.) it may perhaps be identical, in
which case that name must be adopted for it : until this is decided we must call our shell
N. punctata, as it is clearly the species so designated by Yoltz.

Sutural angle, about 92°

Basal angle, about 120°

Length, from 1 to 2 inches.

Locality. Found in the shelly beds near Minchinhampton, and more frequently in the
quarries to the north of the vale of Chalford.

NERIN^A FUNICULTJS, Desl. Plate VII, fig. 12, 12a, b.

NEBULA FUNICTJLUS, Deslongchamps. 1842. Mem. Soc. Linn. Normandie, vol. vii,

p. 186, t. 8, figs. 30—32.

CYLINDRICA, Deslongchamps. L. c., t. 8, fig. 33.
CERITHITJM BLAINVILLII (?), Deslongchamps. L. c., t. 8, fig. 35.
NERINJEA FUNICULOSA, D'Orb. Prod. Pal^ont., p. 298.

]V. Testa turritd, longissimd; anfractibus superioribus concavis, transverse striatis,
inferioribus subplanis, aliis ad suturas tumescentibus, aliis via; prominulis; columella solidd,
triplicatd, labro dcxtro uniplicato. (Deslongchamps, 1. c.)

Shell very long and taper, but differing in the spiral angle in different specimens from
8° to 12°; the upper whorls are concave, with a strong projection at the suture, variously
ornamented with from 5 to 10 transverse ribs of unequal fineness, one or two of which (in
very well-preserved specimens) are seen to be composed of small knobs ; the lower whorls
become gradually flatter and smoother, and finally lose all traces of ribbing : columella
solid. Four internal folds, viz. : one strong, thick fold on the outer lip, rather below the
middle of the whorl ; two on the columella, of which the lower sharp and well-defined is
situated below that on the outer lip, and the upper faint and sometimes hardly visible, is
placed opposite to the upper edge of the outer fold ; and one sharp and long fold on the
top of the whorl, close to the columella.

Nerinaa cylindrica of Deslongchamps appears to be a tapering variety of the same shell,
in which the upper fold on the columella is ill-developed, or perhaps imperfectly seen.

This species is also closely allied to N. fibula, N. Goodhatti (not Sowerby's species), and
N. clavus of Deslongchamps, all of which are probably one species : it differs from them in
the greater concavity of the whorls, the transverse ribbing, and the presence of the upper
small fold on the columella. It has probably been confounded with N.fasciata of Romer —
a species which sadly wants revision.

Sutural angle, about 105°.

Basal angle, about 120°.

Length, up to 5 inches, but rarely exceeding 3 inches.

Locality. It is tolerably abundant in the shelly beds near Minchinhampton ; but owing
to its great fragility, large specimens can rarely be procured entire.

GASTEROPODA. 37

CERITELLA. Nov. Gen.

C. Testa turritd, spird acutd, subulatd, anfractibus plants, marffinibus sapissime sulcatis ;
anfractu ultimo aniplo ; aperturd clongatd, obliqud (canali (?) brevissimd) columelld laevigatd,
rotundatd ad basim subrcflexd.

Shell turreted, spire acute, subulate, volutions flattened, their margins usually sulcated ;
the last whorl large, aperture lengthened and oblique, canal very short ; columella smooth,
rounded, and slightly reflected at the base ; outer lip thin.

This genus is constituted to receive several species of subulate univalves, usually smooth,
but sometimes sculptured longitudinally, which seem to be equally removed from Terebra
on the one hand, and CeritMum on the other ; from the genus Fusus they are still more
remote. The increased size of the last whorl, together with the elongated narrow aperture,
detach it from the Ceritltice ; neither has it the decided twist of the columella, which we
find in Terebra; the base never terminates in a notch, but in a narrow, very short,
channel, which is turned slightly forwards and outwards ; the whorls are generally flattened,
the length of the spire exceeding that of the aperture.

The Ceritellce, from their individual number and variety of species, constitute an,
important group in the Great Oolite univalves. The delicacy of the outer lip is such, that
a specimen with that part perfect has scarcely ever been obtained, the remaining portion
usually giving to the base the aspect of a short channel, slightly directed outwards. It is
certain, however, that in several of these species the base of the aperture is very narrow,
and slightly twisted, approaching nearly to the channelled form, a character which, together
with that furnished by the spire, separates it sufficiently from the Acteoninte properly so
called, and to which some of the species have a slight resemblance. We have, therefore,
provisionally arranged these shells in this part of the series, until the characters of the
aperture are more fully developed.

CERITELLA ACTJTA. Plate V, figs. 17, \la, 18, ISa.

C. Testa turritd, lavigatd ; spird elatd, acutd ; anfractibus ($) convexiusculis ; aperturd
obliqud anyustatd, caudd recurvd brwi.

Shell turreted, smooth; spire elevated, acute; whorls (6) rather convex, aperture
oblique, narrow ; canal recurved and short.

The figure of this species varies considerably. The young shells are usually the most
subulate. The length of the last volution is generally half that of the entire shell. Axis
10 lines, transverse diameter 4 lines.

Locality. It is numerous in all the shelly beds in the vicinity of Minchinhampton.

6

88 MOLLUSCA FROM THE GREAT OOLITE.

CERITELLA UNILINEATA, Sow., sp. Plate V, fig. 13.

BUCCINUM UNILINEATUM, Sow. 1825. Min. Con., t. 486, figs. 5, 6.

Morris. 1843. Cat. Brit. Foss., p. 139.
PURPURINA. TOILINEATA, If Orb. 1850. Prod. Pateont., p. 302.

C. Testa parvd, ovato-elongatd, gibbosd; spird acutd; anfractibus (7 — 8) anywtatis,
superne plants et subangulatis.

Shell small, ovately elongated, gibbose, ; spire acute ; whorls (7 — 8) narrow, flattened
in their upper portions or subangulated.

This little gibbose shell has a spire about equal in length to the last whorl ; the whorls
are bevilled near to their upper junctions, or slightly depressed, which gives the appearance
of a line or furrow encircling them. Axis 4| lines, transverse diameter 2 lines ; but the
Ancliff specimens are usually smaller.

Locality. The white stone of Bussage has furnished only one specimen near Minchin-
hampton ; but it is much more abundant at Ancliff.

CERITELLA PLANATA. Plate V, figs. 14, 14«.

C. Testa turritd, acutd ; anfractibus anymtatis, numerosis, plants ad basim unilineatis ,
aperturd et caudd ut in C. acutd.

SheU turreted, acute ; whorls narrow, numerous, flattened ; a single encircling line is
placed at the lower part of each whorl, a little above the suture; aperture and canal as in
C. acuta. Axis 4^ lines, transverse diameter 2| lines.

Locality. Rare : the specimen figured is from the white stone of Eastcombs, in the
parish of Bisley.

CERITELLA SOWERBII. Plate V, fig. 16.

C. Testa turritd, subfusiformi, acutd; anfractibus (7 — 8) convexiusculis, infra suturam
unilineatis ; aperturd obliqud, elonyatd ; cawdd brevi.

Shell turreted, subfusiform, acute; whorls (7 — 8) slightly convex, with a transverse
line beneath the suture ; aperture oblique, lengthened ; canal short.

This species varies considerably in the elevation of the spire. Axis 8 lines, transverse
diameter 3 lines.

Locality. It occurs in the upper portion of the shelly beds, both north and south of
the vale of Brimscomb. It is rare.

GASTEROPODA.

CERITELLA MITRALIS. Plate V, fig. 15.

C. Testa conicd, apice acuminatd, anfractibus (7) angustatis, plants, marginibus sub-
tumescentibus ; aperturd parvd, obliqud ; canali brevi.

Shell conical, apex acute, whorls (7) narrow, flattened, their upper margins slightly
turned ; aperture small, oblique ; canal short.

This species is unusually short and conical. Axis 5 lines, transverse diameter 3 lines.

Locality. The planking of Minchinhampton Common, where it is rare.

CERITELLA CONICA. Plate V, figs. 10, 10a, 105, lOe.

C. Testa turritd, acutd ; anfractibus angustatis plants (8) ; costis longitudinalibus, a
dextro ad sinistram oUiquis ; aperturd angustatd, canali obliquo.

Shell turreted, acute; whorls narrow, flattened (8), with longitudinal oblique ribs,
passing obliquely from right to left ; aperture narrow, canal oblique.

The upper margin of each whorl has a slight encircling rib, which is united to the
oblique costae. The character of the markings in this species resembles C. gibbosa ; but in
that species, although the whorls are equally numerous, the spire is very small, and the
canal is almost obsolete. The length of the last whorl is two fifths of the entire shell.
Axis 6 \ lines, transverse diameter 3 lines.

Locality. The planking of Minchinhampton Common and white stone of Bussage
have furnished it but rarely.

CERITELLA GIBBOSA. Plate IX, fig. 17.

C. Testa parvd turritd, spird mediocriter elatd, apice acuto, anfractibus planatis, angus-
tatis et angulatis, longitudinaliter costatis ; costis numerosis, a dextro ad sinistram obliquis ;
anfractw ultimo, magno ; aperturd obliqud, angustatd et elongatd.

Shell small, turreted ; spire moderately elevated ; apex acute ; whorls flattened at the
sides, narrow, and angulated at their upper portions; longitudinally costated; costae
numerous, directed obliquely from right to left ; the last whorl large ; aperture oblique,
narrow, and elongated.

The angle of the whorls is slightly thickened and prominent ; the costae are distinct
immediately beneath it, but are not discernible upon the lower portion of the whorls. The
length of the aperture is equal to the remaining portion of the shell. The specimen figured
is rather more gibbose than usually obtains, for the proportions vary, but in point of size
there is no considerable difference. It is somewhat rare, and occurs in the soft shelly
Oolite which underlies the planking. Axis 3 lines.

Locality. Minchinhampton Common.

40 MOLLUSCA FROM THE GREAT OOLITE.

CERITELLA LONGISCATA, Buv. sp. Plate IX, fig. 14.

PLEDKOTOMA LONGISCATA, Buvignier. Mem. Soc. Philom., Verdun, 1843, pi. 6, fig. 8.

Testa pared, iurritd, elonyatd; apice acuto ; anfractibus (9 — 10) subplanatis ; costis
lonffitudinalibus rectis numerosis, carinatis; carind unicd marginali; aperturd angmtatd;
caudd subrectd.

Shell smooth, turreted, elongated; apex acute; whorls (9 — 10) rather flattened, with
longitudinal, straight, numerous ribs ; and a single encircling smooth carina upon the
upper margin of the whorls ; aperture narrow, canal straight, short. Axis 3 lines.

Locality. This little species accompanies its allied forms in the soft shelly Oolite
beneath the planking of Minchinhampton Common. It is very rare.

CERITELLA RISSOIDES, Buv. sp. Plate IX, fig. 7.

? PLEUROTOMA RISSOIDES, Buvignier. Me"m. Soc. Philom., Verdun, 1843, pi. 6, fig. 9.

Testd parvd, turritd; spird mediocri elatd ; apice acuto ; anfractibws angmtatis, posticis
carinatis, carind rotundatd ; costis lonffitudinalibus, rectis, subincurvis ; anfractu ultimo
elongate ; aperturd angustatd.

Shell turreted, spire moderately elevated, apex acute, whorls narrow, carinated at their
posterior margin ; carina rounded ; costse longitudinal, straight, or slightly curved ; last
whorl elongated ; aperture narrow. Axis 2 lines.

Locality. This pretty minute species is usually found in the soft shelly Oolite beneath
the planking of Minchinhampton Common. It is somewhat rare.

Family — NATICID^E.
NATICA, Adanson. 1757. Lam.

The species of Natica in the Great Oolite are divisible into two groups; one the
Natica proper, the others we have arranged in the sub-group Euspira, a name suggested by
Agassiz, for those species which have the spire more or less elevated, and the volutions
distinct.

The Natica!, though consisting of a considerable number of species, have, with one
exception, furnished but a small number of individuals ; and those belonging to the sub-
group Euspira are all rare in the Great Oolite.

GASTEROPODA. 41

NATICA.

Shell subglobose, thick, smooth ; spire pointed, more or less elevated, of few volutions ;
aperture large, oblique, ovate, entire ; columella lip oblique, thickened, the umbilicus being
nearly covered by a deposition of shelly matter upon the columella ; outer lip simple,
smooth.

NATICA INTERMEDIA. Plate VI, figs. 1, la.

N. Testa ovatd, spird elatd, anfractibus (5) convexis, angustis, superne planis ; averturd
ovato-elongatd, basi laid.

Shell ovate, spire elevated, whorls (5) convex, narrow, flattened above ; aperture ovately
elongated, base wide.

The general contour of this shell approaches nearer to Natica adducta, Phillips, than
any other Great Oolite species which we have examined. Its position is intermediate to
that species and our Natica Stricklandi, which latter species is more elongated. In all
these shells the upper portion of the whorls is horizontal ; but in N. adducta it is even
depressed as it approaches the suture, forming a narrow channel. N. intermedia is more
ovate, or less globose, than N. adducta. In that species the transversal is equal to the
longitudinal diameter ; but in N. intermedia the dimensions are as follow : Length 2 inches,
breadth 1 inch 7 lines.

Locality. The planking of Minchinhampton Common has supplied the few specimens
we have met with.

NATICA' GRANDIS, Gold/. Plate VI, fig. 12.

NATICA GRANDIS, Goldfuss. Petref., iii, p. 118, t. 199, fig. 8.
Bronn. 1848. Index Palaeont., p. 783.

N. Testa globoso-deprcssd, spird subexsertd, anfractibus convexiusculis, ultimo anfractu
ventricoso ; margine dcpresso ; aperturd semilunari ; umbilico tecto.

Shell globose, depressed ; spire little elevated ; whorls rather convex, their margins
rather depressed, the last volution ventricose ; the aperture large, semilunar ; the umbilicus
covered by a callosity of the lip.

We have only met with three examples of this species : two of these were obtained
from the upper limestone beds, the other from the planking. The general form is more
ventricose, and the last whorl more expanded, than either of our other species. The nearest
approximation to it is the Natica adducta, Phillips, of which, possibly, our shell may only
exhibit a more advanced stage of growth ; but as the spire of that species is more produced,
and as our shell perfectly agrees with the species figured by Goldfuss, we prefer, for the
present, to retain his designation.

Locality. Minchinhampton.

42 MOLLUSCA FROM THE GREAT OOLITE.

NATICA STRICKLANDI. Plate XI, figs. 24, 24#.

N. Testa ovatd, spird elatd, anfractibus convexiusculis, superne rotundatis, sutnris sub-
depressis ; aperturd oblique ovatd ; basi angustatd.

Shell ovate, spire elevated, whorls rather convex, rounded above, their sutures slightly
depressed ; aperture oblique and ovate ; base attenuated.

The length of the aperture scarcely exceeds half of the entire shell ; the whorls, which
are not numerous, are moderately wide, and somewhat flattened at their base ; the apex is
rather obtuse, and the general form is more cylindrical than is usual with shells of this
genus, the largest transverse diameter being only equal to the length of the last and penul-
timate whorl. We have only obtained two specimens which occurred in the soft shelly
Oolite underlying the planking, but, judging from casts, we should be inclined to believe
the upper portion of the formation likewise contains it. It has been named as a trifling
tribute of respect to H. E. Strickland, Esq., one of the few English geologists who, of late
years, have contributed to our knowledge of the Oolitic system.

Locality. Minchinhampton.

NATICA FORMOSA. Plate VI, fig. 10.

N. Testa ovato-elongatd, spird elatd, anfractibus (5) convexis, ultimo anfractu oblique
ventricoso ; aperturd magnd ovatd ; basi rotundatd, labro sinistro excavate.

Shell ovately -elongated, spire elevated, whorls (5) convex, the last whorl ventricose and
oblique ; the aperture large, ovate, the inner lip excavated, the base rounded.

We were at first disposed to refer this species to Natica elegans, Sowerby, but an
examination of additional specimens has convinced us of its specific distinctness. As com-
pared with that species, the spire is always much larger, and less angulated, and the
aperture bears a much less proportion to the entire length, its longer diameter scarcely
amounting to three fifths of the entire length of the shell. It occurs both in the planking
and upper portion of the formation, but is somewhat rare. Length 26 lines, breadth
20 lines. The apex, when perfect, is more acute than our figure represents.

Locality. Minchinhampton.

NATICA TANCREDI. Plate VI, fig. 11.

N. Testa ovatd, spird elatd, anfractibus (5) anyustatis in media subangvlatis ; apice
obtuso ; anfractu ultimo subcylindrico, permagno ; aperturd obliqud angustatd ; basi sub-
acuminatd.

Shell ovate, spire elevated, whorls (5) narrow, somewhat angulated in their middle
portions ; the apex is obtuse, the last whorl is very large, and subcylindrical ; the aperture
oblique and narrow, the base somewhat pointed.

GASTEROPODA. 43

The narrowness of the base, narrow subangular whorls, obtuse apex, and subcylindrical
figure of the last whorl, are the prominent features.

It has been named in compliment to Sir Thomas Tancred, Bart., the founder of the
Cotswold Naturalists' Club.

Locality. The fine specimen figured was obtained in the hard white limestone of the
upper portion of the Great Oolite formation near Minchinhampton, but it likewise occurs
in the planking, being rare in both situations.

NATICA GLOBOSA, JRoem. Plate VI, fig. 14.

NATICA GLOBOSA, Roemer. 1836. Nordd. Oolith., p. 156, pi. 10, f. 9.

Bronn. 1848. Index Paheont., p. 783.
t

N. Testa globosd, obliqua, ovato-orbiculari, hemisphericd ; spird laid, prominuld;
aperturd subreniformi ; umbilico amplo.

Shell globose, oblique, ovately orbicular, hemispherical ; spire large, but not much
elevated ; aperture kidney-shaped ; umbilicus large.

All our specimens have been obtained from the upper or limestone portion of the Great
Oolite ; we have, consequently, been able to obtain only portions of the shell. The figure
approaches so near to some of the casts of Purpuroidea Moreausia, that it is difficult, in
the absence of nodules, to distinguish them. Our species is, however, more depressed, and
the preserved portions of the shell are thicker than in the Purpuroidea -, but we should
always expect to find some traces of nodules in well-preserved casts of the latter genus.
Length 14 lines, breadth 16 lines.

Locality. Minchinhampton.

NATICA NERITOIDEA. Plate VI, fig. 4.

N. Testa oblique-ovatd ; spird parvd, obtusd, dcpressd ; anfractu ultimo clongato ;
aperturd anyustatd, obliqud ; labio inferno calloso.

Shell smooth, oblique, ovate ; spire small, depressed, and obtuse, the last whorl
elongated and narrow at the base ; the aperture narrow and oblique, the inner lip
thickened.

Two examples, with the shell partially preserved, are our authority. They are remark-
able for the rounded and depressed form of the spire, which gives it a truncated aspect : it is
likewise turned to one side simulating a Nerita. The form of the aperture and base is more
narrow or contracted than any other Great Oolite species. Length 13 lines, width 9 lines.

Locality. A bed of sandy limestone, about 100 feet above the Fullers-earth.

44 MOLLUSCA FROM THE GREAT OOLITE.

NATICA VERNEUILI, Archiac. Plate VI, figs. 6, 6a, 7, la.

NATICA VEENEUILI, Archiac. 1843. Mem. Soc. Geol. France, t. 5, p. 378, pi. 30, fig. 3.
Bronn. 1848. Index Palaeont., p. 788.
D'Orb. 1850. Prod. Paleont., p. 299.

.A7! Testa subhemisphericd, spird data, anfractibus (5) angustis et convexiusculis, apice
acuto ; anfractu ultimo per magno, ventricoso ; aperturd magnd scmilunari ; basi laid et
rotundatd.

Shell subhemispherical, spire elevated, whorls (5) narrow and slightly convex, apex of
the spire acute, last whorl very large and ventricose, aperture large, semilunar, base wide
and rounded.

The planking has supplied the only good specimens of this rare species. It would
also seem to occur in the calcareo-arenaceous beds of the upper portion of the formation,
judging by the aspect of casts. Length 23 lines, breadth 22 lines.

Locality. Minchinhampton. Eparcy, France.

NATICA MICHELINI, Archiac. Plate VI, figs. 2, 20, 3, 3«.

NATICA MICHELINI, Archiac. 18-43. Mem. Geol. Soc. France, t. 5, p. 377, pi. 30, fig. 1.
Bronn. 1848. Index Palseont., p. 785.
D'Orb. 1850. Prod. Paleont, p. 299.

N. Testa ovatd, spird parva, apice submamillato ; anfractu ultimo elongato, basi lata ;
aperturd superne angustatd ; labro interno cattoso convexiusculo.

Shell ovate, spire small ; apex submamillated, last whorl elongated, its base wide ;
aperture narrow above ; lip somewhat thickened, straight, and convex.

The straight border of the inner lip, its convexity, and the minute spire, sufficiently
characterise it. The spire consists of 5 or 6 whorls, of which the first two or three form a
minute mamillated apex. Our figures sufficiently represent the varieties of form, of which
the more elongated is the most common. The planking contains it not unfrequently ; and
some beds in the upper limestones contain numerous casts, which can scarcely be referred
to any other shell.

Length of the globose variety 18 lines, width 16 lines; length of the elongated variety
18 lines, width 13 lines.

Locality. Minchinhampton. Eparcy and Sancerre, France.

NATICA AMBIGUA. Plate VI, fig. 5.

? CASSIS EPARCYENSIS, Archiac. 1843. Me"m. Soc. Geol. France, torn, v, p. 385,

pi. 31, fig. 10.
? ACTEONINA EPAKCYENSIS, D'Orb. 1850. Prod. Paleont., p. 299.

GASTEROPODA. 45

N. Testa hemispharicd, spird j)arvd, depressd ; apice acuto ; anfractibus angustatis,
planis, anfractu ultimo ventricoso ; aperturd ellipticd.

Shell hemispherical, spire small, depressed; the apex acute; whorls narrow and
flattened, the last whorl ventricose ; aperture of moderate size, and elliptical ; inner lip
rounded.

The general figure approaches to globular, except at the base of the spire, which is
flattened, and only the small volutions rise above the wide and flattened upper surface of
the last whorl ; the base is comparatively narrow ; the inner lip is gracefully curved, but
not apparently thickened, nor is there any trace of an umbilical fissure. One specimen only
was obtained in the planking. It is imperfect about the outer lip, and scarcely half the
dimensions of the shell figured by D'Archiac. Length 10 lines, breadth 10 lines.

Locality. Minchinhampton ; Eparcy, France.

Sub-Genus — EUSPIRA, Ag.

Shell smooth, ovate ; spire elevated ; of few whorls, which are angulated, the angles
sometimes taking the form of a carina ; less frequently the last whorl has a second carina,
or the carina becomes nodulous or tuberculated ; aperture entire, elliptical, modified by the
angle of the whorl ; base wide, rounded ; pillar lip smooth and excavated, outer lip thin
and smooth.

The Great Oolite shells referable to this genus are all rare. One of them, however
(E. canaliculatd], though rare in this formation, is abundant in the middle division of the
Inferior Oolite.

EUSPIRA CANALICULATA.* Plate XI, fig. 23, 23a.

E. Testa oblongd, spird sub-exsertd, apicc. acuto, anfractibus anffulosis, angulis acutis;
anfractibus superne profunde canaliculatis, inferne sub-convcxis ; anfractu ultimo obliquo,
basi attenuatd; apcrlurd ellipticd, fssurd umbilici anyustatd.

Shell oblong, spire but little elevated, apex acute, whorls angulated, the angles acute,
the upper portion of the whorls deeply channelled, their lower portions rather convex, the
last whorl oblique, its base attenuated ; aperture elliptical, the umbilical fissure narrow.
Several obscure encircling lines may be traced upon the middle of the last whorl. The
specific characters of this shell are so strongly marked that it will not readily be mistaken
for any other; several specimens have been extracted from the limestone beds in the upper
portion of the Great Oolite ; but in the middle bods of the Inferior Oolite in Gloucester-

1 Although we have provisionally arranged this and the four following species under a sub-genus of
Natica, they present considerable affinities to the Palaeozoic genus, Scalites (Hall), in the lines of growth
having the appearance of a slight fissure where the angle occurs m the volution.

7

46 MOLLUSCA FROM THE GREAT OOLITE.

shire it is much more common. Length 14 lines, breadth 12 lines, length of aperture
10 lines, breadth 6 lines.

Locality. Minchinhampton.

EUSPIRA SHAEPEI. Plate XI, fig. 22.

E. Testa oblongd; spird elatd, apice acuto, anfradibm angulosis; angulis acutis et
prominentibus, superne tabulatis, infcrne planis; aperturd ma^nd, labro sinistro excavato et
umbilicato.

Shell oblong, spire elevated, its apex acute, volutions angulated, the angles acute and
prominent, the upper surfaces of the whorls nearly flat, but rising a little towards the
suture, the lower portion flattened; aperture large, inner lip excavated with an open
umbilicus.

This species most nearly resembles E. canaliculata, but in the present shell the spire
is very much more elevated ; the upper surfaces of the whorls are not channelled, and their
lower portions are not convex.

Locality. Minchinhampton. It is very rare, and has been found only in the planking.
Length 18 lines, breadth 15 lines.
Named in compliment to D. Sharpe, Esq., F.R.S.

EUSPIRA PYRAMIDATA. Plate VI, fig. 8, 8a.

E. Testa ovatd, spird data, pyramidatd, apice acuminate, anfradibus (4) anffulatis;
angulo in carinam obtusam producto; anfractibus superne tabulatis, in/erne planis, aperturd
ovatd, basi rotundatd,jissurd angustd.

Shell ovate, spire elevated, pyramidal, apex pointed, whorls (4) angulated, the angle
forming an obtuse carina ; upper surface of the whorls tabulated, lower flattened, aperture
ovate, base rounded, umbilical fissure narrow.

In this species the spire and aperture are nearly of equal length, beneath the angle of
the body whorl a slight depression is perceptible ; the flattened upper area of the whorls
is naiTow compared with the other contemporaneous species.

Locality. Minchinhampton. It occurs in the planking, and is rare.

EUSPIRA CORONATA. Plate VI, fig. 9.

E. Testa subfflobosd, spird elatd, anfractibus (4 — 5) anffulatis, angulis nodulatis ; nodulis
numerosis ; anfradibus superne tabulatis, in/erne subplanis ; an/ractu ultimo globoso, carinis
duobus nodosis cincto ; aperturd magnd el/ipticd, basi rolundatd ; umbilico parvo.

GASTEROPODA. 47

Shell subglobose, spire elevated, whorls (4 — 5) angulated, the angles nodulated, the
nodules being small and numerous ; the whorls are flattened above and beneath the angle ;
the last whorl is globose, and has two encircling nodulous carinre, with a depression between
them ; the aperture is large and elliptical ; the base rounded and wide ; the pillar lip with
an open umbilicus.

This may be regarded as an aberrant form of Euspira, in which the carina becomes
nodulous ; the nodules, however, are not prominent nor large, those of the second carina
being smaller, more numerous, and rather indistinct. There is also a slight sulcus between
the carinac which are connected together by obscure elevations, but these merely appear as
slight plications. The general form being globose, and the carina broken into nodules,
renders its aspect less angular than is usual in the genus. Length 21 lines, breadth
19 lines.

Locality. Minchinharapton : the planking has furnished our only example.

EUSPIRA STJBCANALICULATA. Plate VI, fig. 13.

E. Testa oblongd ; spira sitb-cxsertd ; anfractibus (4) anyulosis, marginibiis subdepressis,
sujjerne tabulatis, inferne subconvexis ; anfractu ultimo obliquo ; aperturd subtrigond;
obliqud, basi angustatd ; labro inferno calloso umbilicum obtigcnte.

Shell oblong; spire but little elevated; whorls (4) angulated, their margins rather
depressed, flattened above the angle, and rather convex beneath ; the last whorl oblique ;
aperture subtrigonal, the last whorl oblique, the base narrow ; the inner lip thickened, and
covering an umbilicus.

Unfortunately we possess only one specimen of this little shell, which was obtained in
the planking ; it may possibly be a young variety of E. canaliculata, in which the upper
portions of the whorls may become channelled with advance of growth, and the general
figure more globose ; the appearance of the inner lip and umbilicus, however, are certainly
different; and we, therefore, prefer to keep this as a distinct species. Length 8 lines,
breadth 7 lines.

Locality. Minchinhampton.

Family — PYRAMIDELLID^E.

EULIMA, Risso. 1826.

Turreted, smooth, pyramidal ; spire long, consisting of numerous whorls ; apex acute,
slightly tortuous ; aperture oval, rounded anteriorly ; outer lip slightly thickened ; colu-
mella smooth.

48 MOLLUSCA FROM THE GREAT OOLITE.

EOLIMA COMMUNIS. Plate IX, figs. 21, 21a.

E. Testa iurritd, lavigatd; spird regulari, obtusd ; anfractibus subplanis in (state
juniori, aetate progrediente convexis ; aperturd ovatd ; labro tenui.

Shell turreted, smooth ; spire regular, obtuse ; whorls rather flattened in the young
state, but with advanced age more convex ; aperture ovate ; lip thin.

When young the shell is much more flattened and obtuse ; but in all stages of growth
the junctions of the whorls are strongly marked — the oldest specimens have the lines of
growth strongly developed upon the last volution. The contrast between the peculiar
flatness and almost conical figure of the young shells and older specimens which have lost
their apex is so great, that without the assistance of intermediate forms they would
probably be regarded as distinct species. The length never exceeds an inch.

Locality. This is decidedly the most common univalve of the Great Oolite, and occurs
in all the shelly beds, more especially in the soft shelly Oolite beneath the planking at
Minchinhampton Common.

ECLIMA PYGMJEA. Plate IX, fig. 1.

E. Testa Icevigatd, turritd ; spird obtusd; anfractilus paucis, subplanis ; aperturd sub-
contractd.

Shell smooth, turreted ; spire obtuse ; whorls few, nearly flat ; aperture oblique, and
somewhat contracted laterally.

The last whorl is large, its length being half of that of the entire shell ; the obtuseness
of the spire, fewer volutions, nearly cylindrical figure, and obliquity of the aperture,
separate it from E. vagans.

Locality. A single specimen is all we have met with : it occurred in the white stone
of Bussage.

EULIMA VAGANS. Plate IX, figs. 3, 4.

E. Testa turritd, lavi, elatd; spird acutd, anfractibus paucis subplanis; aperturd
ovatd ; labro dcxtro subexpanso.

Shell turreted, smooth, elevated; spire acute; whorls few, high, and nearly flat;
aperture ovate ; right lip somewhat expanded.

The last whorl is nearly equal in length to all the others together.

Locality. It occurs in the shelly planking rarely ; and a few casts have also been
obtained in the upper portion of the formation, east of Minchinhampton.

GASTEROPODA. 49

EULIMA SUBGLOBOSA. Plate IX, fig. 6.

E. Testa lam, ovato-conicd ; spird subcontortd; anfractibus convexis, angustatis, anfractu
ultimo subgloboso ; aperturd oUiqiid, ovatd.

Shell smooth, ovately conical ; spire rather contorted ; whorls convex, narrow, the last
whorl subglobose ; aperture oblique and ovate.

A small globose species, the spire of which is rather angular, its length being somewhat
less than that of the last whorl.

Locality. It is rare, and occurs in the soft shelly Oolite of Minchinhampton Common.

CHEMNITZIA, D'Orbigny. 1839.

Shell turreted, elongated, not umbilicate ; volutions numerous, frequently costulated ;
aperture oval or angular, anteriorly large, retracted posteriorly ; columella straight and
smooth ; outer lip thin and smooth.

CHEMNITZIA LONSDALEI. Plate VIII, figs. 13, 13a.

C. Testa turritd, apice acuto, lavigato ; anfractibus in medio profunde constrictis vel
sulcatis, suturis vix impressis ; aperturd, elongato-ovatd, superne constrictd.

Shell turreted, elongated, acute, smooth; whorls deeply constricted, or sulcated in their
middle part ; sutures of the whorls sometimes scarcely distinguishable ; aperture elongated
and ovate, narrow posteriorly.

For the first four volutions the mesial depression is but slightly marked; but it gradu-
ally increases in depth, the last two or three whorls being deeply grooved. Several oolitic
species approach this shell, more especially the Melania lineata of the Mineral Conchology
and the M. procera of Deslongchamps ; in the latter species, however, the concavity of the
whorls is always very slight, and is sometimes not appreciable. Axis 3 inches 3 lines ;
transverse diameter 10 lines; length of aperture 10 lines; breadth of aperture 5 lines.

Locality. Our species is moderately rare ; it has been found only in the planking of
Mmchinhamptou Common.

Named after W. Lonsdale, Esq., F.G. S., whose valued contributions to Geology,
especially among the oolitic series, are well known.

CHEMXITZIA SIMPLEX. Plate VII, fig. 15.

C. Testa magnd, turritd, elongatd, l<zvi; anfractibus convexis, suturis prof unde imp,
aperturd olliqud ovatd ; columelld marginatd, rofundatd, subrectd ; labro inferno cfftiao.

Shell turreted, elongated, smooth; whorls convex, the sutures deeply impressed, aperture
oblique, ovate; columella marginated, rounded, nearly straight ; inner lip effuse.

50 MOLLUSCA FROM THE GREAT OOLITE.

In this large species the volutions are high and globose, the base of the shell is rather
contracted.

Locality. The few specimens found, have been obtained from the planking ; the fine
example figured is from the hard weatherstone of Bisley Common.

CHEMNITZIA HAMPTONENSIS. Plate VII, figs. 1, la.

C. Testa elongato-conicd, spird mediocriter oltusd; anfractibus (10 — 11) plants et
costatis; costis longitudinalibus (20 — 22) numerosis, rectis, vel subjlexuosis ; aperturd parvd,
dlipticd.

Shell conical, but much elongated ; spire, with the apex, somewhat obtuse; whorls
(10 — 11) flattened and costated; costae numerous, perpendicular, but slightly bent in the
middle, inclining from left to right ; aperture small, and elliptical.

The whorls are narrow, their axis being equal only to half their transverse diameter ;
the costae are narrow, and moderately elevated in young specimens, but after seven
volutions have been formed, became much more faintly marked, and finally are obsolete ;
the less subulate form and very narrow whorls separate it from Terebra vetusta (Phil. Geol.
York., t. 9, f. 11), to which the markings upon its surface have a near resemblance.
Axis of largest specimen 15 lines; transverse diameter 5 lines.

Locality. Minchinhampton Common and vicinity, where it is moderately rare : it is
usually found in the soft oolite beneath the planking.

CHEMNITZIA LECKENBTI. Plate VII, fig. 4.

C. Testa parvd, leevigatd, subulatd ; anfractibus numerosis, subplanis, superne convcxis,
nnfractu ultimo symmetrico.

Shell small, smooth, subulate, acute ; whorls numerous, narrow, flattened, except upon
their upper portions, where they are convex ; the last whorl symmetrical.

This small species approaches in figure two contemporaneous species, viz., the young
state of NcrincEa Voltzii and of Eulima? communis; from the former of these it is dis-
tinguished by the greater flatness of the whorls; from the young state of the latter by the
much greater number of whorls, more subulate form, and acute apex. Axis 85 lines.

Locality. Minchinhampton Common.

CHEMMTZIA WETHERELLII. Plate VII, figs. 5, 5a.

C. Testa cylindrico-clongata ; anfractibus numerosis (12) subconvexis, longitudinaliter
costatis ; costis (14) rectis obtusis ; aperturd parvd, ovatd.

Shell cylindrical, elongated, whorls numerous (about 12), somewhat convex, longi-
tudinally costated; costae perpendicular, obtuse, closely arranged, about 14 in a volution;
aperture small, ovate.

GASTEROPODA. 51

A small, slender species, with closely-arranged costas, which are rather large, but not
much elevated; the sutures of the whorls are strongly marked ; it is rare, but has occurred
in more than one of the shelly beds. Axis 1U lines ; transverse diameter 2 lines.

Locality. Minchinhampton Common.

This species is named in compliment to our kind and liberal friend, N. T. Wetherell,
Esq., F.G.S.

CHEMNITZIA VARIABILIS. Plate VIII, figs. 7, la, 6.

C. Testa turritd, subulatd; anfractibus convexiusculis, transversim striatis, plus
crenulatis, lonyitudinaliter costatis, costis curvatis circa 1 2 in ambitu; costis interdum inter-
ruptis nodulosis ; aperturd ettipticd obliqud ; columelld marginatd.

Shell turreted, subulate ; whorls rather convex, transversely striated, striae more or less
longitudinally costated, costae curved, about 12 in a volution; ribs sometimes obsolete, and
replaced by nodules ; aperture elliptical, oblique ; columella marginated.

Specimens differ in the convexity of the whorls, those which are most convex have the
ribs shortest, or reduced merely to nodules placed upon the upper border of each whorl : in
all specimens the costse become obsolete before reaching the base of each whorl. Occa-
sionally upon the same specimen the ribs degenerate into nodules, only the smaller whorls
are then costated. This species was first mistaken for Mdania undulata (Deslongchamps) ,
but in that shell the sides of the volutions are flat, the costae are more numerous, and
extend to the junction of the whorls, and have no curvature except in the last one ;
they are likewise less subulate than in our species. Axis 5 lines; transverse diameter
\\ lines.

Locality. It is abundant in all the shelly beds of the Great Oolite, near Minchin-
hampton.

CHEMNITZIA PHASIANOIDES. Plate IX, fig. 5.

C. Testa ovato-subcylindricd, spird elatd, apice obtuso ; anfractibus (5) plants, anfrarlu
ultimo subcylindrico, dongato ; aperturd obliqud ; labro dilatato.

Shell ovately-subcylindrical, spire elevated, apex obtuse, whorls (5) flattened, the last
whorl subcylindrical, elongated ; aperture oblique ; outer lip dilated.

This species has a considerable resemblance to Eulima vayans, but the spire is much
shorter, the whorls are fewer, and the apex is more obtuse ; the aperture is rather narrow, its
length being two fifths of the entire shell.

Locality. The planking of Minchinhampton Common has furnished our specimens.

52 MOLLUSCA FROM THE GREAT OOLITE.

Family — LITTORINID.E.

RISSOINA, D' Orbigny. 1842.

Shell turrcted, acuminated; spire long, consisting of several whorls; aperture oval,
rather pointed at the two extremities ; outer lip thickened, emarginated ; columella
rounded, straight.

RISSOINA DUPLICATA, Sow. Plate IX, fig. 10.

RISSOA DUPLICATA, Sow. 1829. Min. Con., t. 609, fig. 4.

Brown. Illust. Foss. Conch., t. 38, figs. 14, 15.

Morris. Cat. Brit. Fossils, p. 161.

Bronn. Index Palseont., p. 1092.
RISSOINA DUPLICATA, D'Orb. Prod. Paleont., p. 297.

If Orb. Pal. Franc. Terr. Jurass., t. 237, figs. 1, 2.

A. Testa parvd turritd, acutd ; anfractibus (6) in media angulatis; costulis longi-
tudinalibus anffustatis, remotiiisculis ; carind unicd in media anfractuum sitd; anfractu
ultimo, costulis numerosis longitudinalibm rectis ornafo, carind evanescence.

Shell small, turreted, acute ; whorls (6) angulated, with remote, narrow, longitudinal
costse; each whorl has a low carina, situated a little beneath its middle part; the last
whorl has very numerous small, longitudinal and straight ribs ; the carina is scarcely dis-
cernible upon the last whorl. The costse upon the last whorl are twice as numerous as
upon the spire, and the figure of the whorl is nearly cylindrical, or slightly biangulated ;
and the carina becomes obsolete ; the JKissoa unicarina of Buvignier, and the Fusus cari-
natus of Roe'mer, approach very nearly to this species, with which they may possibly
be identical ; judging from the descriptions, however, there are certain points of distinction
which appear to separate them from our species. Length 2 lines.

Locality. Ancliff and Minchinhampton Common ; at the latter place it is very rare,
and found only in the beds of planking.

RISSOINA OBLIQUATA, Sow. Plate IX, fig. 19.

RISSOA oBLiauATA, Sow. 1829 Min. Con., t. 609, fig. 3.

Brown. Illust. Foss. Conch., p. 79, t. 38, figs. 19, 20.
— Bronn. Index Palseont., p. 1093.
RISSOINA OBLIQUATA, D'Orb. Prod. Paleont., p. 297.

R. Testa turritd, turbinatd, acutd; anfractibus (6—7) convexis et costatis ; costis a
dextro ad sinixlram obliquis.

GASTEROPODA. 53

Shell turreted, turbinated, acute ; whorls (6 — 7) convex and costated ; costse oblique,
directed from right to left.

The costse are rather more elevated than in R. acuta, and the entire figure is more
turbiniform, the whorls being much more convex. Length from 2^ to 3 lines.

Locality. Ancliff ; also very rarely at Minchinhainpton Common, in the planking.

RISSOINA ACUTA, Sow. Plate IX, fig. 9.

RISSOA ACUTA, Sow. 1829. Min. Con., t. 609, fig. 2.

Brown. Illust. Foss. Conch., p. 79, t. 38, figs. 25, 26.

Bronn. Index Palseont., p. 1090.
RISSOINA ACUTA, D' Orb. Prod. Pal&mt, p. 297.

It. Testa pared, turritd, acutd; anfractibus convexiusculis 6, costulis angustatis subre-
motis longitudinalibus ; aperturd ovatd; labio dextro expanso.

Shell small, turreted, acute ; whorls (6) slightly convex, with narrow, rather remote,
longitudinal ribs ; aperture oval ; right lip expanded.

The surface is nearly smooth ; the longitudinal ribs, or rather lines, scarcely affecting
the evenness of the surface ; it is the most slender example of the genus which the Great
Oolite has produced. Length, 3 lines.

Locality. Ancliff; and very rarely Minchinhampton Common, in the planking.

RISSOINA CANCELLATA. Plate IX, figs. 12, 120.

JR. Testa turbinatd, turritd, acutd; anfractibus convexis (8), angustis, transverse costatis;
coslis (6 — 7) intequalibus, lineis lonyitudinalibus decussatis ; aperturd laid.

Shell turreted, turbinated, acute ; whorls convex (8), narrow, transversely costated ;
costae (6 — 7) unequal, decussated by longitudinal lines ; aperture wide.

The upper costae of each whorl are smaller and more approximated than the lower ; the
convexity of the whorls is chiefly upon their lower portions ; the fine longitudinal lines
crossing the narrow encircling costae give to the surface a cancellated aspect ; the aperture
is acute above, rounded beneath.

Locality. The soft Oolite beneath the planking of Minchinhampton Common furnished
this pretty little shell, of which we have not seen another example.

RISSOINA TRICARINATA. Plate IX, fig. 13.

R. Testa parvd, turbinatd, acutd; anfractibus convexis ; tricarinatis ; carinis crenulatis;
carind superiore apud suiuram positd; aliis in media et approximates ; anfractu ultimo ad
basem lineis tenuissimis notato; aperturd parvd, suborbiculari.

8

54 MOLLUSCA FROM THE GREAT OOLITE.

Shell small, turbinated, acute; whorls very convex, and thrice carinated; carinae
crenulated, the upper one placed near to the suture ; the others about the middle of the
whorl, and near together; the last whorl has near to its base very fine encircling lines; the
aperture is small, and nearly orbicular.

In this minute shell the largeness and roundness of the carinae, and the great convexity
of the whorls are the most prominent features.

Locality. We have procured two specimens from the white stone of Bussage ; but in
this, and probably other instances of minute shells, the small number known may indicate
rather our defective observation than the true relative numbers which they present.

RISSOINA? L^VIS, Sow. Plate IX, fig. 16.

RISSOA LEVIS, Sow. 1829. Min. Con., t. 609, fig. 1.

Brown. Illust. Foss. Conch., p. 79, t. 38, fig. 12.
— — Bronn. Index Paheont., p. 1092.

R. Testa pared, turritd, leevi, subcylindricd; anfractibus (6) subplanatis; anfractu
penultimo, et ultimo subcylindrico ; aperturd parvd, obliqud.

Shell small, turreted, pointed, smooth, and subcylindrical ; whorls (6) rather flattened ;
the last whorl, and also the penultimate whorl, are nearly cylindrical ; aperture small and
oval, oblique. Length 2| and 3 lines.

Locality. Ancliff ; also very rarely at Minchinhampton Common, where it has been
found in the planking.

This species scarcely exhibits the anterior notch characteristic of Rissoina.

PAGODUS, Gray.

Sub-genus — AMBERLYA.

P. Testa turritd, turbinatd, apice acuto; anfractibus superne plants, infra convexis et
nodulatis; anfractu ultimo ventricoso; aperturd ovatd, integrd, labio interno calloso umbili-
cum vix obtigente ; suturis profunde impressis; columelld nulld.

Shell turreted, turbinated, apex acute ; whorls flattened above, convex, and nodulated
beneath, the last whorl ventricose ; aperture ovate, entire ; inner lip thickened, and nearly
covering a small umbilicus ; sutures deeply impressed ; no columella.

The whorls are received into the concavity of those which succeed, the latter at then-
junctions being slightly overwrapped by the former, after the manner of Scalaria ; the
aperture is oval and oblique ; the outer lip thin ; the figure varied somewhat according to
the stage of growth, the last one or two volutions in adult specimens becoming more tumid
than the others ; in such examples, therefore, the spire acquires a slightly concave figure.

GASTEROPODA. 55

This shell may be considered to form only a section of Littorina, agreeing in the
general characters with the genus Pagodm of Gray, with which, probably, the discovery of
more perfect specimens may assimilate it.

AMBKRLEYA (PAGODUS) NODOSA. Plate V, fig. 19.

TEREBUA NODOSA, Buckman. 1845. Geol. of Cheltenham, p. 102.

A. Testa turrild, ventricosd; spird elatd, apice acuto; anfractibus (6) infra nodulosis,
nodulis numerosis superne apud suturam cingulo nodulorum minorum ornatis; anfractu
ultimo basi costulis obscuris tribits cincto.

Shell turreted, ventricose; spire elevated; apex acute; whorls (6) convex on their lower
portions, and nodulated ; the nodules closely arranged, and forming a small belt near to
the base of the whorl ; another, much smaller and indistinct, circle of nodules encompasses
the whorls upon their upper portions near to the suture ; the last whorl has at its base
three indistinct, narrow, encircling costae.

The number of nodules gradually increases in each volution, the last whorl having
about 18 ; the last two volutions are very ventricose, which give to the spire a slightly
concave figure ; in the younger state, consequently, the figure is more slender than in the
adult. Our two specimens, which are of different stages of growth, present the following
proportions: — Adult. Axis 24 lines, transverse diameter 15 lines, length of aperture 11
lines, breadth of aperture 8 lines. Young state. Axis 16 lines, transverse diameter 9
lines, length of aperture 6 lines, breadth 4£ lines.

Locality. It is very rare, the planking of Minchinhampton Common has furnished five
examples, and several imperfect casts have been obtained in the Stonesfield slate at another
place in the same vicinity : these casts have enabled us to ascertain the absence of a central
columella.

Obs. The specimen submitted to the artist was rather imperfect at the base of the
aperture, which, together with the position, give it the aspect of a regular notch at that
part of the shell.

Family — NERITID.E.

NERITA, Linn. 1758.

Shell semiglobose ; spire short, sometimes not produced, consisting of few volutions ;
aperture large, semilunar; outer lip thick, inner lip thickened, usually flattened, and
striated or dentated at its inner edge.

The fossil species of Nerita, from the Great Oolite, may be divided into the three
following sections, as dependent on the character of the inner lip : —

56 MOLLUSCA FROM THE GREAT OOLITE.

SECT. 1. Inner lip smooth.

N. Testa crassd, subhemisph(ericd ; spird parvd obliqud, depressd; anfractibus paucis,
carinatis; aperturd semilunari ; labio dextro crasso, labio inferno planato, amplo.

Shell thick, subhemispherical ; spire small, oblique, depressed ; whorls few, carinated ;
aperture semilunar ; outer lip thick and smooth; inner lip flat, broad, and smooth, without
notch or striae.

NERITA CANCELLATA. Plate XI, fig. 15,

N. Testa crassd, hemispkcericd ; spird parvd, depressd, obtusd; anfractibus (3) carinis
tribus cancettatis; carinis obtusis, striis longitudinalibus decussatis, et lineis incequalibus
et irregularibus cinctis ; aperturd transverse oblongd.

SheU thick, hemispherical; spire small, obtuse, depressed; whorls (3), with three carinae
cancellated ; carinae obtuse, decussated with longitudinal striae : the last whorl has also
irregular, unequal, encircling lines, which form, with the longitudinal striae, a cancellated
surface ; aperture transversely oblong ; inner lip very wide.

The most frequent aspect is that of a very rugose, depressed Nerite, with large, obtuse
carinae and intermediate sulcations ; the distinctly cancellated surface is observable only in
the younger examples. The first and second carinae are placed near together ; between
these and the basal carina is a large surface, with encircling lines crossing the striae.
Portions of coloured surface are sometimes observed upon the carinse and upper portion of
the last volution.

Locality. It is moderately rare at Minchinhampton Common and Bussage.

NERITA RUGOSA. Plate XI, fig. 17, 17 a.

R. Testa hemisphcericd ; spird parvd, depressd; anfractibus (2 vel 3) carinato-striatis ;
ultimo anfractu subangulato, carinis tribus (carina mesa majore), et striis profundis longi-
tudinalibus plus minusve crebris; coloribus fuscis stepe pictis; labio inferno, lato, planato.

Shell hemispherical; spire small, depressed; whorls (2 or 3) carinated and striated;
the last whorl subangulated, having three carinae, of which the middle one is the most
prominent and rounded ; the last whorl has, also, longitudinal, deeply-marked striae, more
or less closely arranged, and not unfrequently marked with colours, arranged into two
broad encircling bands, separated by the mesial carina.

The longitudinal striae might sometimes, with more propriety, be termed costae ; when
the costae are large and distant the carinae are likewise most prominent, and occasionally
both conditions may be observed in the growth of the same specimen — the smaller

GASTEROPODA. 57

examples being such as usually have the most widely-separated longitudinal lines or striae.
The surface markings vary so considerably that they may be conveniently described under
the three following aspects : —

a. Ribs elevated and separated ; carinae smooth and prominent.

b '. Surface with longitudinal closely-arranged plications, but no distinct ribs; plicae
impressed with very fine longitudinal lines.

c. In which the characteristics of the two former varieties are sometimes exhibited
upon the same specimen, in which case the carinae are imperfect, or, in lieu of them, there
are slight depressions or furrows.

The most common aspect is that of the variety a. It is one of the most generally-
noticed univalves of the shelly beds. Very rarely all traces of ribs and plications are
wanting, the surface is then shining, smooth, and highly coloured. The dimensions vary
from that of a duck-shot to the largest-sized pea.

Locality. Minchinhampton Common. In all the shelly beds of the district.

NERITA COSTULATA, Desk. Plate VIII, figs. 6, 6«, b, c. Plate XI, figs. 18, 18«, b.

NEEITA COSTATA, Sow. 1824. Min. Con., t. 463, figs. 5, 6.

— — Phillips. Geol. of Yorkshire, vol. i, t. 1 1, fig. 32.

Brown. Illust. Foss. Conch., p. 91, t. 44, figs. 1, 2.

— COSTULATA, Desk. 1838. Lam. Anim. sans Vert., 2d Edit., vol. viii, p. 617.

D'Orb. 1850. Prod. Paleont., p. 299.

JY. Testa parvd; spird obliqud depressd, minutd, vix elatd; anfractu ultimo superne
planato, costis longitudinalibus, numerosis, subundatis, et approximatis ornato.

Shell small; spire oblique, depressed, minute, scarcely elevated; the last whorl
flattened upon its upper portion, and covered with costae, which are longitudinal,
numerous, closely arranged, and slightly waved ; the aperture is very large, the inner lip
very wide and flat.

The absence of carinae at once distinguishes this little shell from our Nerita rugosa, for
one variety of which it might otherwise be mistaken. It has not been found in the
Minchinhampton Great Oolite, but occurs occasionally in the Inferior Oolite of that district.
Axis 2 lines.

Locality. Ancliff; Stonesfield. Inf. Ool., Yorkshire.

SECT. 2. Inner lip convex. Neridomus.

N. Testa lavigatd, ovato-globosd; vpird parvd, obliqud; anfractu ultimo permagno;
aperturd ovatd, vel semilunari; labio externo crasso; labio interno crasso, convcxo et
Iteviffato.

Shell smooth, ovately globose; spire small, oblique; the last whorl very large; aperture
ovate, or semilunar ; outer lip thick ; inner lip thick, convex, and smooth.

58 MOLLUSCA FROM THE GREAT OOLITE.

NEBITA HEMISPHJERICA, Roemer. Plate XI, fig. 16, 16«; 14, 14«.

NEEITA HEMISPH^EICA, Roemer. 1836. Nordd. Oolith., p. 156, t. 10, fig. ".

•

N. Testa leevigatd, transversd ovali-hemisphtericd; spird parvd, prominuld; aperturd
semilunari; labio inferno magno, convexo et incrassato.

Shell smooth, transverse, ovately hemispherical ; spire small ; aperture semihmar ; inner
lip large, convex, and incrassated.

The surface of this species varies considerably ; the younger specimens being smooth,
and not unfrequently exhibiting portions of colouring in dark, encircling lines : the older
specimens are rendered rugose by numerous large plications of growth. It is not
uncommon, being found in all the shelly beds, more especially in the coarse planking.

Locality. Minchinhampton Common.

NERITA MINUTA, Sow. Plate XI, figs. 19,

NEEITA MINUTA, Sow. 1824. Min. Con. t. 463, figs. 3, 4.

— Desk., 1838. Lam. Anim. sans Vert., 2d Edit., vol. viii, p. 617.

— D'Orb. 1850. Prod. Parent., p. 299.

— PULLA, Roemer. 1836. Nordd. Oolith., p. 155, t. 9, fig. 30.

— OVATA, Roemer. Nordd. Oolith., p. 156, t. 10, fig. 6.

— MAIS, Buvignier. 1843. Mem. Soc. Phil. Verd., t. 5, figs. 18, 19.

N. Testa parvd lavigatd; spird obliqud exsertd et minutd; anfractu ultimo coloribus
lineatis undulatis sapissime picto.

Shell small, smooth; spire oblique and minute; the last whorl most commonly exhibits
undulating-coloured lines, which occasionally coalesce, and are very irregular.

This little shell is a longer oval figure than both Nerita ItcmispluErica (Rom.) and
Neritina Cooksoni (Desl.) ; the latter little species, with which it nearly agrees in size, is
more globose, and has a larger, more prominent, and less oblique spire than N. Pulla.

N. minuta occurs abundantly in all the shelly beds; its surface is very smooth and shining;
the most frequent size is that of duck shot ; the longer diameter not exceeding two lines.
Locality. Minchinhampton Common and neighbouring district.

SECT. 3. Inner lip notched. Neritopsis, Grateloup. 1840.

N. Testa crassd, neritiformi, ovato-fflobosd ; spird parvd, obliqud, anfractu ultimo
inflate, costis numerosis cincto; aperturd suborbiculari, labro cxterno incrassato et lavigato,
labio interno concavo, sulco lato margine excavato.

Shell thick, neritifonn, ovately-globose ; spire small, oblique ; the last whorl inflated,
encircled with numerous costse; aperture suborbicular; the outer lip thickened, but smooth;
the inner lip concave, with a wide notch upon its inner border.

GASTEROPODA. 59

NERITOPSIS STRIATA. Plate XI, figs. 13, 13a.

N. Testa ovatd; spird elatd; anfractibus tribus, convexis; anfractu ultimo costis nume-
rosissimis crebris cincto, costis subundulatis ; aperturd ampld, ovatd.

Shell ovate ; spire elevated ; whorls (3) convex ; the last whorl encircled with numerous
and closely-arranged costae, which slightly undulate ; aperture large and ovate.

The costae are narrow, but slightly elevated, the interstitial spaces being so narrow as
to appear like striae ; hence, in badly-preserved specimens, the costae can scarcely be dis-
cerned ; the spire is small, moderately prominent, and has its surface distinctly sculptured
in good examples : the specimen figured is rather beneath the average size.

Locality. Minchinhampton Common, where it occurs somewhat rarely in the soft,
shelly oolite which underlies the planking.

NERITOPSIS SULCOSA. Plate XI, fig. 12.

? NEEITA SULCOSA, Archiac. 1843. Mc§m. Soc. G£ol. Fr., vol. v, tab. 28, fig. 8. (Non Brocchi.)

N. Testa ovatd; spird parvd; anfractibus tribus vel quaternis, convexis, sulco lato
spirali superne instructis ; anfractu ultimo permagno, cingulis ineequalibus, numerosis,
et magnis ornato.

Shell ovate ; spire small ; whorls (3 or 4) convex, with a wide, encircling sulcus upon
their upper portions; the last whorl very large, with numerous, unequal, and large
encircling bands.

The encircling ribs extend only upon the last volution, their inequality and large size
give to the surface a rugose aspect ; the sulcus upon the upper part of the last whorl is
without costae ; the specimen figured is of the largest dimensions.

Locality. Minchinhampton Common, where it occurs somewhat rarely in the shelly
beds of coarse planking.

PILEOLUS, G.B. Sowerby, 1823.

" Shell conical, with a subcentral upright vertex ; base concave, with a thin margin
and tumid centre ; aperture small, within the margin of the base, sublateral, semilunar, its
outer Up prominent, the inner one crenulated ; spire internal, very short." — Sowerby.

60 MOLLUSCA FROM THE GREAT OOLITE.

PILEOLUS PLICATUS, Sow. Plate IX, figs. 36, 360, 6,c.

PILEOLUS PLICATUS, G. B. Sow. 1823. Genera of Shells, No. 19, figs. 1—4.

Sow. Min. Con., t. 432, figs. 1—4.

Bronn. Leth. Geogn., p. 392, t. 27, fig. 6.

Brown. Illust. Foss. Conch., p. 92.

D'Orb. 1850. Prod. Pal6ont., p. 299.

Bronn. Index Palseont., p. 973.
PATELLA COSTATULA, Goldfuss. Petref., t. 177, fig. 9.

P. Testa turbinatd; amditu orbiculari; vertice elato, subacuto, erecto; costis radiantibus
majoribus (16) acutis, minoribus intermediis ; costis posterioribus maasimis ; margine
dentatd; basi in media convexiusculd, ad peripheriam subconvexd; peripherid integrd aut
subsinuatd.

Shell turbinated, suborbicular, summit elevated, erect, and rather acute; ribs radiating,
the larger series (16 in number) are acute, with smaller ones between them; the posterior
ribs are the largest and most distant ; the margin is toothed, the base is convex in its
middle part, and slightly convex at the periphery ; the periphery is entire, and slightly
sinuated.

Four of the posterior ribs occupy one third of the circumference; they are more elevated
and distant than the others. The specimens of this species in the Great Oolite never
occur of so large a size as those of P. lewis ; the usual basal diameter being about
3 lines, and very rarely exceeding 4 lines. Pileolus plicatus is scattered, indifferently,
over the shelly beds, but in fewer numbers than the other species; the shell being very
thick and strong, is usually entire and uncompressed ; both species are always found in
the upright position.

Locality. Minchinhampton Common ; Ancliff, Wiltshire ; Langrune, France.

PILEOLUS L^EVIS, G. B. Sow. Plate IX, figs. 37, 37«, b.

PILEOLUS L^EVIS, G. B. Sow. 1823. Genera of Shells, No. 19, figs. 5 — 8.
Sow. Min. Con., t. 432, figs. 6—8.

— Brown. Illust. Foss. Conch., p. 92, t. 44, figs. 16, 17.

— D'Orb. 1850. Prod. Paleont., p. 299.
Bronn. 1848. Index Palseont., p. 973.

? PATELLA MAMILLARIS, Goldfuss. Petref., t. 177, fig. 10.

? — PAPYBACEA, Bronn. Letheea Geogn., pi. 27, figs. 7, a, b.

P. Testa pared, conico-depressd, Icevi, aut sulcis raris, obsoletis notatd; basi in media
convexiusculd.

Shell small, conical, but much depressed ; sometimes discoidal, smooth, or with a few
faintly-marked longitudinal irregular sulcations ; base rather convex in the middle part.

GASTEROPODA. 61

Specimens, as small as the head of a pin, are scattered over the blocks of white stone
at Bussage, and planking at Minchinhampton Common — these are smooth. The larger
shells are more distinctly sulcated, and occasionally attain a diameter of three eighths of
an inch.

Locality. It occurs in all the shelly beds at Minchinhampton; at Ancliff, in Wiltshire;
and at Charter House, Hinton, Somersetshire. Langrune, France.

Family — TURBINID.E.

TROCHUS, Linnaeus, 1758.

Shell turbinated, conical; spire elevated, consisting of numerous whorls; under surface
discoidal ; aperture more or less depressed obliquely, entire, generally angular ; columella
curved, more or less prominent at its union with the outer lip, contiguous to the axis of
the shell.

The fossil species of the Great Oolite are all very small, and are tolerably numerous in
the shelly beds.

TROCHUS DUNKERI. Plate X, figs. 3, 3a.

T. Testa conicd, glabrd; anfractibus l&vigatis et plants (4 — 6); apice acuto; aperturd
obliqud, umbilico nullo.

Shell conical, smooth; whorls very smooth and flattened; apex acute; aperture oblique;
no umbilicus.

The extreme flatness of the whorls, and moderate elevation of the spire, are the chief
features ; the good specimens have oblique lines of growth upon the last whorl, near to
the aperture.

Locality. This little species is tolerably abundant in the white stone of Eastcornbs
and Bussage.

Named after Dr. W. Dunker, Professor at the Polytechnic School of Cassel.

This species has some affinity with the Trochus glaber, Koch (Goldf. Pet. t. 1796. 12);
but the volutions are striated and the base more convex.

TROCHUS PLICATUS, ArcMac. Plate X, figs. 8, 8«.

TKOCHUS PLICATUS, Archiac. 1843. Mem. Soc. Geoll France, vol. v, p. 379, t. 29, fig. 5.

D'Orb. 1850. Prod. Paleont., p. 300.

— Bronn. 1848. Index Palseont., p. 1304.

9

62 MOLLUSCA FROM THE GREAT OOLITE.

T. Testa turbinatd; spird elatd; anfractibus (5) subconvexis, longitiidinaliter costatis;
costis 12 rectis elatis; basi leevi; aperturd parvd, depressd.

• Shell turbinated; spire elevated; whorls (5) rather convex, longitudinally costated;
costae straight, elevated, smooth, about 12 in a volution; the base smooth; the aperture
small and depressed ; the sutures of the whorls are strongly marked. Axis 3 lines, basal
diameter 6 lines.

Locality. The specimen figured is rather flattened ; it occurred in the planking of
JVlinchinharnpton Common, and is more acutely conical than that figured by M. d'Archiac,
of which it is considered to be only a variety.

TROCHUS IBBETSONI. Plate X, figs. 4, 4«.

T. Testa conicd, spird elatd, oblusd; anfractibus (5 — 6), lavigatis ct jjlanis, aut sub-
convexis; aperturd depressd, obliqud; umbilico nullo.

Shell conical ; spire elevated, obtuse ; whorls (5 — G) smooth and flattened, or slightly
convex ; aperture depressed, oblique ; no umbilicus , columella lip thick and excavated.

This species somewhat resembles T. Dunkeri, from which it differs in the more elevated
spire, obtuse apex, and somewhat convex form of the whorls ; the base is, likewise, more
convex and narrow : in the larger specimens these distinctive characters become more
prominent, and the sutures of the whorls are strongly marked. It occurs together with
T. Dunkeri, but in smaller numbers.

Locality. Eastscombs and Bussage.

The name in compliment to Capt. L. L. 13. Ibbetson, F.R.S., whose geological surveys
of the different railways have been of considerable interest to science.

TROCHUS SQUAMIGER. Plate X, figs. 2, 2a, l>.

T. Testa conicd; apice obtuso; anfractibus (6 — 8) subcompressis, siduris impressis;
i/iifractibus cingulis quaternis tubuloso-squamosis; cinyulo inferiori minima; basi pla/ni ct
lu-ri ; tipcrlitrd dcprcsssd; umbilico nullo.

Shell conical ; apex obtuse ; whorls (0) rather compressed, the sutures well marked ;
whorls witli four circles of nodules or plications which are squamosely tubular or excavated
towards the aperture, the lowest circle of nodules being much the smallest ; the base is flat
and smooth ; the aperture depressed ; no umbilicus.

In this species the height exceeds the basal diameter. It occurs not very unfrequently
in the planking, a rock which usually adheres very closely to shells, and the plications
become entangled with the particles of stone, so as to render good specimens very rare.

Locality. Mincliinlmmpton.

GASTEROPODA. 63

TROCHUS BUNBURII. Plate X, fig. 1, la, 16.

T. Testa conicd; apice acuto; anfractibus (5) cingulatis; cingulis acutis inaqualibus,
basi lavi; aperturd obliqud.

Shell conical ; spire acute; whorls (5) cingulated ; encircling ribs unequal, and varying
in different individuals ; the base smooth ; the aperture oblique. m

The costae are very large, elevated, and unequal, so as to obscure the sutures of
the whorls.

Locality. It is by far the most abundant of the Great Oolite species in the vicinity of
Minchinhampton, and is common to all the shelly beds.

This species is named in compliment to E. H. Bunbury, Esq., M.P., F.G.S.

TROCHUS PILEOLUS. Plate X, figs. 5, 5«, 55.

T. Testa turbinatd, lavissimd; anfractibus (4) plants; apice obtuso; anfractu ultimo ad
basin angulaio; basi convexd; aperturd parvd.

Shell turbinated, very smooth ; whorls (4) flattened ; apex obtuse ; the last whorl
encircled with a prominent rib near to the base ; base convex ; aperture small.

The very obtuse spire, and nearly cylindrical form of the last volution, give to the shell
a cap-like figure.

Locality. From the white stone of Bussage. It is rare.

TROCHUS ANCEUS, Gold/. Plate X, figs. 7, la.

TROCHUS ANCEUS, Goldfuss. 1842. Petref., iii, p. 55, t. 180, fig.,3.
— Bronn. 1848. Index Paleeont., p. 1296.

T. Testa turbinatd, parvd, oblique costatd, basi cingulatd; anfractibus (5—6) tetra-
gonis cingidatis; cingulis quaternis granulatis.

Shell small, turbinated, obliquely costatcd, base cingulated ; whorls (5—6) angular,
encircled with four rows of granules.

Locality. Of this minute shell we have only obtained two examples, from the white
stone of Bussage, and believe it to be rare.

The sutures in the specimens, figured by Goldfuss, are more distinct.

TROCHUS OBSOLETUS, Roemcr. Plate XI, figs. 1, la.

TROCHUS OBSOLETUS, Roemer. 1836. Nordd. Oolith., p. 151, t. 11, fig. .i.
— — Bronn. 1848. Index Palseont., p. 1303.

64 MOLLUSCA FROM THE GREAT OOLITE.

T. Testa conicd; anfractibus tribus Itevibus, lateribus planis; umbilico nullo ; aperturd
depresso-ovatd.

Shell conical; whorls (3) smooth, the sides flattened, no umbilicus; aperture de-
pressed, ovate.

Possibly this may be the young of T. t/laber, Bunker ; the only apparent difference
between them being, that T. obsoletus has a base wider in proportion to the height, and
fhat the upper margins of the whorls are somewhat tumid, causing the sides to appear
less flattened.

Locality. It is moderately common to all the shelly beds near Minchinhampton. In
the Stonesfield slate of Wagboro' Bush (Buckman).

TURBO, Linneeus, 1758.

Shell thick, ventricose, turbinated, usually sculptured or tuberculated ; spire short;
aperture usually rounded, entire, somewhat spread out anteriorly.

TURBO HAMPTONENSIS. Plate IX, figs. 30, 30«, b.

T. Testa parvd, turbinatd; anfractibus (4) convexis. costulis (4) gmnulatis elatis cinctis;
aperturd orbiculatd; umbilico parvo.

Shell small, turbinated ; whorls convex (4), turreted, encircled by four ribs, which are
elevated and closely granulated ; the aperture is nearly round ; the umbilicus small.

Locality. A single, good example from the planking of Minchinhampton Common is
all we have seen.

TURBO ELABORATES. Bean, MS. Plate IX, fig. 27.

TURBO ELABORATE, Lycett. 1850. Aunals of Nat. Hist., vol. vi, p. 416, pi. 11, fig. 1.

T. Testa conoided; anfractibus (4 — 5), super neplanatis, in/erne subconveasis, et costatis;
costis maynis longitudinalibus numerosis et elatis, lincisque transversis decussatis; aperturd
ovatd; umbilico nullo.

Shell conoidal ; whorls (4 — 5), their upper borders flattened or nearly horizontal,
smooth ; their lower portions slightly convex, with numerous elevated large, longitudinal
costae, decussated by numerous, closely-arranged transverse lines ; aperture oval ; no
umbilicus.

Locality. The planking of Minchinhampton Common and white stone of Bussage
have furnished this species, but it is rare at both localities ; it has, likewise, been
obtained from the middle division of the Inferior Oolite in the same district, and occurs
also in the same formation in Normandy.

GASTEROPODA. 65

TURBO SHARPEI. Plate IX, figs. 28, 28a.

T. Testa conoided; anfractibus (4) convexis, gradatim tumescentibus, suturis profundv
impressis; anfractibus lincis elatis tequalibus, longitudinalibus et regularibus ornatis, aliis
transversis decussatis; lineis transversis superne distantibus, inferne approximates ; aperturd
ovatd; umbilico nullo.

Shell conoidal ; whorls (4) convex, gradually increasing in size, their sutures deeply
impressed ; the surface of the whorls is ornamented with numerous equal and regular lon-
gitudinal lines, tranversely decussated by others of equal size; the transverse lines are
arranged distantly upon the upper portions of the whorls, but more nearly upon the lower ;
aperture oval ; no umbilicus.

Both descriptions of lines are scarcely discernible, except upon the last volution, where
they are prominent ; but the lower portion of this whorl is destitute of the longitudinal
lines, which extend over only the upper half.

The general figure differs from Turbo claboratus (Plate IX, fig. 27), in the more gradual
increase of the whorls, which are likewise more convex, and have not the distinct sulcus
or area upon their upper portions, nor the large elevated costse ; these distinctive features
have been faithfully delineated by the artist. The longitudinal lines are equal in size to
those which are transverse, forming a simple cross-barred surface.

Locality. It is rare ; but has been found both at Bussage and Minchinhampton
Common. This species is dedicated to D. Sharpe, Esq., F.R.S.

•

TURBO PYGM.EUS. Plate IX, figs. 29, 29«.

T. Testa parvd, conicd; apice obtuso; anfractibus (4 — 5) planatis, costis longitudi-
nalibus numerosis (circa 16 in ambitu), cum pttnctis interstitialibus ornatis; aperttini
depressd.

Shell small, conical, apex obtuse; whorls (4 — 5) flattened, ornamented with numerous
longitudinal ribs (about 16 in a volution), the interstitial spaces being closely and deeply
punctated ; aperture depressed. The costa3 are large and equal ; their continuity is inter-
rupted by a narrow, encircling band at the base of each whorl ; the height of the entire
shell is somewhat greater than its transverse diameter at the base ; the exact character of
the mouth not being exposed, it is placed only provisionally in the genus Turbo.

Locality. Minchinhampton Common, at which place it would seem to be rare.

TURBO CAPITANEUS, Goldf. Plate IX, figs. 33, 33a.

TUKBO CAPITANEUS, Goldfuss. 1842. Petref., iii, p. 97, t. 194, fig. 1.
— Bronn. 1848. Index Palwout., p. 1318.

66 MOLLUSCA FROM THE GREAT OOLITE.

T. Testa turbinato-conicd, acutd, lineatd; basi granulate! cingulaid; anfractibus (6)
subteretibus bicarinatis, carinis (/ranulis erectis coronatis; interstitiis canaliculatis.

Shell turbinated or conical ; apex acute, the base with a granular band encircling it ;
the whorls (6) are turreted, and have two encircling carinse, the carinae are elevated and
fringed with closely-arranged granules, the interstitial spaces are canaliculated. .

Locality. This elegant species occurs rarely in the planking of Minchinhampton
Common ; it is usually crushed or otherwise imperfect ; it occurs likewise in the Inferior
Oolite of Gloucestershire more frequently, and is usually better preserved.

We have ventured to assign this shell to the species described by Goldfuss, although
its state of preservation does not show the longitudinal markings characteristic of that
species.

TURBO OBTTJSUS, Sow. Plate XI, figs. 9, 90.

TURBO OBTCSUS, Sow. 1827. Min. Con., t. 551, fig. 2.

Brown. 1849. Illust. Foss. Conch., p. 73, t. 38, figs. 41, 42.
TURBO SUBOBTUSUS, D'Orb. 1850. Prod. Paleont., p. 300.

T. Testa pared, conicd; spird obtusa; anfractibus (4) planatis, ultimo supcrne sub-
concavo, inferne convexo, sir Us crebris, subundatis, transfer sis cincto; aperturd ovatd;
umbilico nullo.

Shell small, conical ; spire obtuse ; whorls 4, their sides flattened, the last whorl
slightly concave in the upper and convex in its lower part ; the whorls are encircled with
striae, closely arranged and slightly undulated; aperture ovate; no umbilicus.

In this minute species, the junctions of the whorls are strongly marked ; the striae are
slightly punctated, giving to the spaces between them a rough or scabrous aspect ; the
stria;, however, are but faintly impressed, and are scarcely visible upon some specimens ;
the substance of the shell is thick, its axial slightly exceeding its transverse diameter, or
being equal to about 2 lines.

Locality. Minchinhampton Common and Bussage. At both places it is somewhat
rare, but occurs in more than one shelly bed. Ancliff, Wiltshire.

TURBO GOMONDEI. Plate XI, fig. 5.

T. Testa conoided, spird elatd, acutd; anfractibus (5) planatis et costatis; costis trans-
versis (4) dense nodulosis; aperturd ovatd, subdepressd, umbilico nullo.

Shell conoidal, spire elevated, acute ; whorls (5) flattened and costated ; the costae
( I- in number) are transversal, and densely nodulated ; the aperture is ovate and somewhat
depressed ; and there is no umbilicus.

The length of the aperture is scarcely equal to half the entire length of the shell, and

GASTEROPODA. 67

somewhat exceeds its transverse diameter ; it is moderately large, and wide at the base ;
the junctions of the whorls are strongly marked ; the encircling costae are large, closely
arranged, and very densely nodulated. Axis 8 lines, transverse diameter of the last
volution 6 lines.

Locality. Minchinhampton Common, where it occurs in the coarse planking : it is
moderately rare.

We have dedicated this species to H. Gomonde, Esq., of Cheltenham, who has kindly
allowed us the use of his collection of oolitic fossils.

MONODONTA, Lamarck. 1801.

Shell turbinated, aperture entire, base of the columella forming a tooth, with an
exposed umbilicus half surrounding it ; beneath the tooth is a longitudinal groove, the
edges of which are acute ; the outer lip is thick, striated within.

MONODONTA LVELLII, Archiac. Plate XI, figs. 4, 4«, b.

MONODONTA LYELLII, Archiac. 1843. Mem. Geol. Soc. France, torn, v, t. 29, fig. 8.

Bronn. 1848. Index Palseont., p. 742.
TUEBO LYELLII, D'Orb. 1850. Prod. Pale"ont., p. 301.

M. Testa turbinatd, spird acutd, anfractibus (4) convexis, tricinctis; cingillis clatis et
nodulosis; nodulis approximatis, antrorsum concavis; anfractu ultimo ventricoso, cingillis
7 ornato, ultimo cingillo maxima et profunde crenulato; umbilico magno.

Shell turbinated ; spire elevated, acute ; whorls (4) convex, encircled with three cariiias ;
carinse elevated and nodular ; nodules placed close together, and concave on their anterior
sides ; the last whorl ventricose ; encircling bands 7, the last being the largest and is
deeply crenulated ; the umbilicus is large.

The markings vary considerably in this species. In some specimens the encircling
costae are nearly smooth, in others they are merely notched ; but the greater number are
distinctly nodulated ; the junctions of the whorls are deeply impressed ; and the entire
shell is very thick.

Locality. This shell is abundant in the shelly beds near Minchinhampton ; the si
varies from a diameter of 1 line to 5 lines. In the Great Oolite, Eparcy (Aisne), France.

MONODONTA IMBRICATA. Plate XI, figs. 3, 3 a.

M. Testa parvd, conicd; spird acuminatd; anfractibus subplanis; striis imbricatis,
transversis (4) cinctis; anfraciu ultimo ad basin subangulato .

68 MOLLUSCA FROM THE GREAT OOLITE.

Shell small, conical; spire acuminated; whorls rather flattened, and encircled with
four imbricated striae ; the last whorl is somewhat angulated towards its base.

The imbricated striae are fine and closely arranged, those beneath the angle upon the
last whorl are larger; the aperture is semilunar and contracted. As compared with
M '. decussata, this shell is more lengthened, the apex pointed, and the encircling striae
much fewer.

Locality. It is rare, and occurs, with the species before mentioned, at Minchinhampton.

MONODONTA FORMOSA. Plate XI, figs. 6, 6 a, b.

M. Testa turbinatd, spird subdepressd, prominuld, oltusd; anfractu ultimo in media
carinato, striis transversis crebris tenuissimis cincto; carind lesviyatd, rotundatd, obtusd,
striis supra carinam positis mat/is elatis; upcrturd semilunar i subcontractd.

Shell turbinated, spire rather depressed, small, obtuse ; the last whorl carinated in its
middle part ; the carina smooth, rounded, and obtuse ; the last whorl has likewise trans-
verse, closely arranged, fine, and crenulated striae, those above the mesial carina being
larger than the others ; aperture semilunar, somewhat contracted.

In the greater number of specimens, more especially those of large dimensions, the
encircling striae are obsolete, the only markings being the lines of growth. Diameter of
largest specimens, 4| lines.

Locality. It is abundant and common to all the shelly beds near Minchinhampton.

MONODONTA DECUSSATA. Plate XI, figs. 9, 9a.

M. Testa parvd, conicd; apice obtuso; anfractibus planis, suturis impressis; striis
crebris transversis et longitudinalibus decussatis.

Shell small, conical ; apex obtuse ; whorls flattened, their sutures impressed, encircled
with numerous transverse striae, decussated and impressed by others longitudinally.

This shell is more obtuse than M. imbricata ; the last whorl is more cylindrical than
the others ; the lines upon its surface are so delicate as to be scarcely visible, unless under
a magnifier.

Locality. It is rare, and occurs with M. imbricata, in the soft shelly Oolite of
Minchinhampton Common.

MONODONTA LABADYEI, Archiac, sp. Plate XI, fig. 2; var. fig. 11, 11«.

TROCHDS LABADYEI, Archiac. 1843. Mem. Soc. G6ol. de France, iii, p. 379, t. 29,
figs. 2, la.

TURBO D'Orb. 1850. Prod. Paleont., p. 301.

? MONODONTA J^EVIGATA, Goldfuss. Petref., p. 101, t. 195, fig. 5.
? TURBO DESLONOCHAMPSI, Desk. Elem. de Conchyl., t. 68, figs. 17, 18.

GASTEROPODA. 69

M. Testa turbinato-conicd, leevi; spird elatd, obtusd; anfractibus planis seu subconvexis;
suturis vix impressis; anfrdctu ultimo permagno; aperturd ovatd; umbilico nutto. jEtate
adultd testa elatiore.

Shell turbinated, conical, oblique, smooth ; spire elevated, obtuse ; whorls flattened, or
slightly convex, the sutures rather indistinct ; the last whorl very large ; the aperture ovate,
and the base without umbilicus or sulcus.

The young shells are rather discoidal, but with increase of growth gradually become
obliquely conical, so much so, that the two extremes of the figure would scarcely be taken
for the same species.

Locality. It is abundant in all the shelly beds of the Great Oolite formation near
Minchinhampton. Eparcy, France.

SOLARIUM, Lam. 1801.
OMALAXIS. BIFRONTIA, Deshayes.

Shell depressed, conical, or discoidal ; base concave, or widely umbilicated, the spiral
margin of which is angulated and crenulated ; aperture trapezoidal, with a thin peritreme.

SOLARIUM POLYGONIUM, Archiac. Plate IX, figs. 24, 24#, b.

SOLARIUM POLYGONIUM, Archiac. 1843. Mem. Soc. Geol. de France, torn, v, p. 378,

pi. 29, fig. 1.

Bronn. 1848. Index Palaeont., p. 1152.
D'Orb. 1850. Prod. Parent., p. 300.

S. Testa discoided, spird parvd, anfractibus (4) planis, ultimo carinato ; angulis (9)
costatis ; costis elatioribus ; lineis transversis et longitudinalibus decussatis ; carind parvd,
nodulosd prope suturam sitd.

Shell discoidal, spire small, whorls (4) flattened, the last whorl carinated and angulated ;
angles (9) costated ; costse elevated ; there are also encircling lines decussated by others
which are longitudinal, and a small, closely nodulated carina, surrounding the upper portion
of the whorls, near to the suture ; the first two volutions are smooth, rounded, elevated,
but minute.

Locality. This species occurs in the vicinity of Minchinhampton more frequently than
any other of the genus, but, owing to its thinness and delicacy, few examples are well
preserved. The white stone of Bussage is the most favorable position for obtaining it.

Great Oolite, Eparcy, France (D' Arcldac).

SOLARIUM VARICOSUM. Plate IX, figs. 23, 23«, b.

S. Testa conico-depressd ; anfractibus (4) angulatis, lineis crebris transversis et lonai-

10

70 MOLLUSCA FROM THE GREAT OOLITE.

tudinalibus decussantibus et varicibus irret/ularibus angulatis, ornatis ; umbilico contracto,
basi latd, tenuissime cancellato.

Shell conical, depressed; whorls (4) angulated, and encircled with closely-arranged
lines, longitudinally crossed by others, and equally densely arranged ; varices elevated,
longitudinal, angulated in their middle part, and placed at irregular distances ; the um-
bilicus is contracted ; the base is wide, slightly convex, and has a finely-cancellated surface.

Locality. It occurs in the planking of Minchinhampton Common, very rarely.

SOLARIUM DISCULUM. Plate IX, figs. 25, 250, b.

S. Testa parvd, superne discoided, inferne concavd, lateribus angustatis, planis ; spird
vix elatd; anfractibus 3, marginibus angulatis et nodulosis, nodulis crebris, depressis>
umbilico magno, margine noduloso.

Shell small, discoidal above, concave beneath, the sides narrow and flattened ; the spire,
scarcely elevated, consists of 3 whorls, their margins angulated and nodulated, the nodules
closely arranged and depressed ; the umbilicus is large and deep, its margin is nodulated ;
the flattened sides of the last whorl are finely striated transversely.

The extreme flatness of the upper surface, the generally depressed form, and angular
outer margin, distinguish it from contemporaneous species.

Locality. It is rare, and occurs in the planking at Minchinhampton, and in the white
stone of Bussage and Eastcombs.

DELPHINULA, Lam.

Shell turbinated, thick, rugose ; whorls few, convex or angular ; aperture orbicular,
entire ; peritreme continuous, thickened ; umbilicus conspicuous and denticulated.

DELPHINULA CORONATA, Sow. sp. Plate IX, fig. 26.

EUOMPHALUS CORONATUS, Sow. 1824. Min. Con., t. 450, fig. 3.

— Brown. Illust. Foss. Conch., p. 82, t. 43, figs. 20—22.

DELPHINULA CORONATA, Flem. 1827. Brit. Anim., p. 312.

— — Bronn. 1848. Index Palseout., p. 406.

? DELPHINULA STELLATA, Buvignier. Me"m. Soc. Pkilom. Verdun, 2. pi. 5. figs. 35, 36.
SOLARIUM CORONATUM, JfOrb. Prod. Pal6ont., p. 300.

D. Testa discoided, parvd, superne pland, angulatd et spinigerd ; spinis latis, acutis et
prominentibm ; basi concavd.

Shell discoidal above, flattened, angular, and spined ; spines broad, pointed, placed at
the angle of the last volution ; base concave.

GASTEROPODA. 71

Locality. This little species is very rare. It occurs in the planking of Minchinhampton
Common.

The specimen figured in the ' Min. Con.' is from the Oolite of Ancliff, Wiltshire ;
M. Buvignier describes his species as occurring in the Coral Rag of St. Mihiel, France.

DELPHINULA BCCKMANNI. Plate V, fig. 8.

D. Testa turbinatd, spird elatd, anfractibus (3 — 4) costatis ; ultimo anfractu ventricoso,
subquadrato, in media costato ; costis lonyitudinalibus, numerosis, rectis, et rotundatis, superne
acutis, striis transversis impressis ; umbilico contracto, striis tenuissimis cincto.

Shell turbinated, spire elevated, whorls (3 — 4) costated, the last whorl ventricose,
subquadrate, costated in its middle portion ; the costa? are longitudinal, numerous, perpen-
dicular, acute at their upper extremities, and impressed with transverse striae ; the umbilicus
is contracted, and encircled with very fine stria3.

The costee are scarcely visible upon the upper surface of the last whorl, and nearly
disappear towards its base ; the aperture is suborbicular, the lips being less incrassated than
is sometimes seen in this genus. Individual specimens vary very much in the elevation of
the spire, and in the degree of squareness or angularity which the last whorl acquires ; in
some the umbilicus is scarcely visible, which usually happens in the more elevated shells.

Locality. This shell occurs in the beds of coarse planking on Minchinhampton
Common ; but well-preserved examples are rare.

DELPHINULA ALTA. Plate IX, fig. 31.

*

D. Testa turbinatd; spird elatd, obtusd; anfractibus angulatis (interne rotundatis) ;
anfractu ultimo tuberculis acutis, crebris sed distinctis ornato ; basi quadricinctd, costulis
tuberculatis ; umbilico magno prof undo ; aperturd subquadratd.

Shell turbinated j spire elevated, obtuse ; whorls angular (the moulds of the interior
being convex) ; the last whorl has, surrounding its upper part, a circle of elevated, acute,
distinct, and closely-arranged tubercles ; the base is encircled with four elevated ribs,
which are closely tuberculated ; the upper or flatter part of the last whorl has several fine
encircling lines (often indistinct) ; the umbilicus is large and deep, the aperture subquadrate
and rather small.

Locality. Minchinhampton. This pretty shell occurs in the planking, and is not
uncommon ; but the coarseness of the deposit is unfavorable to the preservation of its
more delicate features. Our best specimens may therefore be regarded as some of the
choicer productions of the formation.

72 MOLLUSCA FROM THE GREAT OOLITE.

Sub-genus, CROSSOSTOMA.

C. Testa crassa, turbinatd, lavi, subdepressd; anfractibus subplanis, paucis; apice
obtuso; aperturd subrotundd, integrd; columelld dentem obtusam formante; labio externo
Itevi, umbilico nullo. In estate senici aperturd contractd crassa, orbiculari, lamina
testaced Jlabelliformi cinctd.

Shell thick, turbinated, smooth, somewhat depressed or Rotelliform ; whorls more or
less flattened, few ; apex of the spire obtuse, depressed ; aperture nearly circular, entire ;
the columella forms at its base a simple prominent obtuse tooth ; the outer lip is smooth ;
there is no umbilicus. In the oldest state of growth, the aperture becomes contracted
by the deposition of shelly matter; it is perfectly orbicular, the circumference very
thick, and is encircled with a thin frilled appendage, always irregular, and more or less
produced.

In this genus the aperture undergoes a remarkable change as it approaches the last
state of growth. The surface is very smooth, the figure Rotelliform, and the aperture is
that of a smooth depressed Monodonta ; and this is the usual condition in which the several
species occur. Finally, however, a few thick lines of growth closely follow each other ; the
columella is concealed by a deposition of shelly matter ; the aperture becomes precisely
that of a DelpMnula, and is surrounded by an additional shelly irregular lamina, which
projects from it in every direction.1

CROSSOSTOMA PRATTII. Plate XI, figs. 21, 21 a.

C. Testa pared discoided l&vi; spird subpland, vix elatd; lineis incremcnti rugis prope
aperturam sitis; aperturd parvd, orbiculatd, labris incrassatis, lamina testaced abnorme
cincto.

Shell small, discoidal ; spire nearly flat, or but slightly elevated ; the last volution has
some rugose lines of growth situated near to the aperture ; aperture small, orbicular ; the
lips incrassated, and encircled with an irregular shelly lamina.

The shelly encircling lamina is produced by an irregular expansion of the ultimate fold
of growth ; the few rugose plicae have the more remarkable aspect, as the whole of the
shell, excepting within the brief space of two lines from the aperture, is perfectly smooth.

Locality. Inferior Oolite near Bath.

We are indebted to S. P. Pratt, Esq., F.R.S., for the original specimens obtained from
that locality.

1 M. A. D'Orbigny has described a species belonging to this sub-genus, under the name Delphinula
reflexilabrum, from the Lias of Fontaine-Etoupefour : " Shell smooth, resembling a Turbo, but having a
reflected, sharp, lamellar peristome surrounding the mouth." — Prod. Pattont., p. 229.

GASTEROPODA. 73

CROSSOSTOMA ? DISCOIDEUM. Plate XI, figs. 1, la, Ib.

C. Testa l<evi, depressd; spird prominuld; anfractibus angustatis, suturia impressis;
aperturd parvd, suborbiculari.

Shell smooth, depressed ; spire but little elevated, or nearly flat ; whorls narrow, the
sutures distinct ; aperture small, basal nearly round. The height is equal to half the basal
diameter.

This is, probably, only a variety of C. Prattii, and in a state in which all our Great
Oolite specimens occur — the outer lip not being quite entire, and extremely thin and
slightly rugged, never perfecting a well-defined lip (C. discoideum) ; the change to the
ultimate condition occupies a space which does not exceed one fourth of a volution, a
few rugged lines of growth are formed; an irregular lamina next protrudes, forming a kind
of frill around a contracted, thickened, and orbicular aperture, as in C. Prattii.

Locality. Minchinhampton Common and Bussage, at which places it occurs somewhat
rarely, and in more than one of the shelly beds.

CROSSOSTOMA? HELICIFORME. Plate XI, fig. 8.

(7. Testa Icevi, turbinatd, subdepressd; spird parvd prominuld; anfractibus convexi-
usculis; aperturd ettipticd.

Shell smooth, turbinated, somewhat depressed ; spire small, but little elevated ; whorls
rather convex ; aperture elliptical.

Locality. It is somewhat rare ; our specimens have been obtained from the planking
of Minchinhampton Common ; it is likewise found in the middle division of the Inferior
Oolite at Leckhampton, near Cheltenham.

This species has the general form of C. discoideum, but the spire is more elevated ;
they are only provisionally referred to Crossostoma, having somewhat the aspect of Mono-
donta, and even (in C. discoideum}, the thickened base of Botella.

PHASIANELLA, Lam. 1812.

Shell oval, smooth; aperture oval, entire, forming an acute angle posteriorly at the
junction of the columella and outer lip ; outer lip thin ; inner lip spread over a portion of
the columella.

The Great Oolite shells provisionally referred to this genus are small, and like their
recent congeners, individuals of the same species offer a considerable variety of form, which
makes their determination rather difficult.

74 MOLLUSCA FROM THE GREAT OOLITE.

PHASIANELLA ELEGANS. Plate XI, figs. 27, 270.

P. Testa ovato-elongatd; anfractibus (7) convexiusculis ; spird acutd, aperturd longiore.

Shell ovately elongated, whorls (7) convex, the spire acute, larger than the aperture.

The height of the last volution is rather more than the remainder of the spire ; the
whorls are narrow and convex; the sutures strongly impressed. Axis 16 lines, transverse
diameter 8 lines.

Locality, The planking of Minchinhampton Common has supplied this species in
considerable numbers.

PHASIANELLA LEYMERIEI, Archiac. Plate XI, figs. 31, 310, 32.

PHASIANELLA LEYMERIEI, Archiac. 1843. M£m. Soc. G&>1. Fr., torn, v, t. 28, fig. 12.

VOrb. 1850. Prod. Paleont., p. 301.
Bronn. Index Paleeont., p. 956.

P. Testa ovatd, sub-globosd; spird parvd; anfractibus (6) angustis, convexiusculis, anfractu
ultimo amplo; aperturd obliqud magnd.

Shell ovate, subglobose ; spire small ; whorls (6) narrow, convex ; the last whorl large ;
aperture oblique and large.

The length of the aperture is greater than that of the remainder of the spire, and the
length of the last volution is twice as great as the spire. The variety of figure in this
species is more than usually considerable. Axis 12 lines, transverse diameter 8 lines.

Locality. It is the most common of the Great Oolite Phasianella, and occurs in
all the shelly beds near Minchinhampton.

PHASIANELLA CONICA. Plate XI, figs. 30, 300.

P. Testa ovato-conicd, acutd; spird mediocriter elatd, conicd; anfractibus (6) plants,
ultimo elongato; aperturd obligud angustd.

Shell ovately conical, acute ; spire moderately elevated, conical ; whorls (6) flattened ;
the last whorl elongated; aperture oblique and narrow.

This species is somewhat spindle-shaped, narrowing at both ends ; the length of the
aperture is less than that of the spire ; but the last two volutions occupy more than two
thirds of the entire length of the shell. Axis 1 0 lines, transverse diameter 4 lines.

Locality. It is not uncommon, and occurs in all the shelly beds, more especially at
Minchinhampton Common.

GASTEROPODA. 75

PHASIANELLA ACUTITJSCULA. Plate XI, figs. 28, 280.

P. Testa ovato-conicd; spird elatd, acutd; anfractibus plants, angustis; anfractu ultimo
ovato, magnitudine modico.

Shell ovately conical ; spire elevated, acute ; whorls flattened, narrow ; the last whorl
ovate, its size moderate.

The figure most nearly approaches to P. conica, but it is less gibbose ; the spire is
more acute, elevated ; the whorls less numerous and narrow.

Locality. It is not uncommon, and is found in all the shelly beds near to Minchin-
hampton.

PHASIANELLA NUCIFORMIS. Plate XI, fig. 26.

P. Testa ovato-elongatd; spird parvd; anfractibus (6) subplanis, ultimo elongate;
aperturd angustatd.

Shell ovately elongated ; spire small ; whorls (6) flattened, the last elongated ; aperture
narrow.

The length of the aperture is equal to that of the spire ; the spire is acute ; the volutions
very narrow, except the last two turns, which are much elongated. Axis 9 lines, transverse
diameter 5 lines.

Locality. It occurs in the planking of Minchinhampton Common, but is rare.

PHASIANELLA PARVCLA. Plate XI, figs. 29, 29a.

P. Testa parvd; spird elatd, apice acuto; anfractibus (6 — 7) plants aut subconvexis,
angustis; anfractu ultimo subgloboso; aperturd obliqud; columelld arcuatd.

Shell small; spire elevated; apex acute; whorls (6 — 7) flattened, or rather slightly
convex and narrow ; the last whorl globose and large ; the aperture oblique and oval ; the
columella curved at its base.

The length of the aperture is two fifths of the entire shell ; the whorls are more numerous,
and the apex more acute, than is found in the other Great Oolite species ; the aperture is
rather small and contracted at its base. Axis 5 lines, transverse diameter 2£ lines. Rare.

Locality. Minchinhampton Common.

76 MOLLUSCA FROM THE GREAT OOLITE.

PHASIANELLA TUMIDULA. Plate XI, figs. 25, 250.

P. Testa turbinatd, elongatd; spird acutd; anfractibus convexis (8), suturis depressis;
anfractu ultimo globoso; aperturd magnd ovato-rotundatd.

Shell turbinated, elongated; spire acute; whorls (8) convex, the sutures deeply
depressed ; the last whorl globose ; the aperture large, ovately rounded.

This species has an elevated, acute spire, and convex whorls, and is remarkable for the
sudden increase of the last two volutions, which are very ventricose. Neither of our
specimens are quite perfect about the outer lip ; but the distinctive character of the species
is sufficiently evident. Axis 19 lines, transverse diameter 11 lines.

Locality. It occurs rarely in the planking at Minchinhampton Common.

Family — PLEUROTOMAKID^;.
PLEUROTOMARIA, Defiance. 1825.

SCISSURELLA, D'Orligny. 1823.

Shell turbinated or conical ; aperture subquadrate, the angles rounded ; outer lip thin
and sharp, having a fissure or deep notch in the middle part, or near to the suture ; an
encircling band or rib round each whorl follows the fissure.

The Pleurotomaries are rare in the Minchinhampton beds, and the larger specimens are
usually broken. It will be observed, in the following descriptions, how very few examples
of each species have been obtained, so that we are almost enabled to give then- number
with exactness. Placed amidst such a multitude and variety of molluscous relics, in spots
teeming with life, it is not easy to account for their rarity and imperfect condition.
Inferring that they were usually gregareous, we are led to suspect that the littoral condition
of these shelly beds was not suited to their propagation, and that the larger imperfect
specimens were denizens of greater depths, the shells occasionally being stranded among
the more littoral Mollusks. As a remarkable instance of the recurrence of similar phe-
nomena at a very distant locality, we would direct attention to the elaborate and valuable
Memoir of M. Deslongchamps,1 on the Pleurotomariee of the secondary formations of
Calvados, in which 53 species are mentioned as occurring in the Lias and the Lower and
Middle Oolitic systems. It is stated that they are exceedingly abundant ; but, on referring
to the Great Oolite species, 1 1 in number, we find, with one exception only, a repetition
of the following remarks appended to them : " One example ; two examples ; rare ; very
rare.'' In fact, when describing the species which we have identified in that Memoir, we
seem, when stating their numbers, to be repeating the words of its author.

1 Mem. Soc. Linn, de Normandie, vol. viii.

GASTEROPODA. 77

PLEUROTOMARIA SCALARIS, Desl. Plate X, fig. 14.

PLKUROTOMARIA SCALARIS, Deslongchamps. 1848. Mem. Soc. Linn, de Normandie,

vol. viii, p. 67, pi. 8, fig. 1.
Var. a, TURGIDULA, Desl., ibid., p. 67.
SCALAKIS, D'Orb. 1850. Prod. Paleont., p. 269.

P. Testa crassd, trocldfortni; spirdplus minusve exsertd; apice acuto; anfractibus cari-
natis, subgradatis aut gradatis, tranverse striatis, sinu magno pro/undo; fascia sinus
prominente, leevi aut longitrorsmn densissime striatd, in media anfractuum sitd; ultimo
anfractu ad basim angulato, obtusiusculo ; basi pland aut subconvexd; umbilico aut
parvo, aut minima, aut nullo; aperturd subquadratd, labro sinistro crassiori reflexo.
(Deslongcharaps.)

Shell thick, trochiform ; spire more or less elevated ; apex acute ; whorls carinated,
more or less step-like, transversely striated; sinus large and deep; band of the sinus
prominent, smooth, or very finely striated longitudinally, and placed in the middle of the
whorl; the last whorl is angulated, or somewhat obtuse at the lower margin; the base
is flat, or slightly convex ; the umbilicus small, very minute, or wanting altogether ; the
aperture subquadrate, the left lip being thick and turned outwards.

Altogether we have obtained eight or nine specimens. They vary in the elevation of
the spire, and agree with the first variety of P. scalaris of M. Deslongchamps, viz. the
turyidula which he thus characterises :

"Testa conicd, anfractibus subrotundato angulatis, vlx gradatis, transversim obsoletissime
striatis, striis in ultimo basis vicinis; basi subconvexd, striis radiatis incrementi tantum
notatd, umbilico minima."

Axis 29 lines, basal diameter 26 lines.

Locality. The planking of Minchinhampton Common has furnished all our specimens,
only three of which are well preserved. Inferior Oolite, Bayeux. (Desl.)

PLEUROTOMARIA PAGODUS. Plate X, fig. 9. Var. DEPAUPERATA.

? PLEUROTOMAIUA PAGODUS, Deslongchamps. 1848. Mem. Soc. Linn, de Normandie.

vol. viii, pi. 14, fig. 4.
D'Orb. 1850. Prod. Pateont., p. 301.

P. Testa trochiformi, subturritd; apice acutiori; anfractibus gradatis, infra fasciam
constrictis, transversim et tenuissime striatis, in media nodis coronatis ad suturam subundu-
latis; sinu magno, pro/undo; fascia sin/is pland, densissime lonyitrorsum striatd, infra

11

78 MOLLUSCA FROM THE GREAT OOLITE.

nodos sitd; ultimo anfractu ad basim angulalo siibnodoso; basi subconcavd, concentrice
striatd, striis tenuibus, profundis ad umbilicum minimum nuttis; aperturd subpentagond.

Shell trochiform, subturreted ; apex rather acute ; whorls step-like, narrowed beneath
the band, transversely and finely striated, coronated in the middle by a circle of nodules,
subundulated even to the suture ; the sinus is large and deep, the band of the sinus is flat,
densely striated longitudinally, and situated beneath the nodules ; the last whorl is
angulated at lower margin and slightly nodulated; the base is somewhat concave, con-
centrically and very delicately striated; the umbilicus is very small or obsolete; the aperture
is nearly pentagonal.

Locality. Two specimens only have been found in the Minchinhampton district. Both
are small compared with the fine specimen figured by M. Deslongchamps, who is very
fortunate in that respect, considering that the species is likewise very rare in Normandy.
Its position is the soft shelly Oolite beneath the planking at Minchinhampton Common.

PLECROTOMARIA DISCOIDEA. Plate X, fig. 12.

P. Testa turbinato-depressd, spirdobtusd, anfractibus subconvexis, lavibus et angustatis ;
sinu anffustissimo ; fascia sinus strictd, et planatd interdum vix notatd, infra medium an-
fractuum sitd; ultimo anfractu ad basim angulato convexo, basi subconvexd, laevi ,- umbilico
minuto out nullo, aperturd subquadratd.

Shell turbinated, depressed: spire obtuse; whorls somewhat convex, smooth, and
narrow ; sinus very narrow ; the band of the sinus narrow, flattened, and smooth, some-
times scarcely distinguishable, and placed beneath the middle of the whorls ; the last whorl
is angulated, and convex at the margin ; the base is slightly convex, and smooth ; the
umbilicus minute or wanting ; the aperture subquadrate.

The small elevation of the spire, which is only equal to two fifths of the basal diameter,
necessarily renders the whorls narrow ; the basal angle of the last whorl is unusually acute ;
the sutures of the whorls are strongly marked.

Though possessing few distinctive characters, it is little liable to be confounded with
others ; the extreme smoothness, depressed form, and proximity of the sinus and fascia to
the base of the whorls, are obvious and sufficient features. Height 4 lines, basal diameter
10 lines.

Locality. We can enumerate seven specimens ; they occurred in the white stone at
Bussage ; also in the lower portion of the formation on the south side of Minchinhampton
Common, where the rock is not very shelly.

GASTEROPODA. 79

PLEUROTOMARIA OBESA, Desl. Plate X, fig. 11.

PLECROTOMAHIA OBESA, Deslmgchamps. 1848. Mem. Soc. Linn, de Normandie.

vol. viii, p. 134, pi. 14, fig. 1.
D'Orb. 1850. Prod. Paleont., p. 302.

P. Testa trochiformi, apice subacuto, anfractibus rotundatis, in media subdepressis,
transverse striatis ; striis frequentibtis obsoletis, eequalibus, sinu angustissimo, profundissimo,
fascia sinus strictissimd, vix a striis distinctd, longitrorsum tamen densissime striatd, in media
anfractuum sitd, ultimo anfractu ad basim angulato-convexo ; basi subconvexd concentrice
striatd, striis rarioribus obsoletissimis, hinc et inde evanescentibus, umbilico magno, pervio
(parietibus subplanis), ad marginem sulcato, sulco sat parvo, spiraliter ascendente, sutures
internee vicino, sed ab ea distinctissimo ; aperturd subquadratd. (Deslongchamps.)

Shell trochiform, apex subacute ; whorls somewhat convex, slightly depressed in their
middle, and transversely striated ; the striae, which are equal, are frequently obsolete ; the
sinus is narrow and deep, the band very narrow, so as scarcely to be distinguished from
the striae ; but it is densely striated longitudinally, and situated in the middle of the whorls ;
the last whorl is convexly angulated at the lower margin ; the base is somewhat convex,
concentrically striated, the striae being frequently scarcely distinguishable ; the umbilicus
is large, pervious (the sides nearly flat), sulcated at its margin, and ascends the interior
spirally, near to the internal sutures, but distinct from them; the aperture is subquadrate.

Locality. We have only procured two specimens, which do not fully exhibit the
minute features of this species, so carefully described by M. Deslongchamps. Both were
obtained from the planking of Minchinhampton Common. Great Oolite, Ranville.
(Desl}

PLEUROTOMARIA CLATHRATA, Goldf. Plate X, figs. 6, 6a.

? PLEUROTOMARIA CLATHRATA, GoMfuss. 1843. Petref, p. 74, t. 186, fig. 8.
— — D'Orb. 1850. Prod. Paleont., p. 356.

P. Testa trochiformi subdepressd, apice acuto, anfractibus planis, (5,) cingillis lineisque
crebris clathratis ; basi convexo-pland tenuissime clathrata; umbilico minima aut nullo;
anfractibus superne obsolete tuberculatis ; fascia sinus marginali.

Shell trochiform, somewhat depressed; apex acute; whorls (5) flattened, their sutures
well marked ; covered with very fine, regular, equal lines, both longitudinal and transverse ;
the base is flattened or slightly convex, with a very fine cancellated surface ; umbilicus

80 MOLLUSCA FROM THE GREAT OOLITE.

minute or obsolete ; the upper border of the whorls has an obscure encircling row of
tubercles ; fascia of the sinus marginal ; the aperture quadrate.

The delicate markings upon the surface are only visible under a magnifier. The general
figure and character of the surface nearly approximates to Pleurotomaria punctulata,
Deslongchamps, but in that species the fascia of the sinus is placed upon the middle of the
whorls, and it is destitute of the upper encircling band of tubercles.

Axis 4 lines, basal diameter 6 lines.

Locality. The white stone of Bussage has furnished our specimen, but the species is
very rare.

PLEUKOTOMARIA COMPOSITA. Plate X, figs. 13, 13a.

P. Testa turbinatd, conicd ; spird subacutd ; anfractibus supcrne convexis, infra
planatis vel subconcavis ; sinu mayno ; fascia sinus laid, lotwitudinalifer striatd, in medio
anfractuum sitd ; anfractibus supra fasciam densissime lonyitudinaliter et oblique striatis ;
striis ineequalibus ; infra fasciam striis transversis (Bqualibus profundis subdistantibus ;
anfracttt ultimo ad basim rotundato ; facie infimd pland, vel subcotivexd, lonyitudinaliter
tenuissime et in&qualiter undulatim striatd; umbilico nullo ? vel minima ; aperturd sub-
pentagonali.

Shell turreted, conical ; spire subacute ; whorls convex in their upper portions,
flattened or slightly concave in their lower; the sinus large, the band of the sinus wide,
longitudinally striated, and situated in the middle of the whorls ; the whorls above the
band are, longitudinally, densely and obliquely striated ; the striae are unequal ; beneath
the band the whorls are transversely striated ; the striae are equal, deeply impressed, and
rather distant ; the last whorl is rounded at the lower margin ; the base is flat or slightly
convex, it is longitudinally, densely, and unequally striated ; the striae undulate ; umbilicus
none or minute; aperture subpentagonal. Axis 9 lines, basal diameter 11 lines.

Locality. The lower weatherstone beds at Quarrhouse and Minchinhampton have
yielded several specimens.

TROCHOTOMA, Lycett. Lesion g champs, 1842.

RIMULTJS, D'Orb. 1839.
DITREMAKIA, If Orb. 1842.

T. Testa turbinatd, conicd; anfractibus sapissime angulatis, in medio vittd strictd
notatis ; periplicerid subangulatd ; aperturd subquadratd ; columelld arcuatd ; basi excavatd,

GASTEROPODA. Xfi^ft,,, UrtfeX 81

infundibuliformi, umbilicum simulante; fasurd elongatd, antics dausd, non longim ab ore,
ultimum anfractum subdepresmm perforante. (Deslongchamps.)

Shell turbinated, conical ; whorls usually angulated, having a band or rib encircling
the middle of each whorl ; periphery subangular ; aperture basal, subquadrate ; columella
curved ; base excavated, excavation large, and resembling an umbilicus ; fissure transversely
elongated, closed anteriorly, but not far from the outer lip, its length being about equal to
the distance which separates it.

Our specimens exemplify the changes which the shell underwent during its advance of
growth. The perfect aperture, and likewise certain oblique furrows, to be seen upon other
parts of the shell, indicate so many stages of repose, each of which probably continued a
considerable period ; the amount of advance at each stage varied from one half to three
fourths of a volution.

During the period of repose, the egress currents probably passed through the fissure ;
the edges of which are worthy of notice. The substance of the shell generally is thick,
but the edges of the fissure are extremely thin, and exhibit that irregular, ragged, or im-
perfect outline which is seen in bone or shell during the process of growth or absorption.
When, however, the animal was forming new shell in advance of the aperture, the fissure
was not advanced forward with it, but the anal siphon remained in the same position
until a considerable progress had been made in the formation of new shell. At length
that organ was withdrawn, to be protruded from the aperture, and the formation of a new
fissure immediately commenced. One specimen in our possession exhibits the fissure still
open, although the formation of new shell had proceeded beyond the old aperture to the
extent of one fourth of a volution. In this condition the outer lip is ragged and imperfect ;
and during the brief period of the formation of a new fissure, the aperture acquires exactly
the aspect of a Pleurotomaria ; and it is not uncommon to find specimens in this condition.
The new shell is then very thin, and consequently is more or less crushed or imperfect.
These several removals of the anal siphon, and formation of new fissures at distant
intervals, are analogous to what is observed in Haliotis, except that in the latter genus
several perforations remain open during the formation of a new one, and their borders are
regular and smooth, not being destined to undergo the change which we observe in Tro-
chotoma. It seems indeed not improbable, that in the young state, or until three volutions
had been completed, that no fissure was formed, and that the siphon was protruded from
the aperture. This idea is founded upon the fact that those volutions are always smooth,
convex, and destitute of the encircling rib which subsequently follows the fissure. This
character is best seen by contrast in such species as in advanced growth become very
angular or step-like, as in T. tabttlata, T. discoidea, and T. extcnsa. The reader is referred
to the interresting observations on this genus, by M. E. Deslongchamps, ' Mem. Soc. Lin.
Normandie,' vol. vii, pp. 99 — 104.

82 MOLLUSCA FROM THE GREAT OOLITE.

TROCHOTOMA ACUMINATA, Deal. Plate X, figs. 180, 20.

TKOCHOTOMA ACUMINATA, Deslongchamps. 1842. M6m. Soc. Linn, de Normandie,

torn, vii, p. 108, pi. 8, figs. 11—15.
DITEEMAEIA ACUMINATA, If Orb. 1850, Prod. Pal6ont., p. 301.

T. Testa conicd, spird plus minusve elatd, lavi aut substriatd; apice acuminato ;
anfractibus (7, 8) ex apice ad aperturam magis d magis tumescentibus donee ultimus sub-
quadratus fiat ; infond facie dilatatd, in medio cavum infunbibuliformem ferente, ad peri-
phaeriam concentrice striatd. (Deslongchamps.)

Shell conical, spire more or less elevated, smooth, or slightly striated ; apex acute ;
whorls (7, 8) gradually increasing from the apex until the last whorl becomes subquadrate ;
the lower surface has a very deep but somewhat contracted cavity, which is concentrically
striated.

This is the most elevated or conical of the Great Oolite species. The last volution is
distinctly striated, the rib posterior to the aperture being very prominent ; the height and
basal diameter are about equal.

Locality. Great Oolite of Minchinhampton and Bussage ; Langrune, France.

TROCHOTOMA CONULOIDES, Desl. Plate X, fig. 16.

TROCHOTOMA CONULOTDES, Deslongchamps. 1842. Mem. Soc. Linn, de Normandie,

torn. Yii, p. 109, pi. 8, figs. 16—19.
DITEEMARIA D'Orb. Prod. Pal&mt., p. 301 .

T. Testa conicd, apice acuto; anfractibus (5, 6) concentrice striatis, planis ; ultimo
anfractu vix ad fasuram dilatato ; basi ad peripheeriam convexiusculd, striatd, in medio
profunde excavatd.

Shell regularly conical, apex acute ; whorls (5, 6) concentrically striated, flattened ;
the lower surface convex, striated, and deeply excavated.

The volutions are narrow and flattened, the encircling rib narrow and elevated ; the
figure is very oblique, the basal diameter exceeds the height by one fourth.

Our figure is somewhat reduced.

Locality. Great Oolite of Minchinhampton and Bussage ; Luc, Langrune, France.

GASTEROPODA. 83

TROCHOTOMA TABULATA. Plate X, figs. 17, 17 a.

T. Testa conicd, apice acuto, anfractibus (5) tenuissime striatis subquadratis, media
angulatis ; anfractu, ultimo subangulato ; basi planato, profunde excavatd.

Shell conical, apex acute ; whorls 5, very finely striated, step-like, and angulated in
their middle portion ; the last whorl is angulated, the base flattened and deeply excavated.

The sides of the volutions are nearly flat, both above and beneath the angle, which,
together with the srnallness of the encircling rib, fineness of the striae, and acute apex,
serves to distinguish it from T. calix or T. affinis, Desl., which is an Inferior Oolite species.
It is moderately common. Height 10 lines, basal diameter 12 lines.

Our figure is of medium dimensions.

Locality. Great Oolite of Minchinhampton.

TROCHOTOMA OBTTJSA. Plate X, fig. 15«, b.

T. Testa turbinatd; apice obtuso; anfractibus (5) convexiusculis, striatis, basi dilatatd,
media late excavatd; peripli&rid striata.

Shell turbinated ; apex obtuse ; whorls (5) rather convex, striated, the lower surface
dilated, its middle widely excavated, periphery striated.

The encircling rib is large but depressed, and contributes to give a convex aspect to
the whorls ; the striae are large, the general figure being more turbinated, or less regularly
conical than is usual with the Trochotomce, each advance of growth was equal to two thirds
of a volution : it is by far the most abundant of the genus. Height 10 lines, basal
diameter 13 lines.

Locality. Great Oolite of Minchinhampton.

TROCHOTOMA EXTENSA. Plate X, figs. 19a, 195.

T. Testa conicd; apice obtuso, depressd; anfractibus (4, 5) subangulatis, planis, et
leevibus; basi ampld, profunde excavatd.

Shell conical; apex obtuse, depressed; whorls (4, 5) subangular, flattened, and
smooth ; base wide, rather convex ; cavity large and deep.

This is by far the largest and most rare of the Great Oolite species, the base is
enormously wide, and the cavity very large. Height 16 lines, basal diameter 30 lines.

Locality. Minchinhampton.

84 MOLLUSCA FROM THE GREAT OOLITE.

TROCHOTOMA DISCOIDEA, Roemer, sp. Plate X, figs. 10, 10«, 10*5, lOe.

?TKOCHUS DISCOIDEUS, Roemer. 1836. Nordd. Oolith., p. 150, t. 11, fig. 12.
D'Orb. 1850. Prod. Paleont,, p. 354.
Bronn. 1848. Index Palseont., p. 1300.

T. Testa discoided, plano-convexd, basi concavd, lato-umbilicatd; anfractibus (3) depressis,
subconvexis, transversim lineatis, basi acutis ; aperturd transverse depressd, ovatd.
(Roemer.)

Shell discoidal, slightly convex, base concave, widely umbilicated ; whorls (3) depressed,
rather convex, transversely lineated, lines impressed by closely-arranged longitudinal and
very fine oblique striae ; lines upon the base acute j aperture depressed and excavated.

We have never been able to discover an open fissure upon this small species, but the
general figure agrees with this genus so well that we have not ventured to assign it to any
other. Four lines are visible upon the lower and seven upon the upper face of the last
volution, which is angular or step-like ; the first two turns are smooth and rounded : rare.
Height 3 lines, basal diameter 1\ lines.

Locality. Minchinhampton ; Coral Rag, near Hildesheim (Roemer).

STOMATIA, Lam. 1801.

STOMAX, Montfort. 1810.

Shell suborbicular or oblong, generally ear-shaped and depressed ; in most species the
spire is prominent, but not produced, nor elongated ; sometimes, however, it is very small,
marginal, and inconspicuous. Aperture mostly longitudinal; in some species nearly
orbicular ; in others much elongated ; always very large j its edges entire, united, at the
upper part, and scarcely modified or altered in form by any portion of the last volution.
Volutions from two to four. (G. £. Soivcrby.)

From the characters of the aperture and the presence of the carina, we have
ventured to assign the following shell to the genus Stomatia (Lam.), from most of the
recent species of which it differs in having a depressed spire, and the lines of growth and
spiral stria3 very regular, and sharply defined. Should other specimens afford further
generic distinctions, we would suggest the name Mega&toma for it.

GASTEROPODA. 85

STOMATIA? (MEGASTOMA), Buvignieri. Plate IX, fig. 32, 32 a.

8. Testa semiglobosd; spird parvd, depressd; anfractu ultimo transversim costulato, et
in media carinato, carind acutd, elatd, costis longitudinalibus densis, lineis tenuissimis
impressis notatis; aperturd magnd semilunari ; labio externo Jisso ?

Shell semiglobose ; spire depressed; last whorl with a mesial, elevated, acute carina,
crossed by longitudinal, narrow, elevated ribs — the ribs being impressed by fine encircling,
transverse lines ; aperture very large ; outer lip slightly notched. The shell above the
carina is flattened ; the ribs, which are perfectly regular, pass over the carina, and beneath
are decussated by fine transverse lines.

Locality. This rare shell, which attains the size of a small bean, has only been found
in the soft oolite beneath the planking on Minchinhampton Common.

We have dedicated this species to M. Buvignier, who has figured and described some
apparently congeneric forms under the name of Stomatella carinata and S.funata. (See
' Mem. Soc. Phil. Verdun/ 1843, p. 19, t. 5, f. 27—30.)

Family — FISSURELLID^E.

FISSUREI.LA, Lam. 1801.
FISSURELLUS, Montfort, 1810.

Shell conical, base entirely open, orbicular or oval ; apex central or subcentral, having
a foramen of an oval figure, central, or near to the anterior or shorter side ; surface usually
cancellated, or ornamented with ribs and lines ; margin generally thickened ; muscular
impression nearly continuous.

FISSURELLA ACUTA, Desl. Plate VIII, fig. 5, ba — c.

FISSURELLA ACUTA, Deslonffchamps, 1842. M&n. Soc. Linn, de Normandie, torn, vii,

pi. 7, figs. 22—24.
RIMULA — D'Orb. 1850. Prod. Paleont., p. 303.

F. Testa conicd, altd; basi subcirculari ; apice acuto, subcentrali; foramine subapiciali,
antice versato, swperne rotundato, inferne rimd angustd producto, striis longitudinalibus
parvis crebris, aliis transversis testam decussantibus. (Deslong.)

Shell conical, elevated, nearly circular; apex acute, nearly central; foramen a little
anterior to the apex, rounded above, narrow below; stria? longitudinal, small, closely-
arranged, crossed by others, transverse and less prominent. Height 3 lines, base 3 lines.

12

86 MOLLUSCA FROM THE GREAT OOLITE.

Locality. This little conical shell ranks with the rarest productions of the Great
Oolite ; the white stone of Eastcombs and Bussage have furnished the only known English
specimens : Langrune, France.

RIMULA, Defrance, 1827.

RIMULARIA, Defrance. 1827.
SIPHO, Brown. 1847.

Shell conical, base entirely open, oval ; apex curved more or less posteriorly ; surface
near the anterior border with a fissure, or oval foramen, usually placed upon a prominent
longitudinal rib ; the fissure does not reach the margin.

RIMULA TRICARINATA, Sow., sp. Plate VIII, fig. 2, 2a — c.

EMARGINULA TEICABINATA, Sow. 1826. Min. Con., t. 519, fig. 2.

Brown. 1847. Illust. Foss. Conch., p. 104, t. xlviii,

figs. 14, 14*.

Bronn. 1848. Index Palseont., p. 457.
D'Orb. 1850. Prod. Pal<§ont., p. 303.

R. Testa parvd, conicd; apice postice curvato, costis tribus magnis anticis, aliis minoribus
posticis, lineis interstitialibus, transversis numerosis.

Shell small, conical ; apex curved posteriorly, with three large diverging, anterior ribs ;
other smaller ribs occupy the sides and posterior part of the shell ; the interstitial spaces
have numerous tranverse lines.

In this species, as in the R. Elotii, the fissure is of a lengthened oval figure, and is cut
out of the middle and more elevated rib. Having examined the original specimen figured
in the Mineral Conchology, we are enabled to assign it to the present genus without
hesitation; in two of the specimens on the same tablet, an imperfection at the anterior
extremity of the mesial rib gave them somewhat the aspect of an Emarainula, and may have
been the reason, probably, for assigning both this and R. clathrata *wrk that genus.

Locality. Ancliff: two specimens have, likewise, been found at Minchinhampton.

RIMULA CLATHRATA, Sow., sp. Plate VIII, fig. 1, la — c.

EMARGINULA CLATHRATA, Sow. 1826. Min. Con., t. 519, fig. 1.
? GOLDFUSSII, Roemer. 1836. Nordd. Oolith., t. 19, fig. 23.

? Goldfuss. 1845. Petref., t. 167, fig. 15.

SIPHO CLATHKATA, Brown. 1847. Illust. Foss. Conch., p. 103, t. 48, figs. 1, 2.
RIMULA — Morris. 1843. Catalogue of British Fossils, p. 1 GO.

— Bronn. 1848. Index Palseont, p. 1088.

— — D'Orb. 1849. Prod. Paleont., p. 303.

GASTEROPODA. 87

R. Testa conicd; apice postice curvato; ambitu ovali; rimd angustd, costis majoribus
radiantibus (circa 18), minoribus tranversis decussatis.

Shell conical ; apex somewhat spiral, and curved posteriorly ; base oval, foramen
narrow, lengthened, and rather distant from the anterior margin ; ribs radiating (about 18
in number), crossed by others, smaller and transverse.

The indifferent condition of the original specimen will account for its having been
placed with Emarginula.

Locality. AnclifF and Minchinhampton ; at the latter place it occurs only in the bed
of planking : it is rare.

RIMTJLA BLOTII, Desl., sp., Plate VIII, fig. 3, 3«, 6, c.

EMAKGINTJLA BLOTII, Deslongchamps. 1842. Mem. Soc. Linn, de Normandie, torn, yii,

pi. 10, figs. 1 — 3.
If Orb. 1850. Prod. Pal£ont., p. 303.

R. Testa pared, crassd, conicd; apice postice curvato, lateribus subplanis; costis radi-
antibus magnis 15 etparvis 14 alternis; sulcis punctis tranversalibus magnis notatis.

Shell small, thick, conical ; apex curved posteriorly, the sides flattened ; ribs radiating,
15 larger and 14 smaller, alternating — the three larger anterior ones being the most
prominent ; the transverse sulci of the interstitial spaces are large.

This species bears a considerable resemblance to R. tricarinata; but it is more com-
pressed laterally, the three large anterior costae are less divergent, and the form of the base
is a longer oval. The R. tricarinata is likewise destitute of the smaller ribs, and has more
numerous transverse lines.

Locality. It occurs rarely at Ancliff; and is likewise scarce in the shelly roestone of
the Inferior Oolite at Leckhampton Hill, Cheltenham. A single specimen, badly preserved,
has also been procured at Minchinhampton. Colleville, Calvados.

EMARGINULA, Lam., 1801.

PATELLA sp., Linn.
EMARGINULUS, Montf. 1810.

Shell conical ; apex usually curved posteriorly, base entirely open, orbicular or oval ;
its anterior margin having a vertical fissure more or less lengthened ; surface ornamented
with ribs, and decussated.

MOLLUSCA FROM THE GREAT OOLITE.

EMARGINULA SOALARIS, Sow. Plate VIII, figs. 4, 40, b, c.

EMARGINULA SCALARIS, Sow. 1826. Min. Con., t. 519, figs. 3, 4.

— Brown. 1847. Illust. FOBS. Conch., p. 103, t. xlviii, fig. 5.

Bronn. 1848. Index Paleeont., p. 456.

D'Orb. 1850. Prod. Paleont., p. 303.
1 — Deal. 1842. Mem. Soc. Lin. Norm. vii. p. 125.

E. Testdparvd, conicd; ambilu suborbiculari; apice plus minusve postico; costis loevibus
radiantibus et transversis decussantibus ; rimd elongatd laid.

Shell small, conical ; base nearly circular ; apex elevated, more or less posterior ; ribs
radiating, smooth, transversely crossed by others. The radiating ribs are narrow, but
are somewhat larger than those which are transverse ; the mesial radiating rib bifurcates
near the margin, forming a lengthened and wide fissure.

Locality. Ancliff and Minchinhampton ; at the latter place it is very rare : Langrune.
Trance.

Family — PATELLID^E.

PATELLA, Linnceus. 1758.

PATELLAKIA, Lhwyd. Lith. Brit. Ich.
HELCION, D'Orbigny.

Shell ovately conical, with an oblong or oval base ; apex subcentral, or inclining towards
the anterior side ; internal surface smooth ; muscular impression horse-shoe shaped ; margin
of the aperture entire.

PATELLA CINGULATA, Gold/. Plate XII, figs. 4, 4a — d.

PATELLA CINGULATA, Goldfuss. 1843. Petref., t. 177, fig. 11.
HELCION D'Orb. 1850. Prod. Paleont., p. 358.

P. Testa conicd, ambitu ovali, vertice subacuto, elato, erecto, antemediano; striis conccn-
tricis confertis irregularibm.

Shell conical, base oval, apex subacute, elevated, erect, placed anterior to the middle
line of the shell, with encircling, irregular, closely-arranged striae.

This may be regarded as one of the most abundant and characteristic of the Patellae of
the Great Ooolite. It occurs in all the shelly beds, but more especially in the white stone
of Eastcombs and Bussage, near Brimscombe. The dimensions vary from the size of a
duck-shot to a diameter of seven lines ; and, from the great thickness of the shell, it is
usually well preserved. The height is equal to two thirds of the longer basal diameter.

GASTEROPODA. 89

PATELLA HUGOS A, Sow. Plate XII, figs. 1, la — g.

PATELLARIA SIMA, Lhwyd. 1760. Lith. Brit. Ich., t. 8, No. 436.1
THE PATELLITE, Park. 1811. Org. Rem., vol. iii, p. 50, t. 5, fig. 21.
PATELLA RUGOSA, Sow. 1816. Min. Con., t. 139, fig. 6.
Fleming. 1827. Brit. Anim., p. 288.

— Brown. 1849. Illust. Foss. Conch., p. 104, t. xlviii, fig. 18.
Morris. 1843. Cat. Brit. Foss., p. 155.

— ANCYLOIDES, Sow. 1824. Min. Con., t. 484, fig. 2.

Brown. Illust. Foss. Conch., p. 105, t. xlviii, figs. 27—29.

? — TESSONII, Deslong champs. Mem. Soc. Linn, de Normandie, vol. vii, t. 7, fig- 3.
HELCION RUGOSA, D'Orb. Prod. Paleont., p. 303.

P. Testa ovatd, postice convened, antice subconcavd, apice depresso, versus marginem
anticum inftexo ; costulis radiantibus crebris, interstitiis lineatis ; striis alteris transversis
decussantibus, antice congestis, testamgue corrugantibus, postice remotis.

Shell ovate, posterior side convex, anterior rather concave ; apex depressed, inclined
towards the anterior margin ; the longitudinal radiating ribs are closely arranged, with fine
lines between them, and decussated by encircling striae, which, upon the anterior side, are
corrugated or compressed closely together ; posteriorly they are remote.

The aspect of this shell varies considerably, even in specimens obtained from the same
quarry ; and these differences are irrespective of those produced by the various stages of
growth. Some approach to the circular form, and in such the apex is more central,
elevated, and less curved forwards ; others, which are a longer oval, have the summit more
beak-like and depressed. The different degrees of magnitude in the radiating costae, and
the depth to which they are impressed by the encircling striae, likewise contribute to the
varieties of aspect. The greater number of specimens obtained from the quarries at
Miuchinhampton Common have a rugose aspect, but those from the quarries situated to
the north of the vale of Brimscombe are usually different ; the shell becomes very thin,
the form is more depressed, and the surface is nearly smooth, the ribs being faintly marked,
and the encircling striae scarcely discernible. When very young, and not exceeding 6
lines in length, the figure is more depressed, of a longer oval, nearly smooth, and the apex
is turned, and even slightly twisted to the right side, constituting the Patella ancyloides of
the 'Mineral Conchology.' It is rare to obtain the shell so small; and the And iff
specimen, upon which the species was founded,, is, in common with all the Great Oolite
shells of that locality, extremely small, but the number of intermediate sizes obtained, leave
no doubt of its identity. It occurs, indifferently, in all the shelly beds. Our largest
specimen has a length of 2^ inches, a width of 2£ inches, and a height of 13 lines.

Locality. Minchinhampton Common ; Bussage ; Ancliff.

Found also in the Stonesfield slate (Sowerby) ; in the roestone of the Inferior Oolite at

1 " Patcllaria sima, fusci coloris, cancellata major. E lapicidina Stunfeldiensi," p. 24.

90 MOLLUSCA FROM THE GREAT OOLITE.

Leckhampton Hill, near Cheltenham (Buckman) ; and in the Great Oolite of Langrune,
Luc, Ranville, &c., Normandy {Deslongchamps).

The Patella Tessonii (E. Desl.), which is referred to this species with some doubt, was
obtained from the Inferior Oolite of Moutiers-en-Cinglais by M. Tesson.

PATELLA PARADOX A. Plate XII, figs. 2, 2 a, b.

P. Testa suborbiculatd, apice depresso, versus marginem anticum inflexo, latere antico
concavo, postico convexo ; costis radiantibus, elatis, rotundatis,undulatis,transversimstriatis,
et distantibus, costis posticis 9 magnis, later alibus obscuris, anticis congestis et corrugatis.

Shell suborbicular, apex depressed, turned towards the anterior margin ; anterior side
concave, posterior convex ; ribs radiating, large, distant, elevated, rounded, undulated and
impressed by transverse striae ; the posterior costae, about 9 in number, are large, those
upon the sides of the shell are depressed and obscure ; the anterior ribs are congested and
corrugated.

The general aspect of this singular shell reminds us of Patella rugosa, which it follows
somewhat in its varieties of aspect. When young, the few posterior costse are prominent,
but the sides of the shell are smooth, and the general figure is more depressed and
elongated ; the costae are much larger than in P. rugosa, more distant, and, in consequence,
much fewer ; and the entire shell has a wrinkled and very rugose aspect. The colours are
usually more or less preserved.

Locality. This may be considered as the most rare of the Minchinhampton Patellae.
The few examples obtained have been found in the planking, or in the equivalent white
stone of Eastcombs and Bussage. The young form, were it known only by a single
specimen, would probably be regarded as a distinct species ; the older specimens attain
nearly the dimensions of a middle-sized P. rugosa.

PATELLA SULCATA, Deslongchamps. Plate XII, figs. 3, 30, b.

PATRLLA SULCATA, Deslongchamps. 1842. M6m. Soc. Linn, de Normandie, vol. vii,

p. 115, t. 7, figs. 9—11.
HELCION — VOrb. 1850. Prod. Paleont., p. 272.

P. Testa subellipticd, conico-depressd ; apice recto; costis elatioribus radiantibus,
incequalibus, squammato-rugosis, sulcis profundis intcrpositis, margine subcrenato.

Shell subelliptical, conical, but depressed; apex erect; ribs elevated, radiating,
unequal, squamose or rugose, with deep interstitial spaces ; margin somewhat crenated.

The costae do not increase in size materially as they approach the margin, and the
additional ribs which are added with increase of growth equal the others in size. This

GASTEROPODA. 91

species possesses a general resemblance to P. Aubentonensis, but the ribs are much more
elevated, closely arranged, and rugose. The figure given by M. Deslongcharnps is more
elevated, but possesses no other essential distinctive character. Length 9 lines, breadth
7 lines, height 3 lines.

Locality. Rare, in the planking of Minchinhampton Common ; also found in the
Inferior Oolite of Port-en-Bessin (Deslony champs).

PATELLA STRIATULA. Plate XII, figs. 5, 5«, b.

P. Testa pared, conicd, obttisd ; ambituovali; costis radiantibus, tenuioribus, crebris,
fiexuosis et nodulosis ; lineis incrementi irregularibus.

Shell small, conical ; apex obtuse ; base oval ; with ribs radiating, fine, closely arranged,
waved, and nodulated ; lines of growth irregular.

This species is more elevated than P. Aubentonensis, and the apex more obtuse ; the
costse are likewise finer and more closely arranged.

Locality. In the soft shelly Oolite beneath the planking at Minchinhampton, where
it is rare.

PATELLA ROEMERI. Plate XII, figs. 6, 6 a, b.

P. Testa ellipticd, depressd ; apice subcentrali ; costis (30) radiantibus elatis ; lineis
interstitialibus numerosis ; striis transversis impressis ; lineis incrementi irregularibus
paucis.

Shell depressed, elliptical ; apex subcentral, with 30 radiating and elevated ribs ; inter-
stitial lines numerous, the whole being crossed and impressed by striae ; lines of growth
irregular and few.

This elegant little species is sometimes nearly discoidal, the central portion being most
frequently denuded of costse ; the form is more nearly circular than P. Aubentonensis, and
more depressed ; the costse are more elevated and less rounded, the interstitial spaces
being much deeper. The longer diameter rarely exceeds 9 lines, the elevation being
about 2.

Locality. It is moderately rare, but not confined to any one shelly bed, in the vicinity
of Minchinhampton.

PATELLA AUBENTONENSIS, Archiac. Plate XII, figs. 7, la, b, c, d.

PATELLA AUBENTONENSIS, Archiac. 1843. M6m. Soc. G£ol. de France, vol. v, p. 377,

t. 28, fig. 8.
HELCION — D'Orb. 1850. Prod. Paleont., p. 304.

92 MOLLUSCA FROM THE GREAT OOLITE.

P. Testa conicd, depressd; ambitu ovali ; apice acuto, antemediano ; costulis radi-
nntibm inoEqualibus irregularibm,flexuosis; striis transversis tenuissimis, irregularibus.

Shell conical, depressed ; base oval ; apex acute, placed anterior to the middle of the
shell; ribs radiating, unequal, irregular and waved; striae transverse, irregular, and
very fine.

The radiating ribs are sometimes only visible towards the margin ; the lines of growth
are few and uncertain ; as in the other Patella, the degree of elevation varies considerably,
the apex approaching more nearly to the anterior border in such as are depressed ; the
colours are sometimes partially preserved.

Locality. It is not uncommon, and occurs in all the shelly beds of the Great Oolite
near Minchinhampton. Our largest specimen is \\ inches in its longer diameter.

M. D'Archiac describes this species as occurring in the Great Oolite of Aubenton,
France, where it is rare.

PATELLA SUPRAJURENSJS, Buv. Plate XII, figs. 9, 90.

? PATELLA. SUPRAJDRENSIS, Buvignier. 1843. Mem. Soc. Philom. de Verdun (Meuse),

pi. 5, fig. 10.

P. Testa ovato-depressd ; apice subcentrali ; ambitu ovali; striis incrementi irregu-
laribus, distinctis ; striis concentricis tenuissimis crebris.

Shell ovate, depressed ; apex subcentral ; base oval ; lines of growth irregular, strongly
marked ; concentric striae closely arranged and very fine.

The absence of radiating costa? sufficiently separates this from P. Aubentonensis, the
general figure of which it nearly resembles ; the lines of growth are likewise much more
strongly marked.

Locality. It is comparatively rare, and is not confined to any of the shelly beds of the
Oolite at Minchinhampton. Found also in the Portland limestone of Varennes. (JSuv).

PATELLA ARACHNOIDEA. Plate XII, figs. 8, 8a, b.

P. Testa parvd, ellipticd et conicd; apice acuto centrali; costulis lonyitudinalibus minutis
et distantibus; lineis transversis numerosis, elatis et irregularibus.

Shell small, elliptical and conical ; apex acute, central ; with longitudinal, minute, and
distant ribs ; transverse lines very numerous, elevated, and irregular.

This small species has an elevated, acute apex, and displays under the magnifier a
beautiful net-work kind of surface ; the encircling lines are three or four times more dense
than the longitudinal elevations. The form is nearly that of Pileolus plicatus, but more
acute, and the character of the surface is altogether different.

Locality. The shelly beds at Quarhouse, which correspond to the planking of Min-
chinhampton Common, have furnished our specimens.

GASTEROPODA. 93

PATELLA INORNATA. Plate XII, figs. 11, 11«.

P. Testa elliptica, lavissimd, lateribus subcompressis ; apice elato, erecto, subaculo, et
postmediano; latere antico concavo, postico recto.

Shell elliptical, very smooth, the sides rather compressed; the apex erect, elevated;
subacute, and situated posterior to the middle of the shell ; anterior side concave, posterior
straight.

The figure is a lengthened oval, the anterior side being rather depressed and pro-
duced ; the concavity anterior to the apex, presents some resemblance to P. nitida
(Deslongchamps); but in that shell the anterior side is much the shortest. P. nitida is,
likewise, much more nearly orbicular and conical, the vertex being distinctly curved
forwards. The smaller specimens have a more depressed figure, the anterior cavity being
scarcely perceptible.

Longer diameter 10 lines, shorter diameter 8 lines, height 5 lines.

Locality. It occurs in all the shelly beds, but is not very common in the Minchin-
hampton district.

PATELLA NAN A, Sow. Plate XII, figs. 10, 10a.

PATELLA NANA, Sow. 1824. Min. Con., t. 484, fig. 3.

— Fleming. 1827. Brit. Anim., p. 288.

— Morris. 1843. Cat. Brit. Foss., p. 155.

— Brown. 1849. Illust. Foss. Conch., p. 105, t. xlviii, figs. 24 — 26.
HELCION NANA, D'Orb. 1850. Prod. Pateont., p. 303.

P. Testa parvd, elliptica, conicd, leevissimd; apice submediano, erecto, obtuso.

Shell small, elliptical, conical, very smooth ; apex nearly mesial, erect and obtuse.

The figure approaches near to P. cingulata, but it is usually a longer oval, and slightly
compressed at the sides ; in the young state the apex is more obtuse and depressed, the
form being then a longer oval. Many of the larger specimens are scarcely to be distin-
guished from P. cingulata, except by the absence of encircling stria3; and in badly
preserved specimens the striae are nearly obsolete. P. nana may, therefore, possibly be
only a variety of P. cingulata; they occur in the same beds, and are equally numerous. It
is true that good specimens of each species are sufficiently distinct; but knowing the
variations to which the shells of this genus are subject, we have thought proper to allude
to the possible specific affinity. The size never equals that of the larger specimens of
P. cingulata.

Locality. Minchinhampton Common : found also in the Oolite of Ancliff, near
Bradford, Wilts.

13

94 MOLLUSCA FROM THE GREAT OOLITE.

DESLONGCHAMPSIA, M'Coy,1 1849.

D. Testa orbiculatd, conicd; apice subcentrali versus marginem anticum inflexo; costulis
radiantibus, antico sulco lato longitudinali, in laminam appendiculatam producto.

Shell suborbicular, conical ; apex acute, subcentral, curving slightly forwards ; with a
wide longitudinal anterior sulcus, produced into a rounded lobe.

This genus has been separated from the Metoptoma of Phillips, on account of the pro-
longation of the anterior excavated side into a rounded process, which it is presumed does
not exist in that genus ; the surface is highly ornamented, but the Metoptomce are smooth.
Two species are known, one of which is the Patella appendiculata of M. Deslongchamps
(Mem. Soc. Linn, de Norm, vii, pi. XI, f. 1, 2); a somewhat oval shell, having simple,
large radiating costae, and the present species which has a cancellated surface. M. Deslong-
champs remarks, that in all the patelloid shells, except the Patella, the apex is turned
posteriorly, and if there exists any notch, furrow, or peculiar mark, it is always found on
the anterior side, and never on the side to which the apex is curved. The situation of
the furrow anteriorly, in the P. appendiculata, or on that side to which the apex of the
shell is turned, as in the Patella, would indicate an important modification in the mantle,
or some other organ of this mollusc.3

DESLONGCHAMPSIA EUGENEI, M'Coy. Plate XII, figs. 13, 13a.

D. Testa suborbiculatd, conicd; apice subcentrali, acuto, sulco antico latostriato; costulis
numerosis, longitudinalibus, transversisque decussantibus ; sulcis inter stitialibus prof undis.
Shell suborbicular, conical j apex subcentral, acute, anterior sulcus wide, striated ; ribs

1 Professor M'Coy having kindly forwarded his notes on this genus, intended for publication, we have,
with his permission, inserted them :

" DESLONGCHAMPSIA, M'Coy.

" Shell convex, radiatingly ridged ; apex eccentric towards the anterior end ; a concave spoon-shaped
hollow extends from the apex, gradually inclining to the outer margin, which it carries downwards into a
small rounded lobe.

"This shell, like Phillips's genus Metoptoma, has a triangular hollow extending from the apex to the
front margin, therein differing from Patella ; the present genus differs from Metoptoma in its ridged surface,
and from it and Patella in the front margin being produced downwards into a rounded lobe. This latter
structure would prevent the firm adhesion of the shell! This group has been recognised by M. E.
Deslongchamps, but not characterised, as he only knew one species. Having obtained another, perfectly
distinct, but identical in generic characters, I have characterised the genus, and dedicated it to M.
Deslongchamps, to whom I think the merit of recognising it in the first instance belongs. Any one who
reads the charming passage in M. Deslongchamps' Memoir (p. 119, vol, vii of the 'Mem. de la Soc. Linn,
de Normandie') will understand the pleasure with which I dedicate this species to his son Eugene, under
the name of Deslongchampsia Eugenei." — (M'Coy's MS. notes, 1849.)

2 In the specimen in the British Museum, (figured Plate XII, fig. 13,) the apex is imperfect, but the
direction of the striae appear to indicate a reverse or posterior direction of the apex, and, consequently,
analogous to the FissurellidcB.

GASTEROPODA. 95

elevated, numerous, transversely crossed by others of nearly equal size; and interstitial
spaces deep.

The anterior sulcus has a hollowed or spoon-shaped figure, and, like the other portion
of the surface, is cancellated ; but the longitudinal ribs are more closely arranged : the
number of ribs in the circumference is about 50.

Height 3 lines, basal diameter 6 lines, width of anterior sulcus at the margin 2 lines.

Locality. It is very rare, and has been obtained only in the white stone of Eastcombs
and Bussage : we are not aware that more than three examples have been found.

UMBRELLA? HAMPTONENSIS. Plate XII, figs. 12,

U. Testa pared, depressd; ambitw orbiculari; apice obtuso, depresso, centrali; costis
radiantibus, lavibus, panels, irregularibus,jlexuosis; sulcis interstitialibw separatis.

Shell small, depressed; base orbicular; apex obtuse, discoidal, and central; ribs
radiating, smooth, few, irregular, and waved ; separated by interstitial sulcations.

This little shell is sometimes perfectly flat, but usually somewhat convex ; it is
extremely thin, and as the under surface has not been fully disclosed, it must be referred
to Umbrella with some degree of doubt; it may, however, be probably considered as
related to the patelliform shells. The basal diameter rarely exceeds 4 lines.

Locality. The soft shelly Oolite beneath the planking usually furnishes it in the
neighbourhood of Minchinhampton : it is rare.

ORDER — OPISTHOBRANCHIATA, M. Edwards.
Family — BULLID^E.

BULLA, Linn.

Shell oval, ventricose, or cylindrical, generally thin and fragile, the last whorl more or
less enveloping the preceding ones ; spire umbilicated, or slightly produced ; aperture
large, the whole length of the shell, narrow above and dilated below ; outer lip sharp.

The specimens of this genus from the Great Oolite are very few, and in a condition less
satisfactory than could be wished. They have been obtained (with a single exception) from
the upper beds of the formation to the east of the town of Minchinhampton. These beds
usually consist of hard gray or brownish calcareo-siliceous sandstones, sometimes con-
cretionary, and contain Ceromyce, certain Pholadomya, and other shells which are never
found in the lower and more shelly beds. The Bullce are rare, but might possibly become
less so, were the stone brought more under the inspection of workmen and connoisseurs ;
but being lifted only in small quantities during the winter season, from little excavations

96 MOLLUSCA FROM THE GREAT OOLITE.

for road mending, and being, moreover, a very intractable material, none but a persevering
local collector can be expected to obtain even a partial knowledge of its fossil contents.
His reward will usually be, as in the present instance, mere imperfect casts, which contrast
unfavorably with the products of the richer and softer shelly beds.

BULLA UNDULATA, Sean. Plate VIII, figs. 8, 8a.

BULLA UNDULATA, Bean. 1839. Mag. Nat. Hist., p. 61, fig. 22.
Morris. 1843. Cat. Brit. Foss., p. 140.

S. Testa ovatd, ventricosd; apice umbilicato ; umbilico contracto ; labro inferno
sinuato ; aperturd magnd, superne angustatd, it/feme dilatiore ; striis increment numerosis,
longitudinaliter undatis.

Shell ovate, ventricose ; apex umbilicated ; umbilicus contracted ; inner lip sinuated ;
aperture large; narrow above, wider below; stria3 of growth numerous, longitudinally
undulated.

Breadth, two thirds of the length.

The specimen figured by Mr. Bean in the ' Magazine of Natural History,' from the
Cornbrash of Yorkshire, is about half as large again as the shell here described, and the
inner lip is not so much sinuated ; but in other respects it is very similar.

The general features of this shell bear a considerable resemblance to the Butta dongata,
Phillips, ' Geology of Yorkshire,' pi. iv, fig. 7 ; but it is much less elongated than that
species.

Locality. Our specimen was obtained from the upper portion of the Great Oolite
formation, in a bed of hard brown shelly sandstone, 95 feet above the Fullers-Earth, one
mile and a half east of Minchinhampton. Rare.

BULLA LOLIOLUM. Plate VIII, figs. 16, 160, 163.

B. Testa cylindro-ventricosd; aperturd angustd, basi subdilatatd, vertice. subcontracto,
profunde excavate, margine elato, et rotundato.

Shell cylindrical, but ventricose ; aperture narrow, its base rather dilated, apicial cavity
somewhat contracted and deeply excavated; the mamillary apex of the whorls being
large, and rising considerably from the base of the cavity, but not so high as the outer
margin ; margin of the cavity elevated, narrow, and rounded.

The figure is nearly barrel-shaped, both the extremities appearing truncated and
narrower than in the middle part. The character of the apicial cavity resembles that of
several species of Cylindrites, figured upon the same plate; we have not been able to expose
the base of the columella ; but, judging from the general figure of the shell and of the

GASTEROPODA. LifoM^ 97

aperture, we prefer to regard it as a Sulla, Upon comparing approximate forms it will
be found that the figure of the base and cavity of the vertex is much wider than in
C.pyriformis; the cavity is much more contracted and deeply excavated than in C. bul-
latus; a third shell, which more nearly approximates in form to our species, is the
Sulla Hildesiensis, figured by Roe'mer, (Verst. Nord. Ool. Geberges, t. ix, fig. 26,) in
which, however, the form appears to be more elongated and the aperture more expanded
towards the base.

Our shell would seem to be rare ; we have obtained it in one small excavation only,
about 100 feet above the Fullers-Earth, in concretionary sandstone: the disintegrating
action of frost has enabled us to detach two specimens, and we have vainly endeavoured to
extricate several others from a matrix harder than themselves.

Axis 7 lines, transverse diameter 5^ lines, diameter of the cavity 2 lines.

Locality. A superficial excavation one mile east of Minchinhampton.

Fam ily — ACT^E o N i D IE .

CYLINDRITES — Nov. gen.

ACTVEON sp., Sow., D'Orb.

Testa subcylindricd vel ovatd, spird parvd ; anfractibus pier unique plants, marginibus
acutis, anfractu ultimo cylindraceo, aperturd elongatd, superne linearis, in/erne Integra
p.t rotundatd; columelld ad basim cortortd, labro dextro tenui eld basim crassiori.

Shell smooth, subcylindrical or ovate ; spire small ; whorls usually flattened, with acute
margins ; the last whorl cylindrical ; aperture lengthened ; linear above ; rounded and
entire at the base ; columella rounded, twisted near to the base, and slightly directed
outwards ; right lip thin, but thicker at the base.

The cylindrical figure, flattened and nearly concealed volutions, their acute margins,
the linear aperture and columella directed outwards at the base, are the characters which
entitle this group to be separated from Actaeon (Tornatella Lam.), and constituted a new
genus, it is in fact a Pyramidella in all but the basal notch ; some of the species will be
found to approach to the Cones, others the Bullae, in each case more nearly than to Actaeon.
Species of this genus also occur in the Inferior Oolite, but they are perfectly distinct from
those which are here described.

All the species of this genus have smooth shells ; in Actaeon most of the species are
transversely striated or punctato-striate.

Mr. Sowerby, in the description of Action cuspidatus, remarks, " So novel is the
contour of this little shell, that it is with difficulty compared to any before known ; it
agrees, however, with the essential characters of Actaeon, but differs in general form, and

98 MOLLUSCA PROM THE GREAT OOLITE.

in having a plain surface ; it comes nearer in shape to Volvaria, but that has a truncated
or notched base, and crenated lip to the aperture, besides several plaits upon the columella."

It has been proposed to form a new genus of it, to be called Cylindrites, but the
following species (A. acutus) having a conical spire, connects it with Action Note. 'Min.
Con.' 5, p. 77, 1825.

Notwithstanding their general resemblance to Actseon, we believe the species here
described to be generically distinct from the typical forms of that genus, and have there-
fore proposed to retain the name Cylindrites for them.

The genus may be divided into two sections :

A, Species with the spire elevated and acute.

B. Species with the spire depressed and mammillated.

The species belonging to the second section appears to pass into the Acteonellse of the
cretaceous system.

A. Species with the spire elevated and acute.

CYLINDRITES ACTJTTJS. Sow. sp. PI. VIII, fig. 9, 9 a, b.

ACTION ACTJTUS, Sow. 1824. Min. Con., t. 455, fig. 2.
— — Morris. 1843. Cat. Brit. FOBS., p. 138.
D'Orb. 1850. Prod. Paleont., p. 299.
Bronn, 1848. Index Palseont., p. 10.

Testa subcylindricd, spird conicd, apice acuto, anfractibus (4) planis sen subconvexis ;
anfractu ultimo margine rotundato.

Shell subcylindrical, spire conical, apex acute ; whorls (4) flat or slightly convex ; the
last volution rounded at its upper margin.

Locality. This shell occurs in much greater numbers than all the individuals of the
other species put together ; it may, in fact, be considered as one of the most common
univalves in the Great Oolite near Minchinhampton.

It occurs in the Oolite at Anclifle, Wiltshire, whence the original specimens were
obtained, which are figured and described in the ' Mineral Conchology,' and Mr. J. de C.
Sowerby has kindly allowed us the use of the same for examination and comparison.

CYLINDRITES COSPIDATUS. Sow. sp. PI. VIII, fig. 10, 10 a.

ACTION CUSPIDATUS, Sow. 1824. Min. Con., t. 455, fig. 1.
Morris. 1843. Cat. Brit. Foss., p. 138.
D'Orb. 1850. Prod. Paleont., p. 299.
— Bronn. 1848. Index Paheont., p. 10.

TOKNATELLA CUSPIDATA, Deslongchamps. Mem. Soc. Linn, de Normandie, vol. vii,

p. 136, t. x, figs. 25, 26.
Brown. Illust. Foss. Conch., p. 85, t. xliii, figs. 11, 12.

GASTEROPODA. 99

Testa cylindricd, spird parvd sub-inversd, apice mammittato ; anfractibus angustisplanis ;
anfractu ultimo margine rotunddto.

Shell cylindrical ; spire small, somewhat inversed in the latter volutions ; apex iiiaia-
millated ; volutions narrow, flattened ; the last one rounded at the upper margin.

The upper margin of the last whorl rises as high as the one or two preceding ones,
leaving their edges exposed so that the small mammillated apex and one or two first
whorls seem to rise from a cavity. In the character of its spire this shell forms a passage
to the remaining species, in none of which does the apex of the spire rise higher than the
margin of the last whorl, the vertex is consequently more or less bowl-shaped or concave,
the volutions never being entirely concealed, but exhibiting their upper edges.

This is a rare shell, and, with the preceding species, is found indifferently in all the
beds of shelly oolite belonging to this Formation.

Locality. Minchinhampton Common ; AncluT, Wiltshire ; Langrune, France.

CTLINDRITES ANGULATUS. PL VIII, fig. 11, 11 a, 6.

Testa cylindricd ; spird mediocriter elatd, sub-concavd; apice acuto ; anfractibus (8)
angustis superne angulatis.

Shell cylindrical ; spire moderately elevated, with rather concave sides, and an acute
apex ; volutions eight, narrow and angular in their upper part.

The general figure of this shell is somewhat shorter than C. acutus, the volutions are
very narrow and angular, which, together with the somewhat concave spire, give it a well-
marked form ; it is more common than the last species.

Locality. The upper beds of the Great Oolite near Minchinhampton.

CTLINDRITES ALTCS. Plate VIII, figs. 12, 12a, b.

C. Testa cylindricd, subfusiformi, spird elatd; anfractibus (8) planis latis.

A cylindrical, subfusiform shell, with an elevated spire, and eight flattened, and rather
broad, volutions.

In this species the spire is flattened with an acute apex, which is equal in length to a
third portion of the entire shell.

Locality. Minchinhampton Common. It is moderately rare.

100 MOLLUSCA FROM THE GREAT OOLITE.

B. Species with the spire depressed and mammillated.
A. CYLINDEICI.

CYLINDRITES GYLINDRICUS. Plate VIII, figs. 19, 19a, b, c.

C. Testa cylindricd, elongatd, truncatd; spird depressd, vel obsoletd, vertice sulconcavo;
anfractibus angulaiis, anfractu •ultimo margine superiore acuto.

Shell cylindrical, lengthened, truncated; spire depressed, almost obsolete j vertex rather
concave ; volutions angular, the last one with the upper margin acute.

This is the most elongated and truncated species of the group, and might easily be
mistaken for a specimen with an imperfect spire : in well-preserved specimens the apex may
be observed to consist of two volutions, which rise above the others, forming a mammillated
summit; the base of the shell is much contracted and lengthened.

Locality. It is rare, and has been found only in the "planking" of Minchinhampton
Common.

CYLINDRITES EXCAVATTJS. Plate VIII, figs. 17, \la, b.

C. Testa cylindricd, truncatd; spird inversd, apice mammillato, vertice mac/no profunde
excavato; anfractibus numerosis, marginibus acutis notatis; anfractu ultimo subconvexo,
margine superiore acuto, subcontract; ceteroB nota desunt.

Shell cylindrical, truncated; spire inverted; apex mammillated, vertex large, deeply
excavated ; whorls numerous, their upper margins acute ; the last whorl somewhat convex,
with an acute margin, and slightly curving inwards. Base not seen.

The specimen being rather imperfect at the base prevents our ascertaining with
exactness the length of the species, which would appear to be intermediate to C. bullatus
and C. Thorcntei, but is certainly less elongated than the latter species ; the vertex is large
and very deeply crateriform, the apex not rising much above the centre of the deep con-
cavity, and not so high as the margin of the last volution, the edges of the numerous whorls
being visible in the concavity.

Locality. This example and a section of another are all which have been obtained ;
they occurred in the upper series of the Great Oolite formation, a little higher than the
hard cream-coloured limestone, and in a rock of nearly equal compactness, two miles east
of Minchinhampton, on the road to Cirencester ; the same rock, also, contains C. acutus
and C. angulatus, but the intractable nature of the material renders it extremely difficult to
obtain good specimens.

GASTEROPODA. 101

CYLINDRITES BREVIS. Plate VIII, figs. 13, I3a, b.

C. Testa parvd, cylindro-truncatd, apice amplo, piano, margine acuto ; lateribus planis ;
apertura ad basin sub-expanso.

Shell small, truncated, cylindrical, vertex large, flattened, its margin acute ; sides of
the shell flattened, marked with lines of growth ; aperture moderately expanded towards
the base.

This is the most truncated species of the genus in the Great Oolite. The vertex is
very wide, almost perfectly flattened ; but the acute edges of the volutions are visible, and
likewise the minute mamillary apex. These characters, together with the short figure,
serve to distinguish it from C. cylindricus, Plate VIII, fig. 19, the shell which most nearly
approaches to it. Axis 5 lines, diameter of vertex 3 lines.

Locality. Minchinhampton Common, where it is very rare.

CYLINDRITES THORENTI, Buvign,, sp. Plate VIII, figs. 22, 22<z, b, c.

BULLA THORENTEA, Buvignier. 1842. Geol. des Ardennes, p. 535, t. v, fig. 9.

Buvignier. 1843. Mem. Soc. Philom. Verd., ii, t. 5, fig. 11.
D'Orb. 1850. Prod. Pale"ont., p. 304.

— ELONGATA, Thorent. Mem. de la Soc. Geol. de France, iii, p. 258. (Not
Phillips, Geol. of Yorkshire.)

C. Testa subcylindricd, lateribus convexiusculis, spird pared, depressd, contractd; anfrac-
tuum marginibus solum exsertis; apertura angustd, columelld ad basin uniplicatd.

Shell subcylindrical, the sides somewhat convex, smooth, or slightly marked by the
lines of growth ; spire small, depressed, and contracted ; the whorls with their margins
only visible ; aperture narrow, basal fold of the columella large.

The apicial excavation is more contracted than in either of the other species ; the apex
is large, but does not rise quite so high as the outer margin; the shell, in its general figure,
is elongated and contracted at both the extremities. Axis 9 lines, greatest transverse
diameter 4 lines, diameter of the terminal excavation 1 line.

Locality. Minchinhampton Common ; it occurs in the bed of planking, but is
very rare.

M. A. Buvignier states that this fossil is found in the white limestone of the Great
Oolite in the environs of Rumigny. M. Thorent has also found it near Aubenton, and
mentions it in the Memoir above referred to, under the name of Sulla elongata, as
occurring in the Coral Rag ; this is considered to be an error by M. Buvignier, as the bed
containing it, in following its course into the Ardennes, is undoubtedly beneath the
Oxford Clay.

14

? •

GASTEROPODA.
C

, * ' _£

7 JL^ * ~* ^ - -*-

, MOW tMcnW JMM rtJKCCO.

Shell ovately oblong; spire rather elevated; the last whori large and
aperture sometimes as long as the last whorl, narrow in its posterior, wider in
put ; lips continooBB and Terr thin, the inner lip not reflected upon the i

The genus Cfriculvg was established by Cape. Brown, «pon the recent
and was afterwards used to comprise certain species of recent a*d basil shells, previously
referred by authors to Battm* Ittatm, far.1 Although the general form of the shells thas
classed together is somewhat ••"I*"' this character cannot always be caasidaed as
definite, inasmuch as the animal inhabitant of the fossil species may hare BMkanaftf cBfland
from the recent type. Ale. d'Orbigny, in recognising the generic duferences of some allied
forms, described as Tbnetetla, subsequently proposed in the ' Prodrome de Paleontologies
the name Jctmtmimt for their reception. The genus OrtAottomm, instituted by Deshayes,
includes an alh'ed series of shells, and connecting them with Jttftm aid Q£*aVifc», if we
may judge from the figures given in the ' Traite Elementaire de Conchyliologie,' but of
which no description has yet been published. Upon the ground, therefore, of the doubtful
generic identity of the recent Btttta obtosa with our fossil sheik, we have preferred to adopt
the name proposed by D'Orbigny.

ACTJ:OM> A OLIVJ;FOR*IS, Dvnker. sp. Plate \Tfl, fig. 14.

BCULA ouTjiTOuns, foe* and Dwtttr. 1 >. : ' . N .-rdd. Oolitlu t. T, fig. 3.
ACTIOSD.A — D'Ord. IS50. Prod. Paleont^ p. 353.

Shell ovatelv cyundrical, smooth ; spire rather small, or but Kttte produced ; whoris
rather convex ; the upper part of the aperture narrow.

Locality. Three examples only, varying much in size, are in our collection. They
occurred in the soft shelly stone (termed ovenstone) which overBes the weatherstooes at
Mmchinhauipton Common. It is a thinly-laminated deposit, which is sometimes nearly
made up of the valves of Ottrea acwmnata ; when these are absent, their place is occupied
by a multitude of small bivalves ; or, when these again become scarce, other and more
interesting forms occur, anioii^ which may be ranked the present species.

1 With regard to the comparative ^eavrto dii&reucw of the fauhr t»tKJm> the reader » nftmd h» aa
intewting p^per by Mr. Clark, published in the « Annals of Natural History,' for August 185*. from which
it appears, by a careful study of the structure of th« anuatls. that the generic subdtYiMM lalihlished by
some authors in this group are not well characterised.

1 04 MOLLUSCA FROM THE GREAT OOLITE.

ACT^ONINA? PARVULA, Roemer, sp. Plate V, figs. 11, lla, 12.

BUCCINUM PARVCLUM, Roemer. 1836. Nordd. Oolith., p. 139, t. xi, fig. 23.
ACTEONINA PAHVULA, If Orb. 1850. Prod. Paleont., p. 353.

A. Testa pared, ovato-conicd ; anfractibus (4) subconvexis superioribus, lateribus sub-
plants ; aperturd integrd dongatd, basi antj/ustatd, columelld contortd.

Shell small, ovately conical ; whorls (4) rather convex upon their upper portions, but
flattened upon their sides ; aperture entire, elongated ; base narrow ; columella twisted.

This little shell varies much in the length of the spire, specimens with narrow whorls
having a greater degree of convexity at their upper part than the others, but in all of them
the spire is shorter than the last volution. The largest specimens have an axis of 4 lines,
and a transverse diameter of nearly 3 lines.

Locality. Minchinhampton. It is found not unfrequently in all the quarries of the
district, and is common to the shelly beds.

ACTEONINA? BULIMOIDES. Plate VIII, fig. 15.

A. Testa ovato-elongatd, l&vi ; spird elatd obtusd ; anfractibus (3 — 4) subconvexis,
anfractu ultimo subcylindrico ; aperturd ovatd ; labro sinistro incrassato.

Shell ovately elongated, smooth, with an obtuse elevated spire ; whorls (3 — 4) some-
what convex, the last whorl subcylindrical ; aperture ovate ; inner lip thickened but not
broad.

The general figure is pupaeform ; the aperture in length does not exceed half that of
the entire shell.

This species has been provisionally arranged under Actaonina, although the great
thickness of the shell and expanded columellar lip do not well agree with that genus, and
rather approximate it with Bulimus. In general form it is very near to the Chemnitzia
Cornelia, D'Orb., ' Terr. Jurass,' t. 245, figs. 2, 3, from the Coral Rag of France ; and
both species may hereafter be found to belong to a genus distinct from Chemnitzia and
Acteeonina.

Locality. Minchinhampton. The specimen figured is the only example which has
come to our knowledge. The exact bed from which it was obtained is rather doubtful ;
but, judging from the matrix to which it is attached, we should infer that its position was
probably the upper portion of the Great Oolite.

GASTEROPODA. 105

ADDENDA.

AMMONITES GRACILIS, Buckman. Plate XIII, figs. 2, 2a ; and Plate I, fig. 3.

The description of this species is given at page 12, but the additional figure is here
given (Plate XIII, fig. 1,) to illustrate the form and general character of the more mature
shell, which differs considerably from the young state of it. (Plate I, fig. 3.)

It has the general form of Am. Charmassei, D'Orb. ; but the costae in A. gracilis are
not interrupted over the back as in that species, and the volutions are more fully exposed.

PTEROCERAS WRIGHTII. Plate XIII, fig. 1.

P. Testa fusiformi, tumidd ; anfractibus (6) rotundatis, l&vibus vel spiraliter striatis ;
ultimo ffibbo, transversim carinato ; carinis tribus rotundatis incequaliter remotis ; in digitos
longiores productis ; dorso ad angulum tuberculin duabus magnis ; labro quinque? digito,
digitis in estate adultd longissimis, Jlexuosis, recurvatis ; caudd longissimd arcuatd.

Shell fusiform, volutions 6, rounded and smooth, or faintly striated ; the body-whorl
inflated, and having three indistinct carinae developed on its upper surface, two of which
have a transverse prominent tubercle ; each carina leads to a digitate process ; labial wing
short, and terminating in four long slender flexuous digitations ; the first digitation ascends
close to the spire, and is attached to it ; it curves a little outwards, and then extends back-
wards an inch and a quarter beyond the apex of the spire, where it is broken off;1 the
second curves gently outwards and backwards ; the third is broken off three quarters of an
inch from the labial wing ; a remaining fragment indicates that it curved gently outwards,
and is represented by a dotted line in the figure ; the fourth passes forwards for an inch
and a half, and then curves outwards ; the canal is long, and arched backwards.

This fine fossil presents some points of resemblance to Strombus Oceani and S. Ponti,
Al. Brongniart, but the latter species has upwards of six carinae upon the last whorl. In size
it exceeds all the other Great Oolite examples of the Strombidce, and would seem to be very
rare. One specimen in the cabinet of the author, which has not the wing developed, and is
in other respects imperfect, is the only other known example. The present remarkable shell
is in the cabinet of Dr. Wright of Cheltenham, who has kindly communicated it, and to

1 There are traces of another digitatiou between the first and second above described, arising near to
the base of the former, but apparently broken off in the specimen figured.

106 MOLLUSCA FROM THE GREAT OOLITE.

whom it is dedicated. The cast of a shell figured by Goldfuss, t. 173, fig. 3, under the
name of Buccinum antiquorum, from the dolomitic Oolite of Bavaria, may possibly belong
to an allied species of the same genus.

Locality. Minchinhampton Common, in the beds of planking.

NERITOPSIS VARICOSA. Plate XI, figs. 20, 20a ; Plate XIII, fig. 5.

N, Testa neritiformi, ovato-oblongd, varicibus magnis longitudinalibus (circa 10 in
ambitu) , plus minusve elatis, et lineis numerosis, transversis, regularibus, elatis decussatis;
lineis cum striis densissimis perpendicularibus instructis.

Shell neritiform, ovately oblong; varices large, longitudinal (about 10 in a volution),
more or less elevated, decussated with numerous regular, elevated, and transverse lines ;
the lines are impressed with extremely fine and dense perpendicular striae ; the aperture
round.

A very thick ovate shell; the varices vary much in magnitude, so that in some
specimens they are nearly obsolete, but the large encircling lines are always conspicuous ;
the dense striations upon the lines are only visible under a magnifier.

Locality. Minchinhampton Common, where it is rare ; but it occurs not unfrequently
in the middle division of the Inferior Oolite.

TROCHUS SPIRATUS, VArchiac. Plate XIII, figs. 6, 6a. Plate X, figs. 2, 2a, 26.

TEOCHUS SPIEATUS, Archiac. 1843. Me"m. Soc. Geol. de France, torn, v, p. 3/8, t. 29
fig. 4« — c.

— Bronn. 1848. Index Palaeont., p. 1306.

— D'Orb. 1850. Prod. Pale"ont., p. 300.

T. Testa conicd, apice acuto, anfractibus (4 — 5) lateribus planis, subter medio sub-
angulatis, cingulis et lineis ornatis ; cingulis duobus, primo prope suturam approximato,
secundo majori, acuto, parte inferiore anfractuum sito ; lineis inter cingulos striis longitudi-
nalibus impressis ; basi lavi subconveasd, umbilico nullo.

Shell conical, apex acute, whorls 5, their sides flattened, somewhat angulated
beneath their middle portions, and encircled with bands and lines ; the bands are two in
number ; the first is wide, flattened, and placed close to the suture ; the second is pro-
minent, acute, forming a slight angle, and placed near to the base of the whorls ; between
the bands are several rather obscure encircling lines, which are indented by longitudinal
stria? ; base smooth, slightly convex ; no umbilicus.

The variation in the prominence of the bands, of the lines, and of the general state of
preservation, occasions considerable diversity in the aspect of this species, and requires

ANNELIDES. 107

several examples for its elucidation. The figures given at Plate X, figs. 2, 2«, 2(5, do not
exhibit the degree of angularity in the whorls and prominence in the bands which is
usually seen, and the longitudinal indentations are more than usually prominent The fine
encircling striae, although not shown in the specimen figured by M. D'Archiac, are par-
ticularly mentioned in the description of the species. The axial and basal diameters are
nearly equal.

Locality. It is tolerably abundant in the Minchinhampton district, occurring in all
shelly beds. Eparcy, France.

CLASS — ANNELIDES, Cuvier.

SERPULA OBLIQUE-STRIATA. Plate V, fig. 19, 19a.

L. Testa vermiformi, lateribus subcompressis, striis crebris irregularibw, obliquis antice
curvatis, in cristam longitiidinalemjlectis.

Shell vermiform, the sides slightly compressed, with striae closely arranged, irregular,
oblique, curved towards the anterior extremity, and bent into a longitudinal ridge.

Locality. It is rare, and occurs in the planking of Minchinhampton Common. Of the
few specimens seen, none exceed an inch in length, and 2 lines in their transverse diameter.

Note on the term "PLANKING."

It will be observed that the term "planking" is frequently used in stating the position and range of
fossils from Minchinhampton Common. This is a name applied indifferently by quarrymen to any stone,
the beds of which divide into thin horizontal slabs or planks. At Minchinhampton Common it is understood
to indicate the uppermost of that series of shelly beds which are known as the weatherstones, or stones which
are supposed to be capable of resisting the disintegrating action of frost. At Bussage and Eastcombs the
term white stone is employed by quarrymen when speaking of this bed, which at the two latter localities
has quite changed its mineral character. It is not improbable that this white stone is the English repre-
sentative of the pierre blanche of the Great Oolite of Normandy, which has yielded to M. Deslongchamps so
numerous a series of shells.

THE MOLLUSCA

THE "GREAT OOLITE OF YORKSHIRE.'

CLASS CEPHALOPODA.1

BELEMNITES GIGANTEUS, Schloth. Plate XIV, figs. 4, 4<z.

BELEMNITES GIGANTEUS, Schloth. 1813. Min. Taschenb., vii, p. 70.

Schloth. 1820. Petref., p. 45, No. 1.

ELLIPTICUS, Miller. 1823. Geol. Trans., 2d Series, ii, pi. 8, figs. 14—16.
1 Blainmlle. 1827. Mem. Belemn., p. 102.

? GLADIUS, Blainmlle. 1827. Me"m. Belemn., p. 86, pi. 2, fig. 10.

? COMPRESSUS, Sow. 1828. Min. Con., t. 590, fig. 4.

AALENSIS, Volts. 1830. Mem., p. 60, pi. iv, fig. 7.

Zieten. 1830. Pet. Wurtemb., pi. 19, fig. 1.
GRANDIS, Zieten. 1830. Pet. Wurtemb., pi. 20, fig. 1.

? COMPEESSCS, Phil. 1835. Geol. of Yorksh., vol. i, pi. 9, fig. 38.

AALENSIS, Phil. 1835. Geol. of Yorksh., vol. i, p. 124.
GIGANTEUS, Quenstedt. 1843. Flozg. Wiirtetnb., p. 329.
If Orb. Ter. Jurrass., pi. 14, fig. 15.
D'Orb. Prod. Paldout., p. 261.

B, Testa elongatd, compressd, crassd, acuminatd vel subinjlatd, postice acuminatd,
laleraliter sulcatd, antice dilatatd ; aperturd subovali. Alveolo angulo, 20 — 25°. (D'Orb.)

1 The following species of Mollusca are chiefly figured from the collection of Mr. Bean, and the
localities are given upon the authority of that gentleman. They include all the species of univalves
enumerated by Professor Phillips as occurring in the " Gray Limestone or Oolite of Cloughton, Brandsby,
and Cave" ('Geol. of Yorkshire,' vol. i, p. 123, &c.) ; and most of the specimens illustrated in this
Monograph appear to have been obtained from the Yorkshire coast. We have previously assigned our
reason for keeping the fossils of this locality distinct from those of the West of England, and shall merely
introduce the following general remarks by Prof. Phillips as bearing upon the subject. " The distribution
of the organic remains in the 'road-stone,' or slaty rock of Brandsby, Cave Oolite, and Inferior Oolite sand,
has yet been carefully ascertained at only a few points ; and the following observations will probably here-

CEPHALOPODA. 109

The guard is more or less elongated and compressed, sometimes conical and acumi-
nated towards the extremity ; at other times contracted near the apex, and enlarged rather
suddenly towards the alveolus ; the furrows, with which the extremity is marked, vary in
different specimens, both in their number, depth, and size ; there are generally two on the
dorsal part, one being prolonged much more than the other. The angle of the alveolar
cavity varies, according to M. D'Orbigny, from 20 to 25°, and is inclined towards the
ventral side. The aperture is generally of an oval form.

This is a very variable species, and has consequently been described under a great
variety of names. M. D'Orbigny, after carefully studying a large number of specimens
obtained from many localities, infers that the variety of form assumed by this species is
mainly to be attributed to sexual differences.

This species is generally considered to be characteristic of the Inferior Oolite in
England, Germany, and France ; but we have not been enabled to detect any specific
difference between the specimens forwarded by. Mr. Bean, from the Bath Oolite of
Yorkshire, under the names of B. Aalensis, B. compressus, and typical specimens of the
B. giganteus, obtained from the Brown Jurassic formation of Wurtemberg.

Locality. The Gray Oolite near Scarborough. • Inferior Oolite of the west and south
of England.1

AMMONITES MACROCEPHALUS, Schloth. Plate XIV, fig. 2.

AMMONITES MACROCEPHALUS, Schloth. 1813. Min. Taschenb., vii, p. 70.

Schloth. 1820. Petref., p. 70, No. 16.
Zieten. -1830. Pet. Wurteraberg, t. v, figs. 1, 4, 7 ;

t. xiv, fig. 3.

Quenstedt. 1843. Flozg. Wiirtemb., p. 363.
D'Orb. Ter. Jurrass., p. 430, pi. 151.
D'Orli. Prod. Paleont, p. 297.
? — TEREBRATDS, Phil. 1835. Geol. of Yorksh., vol. i, p. 1 16.

after receive several corrections. At present it appears to me that the ' road-stone ' is characterised by the
great abundance of Gervillia acuta and Crassina minima, and by the presence of Pholadomya acuticostata,
Rostellaria composita, and the genus Actaon. Where this rock is united with the Middle Oolite, as at
White Nab, these fossils commonly lie near the top ; where it is entirely deficient (as at Ewe Nab), they
are scarcely to be found. The top of the Cave Oolite (as under Gristhorpe Cliffs, at Ewe Nab, Owlston,
and Ellerker) is generally marked by abundance of Millepora staminea, and plates and spines of Echini,
and columnar joints of Pentacrinus caput Medusa. In the substance of the rock occur Belemnites, IsocarJia,
Pholadomya, Cuculleete, Pernee, Pinnae, Pldgiostoma, Pectines, and Terebratulce. So large a proportion of
its organic contents occurs likewise in the Inferior Oolite sand beneath, that it is difficult to point out what
seem to be characteristic."

1 We have had the opportunity of examining some fine specimens of tin species in the collections of
Mr. Bowerbank and Mr. Baber.

15

110 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

A. Testa discoided, subinflatd ; anfractibus involutis subcompressis, rotundatis, lateribm
26 — 30 costatis ; costis subrotundatis, obtusis, in media laterum hi vel trifurcatis continuis ;
aperturd semilunari, umbilico angmtato.

A discoidal, somewhat inflated, shell, with rather subcompressed volutions, and a narrow
and deep umbilicus ; margin of the umbilicus with 26 to 30 obtusely-rounded ribs, which
subdivide into two or three smaller ones in passing over the back ; aperture semilunar,
deeply impressed by the previous volution.

Locality. Near Scarborough.

AMMONITES BLAGDENI, Sow. Plate XIV, fig. 3«, b.

AMMONITES BLAGDENI, Sow. 1813. Min. Con., pi. 201.

CORONATES, Schloth. 1813. (Not Am. coronatus, Brug., 1789.)

Zieten. 1830. Pet. Wurtemb., t. i, fig. 1.
BLAGDENI, Phil. 1835. Geol. of Yorksh., vol. i, p. 124.
CORONATUS, Quenstedt. 1843. Floz. Wurtemb., p. 326.
BLAGDENI, If Orb. Ter. Jurrass., p. 396, t. 132.

A. Testa discoided, subcylindricd, late umbilicatd; anfractibus subdepressis, lateribus
declivibus, costatis ; costis 20 — 28 externe tuber culatis, subacutis ; dor so subconvexo, trans-
versim costato ; aperturd transversd, quadrangulari.

A discoidal, thick, and widely-umbilicated shell, formed of rather depressed quadran-
gular volutions, ornamented with 20 to 28 obtuse costse, terminating in spiniform tubercles
on the outer margin, and from each of which arise 3 to 5 smaller costse, which pass over
the back ; the aperture is transverse and quadrangular.

In some specimens the tubercles are sharper, differently formed, and more numerous
than in others.

In the shell figured, which measures about six inches diameter, there are 1 7 marginal
ribs ; in another specimen from the same locality (Scarborough), about one foot in diameter,
the number is 28. The numerical proportion of these costse, however, do not always
increase or decrease with regularity during the progress of growth. There are two
specimens of Am. coronatus, Zieten, in the British Museum, which are certainly identical
with our shell, in one of which the inner volution has 25, and the outer 27, marginal costae,
showing an increase; in the other specimen, the inner whorl has 21, and the outer only
17 costse, showing a decrease in their number. The specimen figured by M. D'Orbigny
has only 15 tubercular costae surrounding the umbilicus.

Locality. Near Scarborough ; Inferior Oolite, Somerset ; Bayeux, &c., France ; Brown,
Jura S, Stuiffien, Wurtemberg. (Quenstedt.)

GASTEROPODA. Ill

AMMONITES BRAIKENRIDGII, Sow. Plate XIV, fig. 1.

AMMONITES TRIPTOLEMUS, Bean. MS.
? BRAIKENRIDGII, Sow. 1813. Min. Con., t. 184.

VOrb. Ter. Jurrass., t. 135, figs. 2, 3.

A. Testa discoided, anfractibus (5 — 6) expositis, subrotundatis, costatis ; costis (30 — 36)
externe tuberculatis, in media laterum bifidis, subinde trifidis, continuis ; dorso subconvexo ;
aperturd transversd, subdepressd, externe angulatd.

A discoidal shell, with 5 — 6 exposed, somewhat rounded and costated volutions ; with
30 — 36 marginal costse, tuberculated externally, from each of which arise, about the
middle of the side, 2 and sometimes 3, rather obtuse smaller ribs, passing over the back ;
aperture wider than high, somewhat convex, with angular sides.

This Ammonite (forwarded to us with the name, A. Triptolemus), belonging to the
section Coronarii, appears to be intermediate to A. Humphriesianus and A. Braikenridgii,
with the latter of which it is the more closely allied, but differing from it by the smaller
costae (in the cast) not being wholly enveloped by the later volutions. We regard the
specimen figured as only the adult state of this species.

Locality. Near Scarborough.

CLASS — GASTEROPODA.

ALARIA PHILLIPSII, D'0r6. sp. Plate III, fig. 5; and Plate XV, figs. 15, 15a.

, ? ROSTELLAHIA HAMUS, var. ft, Deslongchamps. 1842. Mem. Soc. Linn, de Normandie,

torn, vii, p. 174, t. 9, fig. 36.

(See description, antea page 18.)

We have provisionally retained (page 18) M. D'Orbigny's specific name for the
Yorkshire shell, believing that the one figured as Rostellaria composita, by Phillips, pre-
sented certain differences from that described in the 'Min. Conch.,' occurring in the
Oxford Clay of Weymouth. But Mr. Sowerby distinctly states that he has received the
same species from near Scarborough, so that the differences may prove, when a larger
number of specimens shall have been examined, to be due merely to variations arising
from local conditions. The Yorkshire shell appears to be identical with Rostellaria fiamus,
var. ft, of M. Deslongchamps, cited above, from the Great Oolite of Rauville.

Locality. Near Scarborough. This species is also found in the Inferior Oolite of
Yorkshire, and in the same formation at Dundry and Bridport.

112 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

CERITHIUM BEANII. Plate XV, fig. 5.

C. Testa parvd, turritd, apice obtuso, anfractibus numerosis angmtis, subplanis, 5
costatis ; costis tuberculosis, tuberculis. circa 16 in ambitu ; costis inasqualilus ; suturi*
anfractibus profunde depressis,

Shell small, turreted; apex obtuse; volutions numerous, narrow, rather flattened,
encircled with five rows of costse; costae tuberculated, the tubercles being about 1C in a
volution ; ribs unequal ; the sutures of the whorls deeply depressed.

The third and fifth row of costae are less prominent than the others, the tubercles are
large and prominent, the length of a volution is less than half its transverse diameter, the
first two volutions are nearly smooth. Length 5 lines, transverse diameter 2 lines.

Locality. Near Scarborough.

NATICA ADDUCTA. Plate XV, figs. 17, 17«.

NATICA ADDUCTA, Phillips. 1835. Geol. of York., vol. i, t. 9. fig. 30.
— — Williamson. Geol. Trans., 2d Series, vol. v, p. 241 .

D'Orb. 18.50. Prod. Paleont., p. 264.

N. Testa olobosd, spird elatd, anfractibus (4) convcxis, superne rotunda/is, tsuluris
depressis, anfractu ultimo obliquo ; aperturd ellipticd, umbilico obtecto.

Shell globose, spire elevated and pointed, whorls (4) convex, with depressed sutures,
their upper portions rounded; the last whorl oblique; aperture large, elliptical; inner lip
with a covered umbilicus.

Natica grandis, Goldfuss, is our only Great Oolite species which approaches near to
this form ; but that shell, though greatly expanded, has not more volutions than the present
species, a fact which militates greatly against their identity. Length 9 lines, breadth
8 lines.

Locality. Great Oolite near Scarborough. The original specimen figured by Phillips.

NATICA PCNCTURA. Plate XV, figs. 18, 18«.

LITTOBINA PONCTUEA, Bean. 1839. Mag. Nat. Hist., p. 62, fig. 23.
— Morris. 1843. Cat. Brit. FOBS., p. 149.

N. Testa ovato-ventricosd, spird elatd, acutd ; anfractibus (6) convexiusculis, suturix
profunde impressis ; anfractu ultimo mat/no, punctate et cinoulato ; puncfis minutis, in

GASTEROPODA. 113

lineis transversis sed irreyularibus instructis, et lineis lenuissimis lonyitudinalibus trans-
versisque decussatis ; aperturd ovatd, labro extcrno tenui.

Shell ovately ventricose, spire elevated and pointed, whorls (6) rather convex, with deep
sutures ; the last whorl large, oblique, its surface punctated and cingulated ; punctee minute,
disposed in close but irregular arranged transverse lines ; they are decussated by numerous
very fine lines, both longitudinal and transverse ; the entire surface of the whorl is likewise
divided into several (4 or 5) encircling zones by as many lines, which are prominent,
rendering the spaces between them rather flattened; aperture ovate, outer lip thin, inner
lip rather flattened and excavated. Axis 11 lines, transverse diameter 8 lines.

The following is Mr. Bean's original notice of this species -.

" Shell turbinated, finely striated longitudinally and transversely, which, under a high
magnifier, gives it a very beautiful appearance ; whorls (6) rounded and well divided, the
body whorl occiipying one half the length of the shell. Aperture elliptical, pillar lip thick
and a little flattened, outer lip very thin ; length nearly f inch, breadth \ inch. The only
specimen procured from the Cornbrash ; but in the Inferior Oolite at Peak Hill it is not
uncommon. The specimens found there are larger, coarser, and the spive is not so much
produced."

Locality. Bath Oolite near Scarborough. In the collection of Mr. Morris.

NATICA ? (EUSPIRA) CINCTA. Plate XV, fig. 20.

PHASIANELLA CINCTA, Phillips. 1835. Geol. of York., vol. i, t. 9, fig. 29.

— Williamson. Geol. Trans., 2d Series, vol. v, p. 24 1 .

— D'Orb. 1850. Prod. Paleont., p. 267.

N. Testa ovatd, spird data, anfractibus (4) latis, superne carinatis, suturis canaliculatis ;
anfractu ultimo, bicarinato ; aperturd ampld, sulorliculari.

Shell ovate, spire elevated, whorls (4) broad, their upper portion with an obtuse
encircling carina ; the sutures channelled ; the last volution, with an obtuse carina,
occupying very nearly the middle of the volution ; aperture large and suborbicular.

The specimen placed at our disposal, by the kindness of Mr. Bean, is the original one
figured by Professor Phillips. It is rather compressed, which gives an appearance of
greater breadth to the shell than it possessed; the perfect form would approach our
E. pyramidata, from which it is distinguished by the second carina, which is not less
strongly marked than the upper one. Length 15 lines, breadth (uncompressed)
lines.

Locality. Great Oolite near Scarborough.

114 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

NERITA PSEUDO-COSTATA. Plate XV, figs. 3, Sa.

NEKITA COSTATA, Phillips. 1835. Geol. of York., vol. i, t. 11, fig. 32.

Morris. 1843. Catalogue, p. 154.
— PSEUDO-COSTATA, If Orb. 1850. Prod. Paltfont, p. 264.

JV. Testa parvd, subhemispharicd ; spird parvd, depressd; costis longitudinalibus,
regularibus rotundatis et lavibus.

Shell small, subhemispherical ; spire small and depressed ; ribs longitudinal, numerous,
regular, rounded, and smooth.

This shell appears to be identical with the well-known Inferior Oolite species.
Occasionally there is some little irregularity about the costs, and they are not always so
prominent as in the Yorkshire example. Size that of a moderate-sized pea.

Locality. Near Scarborough; also in the Inferior Oolite of Yorkshire. (Phillips.)

ETJLIMA L.&VIGATA. Plate XV, fig. 4.

E. Testa subulato-turritd, apice acuto ; anfractibus (11) subconvexis, obsolete costatis ;
anfractu ultimo symmetrico.

Shell subulate, turreted; apex acute; whorls (11) very slightly convex, smooth, or
with slightly-marked costse ; the last whorl symmetrical.

This little shell is very subulate, the length of the whorls being nearly equal to their
transverse diameter. This character, and the degree of convexity, separates it from a shell
very abundant in the Great Oolite at Minchinhampton, which we have described under the
title of Eulima communis. In that species the volutions are fewer, and the shell is more
pyramidal. Length 7 lines.

Locality. Near Scarborough.

CHEMNITZIA ? VETUSTA. Plate XV, fig. 7.

TEUEBBA VETUSTA, Phillips. 1835. Geol. of York., vol. i, t. 9, fig. 27.
— Williamson, Geol. Trans., 2d Series, vol. v, p. 241.
CHEMNITZIA — D'Orb. 1850. Prod. Paleont., p. 263.

C. Testa elongatd, turritd ; anfractibus (9) subconvexis, longitudinaliter costatis ; suturis
depressis ; costis circa 12, rotundatis leemgatis curvatis.

Shell turreted, volutions (9) rather convex, and longitudinally costated ; ribs, about 1 2
in a volution, rounded and smooth, bent from left to right ; the sutures of the volutions
deeply impressed.

GASTEROPODA. 115

The figure is lengthened, almost subulate, the convexity of the volutions being but
slight ; their transverse diameter exceeds their length by about one third. Longitudinal
dimensions 5 lines, transverse diameter 2 lines.

Locality. Near Scarborough.

CERITHIUM GEMMATUM. Plate XV, fig. 6.

C. Testa parvd, turritd ; anfractibus conveooiusculis, nodulis dngillatisque 5 ; nodulis
ovalis subdistantibus, circa 24 in ambitu.

Shell small, turreted ; volutions rather convex, encircled with five rows of nodules ;
nodules ovate, about 24 in a volution ; the rows of nodules are slightly curved, and the
last volution has from 7 to 9 rows.

The little nodules are regular, oval, their longer diameter being in the axis of the shell,
and they are distant from each other about their own diameter ; the number of volutions
are but few, apparently not more than 7. Length 7 lines, transverse diameter 2 lines.

Locality. Great Oolite near Scarborough.

CHEMMTZIA ? SCARBURGENSIS. Plate XV, fig. 8.

C. Testa magnd, pyramidato-turritd, lasvi ; anfractibus subplanis ad suturas subplicatis,
aut vittd latiusculd transversd, plus minusve convexd notatis ; aperturd ovatd, superne
strictissimd ; columelld maryinatd, supra subcallosd. ?

Shell large, pyramidal, turreted, smooth ; whorls nearly flat, but with one fold near to
their sutures, or with a broad transverse band more or less convex ; aperture ovate, very
narrow above ; columella marginated, thickened above.

The upper border of the whorls is slightly turned, their junctions are strongly defined.
The longitudinal diameter of the penultimate whorl is 7 lines, the transverse diameter
10 lines.

Locality. The specimen forwarded to us by Mr. Bean is from the dark-gray shale of
the Great Oolite near Scarborough. It is only a cast, and much compressed, so that the
specific character cannot be sufficiently determined.

TROCHTJS LECKENBII. Plate XV, figs. 21, 21a.

T. Testa conico-depressd, anfractibus (4 — 5) plants, costulis rotttndatis crebris cinctis ;

116 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

costulis transverse dense-striatis ; basi subconvexd dense costulatd et concentric^ striatd ;
umbilico nullo.

Shell conical, but depressed ; whorls (4 — 5) flattened, encircled with closely-arranged,
nearly equal rounded ribs ; the ribs are densely striated longitudinally ; the base is rather
convex, having very closely-arranged costas, crossed by concentric striae ; no umbilicus.

The junctions of the whorls are rather obscurely marked, and the lower margin of the
last whorl is angulated. The little ribs upon the base are very delicate and fine ; the outer
lip is imperfect, and does not enable us to describe the aperture ; but there is nothing
visible upon the surface of the whorls which would indicate that it belongs to Pleurotomaria.
The height is two thirds of the basal diameter.

Locality. Scarborough. In Mr. Leckenby's cabinet.

TROCHUS MONILITECTUS, Phil. Plate XV, figs. I, la.

TROCHUS MONILITECTUS, Phil. 1835. Geol. of York., vol. i, t. 9, tig. 33.
D'Orb. Prod. PalSont., p. 265.

T. Testa conicd, anfractibus (8) plants, suturis obscuris 4 — 5 costatis ; costis crebris
oblique crcnulatis.

Shell conical, volutions (8) flattened, with indistinct sutures, and encircled with 4 — 5
rows of costa3 ; the costae are closely arranged, and crenated obliquely.

The costae are large, the crenations closely arranged, and pass obliquely from left to
right. Length 4^ lines, basal diameter 3£ lines.

Locality. Near Scarborough. The original specimen figured by Phillips.

TCRBO ELABORATES, Bean. Plate XV, fig. 2, 2a ; and Plate IX, figs. 27, var.

TUBBO ELABORATUS, Lycett. 1850. An. Nat. Hist., vol. vi, p. 41C, pi. 11, fig. 1.

T. Testa subturritd, apice acuto, anfractibus (4) subconvemis, supcrne plants, in/erne
costulis lonffitudinalibus nmnerosis, aliis transversis decussantibus ; anfractu ultimo ventricoso
obliquo, aperturd ovatd.

Shell turreted, apex acute, whorls (4) convex, their upper borders flattened horizontally,
their sides and lower portions, with numerous longitudinal ribs, transversely decussated
by others ; last whorl oblique ; aperture entire, ovate.

The longitudinal ribs are rendered nodulous by those which are transverse ; the latter
are 4 or 5 in number ; the last volution has numerous encircling ribs, but the longitudinal
ones do not extend beyond the middle of the volution ; and when more than four whorls
have been completed, the last whorl is destitute of longitudinal ribs, but in lieu of them are

GASTEROPODA. 117

very fine densely-arranged longitudinal lines. The latter features are not exhibited by the
specimen from Scarborough ; but one, of more advanced growth, from the Inferior Oolite
near Minchinhampton, is much larger and more satisfactory. The upper portions of the
whorls are flattened, smooth, and even a little sulcated ; the inner lip is thin ; the base is
rounded, so that it neither exhibits the thickened lip of Littorina, nor the basal produced
form of Turbo. Length of the Scarborough specimen 5 lines, transverse diameter of the
last whorl 4 lines.

Locality. Great Oolite near Scarborough.

TURBO PHILLIPSII. Plate XV, figs. 12, 12a, b.

T. Testa trochiformi, cingillatdque costatd ; costis striato-nodulosis ; striis indentis ;
striis lonffitudinalibus numerosissimis ; anfractibus planis ; apertufd subrotundd, basi effusd,
v el production.

Shell trochiform, encircled with numerous ribs ; ribs striated and nodulous ; striae
longitudinal, very numerous, indenting the ribs ; volutions flattened ; aperture rounded ;
its base effuse, or produced anteriorly.

Two ribs, more prominent than the rest occupy the middle of the last whorl, and give
it rather an angulated figure ; the pointed extremity of the base removes it from the
Littorina. Longer diameter 9 lines, transverse diameter 7 lines.

Named in compliment to the author of the ' Geology of Yorkshire.'

Locality. Great Oolite near Scarborough.

PHASIANELLA LATITJSCULA. Plate XV, fig. 16.

P. Testa ovatd, spird acutd, elatd; anfractibus (6) latis, convexiusculis ; anfractu
ultimo subventricoso.

Shell ovate, spire acute, elevated; whorls (6) broad, convex, the last whorl rather
inflated.

This may be considered as a form connecting our P. elegans and P. tumidula ; the
spire is much more elevated than in the latter species, and the whorls are wider than in the
former. These remarks, however, are made with the reservation which must be exercised
in describing casts, for the specimen figured is in that condition. The length is 1 inch,
the transverse diameter 7 lines.

Locality. Near Scarborough.

16

118 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

PHASIANELLA STRIATA, Sow. Plate XV, fig. 19.

MELANIA STRIATA, Sow. 1814. Min. Con., tab. 47.

PHASIANELLA STRIATA, Sow. Min. Con., 1834. Index, p. 5.

TEREBHA Lonsdale. Geol. Trans., 2d Series, vol. iii, p. 275.

Morris. 1843. Cat. Brit. Foss., p. 163.
MELANIA Roemer. 1836. Nordd. Oolith., p. 158, t. 10, fig. 1.

— Gold/. 1844. Petref., p. 112, t. 198, fig. 12.
PHASIANELLA — D'Orb. 1850. Prod. Paleont., p. 333.

P. Testa turritd, ventricosd ; anfractibus (7) subconvexis et striatis ; striis (15) trans-
versis ; basiprofundestriatd; aperturd depressd, suborbiculari ,- columella excavatd.

Shell turreted, ventricose ; whorls (7) somewhat convex and striated ; striae but faintly
impressed, and about 1 5 in number upon each whorl ; the base Deeply striated ; aperture
depressed, nearly circular ; columella excavated.

The figure is subpyramidal, the length of the whorls being rather more than half their
transverse diameter ; the sutures of the whorls are deeply marked, the base of the last
whorl is deeply grooved ; the base of the aperture is very wide, and the transverse diameter
of the aperture is nearly equal to the longitudinal. The length of the entire shell is about
3 inches, the transverse diameter through the last whorl is 21 lines.

Locality. Great Oolite near Scarborough. In the middle and west of England this
species occurs in the upper beds of the Inferior Oolite and Coral Rag.

ACTION, Montfort. 1810.
TORNATELLA, Lam.

Shell ovate, volutions few, transversely striated; spire obtuse; aperture narrow,
lengthened, entire ; columella spirally thickened at its junction with the inner lip ; outer lip
thin, smooth.

ACTION SEDGVICI, Phil. sp. Plate XV, figs. 9, 9a.

AURICULA SEDGVICI, Phil. 1835. Geol. of York., vol. i, t. 11, fig. 33.

Williamson. Geol. Trans., 2d Series, vol. v, p. 241.

Bronn. 1848. Index Paleeont., p. 136.
ACTEON D'Orb. 1850. Prod. Paleont., p. 263.

A. Testa parvd, ellipticd, transversim striato punctatd; striis crebris, punctis impressis ,-
spird subconicd, gradatd; anfractibus subplanis, ultimo injlatu ; aperturd elongato- ellipticd,
angustatd.

GASTEROPODA. 119

Shell small, elliptical, transversely striated, the striae numerous and punctated ; the spire
conical, step-like ; the whorls rather convex, the last inflated ; the aperture is an elongated
ellipse, narrow above and beneath.

The Yorkshire specimen, placed at our disposal by Mr. Bean, is much compressed
and imperfect, and has the spire somewhat less elevated than the following species, which
resembles one figured by M. Deslongchamps from the Inferior Oolite of Les Moutiers,
near Bayeux. The species has not been found in the middle or west of England.
Longitudinal diameter 5 lines, transverse 3 lines.

Locality. Great Oolite near Scarborough.

ACTION PULLUS. Plate XV, fig. 11.

? TORNATELLA PCLLA, Koch. 1837. Nordd. Oolith., p. 33, t. 2, fig. 11.
?? PULCHELLA, Deslongchamps. 1848. Mem. Soc. Linn, de Normandie, viii,

pi. 18, figs. 4a, 4 b. (striis remotis.)

A. Testa ovatd, spird elatd, subacwtd; anfractibus (6) convexiusculis, striis transversis
numerosis regularibus et punctatis ; anfractu ultimo subcylindrico ; aperturd ovatd.

Shell ovate, spire elevated, somewhat acute ; whorls (6) convex, the last whorl sub-
cylindrical ; aperture ovate ; the surface with numerous regular punctated encircling striae'.

As compared with A. Sedgvici, of which it may prove to be only a variety, this is much
more elongated, the length of the aperture but very slightly exceeding half of the entire
length of the shell; the volutions are convex, and of moderate breadth; the base is
rounded, but narrow. Length 3^ lines, transverse diameter 2 lines.

Locality. Great Oolite of Scarborough. It has not been found in the middle or west
of England.

ACT.EONINA, IfOrbigny.

ACT/EOMNA GIGANTEA, Desl. Sp. Plate XV, fig. 13.

TORNATELLA GIGANTEA, Deslongchampg. 1842. Me"m. Soc. Lin. de Normandie, vol. vii,

pi. 10, figs. 27, 28.
ACTEONINA DESLONGCHAMPSII, D'Orb. 1850. Prod. Parent., p. 299.

A. Testa ovato-turritd, spird elatd, apice acuto ; anfractibus subplanis, superne rotun-
datis; aperturd angustd, basi dilatatd ; columelld ad basin marginatd.

Shell ovate, turreted ; spire elevated, acute ; whorls rather flattened at their sides, but
rounded above ; aperture narrow above, dilated below ; columella marginated at its base.

The specimen forwarded to us from Yorkshire is only a cast, but there is no doubt of

120 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

its identity with the Normandy species, which is from the Great Oolite of Ranville. It
likewise occurs in the upper beds of the Inferior Oolite near Minchinhampton. Length
21 lines, breadth 10 lines; the aperture is about three fifths of the entire length of
the shell.

Locality. Bath Oolite near Scarborough.

ACT^ONINA GLABRA, Phil. sp. Plate XV, fig. 10.

ACTEON GLABER, Phil. 1835. Geol. of York., vol. i, t. 9, fig. 31.

Williamson. Geol. Trans., 2d Series, vol. v, p. 241.
UTRICULUS — Brown. 111. Foss. Con., p. 101, t. 47, fig. 30.
ACTEONINA GLABRA, D'Orb. 1850. Prod. Pale"ont., p. 264.

A. Testa subcylindricd, apice obtmo, spirdparvd; anfractibus (5) angustis, subconvexis ;
anfractu ultimo cylindrico ; aperturd angustd, basi effusd.

Shell subcylindrical, apex obtuse, spire small, whorls (5) narrow, rather convex ; last
volution cylindrical ; aperture rounded, and expanded beneath.

The spire is very blunt and depressed, the volutions being very narrow, and without the
slightest angularity. Length 8 lines, transverse diameter 4 lines.

Locality. Great Oolite near Scarborough. In Gloucestershire it is only found in the
Inferior Oolite.

ACTJEONINA TUMIDULA. Plate XV, fig. 14.

A. Testa parvd, spird exsertiusculd ; anfractibus angustis, rotundatis, suturis depresses ;
anfractu ultimo subcylindrico ; aperturd elongato-ovatd.

Shell small, spire depressed, volutions very narrow, rounded, their sutures deeply
depressed ; the last whorl gibbous ; aperture an elongated oval.

This species is shorter than any other of the genus with which we are acquainted. The
figure of the last whorl is only moderately cylindrical ; and the transverse diameter of this
portion is not much less than the entire length of the shell. Length 4| lines, transverse
diameter 3J lines.

Locality. Near Scarborough.

ANNELLIDA.
VERMICDLARIA NODUS, Phil. Plate XIV, figs. 8a, b.

VEHMICCLARIA NODUS, Phil. 1835. Geol. of York., vol. i, p. 124, t. 9, fig. 34.

V. Testa laevi, in spirant turbinatem convolutd, anfractibus (3) convexiusculis ; anfractu
ultimo ad basin convexo, et lined obsolctd submesd cincto.

Shell smooth, forming an obtuse turbinated spire, with three volutions, which are

GASTEROPODA. 121

rather convex ; the last whorl rounded towards the base, with an obscure encircling line
placed a little beneath the middle of the whorl ; aperture not exposed.

Locality. Scarborough, Westow, and Whitwell ; also in the Cornbrash. (Phillips.)

SERPULA PLICATILIS, Gold/. Plate XIV, figs. 5a, b, c.

SERPULA PLICATILIS, Goldfuss. 1833. Petref., p. 229, t. 68, fig. 2.

S. Testa laxd vel curvatd, lateribus subconvexis, l&viusculis, costulis arcuatis per paria
approximatis ; carind continud recta. (Goldf.)

Shell loose or unwound, irregularly curved, slender, rather convex, smooth ; the sides
have little, obscure, closely-arranged, curved costse, not visible upon the majority of
specimens ; the dorsal cariua is simple, continuous, but not much elevated or conspicuous.

This minute species was gregareous, a considerable number being clustered upon a
small Pecten.

Locality. Scarborough.

SERPULA SULCATA, Sow. Plate XIV, fig. 6.

SERPBLA SULCATA, Sow. 1829. Min. Con., t. 603, figs. 1, 2.

S. Testa sublaxd aut curvatd, leevi, subcarinatd; carind dorsali l&vigatd; sulcisque
angustis carinee approximatis ; lateribus subplanis.

Shell partially unrolled, curved, smooth ; dorsal carina smooth, with a narrow sulcus
on each side of it ; sides of the shell rather flattened ; lines of growth visible upon different
portions of the surface.

The mode of growth in this species appears to have been very irregular. In its young
state it was flattened at the sides, but subsequently became much more rounded ; and the
figure of the aperture is nearly orbicular.

Locality. Scarborough. Inferior Oolite near Stroud.

SERPULA IXTESTINALIS, Phil. Plate XIV, fig. 7.

SERPULA INTESTINALIS, Phil. 1S35. Geol. of York., vol. i, p. 110, t. 5, fig. 21.

8. Testa sublaxd, latvi, compressimculd, sulco leeviter depresso, superne et inferne sitd.

Shell smooth, partially unrolled, somewhat compressed above and beneath with a slight
longitudinal sulcus in the middle of the two flattened sides.

This species is destitute of a carina, nor are any lines of growth visible ; the sulcations
are only to be seen upon the unrolled portion of the shell.

Locality. Bath Oolite, Scarborough ; also in Oxford Clay and Cornbrash. (Phillips.)

LIST OF
AUTHORITIES REFERRED TO IN THIS WORK.

ARCHIAC, V. D'. 18-43. Description Geologique du Departement de 1'Aisne. Mem. Soc. Geol. France,

tome v. 4 to, Paris.

BLAINVILLE, D. DE. 1827. Memoire sur les Belemnites. 4to, Paris.
BRONN, H. G. 1836. Uebersicht und Abbildungen der bis jetz bekannten Nerinea-arten, Neues Jahrbuchf

1836, p. 544.

1835—38. Lethaea Geognostica. 2 vols. 8vo, and Atlas 4to, Stuttgard.
1849. Index Palaeontologicus. 3 vols. 8vo, Stuttgard.
BROWN, Capt. T. 1834 — 49. Illustrations of the Fossil Conchology of Great Britain and Ireland.

4 to, London.
BUVJGNIER, M. A. 1843. Sur quelques Fossiles nouveaux, &c. Mem. Soc. Philomath., Verdun.

2 vols. 8vo.

CONYBEARE and PHILLIPS. 1816. Outlines of the Geology of England and Wales. 8vo, London.
DESHAYES, G. P. 1835 — 45. Lamarck's Hist. Nat. des Anim. sans Vertebres. 3d Edition.

1840 — 50. Traite Elementaire de Conchyliologie, &c. 8vo, Paris.
DESLONGCHAMPS, E. 1842 — 48. Memoires de la Societe Linneenne de Normandie. Vols. 7 and 8,

4to, Caen.

DE HAAN. 1825. Monographic Ammoniteorum et Goniatiteorum Specimen, &c. 4to, Leyden.
D'ORBIGNY, ALCIDE. 1848 — 50. Paleontologie Franchise, Terrains Jurassiques. 8vo.

1850. Prodrome de Paleontologie Stratigraphique. 1st vol., 8vo, Paris.
FITTON, Dr. W. H. On the Stonesfield Slate. Zool. Journal, vol. iii.
FLEMING, Rev. Dr. J. 1828. History of British Animals. 8vo, Edinburgh.
GOLDFUSS, A. 1826— 44. Petrefacta Germaniee. 3 vols. foL, Dusseldorf.
IBBETSON and MORRIS. 1847. Notice of the Geology of the Neighbourhood of Stamford and Peterborough.

Report Brit. Association. 8vo, London.
KOCH and DUNKER. 1 837. Beitriige zur Kenntniss des Norddeutschen Oolithgebildes und dessen Versteine-

rungen. 4to, Brunswick.

LLWYD, E. 1760. Lithophylacii Britannici Ichnographia. 8vo, Oxford.

LONSDALE, \V. 1832. On the Oolitic District of Bath. Trans. Geol. Soc. London. Vol. iii, pt. 2.
LYCETT, J. 1848. On the Fossil Conchology of the Oolitic Formations in the vicinity of Minchinhampton,

Gloucestershire. Annals and Mag. Nat. Hist., 2d Series, vol. ii, p. 248.
— 1847. On the Mineral Character and Fossil Mollusca of the Great Oolite. Geol. Proc., 1847,

p. 181.

124

AUTHORITIES REFERRED TO IN THIS WORK.

MARCOU, J. 1848. Recherches Ge'ologiques sur le Jura Salinois. Mem. Soc. Geol. France, 2de Se"rie,

vol. iii.

MORRIS and LYCETT. 1850. On Pachyrisma. Quart. Journ. Geol. Soc., vol. vi, p. 399.
PHILLIPS, J. 1835. Illustrations of the Geology of Yorkshire. Part I, 4to, London.
QUENSTEDT, F. A. 1843. Das Flb'zgebirge Wurtembergs. 8vo, Tubingen.
REINECKE, C. M. 1818. Maris protogaei Nautilos et Argonautas, vulgo Cornua Ammonis, in agro Coburgico

et vicino reperiundos descripsit et delineavit, &c. Dr. J. C. M. REINECKE, cum Tabulis XIII,

col. Coburgi, ,8vo.

ROEMER, F. A. 1836. Die Versteinerungen des Norddeutschen Oolithengebirges. 4to, Hanover.
SCHLOTHEIM, E. F. 1813. Mineral Taschenbuch. 8vo, Frankfurt.

1820—22. Die Petrefaktenkunde. 2 vols. 8vo, Gotha.
SOWERBY, G. B. 1823. Genera of Recent and Fossil Shells. 8ro.

SOWERBY, JAMES, and J. DE C., 1812 — 29. Mineral Conchology of Great Britain. 6 vols. 8vo, London.
STRICKLAND and BUCKMAN. 1845. Murchison's Geology of Cheltenham. 2d Edition, 8vo, London.
VOLTZ, P. L. 1830. Observations sur les Belemnites. 4to, Paris.

1836. Ueber das Fossile genus Nerinea. Neues Jahrbuch, 1836, p. 538.
WILLIAMSON, W. C. 1837. On the Distribution of Fossil Remains on the Yorkshire Coast, from the

Lower Lias to the Bath Oolite inclusive. Trans. Geol. Soc. London. 2d Series, vol. v, pt. 1.
YOUNG, G. and BIRD, J. 1828. A Geological Survey of the Yorkshire Coast. 2d Edition, 4to. Whitby.

( Die Versteinerungen Wiirtembergs. Folio, Stuttgardt.
6

ZIETEN, C. H. 1830—34.

Les Petrefactions de wurtemburg.

CORRIGENDA.

Page 1. Line 18, for Hailsworth read Nailsworth.
„ 2. In foot-note, line 6, for Nuns read Nunnery.
„ 3. Line 26, after Gresslya, erase the word or, and

place a ,.

„ 4. Line 33, for Pterocera read Alaria.
„ 8 and 9. The two Belemnites occur also at Minchin-

fiampion.
„ 16. To the last line add, wing simple, undivided.

Page 49. Chemnitzia Lonsdalii, Plate VIII, read Plate VII.
„ 62. Trochus squamiger, Plate X, figs. 2, 2a, 2A, read

Plate IX, figs. 34, 34a.
„ 86. Line 26, for with, read to.
„ 96. Line 24, for Loliolum read doliolum,
„ 99. Line 8, after "remaining species," read to the

species of section B.

INDEX

or

SPECIES RETAINED IN THIS WORK.

[I. 0., or C-b., affixed, shows that the species also occurs in the Inferior Oolite, or Cornlrash.']

Page

Plate

Page

Plate

ACT.BONINA

CERITELLA

bulinoides

104 .

. 8, f. 15.

acuta

37

. . 5, f. 17, a; f. 18, a.

olivaeformis

103 .

. 8, f. 14.

conica

39

. . 5, f. 10, a, b, c.

? parvula

104.

. 5, f. 11, lla, 12.

gibbosa

39

. . 9, f. 17.

ALARIA

longiscata

40

. . 9, f. 14.

armata

16 .

. 3, f. 1, la.

mitralis

39

. . 5, f. 15.

atractoidea

19 .

. 3, f. 7, 7a.

planata

38

. . 5, f. 14, 14a.

cirrus

22 .

. 3, f. 13, 13a.

Sowerbii

38

. . 5, f. 16.

hamulus

17 .

. 3, f. 4, a, b.

rissoides

40

. . 9, f. 7.

hamus

16 .

. 3, f. 2, a, b.

unilineata

38

. . 5, f. 13 ; 13, f. 8.

hexagona

19 .

. 3, f. 8.

CERITHICM

laevigata

17 .

. 3, f. 3, 3a.

limaeforme

30

. . 7, f. 2.

pagoda

18 .

. 3, f. 6 ; 13, f. 4.

pentagonum

30

. . 9, f. 22.

paradoxa

20 .

. 3, f. 9, 10; 13, f. 3.

Roissii

32

. . 7, f. 14, a.

(var.)

20 .

. 3, f. 9a.

sexcostatum

30

. . 7, f. 3, a.

parvula

22 .

. 3, f. 12, 12a, b.

strangulatum

31

. . 9, f. 22.

Phillipsii

18 .

. 3, f. 5, a. I.O.

quadricinctum

29

. . 9, f. 8.

trifida

21 .

. 3, f. 11, a, b, c. C-b.

Tennantii

32

. . 9, f. 22.

AMMONITES

CHEMNITZIA

arbustigerus

12 .

. 2, f. 4, 4a.

Hamptonensis

50

. . 7, f. 1, a.

gracilis 12, 105,

1, f. 3, a; 13, f. 2, a.

Leckenbyi

50

. .7, f.4.

macrocephalus

12 .

. 2, f. 3, a.

Lonsdalei

49

. . 7, f. 13, a.

subcontractus

11 .

. 1, f. 1, la.

phasianoides

51

. . 9, f. 5.

»»

Jim. f. 2, 2a.

simplex

49

. .7, f.15.

Waterhousei

13 .

. l,f.4, a. I.O.

Wetherellii

50

. . 7, f. 5, a.

variabilis

51

. . 8, f. 7, a, b.

BELEMNITES

CYLINDRITES

Bessinus

8 .

. 1, f. 5, 7.

acutus

98

. . 8, f. 9, a, b.

fusiformis

8 .

. 1, f. 6, 8.

altus

99

. . 8, f. 12, a, b.

BRACHYTREMA

angulatus

99

. . 8, f. 11, a,4.

Buvignieri

24 .

. 5, f. 4.

brevis

101

. . 8, f. 13.

turbiniformis

25 .

. 9, f. 35, a.

bullatus

102

. . 8, f. 18, a, b, c.

BOLLA

cuspidatus

98

. .8, f. 10, a.

doliolum

96 .

. 8, f. 16, a, b.

cylindricus

100

. . 8, f. 19, a, b, c.

undulata

96 .

. 8, f. 8, a.

excavatus

100

. .8, f. 17, a,b,c.

17

126

INDEX.

Page

Plate

Page

Plate

CYLINDKITES (continued).

NATICA (continued).

pyriformis

102 .

. 8, f. 18, a, b, c.

Strickland!

42 .

. 1 1, f. 24, a.

Thorenti

101 .

. 8, f. 22, a, b, c.

Tancredi

42 .

. 6, f. 11.

DELPHINULA

Verneuili

44 .

. 6, f.6, a; {.?, a.

alta

71 .

. 9, f.31.

NAUTILUS

Buckmani

71 .

. 5, f. 8.

Baberi

10 .

. 1, f. 1, a.

corouata

70 .

. 9, f. 26.

dispansus

9 .

. 2, f. 5, a.

(Sub-genus) CROSSOSTOMA.

subtruncatus

10 .

. 1, f. 2, a.

? discoideum

73 .

11, f. 7, a, b.

NERIN^A

? heliciforme

73.

11, f. 8. 1.0.

Dufrenoyi

34 .

. 7, f. 8, a—e.

Prattii

72.

11, f. 21, a. 1.0.

Eudesii

33 .

. 7, f.6, a; 13, f. 10.

DESLONGCHAMPSIA

funiculus

36 .

. 7, f. 12, a, b.

Eugenei

94 .

12, f. 13, a.

punctata

35 .

. 7,f.lO,a,b,c.

EMARGINULA

Strickland!

35 .

. 9, f. 9, a.

scalaris

88. .

8, f. 4, a, b, c. 1.0.

Voltzii

32 .

. 7, f. 11, a; Var.f. 7, a;

and 13, f. 11.

EULIMA

NERITA

communis

48 .

9, f. 21, a.

cancellata

56 .

. 11, f. 15, a.

pygmaea

48 . .

9, f. 1.

costulata

57 .

. 8, f. 6, a, b, c ;

subglobosa

49 . .

9, f. 6.

11, f. 18, a, b. 1.0.

ragans

48 . .

9, f.3, 4.

rugosa

56 .

. 11, f. 17, a.

EUSPIRA

(Sub-genus) NERIDOMUS.

canaliculata

45 . .

11, f. 23, a. 1.0.

hemisphserica

58 .

11, f. 16, a; f. 14, a.

coronata

46 . .

6, f. 9.

minuta

58 .

11, f. 19, a. 1.0.

pyramidata

46 . .

6, f. 8, a.

(Sub-genus) NERITOPSIS.

Sharpei

46 . .

11, f.22.

striata

59 .

11, f. 13, a.

subcanaliculata

47. .

6, f. 13.

sulcosa

59 . .

11, f. 12. 1.0.

FISSURELLA

varicosa

106 .

1 1, f. 20, a ;

acuta

85 . .

8, f. 5, a — c.

13, f. 5. 1.0.

Fusus

PAGODUS

coronatus

23 . .

5, f. 5.

sub-genus AMBERLEYA.

multicostatus

23 . .

5, f. 6, a.

nodosa

55 . .

5, f. 1 9. 1.0.

subnodulosus.

23 . .

5, f. 9, a.

PATELLA

MONODONTA

arachnoidea

92 . .

12, f. 9, a.

decussata

68 . .

1 1, f. 9, a.

Aubentonensis

91 . .

12, f. 7, a, b, c, d.

formosa

68.. .

11, f. 6, a, b.

cingulata

88 . .

12, f. 4, a, d.

imbricata

67. .

11, f.3, a.

inornata

93 . .

12, f. 11, a. 1.0.

Labadyei

68 . .

11, f. 2; Var. f. 11, a.

nana

93 . .

12, f. 10, a.

Lyellii

67 . .

11, f. 4, a, b. 1.0.

Roemeri

91 . .

12, f. 6, a, b.

NATICA

rugosa

89 . .

12, f. I, a—g. I.O..

ambigua

44 . .

6, f. 5.

paradoxa

90. .

12, f. 2, a, b.

forraosa

42 . .

6, f. 10.

striatula

91 . .

12, f. 5, a, b.

globosa

43 . .

6, f. 14.

sulcata

90 . .

12, f. 3, a, b.

grandis

41 . .

6, f. 12.

suprajurensis

92 . .

12, f. 9, a.

intermedia

41 . .

6, f. 1, a.

PHASIANELLA

Micbelini

44 . .

6, f.2, la; f.3, 3a.

acutiuscula

75 . .

11, f. 28, a.

neritoidea

43 . .

6, f. 4.

conica

74 . .

11, f. 30, a.

INDEX.

127

Page

PHASIAKELLA (continued).

elegans 74 .

nuciformis 75 .

Leymeriei 74 .

parvula 75 .

tumidula 76 .

PlLEOLUS

Isevis 60 .

plicatus 60 .
PLEUROTOMARIA

clathrata 79 .

composite 80 .

discoidea 78 .

obesa 79 .

pagodus 77 .

scalaris 77 .
PTEROCEKAS

Bentleyi 15 .

ignobilis 14 .

Wrightii 105 .

PURPUROIDEA

glabra 28 .

Moreausia 27 .

nodulata 28 . ,

RlMCLA

Blotii 87 . ,

clathrata 86 .

tricarinata 86 .
KISSOINA

acuta 53 . ,

cancellata 53 . ,

duplicata 52 . ,

Isevis 54 . .

obliquata 52 . ,

tricarinata 53 . .
SEKPULA

oblique-striata 107 ..
SOLARIUM

disculum 70 . .

polygonium 69 ..

varicosum 69 ..
STOMATIA

Buvignieri 85 . .
TROCHOTOMA

acuminata 82 . .

conuloides 82 . .

discoidea 84 . .

Plate

Page Plate

TROCHOTOMA (continued).

. 11, f. 27, a.

extensa

83 . . 10, f. 19a, b.

. 11, f. 26.

obtusa

83 . . 10, f. 15«, b.

. 11, f. 31, a, 32.

tabulata

83 . . 10, f. 17, a.

. 11, f. 20, a.

TROCHUS

. 11, f. 25, a.

aneeus

63 . . 10, f. 7, a.

Bunbnrii

63 . . 10, f. 1, «, 6.

. 9, f. 37, a, b. I.O.

Dunkeri

61 . . 10, f. 3, a.

. 9, f. 36, a, b, c. I.O.

Ibbetsoni

62 . . 10, f. 4, a.

obsoletus

63 . . 11, f. 1, a.

. 10, f. 6, a.

pileolus

63 . . 10, f. 5, a, b.

. 10, f. 13, a.

plicatus

61 . . 10, f. 8, a.

. 10, f. 12.

squamiger

62 . . 9, f. 34, a; 13, f. 7.

. 10, f. 11.

spiratus

106 . . 10, f. 2, a, b.; and

. 10, f. 9.

13, f. 6, a.

. 10, f. 14.

TURBO

capitaneus

65 . . 9, f. 33, a. I.O.

3, f. 15, a. Var. f. 16.

elaboratns

64 . . 9, f. 27. 1.0.

. 3, f. 14.

Gomondei

66 . . 11, f. 5.

. 13, f. 1.

Hamptonensis

64 . . 9, f. 30, a, b. I.O.

obtusus

66 . . 11, f. 9, a; 10, a.

. 4, f. 5, a; f. 6, a.

pygmseus

65 . . 9, f. 29, a.

4, f. 1, a; {. 2, 3a, 4.

Sharpei

65 . . 9, f. 28, a.

5, f. 1, a; f. 2, 3, 4.

UMBRELLA

[Cor. 0.

Hamptonensis

95 . . 12, f. 12, a.

8, f. 3, a, b, c. I.O.

. 8, f. 1, a, c. 1.0.

s f 9 a P T O

Oj 1 • — j I** ~C» 1 . \_/ .

9, f. 9; 13, f. 9.
9, f. 12, a.

YORKS

HIRE SHELLS.

9, f. 10.

9, f. 16. 1.0.

ACTION

9, f. 19. 1.0.

pullus

119 . . 15, f. 11.

9, f. 13.

Sedgvici

118. . 15, f. 9.

ACT.EONINA

5, f. 19, a.

gigantea

119 .. 15, f. 13. 1.0.

glabra

120. . 15, f. 11. I.O.

9, f. 25, a, b.

tumidula

120 . . 15, f. 14.

9, f. 24, a, b.

ALARIA

9, f. 23, a, b.

Phillipsu

Ill . . 15, f. 15«. I.O.

AMMONITES

9, f. 32, a.

Blagdeni

110 .. 14, f. 3, a. I.O.

Braikenridgii

Ill . . 14, f. 1. I.O.

10, f. 18«, 20.

macrocephalus

109 . . 14, f. 2.

10, f. 16.

BELEMNITES

10, f. 10, a, b, c.

giganteus

108 . . 14, f. 4. I.O.

128

INDEX.

Page

Plate

Page

Plate

CERITHIUM

PHASIANELLA

Beauii

112 . .

15, f. 5.

latiuscula

117 . .

15, f. 16.

gemmatum

115 . .

15, f. 6.

striata

118 . .

15, f. 19. 1.0.

CHEMNITZIA

SERPULA

Scarburgensis

115 . .

15, f. 8.

intestinalis

121 . .

14, f. 7.

vetusta

114 . .

15, f. 7.

plicatilis

121 . .

14, f. 5, a, b.

EULIMA

sulcata

121 . .

14, f. 6.

laevigata

114 . .

15, f. 4.

TROCHUS

NATICA

Leckenbyi

115 . .

15, f. 21, a.

adducta

112 . .

15, f. 17.

monilitectus

116 . .

15, f. 1, a. 1.0.

cincta

113 . .

15, f. 20.

TURBO

puncture

112 . .

15, f. 18. C-b., 1.0.

elaboratus

116 . .

15, f. 2, a. I.O.

NEKITA

VERMICULARIA

pseudocostata

114 . .

15, f. 3, «. 1.0.

nodus

120 . .

14, f. 8, a, b.

INDEX OF SYNONYMS.

ACTJSON

acutus

cuspidatus

glaber
ACT-IONINA

Deslongchampsia

Eparcyensis

oliveeformis
AMMONITES

arbustigerus

Blagdeni

Braikenridgii

coronatus

discus

gracilis

macrocephalus .

terebratus

Triptolemus
AUKICCLA

Sedgvici
BELEMNITES

Aalensis

Bessinus

Page
. 98

BELEMNITES (continued.)
canaliculatus

. 98
. 120

compressus
ellipticus
fieuriausus

. 119

fusiformia

. 44
. 103

. 12

giganteus
gladiua
graudis

BtJCCINUM

. 110
. Ill

parvulum
unilineatum

. 110

BCLLA

. 13
. 105

elongata .
oliveeformis

. 109

Thorentea

. 109

undulata

. Ill

CASSIS

. 118

Eparcyensis

CEKITHIUM

Blainvillii .

. 108

Defrancii .

. 8

Dufrenoyi

Page

8

108

108

8

8

108
108
108

104
38

101

103

101

96

44

36
33
34

CERITHIUM (continued).
limseforme
pentagonum
strangulatum
quadricinctum

CHEMNITZIA

Roissii
vetusta

DELPHINULA

coronata
stellata

DlTREMAEIA

acuminata
conuloides
EMARGINULA
Blotii
clathrata
Goldfussii
scalaris
tricarinata

EUOMPHALUS

coronatus

FlSSBRELLA

acuta
Fusus

nodulosus

subnodulosus
HELCION

Aubentonensis

cingulata

nana

rugosa

sulcata
LIT TORINA

punctura
MELANIA

striata
MONODONTA

tevigata

MUREX

NATICA

Lyellii

nodnlatus
tuberosus

adducta
globosa

INDEX.

Page

NATICA (continued).

30

grandis

30

Michelini

31

Verneuili

29

NERIN^EA

cylindrica

32

Defrancii

114

funiculosa

punctata

70

Voltzii

70

NEUITA

costata

costulata

82

82

hemisphaerica

mais .

minuta

87

ovata

86

O\t

Qfi

pseudocostata

OO

pulla

88

sulcosa

86

NERITOPSIS

sulcosa

70

varicosa

PATELLA

85

ancyloides

Aubentonensis

23

cingulata

23

costatula

mamillaris

91

nana

88

papyracea

93

rugosa

89

sulcata

90

suprajurensis

Tessonii

112

PATELLAHIA

sima .

118

PUASIANELLA

cincta

68

Leymeriei

57

striata

PILEOLUS

28

Isevis

28

plicatua

PLEUROTOMA

112

longiscata

43

rissoides

129

Page

. 41
, 44
, 44

, 36

. 33

36

35

32

114
. 57
. 58
. 58
, 58
, 58
. 114
. 58
. 59

59
, 106

. 89

. 91

. 88

. 60

. 60

. 93

. 60

61

90

92

89

61

113
74

118

60
60

40
40

130

PLEUROTOMARIA
clathrata
obesa
pagodus
scalaris

PCRPURA

Lapierrea
Moreansia

PURPURINA

Moreausia
unilineata
PTEROCERAS

atractoides

cirrus

hamulus

hamus

paradoxa

Phillipsii

RlMULA

RlSSOA

acuta
clathrata

acuta
duplicata
kevis
obliquata
RISSOINA

acuta

duplicata

obliquata

ROSTELLARIA

bicarinata

bispinosa

cirrus

composita

hamulus

hamus

trifida

SERPCLA

intestinalis

INDEX.

Page

SERPULA (continued).

79

oblique-striata .

79

plicatilis

77

sulcata

77

SIPHO

clathrata

28

SOLARIUM

27

coronatum

polygonum

27

TEREBRA

38

nodosa

striata

vetusta

19

TORNATELLA

22

17

cuspidata

16

gigantea

20

pulchella

18

pulla

TROCHOTOMA

acuminata

85

Oi?

conuloides

86

TROCHUS

anceus

53

discoideus

52

54

Labadyei

***»

monilitectus

52

obsoletus

plicatus

53

spiratus

52

TURBO

52

capitaneus

Deslongchampsi

21

elaboratus

21

Labadyei

22

Lyellii

18

obtusus

17

subobtusus

16

TURHITELLA

21

Roissii

UTHICULUS

121

glaber

^^*"*****^^—

• t^^X.

" - - 4 ^^

Page

107
121
121

86

70
69

55
118
114

98
119
119
119

82
82

63
84
68

116
63
61

106

65
68
116
68
67
66
66

32
120

PLATE I.

Fig.

1. Nautilus Baberi, p. 10, side view.
la. front view.

2. Nautilus subtruncatus, p. 10, side view.
2«. front view.

3. Ammonites gracilis, p. 12, young ; and p. 105, Plate XIII, figs. 2, 2a, adult.

4. Ammonites Waterhousei, p. 13, side view.
4 a. front view.

5. Belemnites Bessinus, p. 8.

7. showing the phragmacone.

6. 8. Belemnites fusiformis, p. 8.

n i

TWH-Baily.

Printed bj Bullmandel t, Walton

PLATE II.

Fig.

1. Ammonites subcontractus, p. 11, side view.
Iff. front view.

2, 2«. — young of.

3. Ammonites macrocephalus, var., p. 12, side view.
3«. front view.

4. Ammonites arbustigerus, p. 12, side view.
4a. front view.

5. Nautilus dispansus, p. 9, side view.

5 a. — front view.

PL II.

PLATE III.

Fig.

1. la, c. Alaria armata, /?. 16, back view.

!#• front view; d, portion magnified.

2. Alaria hamus, /;. 16.

20. portion magnified.

2/5. front view.

3. 30. Alaria Isevigata, p. 17.

4. 43. Alaria hamulus. p. 17, back view.

40. specimen magnified.

5. Alaria Phillipsii, p. 18; and p. Ill, Plate XV, figs. 15, 150.
50. portion magnified.

6. Alaria pagoda, p. 18 ; and Plate XIII, figs. 4, 4«.

7. 70. Alaria atractoides, p. 19.

8. Alaria hexagona, jo. 19.

9. Alaria paradoxa, p. 20, front view ; and Plate XIII, fig. 3.
90. var. a, back view.

10. back view.

11, 113. Alaria trifida, p. 21, front view.
110. back view.

lie. portion magnified.

120. Alaria parvula, />. 22.

126. magnified.

13. 130. Alaria cirrus, p. 22.

14. Pteroceras ignobilis, p. 14.

15. Bentleyi, p. 15, front view.

15. back view.

16. — — var. of, back view.

H Buly -id-.' liik-

Trml«d In Hulta.ad.1. * Hl.Hon

PLATE IV.

Fig-

1. Purpuroidea Moreausia, p. 27, front view.
la. — back view.

2. — back view, shell of advanced growth,

larger specimen.

3. — young shell, front view.
3«. young shell, back view.

4. cast of the interior.

5. Purpuroidea glabra, p. 28, front view.
5«. — back view.

6. young shell, front view.
Qa. young shell, back view.

,,,

•

PLATE V.

Fig.

1 . Purpuroidea nodulata, p. 28, front view,
la. back view.

2. another example.

young shell, front view.

4. cast of the interior.

5. Fusus coronatus, p. 23.

6. Fusus multicostatus, p. 23.

7. Fusus (Brachytrema) Buvignieri, p. 24.

8. Delphinula Buckmani, p. 71.

9. Fusus subnodulosus, p. 23.

9«. — portion enlarged.

10. Ceritella conica, p. 39, front view.
10«. — back view.

103. — smaller example.

lOe. — magnified twice.

11. Actaeonina parvula, p. 104, front view.
11 a. back view.

12. younger example.
12«. adult, magnified twice.

13. Ceritella unilineata, p. 38, and Plate XIII, fig. 8, Plate IX, fig. 15, var.

14. Ceritella planata, p. 38, natural size.

14a. magnified three times.

15. Ceritella mitralis, p. 39.

16. Ceritella Sowerbii, p. 38.

17. Ceritella acuta, p. 37, young, front view.
17o. young, back view.

18. adult, front view.
18a. adult, back view.

19. Pagodus (Amberlya) nodosa, p. 55.

rn««l bj HulhnandUl t T»«Hon

PLATE VI.

Fig.

1. Natica intermedia, p. 41, front view.
1°- back view.

2. Natica Michelini, p. 44, front view, elongated variety.
2°- — back view, elongated variety.

another example, front view.
3fl- — another example, back view.

4. Natica neritoidea, p. 43.

5. — ambigua, p. 44.

6. — Verneuili, p. 44, front view.
6«- — back view.

young shell, front view.
^a- — young shell, back view.

8. Natica (Euspira) pyramidata, p. 46, front view.
8°- back view.

9. Natica (Euspira) coronata, p. 46.

10. — formosa, p. 42.

11. Tancredi, p. 42.

12. — grandis, p. 41.

13. Natica (Euspira) subcanaliculata, p. 47.

14. Natica globosa, p. 43.

PI. VI.

iou

ia/

Trimed by Hullro«jid«l fc Walton

PLATE VII.

Fig.

1. Chenmitzia Hamptonensis, p. 50.

] a. magnified.

2. Cerithium limaeforme, p. 30.

3. sexcostatum, p. 30.

3a magnified.

4. Chenmitzia Leckenbyi, p. 50, magnified.

5. Wetherellii,j». 50.

5a. magnified.

6. Nerinsea Eudesii, p. 33.

Ga. magnified.

7. Nerinsea Voltzii, p. 32, young.

la, section magnified.

8. Nerinaea Dufrenoyi, p. 34.

Sa. magnified.

8(5. section magnified.

8c, 8e. p. 34, another variety.

8d. portion magnified.

9. Nerinsea Stricklandi, j». 35

9«. portion magnified.

10. lOc. Nerinsea punctata,jo. 35.

10a. portion of external surface magnified.

10#. section magnified.

11. Nerinsea Voltzii, p. 32.

lla. section.

12. Nerinaea funiculis, p. 36.

12o. portion of the surface magnified.

123. section magnified.

13. Chenmitzia Lonsdalei, p. 49, the young shell.
13a. the adult shell.

14. Cerithium Roissii, p. 32.

140. section of the shell.

15. Chenmitzia simplex, p. 49, reduced one half.

PL VII.

1W>«! t, ifalhniod.l I *.'!.. i.

PLATE VIII.

Fig.

1, !«• Rimula clathrata, p. 86.

1^> lc- magnified.

2, 20. Rimula tricarinata, p. 86.

2<5> 2c. magnified.

3, 30. Rimulff Blotii,jo. 87.

3^, 3e. magnified.

4, 40, 4(5. Emarginula scalaris, jo. 88.

4ff- under surface magnified.

5, 50. Fissurella acuta,j». 85.

5^> ^c- specimen magnified.

6, 60. Nerita costulata, p. 57.

fit' c- specimen magnified.

7, la. Chemnitzia variabilis, p. 51.

'*• magnified.

8, 80. Bulk undulata, p. 96.

9, 96. Cylindrites acutus, p. 98.

®a- magnified.

10, Cylindrites cuspidatus, p. 98.

10«- magnified.

11, 110. Cylindrites angulatus, p. 99.

I**- magnified.

12, 120. Cylindrites altus, ^. 99.

12^- magnified.

12*. Actaeonina?

13, 1 30. Cylindrites brevis, p. 1 0 1 .

*3*. magnified.

14, Actseonina olivaeformis.jo. 103.

15, Actaeonina bulimoides, jo. 104.

16, 160, 16£. Bulla loliolum,^. 96.

17, 170. Cylindrites excavatus, p. 1UO.

1^*- magnified section.

18, 18*5. Cylindrites bullatus, />. 102.

180, 18e. magnified.

19, 190. Cylindritescylindricus, p. 100.

L9^' °- view of apex, and section of the same.

20, 20/5, 20c, 21. Cylindrites pyriformis, p. 102.

20«- magnified.

22, 22£. Cylindrites Thorenti, p. 1 01 .

220, 22c. magnified.

PLATE IX.

Fig.

1. Eulima pygmeea, p. 48 .

2. Phasiauella acutiuscula, p. 75, and Plate XI, fig. 28.

3. 4. Eulima vagans, p. 48.

5. Chemnitzia phasiauoides, p. 51.

6. Eulima subglobosa, p. 49.

7. Ceritella rissoides, p. 40.

8. Cerithium quadricinctum, p. 29.

9. Rissoina acuta, p. 53, and Plate XIII, fig. 9.
10. Rissoina duplicata, p. 52.

12. 12<z. Rissoina cancellata, p. 53.

13. Rissoina tricarinata, p. 53.

14. Ceritella longiscata, p. 40.

15. Ceritella unilineata, ? from Ancliff, p. 38.

16. Rissoina? laevis, p. 54.

17. Ceritella gibbosa, p. 37.

18. Cerithium strangulatum, p. 31.

18o. showing the contracted aperture.

19. Rissoina obliquata, p. 52.

20. Cerithium Tennanti, p. 32.

21. Eulima communis, p. 48, front view.
2 la. back view.

22. Cerithium pentagonum, p. 30.

23. Solarium varicosum, p. 69.

23a. view of the base.

236. — surface magnified.

24. 240, b. Solarium polygonium, p. 69.

25. 25o, b. Solarium disculum, p. 70.

26. Delphinula coronata, p. 70.

27. Turbo elaboratus, p. 64.

28. Turbo Sharpei, p. 65,

28«. surface magnified.

29. Turbo pygmeea, p. 65.

29o. magnified view.

30. 30a. Turbo Hamptonensis, j>. 64.

306, magnified view.

3 1 . Delphinula alta, p. 7 1 .

32. Stomatia? Buvignieri, p. 85.

,•;_'</. surface magnified.

33. 33o. Turbo capitaneus, p. 65.

34. Trochus squamiger, p. 62,* and Plate XIII, fig. 7.
34a. back view.

35. Fusus (Brachytrema) turbiniformis, p. 25.

35a. — — front view.

36. 36a. Pileolus plicatus, p. 60.

366. view of the base and aperture magnified.

3Cc. side view magnified.

37. 3/a. Pileolus Isevis, p. 60.

376. view of the base and aperture magnified.

* Incorrectly printed as Plate X, figs. 2, 2a, b.

fnnud bj Holta«..d.l t -NVlioc,

PLATE X.
Fig.

1. Trochus Bunburyi, p. 63.

la. — magnified three times.

13. — — back view.

2. Trochus spiratus ? var.,p. 106, and Plate XIII, fig. 6.
20. — magnified.

23. — front view.

8. Trochus Dunkeri, p. 61.

30. — magnified.

4. Trochus Ibbetsoni, p. 62.

40. — magnified.

5. Trochus pileolus, p. 63.

50. — magnified.

53. — another example.

6. Pleurotomaria clathrata, p. 79.

60. — magnified three times.

7. Trochus anceus, p. 63.

70. — specimen magnified.

8. Trochus plicatus, p. 61.

80. — magnified.

9. Pleurotomaria pagodus, p. 77.

10. Trochotoma discoidea, p. 84, upper surface.
100. — magnified.
103. — — side view.

10c. costae magnified.

11. Pleurotomaria obesa,jt?. 79.

12. Pleurotomaria discoidea, p. 78.

13. Pleurotomaria composita, p. 80.

130. — - portion magnified.

14. Pleurotomaria scalaris, p. 77,

15. Trochotoma obtusa, p. 83.
150. front.
153. back view.

16. Trochotoma conuloides, p. 82.

17. Trochotoma tabulata, p. 83.

170. front view.

180. Trochotoma obtusa ?,jo. 83, base.

183. surface magnified.

190. Trochotoma extensa, p. 83.

193. — — back view.

20. Trochotoma acuminata, p. 82.

Pl.X

H.BaUy

FrintedbyHuJlmandel fWahon.

PLATE XI.

Fig.

1. Trochus obsoletus, p. 63.

la. — magnified view.

2. Monodonta Labadyei, p. 68.

3. Monodonta imbricata, p. 67.

3a. magnified view.

4. Monodonta Lyellii, p. 67, front view.
4«. back view.

46. the shell magnified.

5. Turbo Gomondei, p. 66.

6. 6a. Monodonta formosa, p. 68.

66. magnified view.

7. 7a. Delphinula (Crossostoma) discoideum, p. 73.

76. magnified view.

8. Delphinula (Crossoatoma) heliciforme, p. 73.

9. Turbo obtusus, var., p. 66.

9o. magnified view.

10. Turbo obtusus, p. 66.

10o. magnified view.

11. 11 a. Monodonta Labadyei, p. 68.

12. Neritopsis sulcosa, p. 59.

13. Neritopsis striata, p. 59, front view.
13a. — back view.

14. Nerita hemispheerica, p. 58, front view.
14a. — back view.

15. Nerita cancellata, p. 56, front view.
15a. — back view.

156. a portion of the surface magnified.

16. 16<z, Nerita hemisphserica, p. 58, a smooth variety.

17. 1 "a. Nerita rugosa, p. 56.

18. 18a. Nerita costulata, p. 57.

186. — a portion magnified.

19. 19a. Nerita minuta, p. 58.

20. 20<z. Neritopsis varicosa, p. 106, and Plate XIII, fig. 5.

21. Delphinula (Crossostoma) Prattii, p. 77.

2 la. — — — an enlarged view.

22. Natica (Euspira) Sharpei, p. 46.

23. Natica (Euspira) caualiculata, p. 45.

23. — — back view.

24. Natica Strickland!, p. 42.

24a. — — back view.

25. 25a. Phasianella tumidula, p. 76.

26. Phasianella nuciformis, p. 75.

27. 27<z. Phasianella elegans, p. 74.

28. 28o. Phasianella acutiuscula, p. 75, and Plate IX, fig. 2.

29. Phasianella parvula, p. 75.

29. — magnified view.

30, 30a. Phasianella conica, p. 74.

31, 3 la. Phasianella Leymeriei, p. 74.

32. — — a globose variety.

1 .1 I., llulUudel t WJlo

PLATE XII.

Fig.

1, la. Patella rugosa, j». 89, variety with large costse.

13- magnified portion of the surface of figs. 1, la.

lc, Id- variety with fine costae.

1<\ magnified portion of the surface of figs, lc, Id.

If, Iff- the young shell.

2, 20. Patella paradoxa, p. 90.

magnified portion of the surface.

3, Set. Patella sulcata, p. 90.

33. magnified portion of the surface.

4, 40, c, d. Patella cingulata, p. 88.

43. magnified portion of the surface.

5, 50. Patella striatula, p. 91.

53. magnified portion of the surface.

6, 60. Patella Roemeri, p. 91.

63. magnified portion of the surface.

7, la. Patella Aubentonensis, p. 91.

73. magnified portion of the surface.

7c, Id. the young shell.

8, 80. Patella arachnoidea, p. 92.

portion of the surface magnified.

9, 9a. Patella suprajurensis, p. 92.

10, 100. Patella nana, p. 93.

11, 110. Patella inornata, p. 93.

12, Umbrella? Hamptonensis, p. 95.

120. the surface magnified three times.

13, 130. Deslongchampsia Eugenei, p, 94, magnified twice.

Primed by Uulbnude! Jt. Wilton

PLATE XIII.

Fig.

1. Pteroceras Wrightii,jy. 105. (In Dr. Wright's collection.)

2. Ammonites gracilis, and Plate I, fig. 3, pp. 12 and 105.

2«. front view. (In Prof. J. Buckman's collection.)

3. Alaria paradoxa, and Plate III, figs. 9, 10, p. 20.

4. Alaria pagoda, and Plate III, fig. 18, p. 18.
4a. — magnified view.

5. Neritopsis varicosa, and Plate XI, fig. 20, p. 106.

6. Trochus spiratus, and Plate X, fig. 2, var.,p. 106.
6a. . magnified view.

7. Trochus squamiger, and Plate IX, fig. 34, p. 62. Magnified view of a por-

tion of the surface.

8. Ceritella unilineata, and Plate V, fig. 13, p. 38.

9. Rissoina? acuta, and Plate IX, fig. 9, p. 53.

10. Nerinea Eudesii, and Plate VII, fig. 6, p. 33. Section of interior.

11. Nerinea Voltzii, and Plate VII, fig. II, p. 32. Section of interior.

PI. XIII

• , i'.,!nn«ndel It Walton

PLATE XIV.

YORKSHIRE SHELLS.

Fig.

Ammonites Braikenridgii, p. Ill, reduced one half.

Ammonites macrocephalus, p. 109, reduced one half.
3«. Ammonites Blagdeni, p. 110, side view.
Sfi- front view, reduced one half.

4. Belemnites giganteus, p. 108.
4fl- transverse section.

5a. Serpula plicatilis, p. 121.
5#- magnified view.

5c. transverse section.

6. Serpula sulcata, p. 121.

7. Serpula intestinalis, p. 121.
80, 0. Vermicularia nodus, p. 120.

YORKSHIRE SHELLS

i y.lV.

fr,n»d by jfa:in.«r<:<l II W.lton

PLATE XV.

YORKSHIRE SHELLS.

Fig.

1. Trochus raonilitectus, p. 116.

la. magnified view.

2. Turbo elaboratus, and Plate IX, fig. 27, p. 116.
20. magnified view.

3. Nerita pseudocostata, p. 114.

30. magnified view.

4. Eulima levigata, p. 314.

5. Cerithium Beanii, p. 112.

6. Cerithium gemmatum, p. 115.

7. Chemnitzia? vetusta, j». 114.*

8. Chemnitzia? Scarburgensis, p. 115.

9. Actaeon Sedgvici, p. 118.

10. Actseonina glabra, p. 120.

11. Actaeon pullus, p. 118.

12. Turbo Phillipsii, /?. 117.

12a. back view.

12£. surface magnified.

13. Actaeonina gigantea, p. 1 1 9.

14. Actaeonina tumidula, p. 120.

15. Alaria composita, var. Phillipsii, and Plate III, fig. 5, p. Ill, and p. 18.
15«. magnified view.

1 6 . Phasianella latiuscula, p . 117.

17. Natica adducta, p. 112, front view.
17«. back view.

18. Natica punctura, p. 112.

18a. surface magnified.

19. Phasianella striata, jo. 118.

20. Natica (Euspira)? cincta,jo. 113.

21. 21a. Trochus? Leckenbyi, p. 115. (In Mr. Leckenby's collection.)

* In this figure the costee near the suture are too much indented.

YORKSHIRE SHELLS

•

by HuJlmnr,£*i fc Y

A MONOGRAPH

OF THE

MOLLUSCA FROM THE GREAT OOLITE,

CHIEFLY FROM

MINCH1NHAMPTON

AND

THE COAST OF YORKSHIRE.

BY

J. MORRIS, F.G.S. AM, JOHN LYCETT.

PART II.

BIYALVES.

LONDON

PRINTED FOR THE VAIJEONTOGRAPHICAL SOCIETY.

1S53.

C. AND J. ADLARD, PRINTERS, BARTHOLOMEW CLOSE.

A MONOGRAPH

OP THE

MOLLUSCA FROM THE GREAT OOLITE,

PART II.
BIVALVES.

UPON a general review of the Oolitic Lamellibranchiate Mollusks, it will be found
that a very large proportion consists of shells whose hinges may be arranged under
one or other of the following two groups, each of which has various generic modifications.
The first consists of a lengthened hinge plate, having a parallel series of transverse or
oblique teeth, as exemplified by Area, with its sub-genera Cucullaa, Nucula, Leda,
Macrodon, Isoarca, Limopsis. The second kind of hinge is altogether destitute of teeth,
and comprises the several genera of fossil Myadce, as Pholadomya, &c., Mytilus with
Modiola, Lithodomus, Pinna, Trichites, and Thracia. Deducting these, together with
the forms whose hinge possesses only a ligamentary fossa, as Lima, Pecten, Hinnites,
Plicatula, and those in which the ligament is inserted in distinct pits, as Gervillia,
Perna, &c., it will be found that shells with hinge teeth constitute only a minority, and
that the great family of the Veneridce, though numerous with respect to individuals and
number of species, pertains only to few genera. Experience has led us to distrust many
generic names which have been given to these fossils, as Pullastra, Donax, Tellina,
Amphidesma, Chama, Lutraria, Sanguinolaria, Mactra, Gastrochtena, and Spondylus ;
Panopea is also a genus to which a very heterogeneous assemblage of testacea has been
referred ; Plagiostoma has by common consent fallen from the list of genera, the Oolitic
species being now referred to Lima. Nor has it in any one instance been ascertained
that any of the Oolitic bivalves have spoon-shaped processes corresponding to those of the
recent Mya and Lutraria. The shelly beds of the Great Oolite appear to have been
accumulated in a sea not sufficiently tranquil to become the habitat of the Myadce ; the
entire family were gregareous, but in the shelly Oolite we rarely discover a single valve of
Arcomya, Ceromya, or of Homomya, the other genera of Myada being absent altogether.
The crypts of Lithodomus prove that genus to have existed in great profusion, although it
is very rare that the shells are found in the perforations themselves, neither can they be

1

2 MOLLUSCA FROM THE GREAT OOLITE.

detected in the substance of the valves of Trichites, although few shells of that genus, or
of the adult specimens of Crassina, can be found, which are not bored or even honey-
combed by their perforations, a fact which should teach us that the numbers of fossil
specimens do not afford in every instance a sure indication of their former actual numbers.
The Trigonice, which hold so important a position in the Oolitic testacea, are represented
in the shelly beds by a great profusion of individuals; nevertheless, these beds do not
appear to have possessed conditions favorable to the development of the several species ;
three occur abundantly in their earliest stage of growth, but in proportion as they
increase in size, their numbers diminish, so that adult specimens are comparatively rare.
In the species referred to Pteroperna (a sub-genus of Avicula), will be found some
interesting forms serving to connect Avicula and Pterinea with the Polyodontte, the hinge
being somewhat identical with that of Macrodon ; it occupies a conspicuous position in the
Oolitic system. Another new generic form which remains to be exemplified is
Tancredia, (Hettangia, Terquem ;) although of small dimensions, and destitute of ornament
or remarkable figure, it is nevertheless the genus which, by the constantly recurring
force of numbers, most strongly dwells upon the recollection of those who have with their
own hands cleaved the shelly beds of the Great Oolite.

On the other hand, in the muddy deposits which are associated with the Great Oolite,
the family of Myadee were tolerably abundant, if we may judge from the numerous species
of Pholadomya, Panoptea, and its allied genera, Pleuromya, Arcomya, Homomya, which are
found in the beds of indurated marl, intercalated with or overlying some portions of the
shelly Oolite, throughout an extensive area; whilst many of the shells, the Pholadomya
especially, retain the normal position in which they appear to have lived.

BIVALVIA, Linn. — LAMELLIBUANCHIATA, Blainv.

OSTREA, Linnaus, 1758.

General Character. Shell adherent, inequivalve, foliaceous, irregular ; umbones sepa-
rated, slightly diverging ; ligament internal, placed in a deep grooved trigonal pit, beneath
the umbones. Muscular impression nearly central.

OSTREA RUGOSA, Goldf. Tab. I, fig. 4.

OSTREA BUGOSA, Goldf. Petref., tab. 72, fig. 10.

Testa ovatd, valvd inferiore profundd concentrice rugosd, margins inferiore plicato ;
wperiore subconvexd, undulatd-ruyosd.

Shell ovate ; inferior valve deep, with concentric rugose plications, the lower margin
plicated; the upper valve slightly convex, rugose, and undulated.

The typical form of this shell, which we have provisionally referred to 0. rugosa,
Goldf., has a considerable resemblance to 0. acuminata ; but the attached surface is

BIVALVIA. 3

usually much larger, and the entire form is more irregular ; it may be regarded as forming
a passage between the crescentric figure of that shell and the less oblique species, with
radiately plicated surfaces and margins ; it was eminently gregareous, and most abundant
upon the flaggy beds or tile stones of the Forest Marble ; in the shelly beds of the Great
Oolite it is much less common, and the specimens are usually small.

Localities. The vicinity of Tetbury and Cirencester in the Forest Marble ; Minchin-
hampton Common in the Great Oolite.

OSTREA ACUMINATA, Sow. Tab. I, fig. 1, 1«.

OSTKEA ACUMINATA, Sow. Min. Conch., t. 135, f. 2 not 3, 1816.
Roemer. Verst. Oolith., ii, p. 25, t. 18, f. 16.
Bronn. Leth. Geog., p. 192.

Testa ovato-elongatd, interdum subcrescenticd ; valvd inferior e convexa, umbone obliquo,
acuminato ; valvd superiore subpland, ovatd, tenui.

Shell ovately elongated, frequently subcrescentric, with concentric plications; umbone s
oblique, acuminated ; the smaller valve flattened, thin, ovate.

This little species exhibits a full share of the varieties of form proper to the genus ; in
the marls and subordinate beds of hard rag in the Fuller's-earth, the valves constitute a
considerable portion of the entire deposit, and in the shelly beds of the Great Oolite it
occurs in great profusion ; in France and the Jura it occupies a similar position, and in
equal prominence.

Localities. Bath, Minchinhampton, and numerous other localities throughout the
course of the Fuller's-earth and Great Oolite.

OSTREA COSTATA, Sow. Tab. I, fig. 5, 5a.

OSTREA COSTATA, Sow. Min. Conch., t. 488, f. 3, 1825.
Gold/. Petref, t. 72, f. 8.
Bronn. Leth. Geog., p. 190, t. 18, f. 18, 1851.
Deshayes. Traite Element., t. 53, f. 10—12, 1850.
KNOEEII, (Foltz.) Zieten Wurtt., Ix, t. 45, f. 2.

Testa parvuld, obliqud, ovali, valvd inferior e profundd costatd; umbone affixo, costis
dichotomis radiatd ; superiore pland subradiatd.

Shell small orbicular, or obliquely oval, the attached valve deep with numerous
branched and somewhat rounded ribs, upper valve flat, margin undulated.

Mr. Sowerby remarks that the "branching, rounded ribs upon the under surface
define this neat little oyster." It is one of the miniature productions of the Ancliff
Limestone.

Localities. In the Cornbrash and Forest Marble of Wiltshire and Somerset ; and in
the Great Oolite of Ancliff, Wiltshire, and in Gloucestershire.

4 MOLLUSCA FROM THE GREAT OOLITE.

OSTREA GREGAREA, Sow., V8T. Tab. I, fig. 2, 20.

OSTBEA GREGAREA, Sow. Min. Con., t. Ill, f. 1 and 3, 1815.
Gold/. Petref., t. 74, f. 2.
Bronn. Leth. Geog., p. 188, t. 18, f. 16, 1851.
— PALMETTA, Sow. Min. Con., t. Ill, f. 2?

Testa crassd, ellipticd, incurvatd costatd, valvd inferiore sub-carinatd, affixd, superiore
convexo-pland, costis numerosis, rugosis, subacutis radiantibus vel distichis.

Shell oblong, irregular, curved, costated, with unequal convex valves, the beaks
slightly produced and incurved ; costse numerous, rugose, diverging.

The specimens figured, are referred to the 0. gregarea, Sow., a social species which
occurs abundantly in the Coralline Oolite of Westbrook, Wiltshire, and near Weymouth
in Dorsetshire. The shells referred to this species in the Great Oolite are not generally
in good condition, and vary in form and plaiting ; some specimens presenting the
characters of 0. solitaria, Sow., others resembling the young state of 0. flabelloides,
Lamarck.

Localities. Minchinhampton, and in the Oolite of Lincolnshire ; Stonesfield, Oxfordshire.

OSTREA STJBRBGCLOSA. Tab. I, fig. 6, 6a.

1 Var. of OSTREA ACUMINATA, Sow.

Testa subtriffond, incurvd, concentrice rugosd ; valvd inferiore convexd, sulcis furcatis
irregulariter radiantibus ornatd ; valvd superiore sub-pland ; apice obliquo sub-acuto.

A somewhat trigonal incurved shell, concentrically imbricated or rugose, and with
irregular diverging small furrows on the convex valve; the umbone incurved and obtuse;
smaller valve flat and nearly smooth.

A very common and characteristic species of the upper portions of the Great Oolite
in Northamptonshire and Lincolnshire, where it occurs in sandy and clayey beds, which
may probably represent the Forest Marble. It bears a general resemblance to the
0. acuminata, Sow., of which it may prove to be only a variety from difference of habitat*
but is distinguished by the more convex form and furrowed surface of the larger valve.

Localities. In the Oolite of Kingsthorpe, Thrapston, Oundle, &c., Northamptonshire;
and near Stamford, Lincolnshire.

OSTREA SOWERBYI. Tab. I, fig. 3, 3«.

OSTREA ACUMIXATA, Sow. Min. Con., t. 135, f. 3 not 2.

Testa depressd, clongatd, curvatd rugosd, concentrice lamellosd ; valvd inferiore sub-
convexd, superiore pland ; umbone obtuso.

A depressed elongated and slightly-curved shell, marked by concentric lamellae at
distant intervals. The umbones are nearly equal in size, broad, and obtuse. The larger
valve is rather convex ; the smaller valve flat, or sometimes a little concave.

BIVALVIA. 5

This species is considered to be distinct from the 0. acuminata, which is more regular,
symmetrical, and incurved. It is very abundant in certain marly deposits belonging to
the upper portion of the Great Oolite in Northamptonshire.

Localities. Sharnbrook and near Bedford ; Blisworth, Kingsthorpe, Yardley and
Aynhoe, Northamptonshire; Sapperton, Gloucestershire.

Sub- Genifs — EXOGYRA.
Shell with the umbones involute.

EXOGTRA AURIFORMIS, Goldfuss. Tab. I, fig. 7.

EXOGYKA ACKIFORMIS, Goldfuss, Petref., t. 86, f. 5

Buckman. In Geol. of Cheltenham, p. 69.
? OSTREA OBSCUKA. Sow. Min. Con., t. 488, f. 2?

Testa ovato-suborbiculari depressd, valvd minore pland, inferiore subconica ; umboni-
bus minutis involutis ; laminis concentricis tenuissimis irregularibus.

Shell ovately-orbicular, depressed, the smaller valve flattened, the larger subconical
with a large adhering surface ; umbones very small and involute ; laminae of growth con-
centrical, very delicate, and irregular.

This pretty species is sufficiently distinct from the contemporaneous species ; it was
collected by Professor J. Buckman, in a bed of yellow clay at Sevenhampton Common,
and he has kindly placed it at our disposal.

Locality. Sevenhampton Common near Cheltenham.

PLACUNOPSIS. Nov. Gen.

Testa suborbiculari, inesquivalvis, irregulari, tenui, non-auriculatd ; valvd major e con-
vexd, subobliqud, umbone depresso, submarginali ; lineis radiantibus undulatis ornatd ;
margine cardinali brevi subrecto. Valvd minore pland Integra, interdum affixd. Cardo
dentibus nullis, foved parvd transversd intend. Impressio musculari magno (biloba) ?
elliptica, subcentrali.

Shell suborbicular, inequivalve, irregular, very thin, without ears; the larger valve
convex, rather oblique, its umbo depressed and subrnarginal, the surface ornamented with
undulated radiating lines ; hinge-margin short, nearly straight. The smaller valve is flat>
destitute of any foramen, and not unfrequently is affixed by its surface to other bodies.
Hinge without teeth, with a small mesial transverse internal groove to contain the
ligament. Muscular impression large (bilobed?), elliptical, subcentral.

This genus in its figure and character of the surface presents a considerable resem-
blance, both to Anomia and Placuna, but although possessing certain features of affinity to
each of these forms, it is not the less separated from them by other characters of some
importance. It is so irregular, that scarcely two specimens have exactly the same figure,
so that the longer diameter may be either lateral or otherwise ; notwithstanding this
irregularity, however, it will be observed that the posterior or left side of the convex valve

6 MOLLUSCA FROM THE GREAT OOLITE.

is more produced, and has more convexity than the other ; the substance of the test is
papyraceous, and the surface of the convex valve often displays markings, which prove that
for a considerable period these shells were attached to other bivalves by the surface of the
flat valve, but that valve has never actually been observed attached, and it is very com-
monly preserved with the outer surface destitute of any traces of having been adherent.
Judging therefore from the varying dimensions of the specimens, it does not appear that it
adhered at any particular stage of its growth, but that it was only occasionally attached.
From Placuna it is distinguished by the absence of internal diverging teeth ; it is never
auriculated, as in Posidonia, and the position of the hinge groove is very different ; in
Posidonia it forms a depression in the hinge plate, lengthened laterally, but in our genus
it is transverse. The form occurs throughout the Oolitic rocks of England, exemplified
by several species, which have usually been referred either to Anomia or to J^lacuna, — an
erosion which not unfrequently occurs at the thinnest part of the valves where the
muscular impression is situated, having apparently been mistaken for the foramen of an
Anomia.

PLACUNOPSIS JURENSIS, Eoem. Sp. Tab. I, fig. 8, 80 b.

PLACUNA JUEENSIS, Roemer. Verst. Nord. Deutsch. Ool., p. 16, t. 16, f. 4.
ANOMIA JUEENSIS, Morris. Cat. Brit. Fos., p. 105, 1843.

Testa orbicularis, irregulari, papyraced, sublamellosd ; valvd convexd, umbone odtuso,
depresso, sulmarginali ; lineis radiantibus nodosis, laminis concentricis impressis. Valvd
alterd planatd, umbone parvo depresso, lineis radiantibus undatis et tenuissimis.

Shell orbicular, irregular, very delicate, somewhat lamellose ; convex valve with the
umbo, submarginal, obtuse, and depressed ; radiating lines knotted, fine, numerous, waved
and irregularly impressed with the concentric lamina?. The other valve flattened or
irregularly concave, its umbo small and depressed, the surface ornamented with numerous
irregular radiating knotted lines.

In numerous instances this species attached itself by the flat valve to Pectens, Lima,
and Triffoniee, whose characteristic markings although scarcely, if ever, indicated on the
interior of either valve, appear distinctly impressed upon the outer surface of the convex
valve, almost obliterating the ornamented structure proper to the valve, so that the surface
of the Placunopsis seems like a delicate tissue or veil spread over the Trigonia or Pecten.
What renders this fact the more remarkable is, that the species of Lima, Pecten, and
Trigonia, are very abundant, and are invariably found free from other attached
shells. The valves of this delicate shell are abundant in the shelly beds of the Great
Oolite, and occur likewise, though more rarely, in the Fuller's-earth and Inferior Oolite
of Gloucestershire ; but care is required to detach specimens, as it breaks with any trifling
concussion.

Localities. Minchinhampton Common and Bisley Common in the Great Oolite.
Leckhampton Hill and Nailsworth in the Inferior Oolite.

BIVALVIA. 7

PLACUNOPSIS SOCIALIS. Tab. I, fig. 9, 9a.

Testa parvd ovato-orbiculari, valvis valde incEqualibus et irregularibus, lineis radiantibus
subtillissimis confertis ; plicis concentricis paucis irreyularibus.

Shell small, ovately orbicular, with the valves very unequal and irregular ; the
umbones are marginal but very depressed, and scarcely distinguishable ; the surface is
covered with extremely fine densely arranged radiating lines, which are commonly visible
under a magnifier upon the convex valve, and very rarely in the flat valve ; the concentric
plications are few, strongly marked and irregular.

This little shell is usually coloured with tints varying from lake to indigo and brown ;
it occurs throughout all the shelly beds of the Great Oolite in the Minchinhampton
district ; and towards the middle of the series in the soft shelly Oolite or oven stone, it is
peculiarly abifndant and gregareous, the largest specimens having a diameter oi about
7 lines ; although it does not exhibit any marks of having been attached or compressed,
the figure of the valves is even more irregular than in P. Jurensis.

Localities. Minchinhampton and Bisley Commons.

PLACUNOPSIS ORNATUS. Tab. I, fig. 11,11«.

Testa parvd, ovato-orbiculari subpland, fragili, umbonibus sub-marginalibus depressis,
contulis radiantibus numerosis cqualibus et regularibus, aliisque interstitialibus tenuissimis,
costulis spinis fistulosis, numerosis, depressis ornatis.

Shell small, ovately orbicular, transverse, compressed, irregular, very thin ; umbones
sub-marginal, depressed, radiating costse elevated, rounded, numerous, equal and regular,
with interstitial and very fine striae ; the costae are ornamented with numerous depressed
fistulous spines.

The radiating costae are elevated and undulated, and the numerous depressed fistulous
spines which ornament them render it a pretty object under the magnifier ; the character
of the surface altogether is very similar to that of Ostrea spondyloides, (Schloth, Goldfuss,
t. 72, fig. 5,) but that species pertains to the Muschelkalk. The other valve has not been
recognised.

Locality. Minchinhampton Common.

PLACUNOPSIS RADIANS. Tab. I, fig. 10.

Testa parvd sub-orbiculatd, umbone parvd, depresso, sub-marginali, lined cardinu
subrectd ; costulis radiantibus rotundis distantibus et fistulosis, interstilialibus l<evigatis ;
plicis concentricis distantibus.

Shell small, sub-orbicular; umbo small, depressed, sub-marginal, hinge line nearly
straight ; radiating costa? rounded, elevated, rather irregular, distant, with fistulous
plications upon their surfaces ; the interstitial spaces are smooth ; the concentric plications
are few and distant ; the general convexity of the shell is moderate, but the convex valve
is unknown : not unfrequently near to the border a second series of costae commence, but

8 MOLLUSCA FROM THE GREAT OOLITE.

which have no particular reference to the size of the shell. The large distant radiating
costae will distinguish this from P. ornatus, to which it is nearly allied.

'Locality. Minchinhampton Common, where it occurs rarely in the soft shelly Oolite
beneath the planking.

PECTEN, Lamarck.

PECTEN, Rumphius, Chemn., Bolten, fyc.
JANIRA, Schum, If Orb.
NEITHEA, Drouet.

Gen. Char. Shell regular, inequivalve, inequilateral, eared, hinge margin straight,
surface with radiating ribs, lines or other elevations : hinge destitute of teeth, but having
a central triangular pit containing the cartilage, muscular impressions one in each valve,
large, sub-central.

PECTEN VAQANS, Sow. Tab. I, fig. 12, 12<z.

PECTEN VAGANS, Sow. Min. Con., t. 543, figs. 3,4, 5, 1826.
— SCLCATUS, Young and Bird. Geol. Yorks. 333, t. 9, f. 9.

Testa ovatd sub-compressd, sub-eequivalvi, lamellis imbricatd, costis raris regularibus
(10 — 11), valves sinistrte angustis, squamis squamosis magnis, regularibus; dextras costis latis
confertim lamello-imbricatis ; auriculis magnis incequalibus lineatis.

Shell ovate, rather flattened, nearly equivalve, with imbricated lamellae ; costae few,
regular (10 — 11), and narrow, with regular elevated squamous folds in the left valve; the
right valve undulated with wide depressed costae crossed by densely arranged imbricated
lamellae ; auricles large, unequal, lineated.

This shell, although so very abundant and well known, has nevertheless been
confounded with another very distinct species by Goldfuss, tab. 90, fig. 8, where an
elongated and convex shell, with few squamous costae, has unfortunately received this
appellation ; this latter shell, which is from the Lias of Bavaria, has only a remote resem-
blance to Pecten vagans. The costae of the left valve are regular, symmetrical, and have
the elevated plicae upon their surface regularly and rather closely arranged, the interstitial
spaces are narrow and slightly impressed with the plications ; the surface of the other valve
is nearly destitute of costae, and exhibits them faintly only and near to the border. It is
rare in the Upper Ragstones of the Inferior Oolite, but very abundant throughout the
Fuller's-earth and Great Oolite, and is usually accompanied by Ostrea acuminata and
Avicula echinata. It occurs also in the Cornbrash near Chippenham, Wiltshire.

PECTEN WOODWARDII. Tab. I, fig. 20.

Testa aBquivalvi suborbiculari, convexd, auriculis magnis intsqualibus, tenuissime striatis;
costis magnis radiantibus rotundis arcuatim divergentibus (circa 40 in ambitu), interstiis
angustis conformibus.

BIVALVIA. 9

Shell equivalve, suborbicular, convex ; auricles large, unequal, and finely striated; costae
large rounded, radiately diverging (about 40 in the circumference), interstitial spaces
narrow and conformable.

The anterior auricle is very large, the posterior one small; the costae are regular, rounded,
and closely arranged, the convexity of the valves is so considerable that the diameter
through both is nearly equal to the lateral diameter. The general aspect is sufficiently
distinct from all the associated species ; Pecten arcuatus, which has the costae similarly
disposed, has a figure much less convex and orbicular, and the interstitial spaces are
punctated.

Locality. This species is not unfrequently found in the white stone of Bussage and
Eastcombs, bordering upon Bisley Common, and we are not aware that it has been found
at any other locality.

The name from Mr. S. P. Woodward, of the British Museum, to whom it is dedicated.

PECTEN PEKEGRINUS. Tab. I, fig. 14.

? Var. of PECTEN VAGANS, Sow.

Testa intequivahi, ovato-orbiculari, auriculis magnis incequalibus costellatis ; valvd
sinistrd subpland, costis radiantibus angustis, plicatis (circa 9), intervallis incequalibus,
nonnunquam costulis interstitialibus evanescentibus hinc et inde dispositis. Valvd dextrd
convexd lamellis tenuissimis concentricis imbricatis, et sulcis magnis radiantibus (circa 10).

Shell inequivalve, ovately orbicular, auricles large, unequal and costellated ; left valve
rather flattened, radiating costse (about 9) arranged at irregular distances, narrow, nearly
equal, with small and irregular plications; there are likewise two or three small interstitial
lines or elevations upon the anterior side of the valve. Right valve convex, with very fine
concentric and imbricated lamella?; radiating sulcations (about 10) large and rather
irregular.

The irregular distances at which the four anterior costse of the left valve are placed,
their narrow figure and small plications, will serve to distinguish it from Pecten vagans,
the great convexity and obliquity of the other valve will equally distinguish it from Pecten
jibrosiis. It occurs somewhat rarely in the shelly beds of the Great Oolite.

Localities. Minchinhampton and Bisley Commons.

PECTEN RETIFERTJS. Tab. I, fig. 15, 15<z.

Testa ovato-orbiculari, convexo-pland, auriculis magnis sudesqualidus reticulatis; lineis
radiantibus clatis numerosis, irregularibus, aliis concentricis et elatis paucioribus decussatis.

Shell ovately orbicular, moderately convex, auricles large, nearly equal and reticulated;
with radiating lines, elevated, numerous and somewhat irregular, crossed by others elevated
and rounded but of unequal size and more distant.

The surface is crossbarred and somewhat rugose, the concentric lines in the more

2

10 MOLLUSCA FROM THE GREAT OOLITE.

advanced stage of growth being very prominent, unequal, rather irregular, and commonly
covered with adherent shells ; some slight undulations or irregularities are visible upon
both descriptions of lines ; young individuals are more depressed and ovate, their lines are
very regular and distinct. It occurs not uncommonly in the planking beds throughout the
Minchinhampton district, but the surfaces of the valves are frequently much obscured by
adherent shells and adventitious matter entangled in the crossbarred surface. Height,
23 lines; lateral diameter, 21 lines.

Localities. Minchiuhampton and Bisley Commons.

PECTEN HEMICOSTATUS. Tab. I, fig. 16.

? Var. of PECTEN VAGANS, Saw.

Testa ovato-orbiculari incequivalvi subnequilaterd, valvd sinistrd convexd, lineis radi-
antibus irregularibus et lamellis concentricis crebris ornatd ; estate adulto costis radiantibus
magnis (51 distantibus plicis magnis instructis ; intervallis latis, costulis minoribus interdum
evanescentibus. Valvd deastrd depressd, lamellis concentricis crebris, interdum interrupts,
et sulcis radiantibus leviter impressis. Auriculis magnis intequalibus, costellatis.

Shell inequivalve, nearly equilateral, ovately orbicular, the left valve convex, with
numerous irregular radiating lines crossed by closely arranged concentric lamellae ; the
adult condition has the valve more convex, with five large elevated plicated and distantly
arranged radiating costae ; the intervals are wide, each having a supplementary costa
more or less distinctly marked. The right valve is much more flattened, with concentric
densely arranged lamellae, sometimes interrupted, and a few radiating sulcations, which
are so faintly impressed, that they are only visible near to the lower border. Auricles
large, unequal, and costellated.

The surface of the convex valve in progress of growth undergoes a striking change ;
in the young state it is beautifully reticulated, but has no indications of the costae which
afterwards distinguish it ; the adult shells have a form more convex, with five prominent
radiating costae, of which those at the sides are the smaller; the costae have a few large
irregular plications ; it is only shells of the largest size that have a supplementary costa in
each of the interstitial spaces. The imbricated lamellae of the right valve are more
prominent than those of Pecten vagans, and the sulcations are much less strongly
impressed, so that they can only be discovered by a close examination. It occurs not
unfrequently in the shelly beds of the formation ; but, from the general coarseness of
the deposit, the more delicate features of the surface are rarely preserved. The right valve
is delicate, and few specimens have been distinguished.

Locality. The Minchinhampton district of the Great Oolite, throughout the
shelly beds.

BIVALVIA. -' ..rvl 11

PECTEN PERSONATUS, Gold/.? Tab. I, fig. 17.

? PECTEN PERSONATUS, Goldfuss. Petref., p. 75, t. 99, fig. 5.

Testa intequivalvi, <Bquilaterali, sub-orbiculari, convexo-pland, pellucidd, interne
(12 — 14) costatd; valvd sinistrd costis externis minutis crebris lineis concentricis
decussatis ; dextrd loevi, auriculis inaqualibus obtusangulis costatis. (Goldfuss.)

Shell inequivalve, equilateral, sub-orbicular, slightly convex, pellucid, its inner surface
having costse (12 — 14), left valve with very numerous external irregular radiating
costae, decussated by closely arranged concentric lines ; the right valve smooth, its auricles
unequal, obtusely angulated and costated.

It is only when the matrix consists of very fine sediment that the surface markings
of this small and delicate shell can be distinguished ; it is consequently rarely obtained.
The specimens recorded by Goldfuss were found in the Inferior (eisenschussiffen) Oolite
of Grafenburg and Besancon.

This species differs somewhat from the figure of Goldfuss, in having the longitudinal
striation on the ears more prominent.

Localities. Minchinhampton and Bisley Commons in the Great Oolite; it occurs
also in the Inferior Oolite of the same district.

PECTEN ARCUATUS, Sow. Tab. I, fig. 18.

PECTEN ARCXJATUS, Sow. Min. Con., t. 205, f. 5 — 7, 1818.

1 Goldfusg. Petref., p. 50, t. 91, f. 6.
? Var. of PECTEN LENS, Saw., fide Bronn and Phillips.

Testa ovato-orbiculari, convexo-pland, cequivalvi, costettis radiantibus confertis, arcuatim
diverffentibus, hinc inde dichotomis, striis interstitialibus punctatis ; auriculis incequalibus
costellatis.

Shell ovately orbicular, slightly convex, equivalve, with radiating, depressed little ribs
closely arranged, diverging with a curvature and sometimes dichotomous, the interstitial
spaces punctuated ; auricles unequal, ribbed.

The radiating ribs are moderately broad, but much depressed, and undulate rather
irregularly where they are crossed by the few concentric folds of growth. This species
occurs rarely in the shelly beds of the Great Oolite.

Localities. Bussage or Bisley Common ; Stonesfield, Oxfordshire.

PECTEN LENS, Sow. Tab. II, fig. 1, la.

PECTEN LENS, Sow. Min. Con., t. 205, f. 2, 3, 1818.
Goldfuss. Petref., p. 49, t. 91, f. 3.
Zieten. Wurtt., p. 69, t. 52, f. 6.

D'Orb. In Murch. Russia, &c., ii, p. 476, t. 42, f. 1, 2.
Quenstedt. Wurtt, pp. 337, 538, 544.
Bronn. Leth. Geog., p. 206, t. 19, f. 7.
? PECTEN ANNULATUS, Sow.' Min. Con., t. 542, f. 1.

— Goldfuss. Petref., p. 49, t. 91, f. 2.

12 MOLLUSCA FROM THE GREAT OOLITE.

Testa obliqud, ovato-orbiculari, plano-convexd, sub-eequivalvi, reticulatd, lineis confertis
concentricis et radiantibus arcuatim diveryentibus, hinc inde furcatis ; auriculis incequalibus
reticulatis.

Shell oblique, ovately orbicular, moderately convex, equivalve, radiating lines narrow,
closely arranged, irregular, curving outwards, the interstitial spaces densely punctated or
reticulated, occasionally bifurcated; concentric lines irregular; auricles unequal and
reticulated.

There does not seem to be any sufficient or constant character which will enable us to
separate this species from the Pecten annulatus of the Mineral Conchology and of
Goldfuss; both have occasionally a certain degree of obliquity; the radiating lines of both
are reticulated and bifurcated, becoming almost evanescent in the ultimate stage of
growth; in the latter condition, the concentric elevated lines become constant, are much
more prominent than the radiating lines, and do not furnish any peculiar or characteristic
feature, we are therefore inclined to reunite the two species, and regard the annulated form
to be merely a variety of the present one. Next to the Pecten vagans, this ranks as the
most abundant Pecten of the Great Oolite, its vertical range is likewise remarkable, as it
is found throughout the rocks of the entire Oolitic system ; but attains its greatest deve-
lopment of size in the Coralline Oolite of Malton.

Localities. Wherever the Great Oolite is fossiliferous.

PECTEN ANNULATUS, Sow. Tab. I, fig. 13.

? Var. of PECTEN LENS.
PECTEN ANNULATUS, Sow. Min. Con., t. 542, f. 1, 1826.

Goldfuss. Petref., t. 91, f. 2.
OBSCDRUS, Sow. Min. Con., t. 205, f. 1.?

Testa ovato-orbiculari, sub-aquivalvi, convexo-pland, striis radiantibus subtillissimis,
ineequalibus arcuatim divergentibus, lineis aut lamellis concentricis distantibus interruptis ;
auriculis incequalibus striatis.

Shell ovately orbicular, nearly equivalve, rather depressed, radiating striations very
fine, unequal, densely arranged, and diverging, the striations are broken and interrupted
by prominent concentric lamellae, which are rather distantly arranged ; auricles unequal,
striated.

The apicial portion of the shell is destitute of the concentric lamellae, which commence
abruptly and continue to the lower border of the shell. It occurs commonly in the
Cornbrash, Forest Marble, and in the upper portion of the Great Oolite ; but is not found
in the shelly beds of the Michinhampton district.

Localities. Near Cirencester, and at Sapperton Tunnel, Gloucestershire ; in the upper
beds of the Great Oolite, at Blisworth, Kingsthorpe, and other places in Northamptonshire
and Lincolnshire ; it occurs also in the Stonesfield Slate.

BIVALVIA. 13

PECTEN CLATHRATUS, Eoemer. Tab. I, fig. 19, 19a.

PECTEN CLATHKATUS, Eoemer. Verst. Nordd. Oolith., t. 13, f. 9, 1836.

Testa ovato-orbiculari sub-eequivalvi, tenui plano-convexd ; auriculis magnis ineequali-
bus, valvd sinistrd convexiord ; lineis radiantibus granulosis crebris ineequalibus et irregu-
laribus, lineis concentricis obsoletis decussatis. Valvd dextrd lineis radiantibus remotioribus
et irregularibus, lineis concentricis clathrato-nodosis.

Shell ovately orbicular, subsequivalve, thin, rather flattened, auricles very large, unequal,
and striated ; left valve moderately convex, with radiating densely arranged granulated
lines, irregular and unequal, crossed by very obscure closely arranged concentric lines, for
the most part obsolete. Right valve more flattened, radiating lines more remote, but
unequal and irregular, nodose where they are crossed by regular and distinct lines consti-
tuting a finely cancellated surface.

This very delicate and elegant species has the anterior auricles remarkably large ; the
right valve varies very considerably in the close arrangement of the radiating lines, and in
their prominence; the concentric lines are very irregular, unequal, and uncertain in
their prominence, so that many specimens which appear shining and smooth to the
unassisted vision, disclose, under a magnifier, a very perfect and distinctly ornamented
surface. Its entire aspect is sufficiently characteristic to render it easily distinguishable
from contemporaneous species.

Height, 18 lines; lateral diameter, 16 lines.

Localities. Minchinhampton and Bisley Commons, in the shelly beds of the
formation.

HINNITES, De France, 1831.

Gen. Char. Shell ovate, sometimes oblique, irregular, inequivalve ; umbones de-
pressed, approximate ; auricles unequal, posterior auricle small, sometimes nearly obsolete,
anterior auricle produced ; left valve convex, right valve flattened, delicate, adherent.
Hinge straight without teeth, with a mesial trigonal fossa, as in Pecten. The surface is
ornamented with radiating, imbricated, or nodulated costaa.

There is usually some degree of obliquity in the valves ; the convex valve is never
adherent, the other constantly so, which together with its extreme delicacy will account for
it having been so rarely discovered.

The shells of this genus have been described as Spondylus by Goldfuss, but they are
really very distinct from that genus ; the extreme delicacy and irregularity of the valves
would lead us to the distinction, irrespective of the hinge characters which are equally
distinct from those of Spondylus.

The finest examples of this genus are found in the Inferior Oolite, both in number,
dimensions, and variety of ornament.

14 MOLLUSCA FROM THE GREAT OOLITE.

HINNITES VELATUS, Gold/., Sp. Tab. II, fig. 2.

PECTEN VELATUS, Goldfuss. Petref., t. 90, f. 2.

— Roemer. Verst., p. 67.
SPONDYLTJS VELATUS, Goldfuss. Petref., t. 105, f. 4.

Testa ovato-orbiculari convexd, auricula untied magnd costellatd, posticd parvd, sub-
obsoletd ; costellis radiantibus (circa 30) nodulosis, subaequalibus, distantibus ; inter-
stitialibus lineatis ; lineis nodulosis irregularibus. Valvd dextrd planatd costellis lineisque
ornatd.

Shell ovately orbicular, rather oblique, convex, anterior auricle large, posterior small,
nearly obsolete, radiating little costa3 (about 30 in the circumference) nodulated, nearly
equal, and distantly arranged; the interstitial spaces have unequal and irregular nodu-
lated lines, from one to three, being contained in each space. The right valve is flattened
and ornamented in a manner similar to the other.

This species would appear to have a considerable range, both stratigraphically and
geographically ; it occurs in the shelly freestone beds of the Inferior Oolite, in the Fullers-
earth, Great Oolite, Forest Marble, and Cornbrash.

Localities. Leckhampton Hill, the Sapperton Railway Tunnel, the entire Minchin-
hampton district of the Great Oolite, and in Northamptonshire and Lincolnshire.

HINNITES TEGULATUS. Tab. II, fig. 3, 3a.

Testa ovato-orbiculari convexd; valvd sinistrd auricula anticd magnd; posticd subnulld ;
costellis radiantibus (32 — 34) tenuibus, regularibus transverse plicatis ; plicis vel tegulis
concentricis crebris sub(equalibus intcrruptis.

Shell ovately orbicular convex, the left valve with a large posterior auricle, anterior
auricle obsolete ; radiating little ribs (32 to 34 in the circumference,) fine, regular, and
transversely plicated ; plications concentric nearly equal, closely arranged but occasionally
interrupted.

The radiating little ribs are delicate, regularly arranged, and impressed by the con-
centric plications, they are prominent about the middle of the valve, and become finer
towards the sides; the right valve is unknown. The figure presents an approximation to
that of H. velatus, but it appears to have more convexity and less obliquity; moreover the
character of the surface, with its fine regular distinct radiating ribs, is very different from
the irregularity observable in the other species. Height, 10 lines; lateral diameter, 8 lines.

Locality. Minchinhampton Common. Rare.

PLICATULA. Lamarck, 1801.

Gen. Char. Shell adherent, inequivalve, irregular, not eared, umbones terminal and
pointed, no external area; ventral margin rounded, and more or less plicated. Hinge
with two large diverging cardinal teeth in each valve, the teeth are striated laterally, and
there is a conical fossa between them to receive the ligament, which is almost internal.

BIVALVIA. 15

PLICATULA TUBERCULOSA. Tab. II, fig. 4.

Testa ovato-orbiculari subobliqud, convexo-pland tuberculis obtusis numerosis in lineis
radiantibus fere disjpositis; umbonibus leevigatis sine tuberculis.

Shell very irregular, ovately orbicular, rather oblique, and depressed with numerous
obtuse tubercles, for the most part disposed in radiating imperfect lines, umbonal extremity
smooth, destitute of tubercles.

The round blunt warty tubercles have an aspect very different from the spines, either
fistulous or pointed, with which the Plicatulce, are for the most part furnished. The
tubercles usually increase in size towards the ventral border of the valve, but in a very
irregular manner, which, together with the very unequal and irregular surface of the valve,
produces a very confused appearance ; thus it happens that no two specimens can be found
which nearly resemble each other ; occasionally, the tubercles may be discovered approxi-
mating to the fistulous character ; the margins of the valves are plicated in a very irregular
manner. It is somewhat rare, but occurs in several of the shelly beds.

The two diameters across the valves are nearly equal, and rarely exceed 10 lines.

Localities. Minchinhampton and Bisley Commons.

PLICATULA FISTULOSA. Tab. II, fig. 5.

Testa ovato-orbiculari depressd, costulis fistulosis radiantibus irregularibus interstitialibus
profundis.

Shell ovately orbicular depressed, costa3 radiating irregular, with numerous irregular
prominent fistulous spines ; interstitial spaces deep.

About 12 or 13 costse are distributed around the circumference of the valve ; owing to
the delicacy of the test, it is very rarely that a perfect specimen can be obtained.

Locality. Minchinhampton Common.

AVICULA, Lam. 1801.

Gen. C/iar. Shell inequivalve, eared, base transverse, straight, its extremities produced
and forming auricles, left valve convex, umbone prominent ; right valve smaller, flattened,
its umbone depressed, and nearly obsolete. Hinge linear with a small indistinct tooth
in each valve beneath the umbones, and a lengthened marginal ligamentiferous area. One
rounded subcentral muscular impression in each valve, with a series of smaller ones in a
Jine near the umbones.

AVICULA COSTATA, Sow. Tab. II, fig. 6, 6a.

AVICULA COSTATA, Sow. Min. Con. t. 244, f. 1, 1819.
Smith. Strat. Syst., pp. 67, 81.
16. Strata Ident. Clay over the Upper Oolite, f. 8.

16 , MOLLUSCA FROM THE GREAT OOLITE.

Testa convexd oblique-ovatd, auriculis parvis subcequalibus, umbonibus prominulis, costis
(circa 18), radiantibus equalibus rotundis, distantibus, interstitiis planis, latis et Iceviffatis.

Shell convex obliquely ovate, auricles small, nearly equal, umbones prominent, costse
(about 18), radiating, equal, rounded and distant, the interstitial spaces flattened, wide
and smooth.

This shell, so characteristic of the Bradford clay of Wiltshire, occurs very rarely in
the shelly beds of the Great Oolite, and these are of very diminutive size.

Locality. Minchinhampton Common.

AVICULA ECHINATA, Sow. Tab. II, figs. 7, la.

AVICULA ECHINATA, Sow. Min. Con., t. 243, 1819.
Smith. Strat. Syst., p. 67.

Ib. Strata Ident., p. 26 ; Cornbrash Plate, f. 8.
? Var. AVICULA TEGULATA, Goldfuss. Petref., ii, p. 132, t. 121, f. 6.

Testa ovato-obliqud, auriculis equalibus parvis, valvd sinistrd convexd costulis radian-
tibus numerosis, aliis minoribus interstitialibm alternatis, et lineis transversis decussatis
nodisformante. Valvd alterd subpland, leevic/atd, lineis radiantibus tenuissimis subobsoletis.

Shell ovately oblique, auricles equal and small ; left valve -convex, with numerous radi-
ating ribs, alternating with a smaller series in the interstitial spaces, and decussated by
transverse, rather distant, regular lines, which form little knots as they pass over the
costae ; the knots are more elevated, and closely arranged upon the anterior side of the
shell. The other valve is nearly flat, smooth, with very fine distant and rather indistinct
radiating lines.

This species is moderately common in the shelly beds of the Great Oolite, but the
valves are always disunited, and its state of preservation very inferior to specimens obtained
from the clay beds of the Fullers-earth, the Bradford Clay, or the Cornbrash, for its
vertical range is very considerable.

Localities. Wherever the Great Oolite is shelly. Other geological positions are the
Fullers-earth clays, of the Cotteswolds ; likewise in the clays of the Cornbrash, the Forest
marble, and the Bradford clay of Wiltshire ; and also at Pavingham and other places in
Bedfordshire.

Sub- Genus — PTEROPERN A .

Testa sub(squivalvi ineequilaterd, utraque latere alatd, aid anticd brevi, posticd pro-
ductd, et marffinatd.

Margo cardinalis rectis, plus minusve obliquis, area ligamenti internd, elongatd,
margini externi paralleld.

Cardo dentibus infra umbonem numerosis angustis parallelis et minutis antrorsum
rergentibus et costis posticis elongatis margine cardinali parallelis.

BIVALVIA. 17

Umbones anteriores parvi depressi. Impressiones musculares duee, in utraque valvis
anticis parvis, poslicis magnis ellipticis.

Fades externa sulco longitudinali elongato, sub-marffinem cardinalem sitam.

Shell nearly equivalve, inequilateral, both extremities winged, anterior wing short,
posterior elongated, its extremity marginated.

Hinge margin straight, more or less oblique, ligamental area internal, and nearly
parallel with the external margin. Hinge with numerous very small parallel teeth placed
beneath the umbones near to the anterior extremity of the shell, and one or two posterior
or internal costse, which are elongated and extend posteriorly nearly parallel with the hinge
margin. Umbones anterior, small and depressed. Muscular impressions two in each
valve, of which the anterior or byssal are very small ; the posterior expanded, elliptical,
and not strongly marked. External surface either ornamented or plain, having an
elongated longitudinal groove extending posteriorly to the umbo, and parallel with the
hinge margin in each valve.

This remarkable Oolitic form replaces and represents the genus Pterinea of the
Palaeozoic formations ; its affinities to that genus are so evident, that it is necessary to
inquire whether Pteroperna should be arranged as a sub-genus of Pterinea only, or is
entitled to rank as a distinct genus. The principal distinguishing features are internal.
In Pterinea the posterior elongated accessory ribs or teeth proceed obliquely downwards
towards the inferior and posterior extremity of the valves, as far as the border of the large
posterior muscular impression, at the anterior side of which they terminate abruptly; the
muscular impression is angular, and extends upwards nearly to the hinge margin
posteriorly. In Pteroperna, on the other hand, the posterior costae extend along the
inner surface of the hinge margin, almost parallel with it, and are consequently placed
upon the hinge plate above the muscular impression, which is rounded or elliptical, and
placed lower or more nearly to the middle of the posterior surface. As minor points of
distinction it may be mentioned, that iu Pterinea the anterior teeth vary in number from
two to four only; but in our typical shell, Pteroperna costatula, they are not less than
sixteen, and are so minute that they scarcely occupy a greater longitudinal space than
those of Pterinea. Externally our genus possesses a characteristic feature very convenient
for the Palaeontologist, who is rarely able to refer to the hinge, and which readily serves
to distinguish it both from Pterinea and Avicula; we allude to the elongated posterior
groove, which is always visible upon the surface, and of which the other two forms are
destitute. Regarding, therefore, the position of the internal ligamental groove and
accessory costae, together with the form and position of the posterior muscular impression
as indicating a corresponding difference in the structure of the animal, when compared
with those parts of Pterinea, we consider ourselves justified in considering the Oolitic
form as a genus distinct from but nearly allied to Pterinea.

Pteroperna also presents considerable analogy to the recent genus, Malleus.

18 MOLLUSCA FROM THE GREAT OOLITE.

PTEROPERNA COSTATULA, Deslongchamps, sp. Tab. II, figs. 8, 8a, 13, 13a.

GEKVILLIA COSTATULA, Deslongchampg. Mem. Soc. Linn, du. Calvados, 1824 ; torn, i,

t. v, figs. 3—5.
AVICULA POLYODON? Buviffnier. M&n. Soc. Philomath. Verdun, 1845, pi. iv, fig. 16.

Testa obliqud, lined car dinali recto, elongato, postico valde producto et emarginato, valvd
sinistrd modico convexo, valvd dexlrd subpland, unbone depresso, latere postico in utraque
valvd curvato aut excavato.

In (Btate juniori, valvd sinistrd convexo-brevi, costulis radiantibus (6 — 8) elatis, acutis
subundulatis, et iruequalibus cum lineis transversis interstitialibus regularibus et tenuis-
simis.

In estate adulto, valvd sinistrd sine costulis aut striis cum laminis incrementi paucis,
distantibus. Valvd dextrd semper l&vigatd.

Shell oblique, hinge line straight, elongated, very much produced posteriorly and
emarginated, left valve moderately convex, right valve more flattened, the umbo depressed;
posterior side in each valve curved, its margin concave.

This species occurs under the following conditions of growth : —

In the young state, the left valve is very convex and short, having radiating costae
(6 — 8) elevated, acute, slightly waved and unequal, the interstitial spaces with regular,
transverse, fine, closely arranged lines.

In the adult state, the left valve is without costae or striae, having only a few distant lines

of growth. Were instances wanting to exemplify the advantage which is derived from the

inspection of a large number of specimens in every stage of growth, undoubtedly the

present species might be selected for such a purpose, the two extremes of growth presenting

an aspect so dissimilar, that until numerous examples of every intermediate grade had been

obtained, we hesitated with respect to their specific distinctness or identity ; minute

specimens occur in great numbers, having a length of only three or four lines ; in these

the costae are always very prominent, the number of costae vary from 6 to 8, they occupy

only the middle portion of the valve, the sides being plain. The costae continue

distinct, but less conspicuous, when the shell has attained a diameter of 16 or 18 lines,

but the costae have then become waved, irregular, and unequal; beyond these

dimensions, the valve is either plain, or has only faint indications of costse, crossed and

interrupted by laminae of growth ; but even in the ultimate stage of growth, when the

hinge line has attained the length of five inches or upwards, and the test has acquired a

considerable degree of thickness, the left valve has never so smooth a surface as the

other, the last faint indication of its having previously possessed a sculptured surface.

The specimens figured by M. Deslongchamps and M. Buvignier have only a very remote

resemblance to each other, and tend to illustrate the foregoing remarks ; Gervillia

coslatula is stated by the former author to have only four or five costae, but the smaller

number is probably owing to the less perfect state of the specimen, or to accident ; in the

BIVALVIA. 19

young state, the shell is thin and delicate, more especially the right valve ; the latter
is consequently comparatively rare ; and M. Deslongchamps had not recognised it in
Normandy, when he published his description of Gervillia costatula in 1824 ; at that
period so few species of Gervillia were known, that the usual character of the surface could
not be considered as ascertained, nor likewise the limits to which any variation in the hinge
was restricted ; but now that a considerable number are recorded, it will be found that in
few instances where the hinge of Gervillia has been disclosed has a sculptured surface
been coincident with it : the hinge of Gervillia costatula given by M. Deslongchamps,
differs somewhat from our own, and from the figure of M. Buvignier ; but as it is still
more unlike the hinge of Gervillia, we might from the hinge alone conclude that it had
been incorrectly allocated. The shell figured by M. Buvignier, though very imperfect, is
readily recognised as our own species in the ultimate stage of growth, and having a degree
of obliquity greater than is usual. It occurs in all the shelly beds of the Minchinhampton
district, but specimens of the ultimate stage of growth have only been obtained in the
planking of Minchinhampton Common. The same species, or one nearly allied to it, has
also been procured, rarely, in the free-stone beds of the Inferior Oolite in the same
district.

Localities. Minchinhampton ; Ranville near Caen, Normandy; St. Mihiel, France.

s

PTEROPERNA PYGMEA, Dunker, Sp. Tab. II, fig. 11, ll<z.

AVICULA PYGMEA, Koch and Dunker. Norddeuts. Ool. Versteinerungen, t. 3, f. 6.

Testa parvd, subtequivalvis, ovato-obliqud, concentrice idque obsolete striatd ; aid
anticd rotundatd, sinuatd, posticd excavatd ; umbonibus promimilis.

Shell small, subaequivalve, ovately oblique, concentrically, but obsoletely striated ;
anterior wing rounded and produced, its lower border sinuated, posterior wing excavated
by a longitudinal furrow; umbones rather large and prominent, rising higher than the
hinge line.

The right valve has a somewhat flatter surface than the other, and exhibits very
slight traces of one or two longitudinal costae ; the transverse lines are not usually pre-
served, and are visible only upon a portion of one of our specimens.

Locality. It occurs somewhat rarely in the soft Oolite which overlies the Weatherstoiie
Beds at Minchinhampton Common.

PTEROPERNA EMARGINATA. Tab. II, fig. 10.

Testa subpland, ovato-elongatd et obliqud, valvd sinistrd laivigatd, striis concentricis
subobsoletis ; aid anticd parvd, posticd emaryinatd. Valvd dextrd ignotd.

Shell rather flattened, ovately elongated, and oblique ; left valve smooth, with con-
centric and nearly obsolete striae ; anterior wing small and pointed, posterior emarginated.
Right valve unknown.

20 MOLLUSCA FROM THE GREAT OOLITE.

The degree of obliquity and flatness is much greater than in the associated species,
and the anterior wing is smaller ; some traces of an elongated groove are visible upon the
posterior wing of the left valve.

Locality. Minchinhampton Common, where it is very rare, and occurs in the bed of
soft shelly Oolite which overlies the Weatherstones.

GERVILLIA, Defiance, 1820.

Gen. Char. Shell subaequivalve or inequivalve, inequilateral, elongated, transverse;
hinge margin usually straight, lengthened, and oblique ; umbones small, oblique, anterior,
contiguous, rarely terminal ; hinge linear, marginal, with many oblong parallel, but rather
distant and irregular pits in each valve, placed transversely to the hinge line ; internal
hinge teeth parallel, oblique, placed anteriorly, or beneath the transverse sulci.

The increased number of species exhibit characters which render it necessary to
arrange them under two sections.

a' Shell subaequivalve, margins of the valves regular.

b' Shell very inequivalve and irregular, more or less contorted ; margins of the valves

close fitting, but sinuated.

Section d comprises the usual well-known subaequivalve species.
Section V has for examples G. monotis, Deslong., G. Hartmanni, Goldf., and
G. tortuosa the Gastrocliana tortuosa of Phillips.

Section a.
GERVILLIA ACUTA, Sow. Tab. Ill, fig. 12, 12a.

GERVILLIA ACUTA, Sowerby. Min. Conch., t. 510, fig. 5, 1826.

LANCEOLATA, Goldfuss. Petref., t. 115, fig. 9.
? ACUTA, Phillips. Geol. York., tab. 9, fig. 36, 1835.

? — siLiaUA, Deslongchamps. Mem. Soc. Linn. Calvados., t. 4, 1824.

Testa lanceolatd in vertice convexd, maraine cardinali perobliquo depresso, umbonibm
angustis acutis foveolis (3) quadratis. (Goldfuss.)

Shell lanceolate, slightly curved, subaequivalve, anterior side moderately convex,
posterior side compressed and attenuated ; hinge margin very oblique, with three
quadrate hinge pits; umbones attenuated, anterior auricle acute and pointed, posterior
auricle forming an obtuse angle with the border beneath it ; folds of growth irregular,
strongly marked. Compared with Gervillia monotis, the valves will be found less
contorted or more nearly equivalve, the hinge border shorter, and the posterior auricle is
not produced as in that species ; in common with other species, the right valve is thinner,
smoother, and more flattened than the other.

Localities. It occurs in the Stonesfield slate of the Cotteswolds (Buckman). In the
slaty Oolite of Collyweston, Northamptonshire.

BIVALVIA. 21

GERVILLIA SUBCYLINDRICA. Tab. Ill, fig. 13, 130, b.

? Var. of GERVILLIA ACUTA, Sow.

Testa sub&quivalvi, elongatd, subcylindricd, margine cardinali majis obliquo ; umbone
in valvd sinistrd obliquo, prominulo, antico ; valves dextra umbone depresso, acuto. Cardo
foveolis 3 aut 4, dentibus internis tribus obliquis, anticis.

Shell subsequivalve, elongated, subcylindrical ; hinge line very oblique, lengthened, and
nearly straight ; umbo in the left valve oblique, prominent, but not terminal ; right valve
with the umbo depressed and acute ; hinge with three or four marginal pits, and three
oblique, anterior, and internal hinge teeth.

Without care this shell may be confounded with G. aviculodes, Goldfuss, t. 115, f. 8,
but upon comparison the latter shell will be found wider, and the umbones straighter, and
more acute ; the hinge line also is inclined at a smaller angle, the general figure being
less elongated and cylindrical. From G. siliqua, Deslongchamps, the very different
inclination of the hinge line and straighter form will distinguish it.

Locality. Minchinhampton Common, where it occurs somewhat rarely in the
planking.

GERVILLIA BATHONICA. Tab. II, fig. 15.

Testa oblongd, planatd, subaquivalvi, umbonibus terminalibus acutis, margine cardinali
recto, obliquo, (plerumque ad angulum 45 gradum inclinantibus,} latere antico recto interdum
subexcavato, basi curvatd; foveolis (9) oblongis, cequalibus et regularibus ; dentibus cardinis
interne duobus, obliquis, anticis.

Shell oblong, flattened, subsequivalve; umbones terminal and acute; hinge line
straight, oblique, (for the most part inclined at an angle of 45 degrees,) anterior side
straight, sometimes rather excavated, base rounded ; hinge pits oblong (nine in number),
equal and regular ; internal hinge teeth two, anterior, and oblique.

The figure varies so considerably, that but for the inspection of a considerable number
of examples of all stages of growth, they would probably be separated into at least two
species, hardly two specimens, indeed, can be found exactly alike in the figure of the
anterior margin, the angle at which the hinge is inclined, the degree of convexity in the
valves, or in the general length of the figure.

The terminal position of the umbones together with the straight or even slightly con-
cave figure of the anterior margin gives to it very much the figure of Perna, but the large
oblique internal teeth in the hinge, and absence of the anterior hiatus or corrugation,
effectually separates it from that genus.

Its habits were eminently gregareous, and in certain layers of the white stone at
Bussage and Eastcombs, it occurs in great numbers to the exclusion of nearly every other
species ; but even in these circumstances, the valves are very rarely found in apposition,

22 MOLLUSCA FROM THE GREAT OOLITE.

and the usual length is about an inch ; it occurs, however, in all the shelly beds of the
Minchinhampton district.

In examining approximate species it will be found that the figure is less quadrate than
Perna quadrata, Phillips ; the terminal umbones separate it from Gervittia acuta, Goldfuss;
and from Perna mytiloides, Goldfuss, the straightness gf the hinge line is a point of
distinction.

Locality. Minchinhampton.

GBRVILLIA OVATA, Sow., Sp. Tab. II, fig. 12, 120.

AVICULA OVATA, Sow. Min. Con., t. 512, f. 2, 1826.

Testa ovato-obliqud, conveccd et lavigatd, valvd sinistrd convexd, umbone obliquo,
mediano, margine cardinali brevi, subrecto, margine antico rotunda ; auriculis submellis,
valvd dextrd plano-convexd, umbone parvo. Sulcis cardinis eccterne tribus, magnis, dis-
tantibus et irregularibus ; dentibus cardinis interni subobsoletis.

Shell ovate, oblique, convex, smooth ; left valve with the umbo oblique, nearly mesial ;
hinge line nearly straight, short, the anterior extremity rounded, auricles small ; right
valve more flattened, the umbo small ; external sulci of the hinge three, large, wide, distant
and irregular ; internal hinge teeth scarcely distinguishable.

The valves are always separated and delicate, the test being usually but imperfectly
preserved; the younger specimens are shorter in proportion, and the hinge line exceeds
half the length of the valves ; but in others of large dimensions it is less than half the
length. Owing to its delicacy it is seldom that the hinge can be exposed, but inde-
pendently of this, it entirely wants the anterior hiatus and corrugation which exists in
Avicula and Perna, from the latter genus, indeed, the character of the surface is different,
and it does not possess the squamous structure of the Perna.

Localities. The whole of the Minchinhampton district, in the shelly beds of which
it is moderately common, more especially about the middle of the shelly series. Also at
Stonesfield, Oxfordshire.

Section V.

GERVILLIA MONOTIS, Deslongchamps. Tab. II, fig. 14, 14«, b.

GERVILLIA MONOTIS, Deslongchamps. Mem. Soc. Linn. Calvados, torn, i, 1824, t. 5, f. 2.

Testa elongatd, subarcuatd, valvd sinistrd convexd ; umbone antico, subterminali ;
laminis incrementi impresses ; valvd dextrd pland, interdum concavd, umbone terminali,
depresso et acuto ; margine cardinali obliquo in auricula postico acuto,producto. Cardine
foveis (5) subremotis, dentibus interni duobus, magnis, anticis.

Shell elongated, somewhat bow shaped, left valve convex; umbo anterior, oblique,
almost or completely terminal, prominent, and impressed with laminae of growth ; right

BIVALVIA. 23

valve flat, sometimes concave, its umbo terminal, depressed, and acute ; binge line very
oblique, elongated posteriorly, and produced into an auricle. Hinge with five large and
rather remote sulci; internal teeth two, large and anterior, margins of the valves
sinuated.

This species forms a link connecting two very dissimilar groups of Gervilliae ; it pos-
sesses the characteristics of the second or contorted group in a more modified form than
G. Hartmanni, Goldfuss, or G. tortuosa, the Gastroch(ena tortuosa of Phillips ; these two
latter species pertain to the Inferior Oolite, and the present one to the Great Oolite.
The degree of contortion varies considerably in individuals ; the young specimens have a
very lengthened hinge line ; the lines of growth are strongly marked upon the left valve,
and there are two short obscure ribs diverging from the umbo, these, however, disappeared
in the progress of growth, and the posterior extremity became more produced.

The right valve is more delicate, and is found more rarely than the other ; the same
circumstance occurs likewise in Normandy, where M. Deslongchamps had not seen the
right valve when he described this species. It ranks as one of the most abundant and
characteristic bivalves of the Great Oolite ; it occurs indifferently in all the shelly beds.
Localities. Minchinhampton ; Normandy.

GERVILLIA CRASSICOSTA. Tab. II, fig. 9.

Testa valde obliqud, elongatd, convexiusculd, auricula antico rotundato, postico truncate
et brevi ; costis radiantibus subundatis, elatis majoribus 8, alternatim minoribus, et cum
striis transversis numerosis, indentatis, latero postico elongato : valvd dextrd ignotd.

Shell very oblique, elongated, convex, anterior auricle rounded, posterior auricle
short and emarginated ; radiating costae slightly waved, elevated, the larger 8 in number,
distant, and alternating with as many smaller, and impressed with numerous rather
indistinct transverse striae : posterior and inferior extremity elongated and slightly
acuminated : right valve unknown.

Of this rare species we have only obtained three examples ; the hinge border is much
shorter than in Pteroperna costatula, the posterior wing being but little produced ; the whole
contour of the shell is very oblique, and the larger costa3 are very prominent ; the greater
degree of obliquity, convexity, and alternation of the costae, readily serve to distinguish it
from P. costatula.

Locality. Minchinhampton Common.

GERVILLIA RADIANS. Tab. VI, fig. 10.

Testa magnd crassd inaquivalvi valde contortd, valvd sinistrd arcuatd, umbone magno
incurvo, valvd dextrd oblique-concavo, umbone depresso ; margine cardinali elongato
subhorizontali, auriculis prominulis ; lateribus lineis radiantibus paucis obscuris ; aliis
concentricis dense dispositis.

Shell large, very thick, inequivalve, very much contorted, the left valve very convex,

24 MOLLUSCA FROM THE GREAT OOLITE.

arched, with the umbo large and incurved ; right valve oblique and concave, its umbo
depressed ; hinge margin elongated, nearly horizontal, with prominent auricles ; the surface
of the convex valve has a few obscure radiating lines decussated by others, which are
concentric, irregular, and very densely arranged.

The general aspect has a considerable resemblance to Gervillia Hartmanni (Goldfuss),
but it is more contorted than that shell; the valves are shorter, the diameter through them
is greater, and the hinge line is so much less oblique as to be nearly at right angles to
the axis ; owing to this figure and the length of the hinge line, the posterior auricle
projects considerably.

Locality. Morcot, Rutlandshire.

INOCERAMUS. Park. 1811.
INOCEHAMUS, CATILLUS, MYTILOIDES, Brong.

Gen. Char. Shell inequivalve, sub-equilateral, ovately trigonal, umbones prominent,
incurved; hinge straight, nearly horizontal, consisting of a series of transverse parallel
teeth in each valve ; substance of the test fibre-lamellar.

INOCERAMUS? OBLIQUUS. Tab. VI, fig. 12.

Testa ovato-obliqud subdepressd, subaquivalvi, umbonibus prominulis subcequalibus,
margine cardinali brevi obliquo, margine anteriore et inferiore curvato, posteriore
subsinuato ; lateribus plicis concentricis elatis, angustis incequalibus ct irregularibuz,
interdum sub-acutis.

Shell ovate, oblique, rather depressed, subaaquivalve, umbones prominent, nearly
equal, hinge margin short, oblique, anterior and inferior margins gracefully rounded,
posterior border slightly sinuated ; the sides of the valves concentrically plicated ; the
plications are elevated and narrow, irregular and unequal, sometimes acute ; the substance
of the shell is thin. It is more oblique, wider, and less pointed than the I. cinctm from
the Oolite of Ireland, and more depressed than any other Oolitic species with which
we have compared it; the valves are thin, frequently in opposition, and are more or
less compressed and distorted ; the surface is smooth, shining, and is destitute of any
striations.

Length, 2| inches; breadth, 2j inches; diameter through both the valves about
1£ inch.

Locality. Morcot, Rutlandshire.

INOCERAMUS FITTONI. Tab. IV, fig. 14.

? INOCERAMUS AMYDALOIDES, Goldf. Pet., t. 115, f. 4.

Testa tenui ovato-acutd depressd : margine cardinali obliquo posteriore subrecto ; umbo-
nibus subacutis, rugis concentricis in&qualibus et irregularibus.

BIVALVIA. 25

A somewhat oval, depressed, and thin shell, with the hinge margin oblique, and rather
prominent umbones ; surface irregularly undulated.

A shell presenting considerable resemblance in form to /. amydaloides, Goldf., but
we have only been enabled to compare it with casts of that species which is found in the
Lias of Germany.

Locality. Stonesfield, Oxfordshire, where it occurs but rarely.

PKRNA, Brugiere, 1791.

Gen. Char. Shell flattened somewhat irregular, with terminal depressed umbones,
hinge linear marginal, with numerous parallel ligamental pits; byssal sinus anterior placed
a little beneath the umbones, and slightly gaping, its margins thickened; muscular im-
pression oval and situated rather posteriorly; texture of the shell fibre-lamellar.

PERNA RUGOSA. Tab. Ill, fig. 1.

? PERNA RUGOSA, Goldf. Petref. 2. t. 108, f. 2.

Testa subquadratd, complanatd, rugosd, tenui, umbonibus acutis, lined cardinali
horizontali -, laminis superficiei scabris irregularibus.

Shell subquadrate, flattened, rugose, thin, with acute umbones, hinge line horizontal
and of moderate length ; laminae of the surface rough and irregular.

The general figure possesses a considerable resemblance to P. rugosa, Munst. (Goldf.
Petref., 1. 108, fig. 2,) our specimen is, however, more compressed, and the umbones less
prominent, the test is also somewhat thin. The tenuity of the test affords a striking contrast
to several massive Inferior Oolite species, whose general contour is not very dissimilar.

Locality. Minchinhampton Common, where it occurs very rarely in the bed of coarse
planking. The P. quadrata, Phil, is probably identical with this species.

LIMA, Bruff., 1791.
PLAGIOSTOMA, Sp., Sow.

Gen. Char. Shell subequivalve, inequilateral, oblique, aurited, hinge margin oblique,
thickened within, forming a transversely flattened plate, in which and beneath the umbones
is a triangular depression, destined to receive a ligament which is partly internal.1

1 In an interesting communication read before the Linnean Society of alvados, (December, 1830.)
Professor E. Deslongchamps stated the general reasons for uniting the species of Playiostoma to Lima.
In this memoir, not yet we believe fully published, M. Deslongchamps described seventeen species of Lima
from the Jurassic strata of Calvados, and arranged them under four sections : —

1 . Margins of the valves entire, not serrated, luuule distinct : L. gigantea, heterotnorpha.

2. Margins of the valves sinuato-dentate, luntile distinct : L. sulcata, variabilis, ratliata, punctata.

3. Margin of the valves serrated, lunule distinct : L. elliptica, lucida, pulchella, uniaurita, typus,

leevis, semistriata.

4. Margins of the valves sinuato-angular, no lunule : L. alternant, duplicata, yibbosa, exigua.

4

26 MOLLUSCA FROM THE GREAT OOLITE.

It may be conveniently divided into the following groups :

a. Species with the umbones divergent, having between them a triangular area, borders

of the valves rounded, lunule distinct and gaping.

b. Umbones approximate, borders of the valves rounded, lunule small and closed.

c. Species more flattened and elongated, or chisel shaped, the borders of the valves

truncated, lunule gaping, its borders folded backwards.

d. Umbones approximate, borders of the valves truncated anteriorly, lunule closed.
Our Great Oolite species will be found to contain examples of each of the foregoing

groups.

LIMA DUPLICATA, Sow., sp. Tab. Ill, fig. 6, 6 a.

PLAGIOSTOMA DUPLICATA, Sow. Min. Con., t. 559, f. 3, 1827.

? PECTENOIDES, Zieten. Wurtt., p. 92, t. 69, f. 2.

LIMA ALTERNICOSTA, Buviffnier. Geol. de la Meuse, p. 22, 1. 18, f. 11 — 13.

Testa convexd oblique-ovatd, antice abrupti truncatd ad cardinem angustatd, postici
rotundatd, auriculis parvis subaqualibus ; costis 25 — 28 angulatis, carinatis, sulcis confor-
mibm in imo sulcorum costd minima ornatis, costis tenuissime transverse striatis.

Shell convex, obliquely ovate, anterior side abruptly truncate, narrow towards the
hinge border, posterior border rounded, auricles small, nearly equal; costae 25 — 28,
angulated, elevated, the angle being crested with a very fine carina, interstitial spaces
wide, conformable, each having a single very fine costa, the costae. and their carinae are
finely and densely striated transversely.

The costae and sulcations are large upon the middle of the shell and become regularly
smaller towards the sides, becoming ultimately only so many fine lines. It is distin-
guished from Limea diiplicata, an Inferior Oolite species, by the more oblique form and
less elevated and acute costae. The Lima alternicosta of Buvignier, from the Ferruginous
Oolite, in the Oxfordian strata of the Department of the Meuse, does not appear to differ
from our species in any essential character, except that the figure he has given is
somewhat more than usually oblique.

It is one of the most common bivalves in the formation, but it is not often that
the fine longitudinal carina upon the costae is preserved. Height, 14 lines ; length, 9 lines.

Localities. The entire Minchinhampton district of the Great Oolite, also in the
Bradford Clay, Forest Marble, and Cornbrash of Wiltshire and Gloucestershire.

(c.) LIMA PECTINIFORMIS, Schloth. Tab. VI, fig. 9.

OSTRACITES PECTINIFORMIS, Schloth. Petref., p. 231, 1820.
OSTREA PECTIMFORMIS, Zieten. Wurtt., p. 62, t. 47, f. 1.
LIMA PROBOSCIDEA, Sow. Min. Con., t. 264, 1821.

Golf/fuss. Petref., p. 8#/t. 103, f. 2.
— PECTINIFORMIS, Bronn. LetU. Gcog., p. 214, t. 19, f. 9, 10, 1851.

BIVALVIA. 27

Testa convexd suborbiculari subcequilaterali, concentrice lamelloso-rugosd ; costis
(11 — 14,) convexis nodosis tubuliferis, canalibus conformibm, auriculis anterioribus sinuosis
hiantibus, lunuld nulld. (Goldfuss.)

Shell convex suborbicular, nearly equilateral with concentric rugose lamellae ; costse
(11 — 14,) convex, with nodose and elevated prominent fistulous plications, interstitial
spaces conformable ; anterior auricles sinuated and gaping, no lunule.

This shell is well known as a constant fossil of the upper ragstones of the Inferior
Oolite ; it likewise occurs occasionally in the shelly beds of the Great Oolite, and is always
very imperfectly preserved, most commonly, only the outer cast remaining, but it never
attains the dimensions of the Inferior Oolite specimens, and would seem therefore to have
degenerated both in size and thickness.

Locality. Minchinhampton Common.

(d.} LIMA CARDiiFORMis, Sow. Tab. Ill, fig. 2, 2 a.

PLAGTOSTOMA CAKDIIFORME, Sow. Min. Con., t. 113, f. 3, 1815.

Testa convexd, oblique ovato-orbiculari ; antice truncatd, costis crebris (circa 52 — 56),
convexis aqualibus, canalibus angustis, lineis transversis regularibus crassiusculis, lunuld
excavatd.

Shell convex, oblique, ovately orbicular, anterior side truncated, costae numerous (about
52 — 56,) convex, equal, the interstitial spaces narrow, with transverse, regular, and promi-
nent lines, lunule excavated.

The shell is moderately lengthened, the longitudinal always exceeding the lateral
diameter, the degree of convexity though varying is considerable, the diameter through both
the valves being about equal to two thirds of the length of the shell, the umbones are but
slightly curved, and the lunule is but moderately excavated, the valves are closed at their
anterior borders, or leave when united the least possible fissure, the hinge border slopes
obliquely from the umbones on each side, and the auricles are small; the umbones are but
slightly separated, the ligamental area being very contracted. The costae are regularly
rounded, and so closely arranged, as to leave the interstitial spaces deep and narrow, the
surface (more especially in older specimens,) are rendered rugose by the transverse striae,
but in this feature, and likewise in the elevation of the ribs, there is much variety, but the
number of the ribs is very constant, and assists to distinguish it from Lima notata, Goldfuss,
in which they are much less numerous, and the interstitial spaces considerably wider, and
the convexity of the valve is less ; in other respects there is a considerable general resem-
blance between the two forms. This is the most universally distributed Lima of the
formation, occurring in every variety of rock, whether composed of sandstone, clay, or
shelly limestone.

Locality. Minchinhampton and Sapperton.

28 MOLLUSCA FROM THE GREAT OOLITE.

(c.) LIMA LUCIENSIS, D' Orbigny. Tab. LU, fig. 4.

LIMA LUCIENSIS, If Orbigny. Prodrome de PaMontologie, p. 313, 1850.

Testa plano-convexd, oblique elongatd, umbonibus acutis depressis, approximates, auriculis
magnis subaqualibus ; costis (10 out 11) magnis plicatis, interstitialibus conformibus.

Shell compressed or rather convex, obliquely elongated, umbones nearly straight,
pointed, and approximated, auricles large, nearly equal and costated longitudinally, the
anterior auricle corrugated and gaping. Costae upon the back of the shell (10 or 11)
large, plicated, rounded, with large conformable interstitial spaces.

This species has less obliquity than is usual with the Lima, and this character will
always serve to distinguish it from Lima angusta, Buvignier, t. 18, f. 27, which occurs in the
middle portion of the Inferior Oolite in Gloucestershire, the character of the costae in that
species is very similar but more curved, the shell is always very oblique, its anterior side
or lunule being concave. Compared with Lima substriata, Goldfuss, our species is much
more elongated, has fewer costse, and has not the distinctly raised murications or plicae
by which the costae of that species are ornamented. It is somewhat rare, but occurs in
several of the shelly beds.

Locality. The Minchinhampton district.

(d.} LIMA GIBBOSA, Sow. Tab. Ill, fig. 7, 7 a.

LIMA GIBBOSA, Sow. Min. Con., t. 152, 1817.

— Bronn. Leth. Geog., 213, t. 19, f. 11, 1851.
Index Palseont., p. 645, (not Goldf. ?)

Testa convexd ovato-subobliqud, elongatd, fornicatd, umbonibus magnis approximatis,
dorso costato ; costis (11 — 13) elevatis acutis, canalibus conformibus; striis tenuissimis,
tranxversis decussatis.

Shell ovate, slightly oblique, convex, elongated, ribbed, umbones large and contiguous,
back of the shell with acute, elevated costse from 11 to 1 3 in number, with conformable
interstitial spaces ; the entire surface has very fine transverse striae.

The sides of the shell are destitute of costae, the smooth surface being about equal in
extent to that which is costated. This species is perfectly distinct from the Lima gibbosa
of Goldfuss, which is more oblique, the costae are curved, they extend even upon the
posterior sides of the valves, and their number is more than twice as great as in our own
or Sowerby's species. In the shelly beds of the Great Oolite it occurs very rarely in
single valves, and never equalling half the size which it attains in the Inferior Oolite, but
in the seams of clay which are associated with Stonesfield slate, casts are found of the
full dimensions, and with the valves in apposition.

Localities, Minchinhampton Common; Ancliff, Wiltshire.

BIVALVIA. 29

LIMA SEMICIRCULARIS, Goldf. Tab. Ill, fig. 3, 3 a.

LIMA SEMICIKCCLAKIS, Goldfuss. Petref., t. 101, f. 6.
PLAGIOSTOMA SEMICIHCULAKIS, Quenstedt. Wurtt., p. 477.

Testa convexd, oblique semicirculari, antice truncatd, costulis crebris aqualibus convexis,
canalibus interstitialibus anffustioribus concentrice confertim striatis, lunuld plano-concavd.

Shell moderately convex, obliquely semicircular, anterior side straight, truncated, ribs
closely arranged, very numerous, convex, the interstitial spaces more narrow, and
impressed with very delicate striae ; lunule flattened, or slightly excavated, umbones
approximated, pointed, auricles small, hinge border straight.

This species has some general resemblance to young specimens of Lima cardiformis,
but may be distinguished from it by the more elongated, depressed, and less oblique form,
and more especially by the more pointed and depressed umbones, the costse also, contrary
to that species, are often slightly undulated, and the lines of growth form two or three
prominent rounded elevations. The average size is about an inch in length. It is
moderately abundant in the shelly beds.

Locality. The whole of the Minchinhampton district.

(c.) LIMA OVALIS, Sow. Tab. Ill, fig. 5, 5 a.

PLAGIOSTOMA OVALIS, Sow. Min. Con., t. 114, f. 3, 1815.
LIMA OVALIS, Goldf. Petref., t. 101, f. 4.

Testa convexd oblique ovatd, antice truncatd, costulis convexis aqualibus crebris, sulcis
i nterstitialibus transversim lineatis, lunuld concavd.

Shell ovate, moderately convex, umbones pointed, auricles very small, anterior border
nearly straight, the side steep and rounded, posterior border curved nearly in a semicircle ;
costa3 convex, but very densely arranged, equal and marked with extremely delicate
transverse striae, the interstitial spaces are very narrow and punctated.

The costae are equal and waved, but so fine as scarcely to be traced without the aid of
a magnifier, the auricles in size are reduced almost to nothing. The general dimensions
nearly accord with Lima semicircularis, but it is more convex and oblique, the anterior side
being more steep and rounded.

Locality. It is not very abundant, but occurs throughout the shelly beds of the
formation over the Minchinhampton district, and likewise at Ancliff.

(d.) LIMA IMPRESSA. Tab. Ill, fig. 8, 8 a.

Testa convexd obliqud, ovato-orbiculari, antice truncatd, costulis depressis, irregularibus
sulcis angustis interstitialibus undulatis, punctis crebris impressis, et striis transversalibus
tenuissimis notatis. Striis incrementi paucis distantibus.

Shell convex oblique, ovately-orbicular, anterior side truncated, costae depressed, of

30 MOLLUSCA "FROM THE GREAT OOLITE.

irregular width, with very narrow and waved interstitial sulcations, which are impressed
with densely arranged punctures ; the surface of the shell has likewise very fine transverse
striae. Striae of growth few and distant.

This shell is moderately convex, the lateral and longitudinal diameters are nearly equal,
the umbones approximate and the auricles are small, the substance of the test is thin, and
the surface, except in young specimens, is usually distorted or crushed, so that it is nearly
impossible to obtain a large specimen which has not suffered in the process of fossilization.
The longitudinal elevations are so slight as scarcely to be considered costse, their surfaces
are smooth, shining, and so much flattened, as scarcely to impress a sensible convexity to the
touch. The numbers of the irregular costse vary from 40 to 48, they are equally distinct
upon every part of the shell, a feature which will always distinguish it from Lima gigantea,
and analogous species. Lima laviiisculd, Deshayes, approximates to our species, but is
destitute of the dense punctations which mark the interstitial spaces; the interstitial
sulcations are likewise evanescent upon the middle of the valves, which is not the case
with our shell. Lima aciculatd, Goldfuss, approaches this species in the character of its
markings, but it is much more flattened, and the costae are regular and more numerous.

This species is nearly as abundant as the Lima cardiiformis, which it everywhere
accompanies, but very frequently only in a crushed condition ; it is shorter than the
other and scarcely so convex.

(d.) LIMA BELLULA. Tab. Ill, fig. 9.

Testa ovato-obliqud, leevigatd ; antice convexd, abrupte truncatd postice subcompressd,
rotundatd ; auriculis parvis inaqualibus ; lunuld magnd excavatd ; superficie striis radian-
tittus tenuibus, nonnunquam obsoletis; striis anticis distinctis subdistantibus, posticis crebris
evanescentibus.

Shell ovate, oblique, smool h ; anterior side convex, abruptly truncated ; posterior side
rather compressed, its margin rounded ; auricles small, unequal ; lunule large and deeply
excavated ; the surface is ornamented with very delicate radiating striations, which
anteriorly are distinct and rather distantly arranged, posteriorly they become much more
closely arranged and are usually indistinct.

The general aspect of this species is shining and smooth, so that it is only upon close
examination that it is discovered to have radiating striations ; in young specimens these
are always more or less visible, but in specimens of advanced growth only a few traces
of the anterior striations remain. The concentric lines of growth are usually strongly
marked and efface the striations.

With advance of growth some change is observable in the contour of the shell, it
becomes more transverse and nearly orbicular.

Specimens from the Great Oolite of Lincolnshire do not attain to one third the
linear dimensions of others from the Inferior Oolite of the Minchinhampton district, but it
does not occur in the Great Oolite of Gloucestershire.

BIVALVIA. 31

Localities. Barnack, Northamptonshire ; Ponton, Lincolnshire ; Culver Hill, on the
western side of Minchinhampton Common, in the Inferior Oolite.

PINNA, Linn. 1758.

Gen. Char. Shell longitudinal, wedge shaped, acute anteriorly, truncated and gaping
posteriorly; umbones straight, terminal and pointed; hinge lateral, linear, and without
teeth ; ligament marginal, linear, elongated, and partly internal ; muscular impressions
two, the anterior or byssal one minute, the posterior large. Substance of the shell thin,
structure fibro-lamellar, composed of two layers, of which the exterior one is fibrous, the
interior lamellar.

PINNA AMPLA, Sow., sp. Tab. IV, fig. 14.

MYTILUS AMPLCS, Sow. Min. Con., t. 7, 1812.
PINNA AMPLA, Goldfuss. Pet., t. 129, f. 1.

— — Deshayes. Lam. An. s. Vert., 2de ed., vii, p. 68, 1836.
Bronn. Index Palseont., p. 977.

Testa mytiliformi, mediocre gibbosd, costellatd ; costettis irregularibus, subplanis, undu-
latis, plurimis dichotomis aut confluentis et nodosis, striis transversis crebris et laminis
increment impressis : wmbonibus obtusis plerumque costellatis.

Shell triangular, moderately gibbose, longitudinally costated ; costellse numerous, very
irregular, waved, for the most part bifurcated, confluent, knobbed and impressed with
transverse striae, which are very fine and closely arranged, and likewise by the laminae
of growth which are irregular. The hinge is straight, short, oblique, forming an angle of
45 degrees with the anterior border, the urnbones are obtuse and usually costellated.

The radiating little ribs are but slightly elevated; they are tolerably distinct upon the
anterior part of the shell, but posteriorly, where the folds of growth are larger, they become
very irregular, confluent, or vanish altogether, a change exactly similar to that exhibited in
the progress of growth of some recent Pinnas ; in fact, well-preserved specimens of Pinna
ampla are sometimes obtained, which are quite destitute of the longitudinal costellae, and
retain only the folds of growth. The substance of the test is thicker than is observed in
recent shells of this genus.

It occurs rarely in the shelly beds of the Great Oolite, but more frequently in the
Stonesfield slate of Gloucestershire.

Localities. Minchinhampton Common, in Great Oolite; Seven hampton Common,
in the Stonesfield slate; Wiltshire^ in the Cornbrash.

In the Stonesfield slate of Stonesfield, Oxfordshire, and also in the Oolite of Mitford,
Somersetshire.

32 MOLLUSCA FROM THE GREAT OOLITE.

PINNA CUNEATA, Phillips. Tab. VI, fig. 11.

PINNA CUNEATA, Phillips. Geol. Yorksh. i, t. 9, f. 17, 1835.

Testa elongatd, subcurvatd, quadriquetrd, latere antico convexo, postim compresso,
margine acuto et excavato ; superficie lineis undulatis radiantibm subnodosis aliis concen-
tricis decussatis.

Shell elongated, somewhat curved, four sided, anterior portion convex, its margin
convex, posterior portion compressed, its margin acute and excavated ; the entire surface
with undulating knotted radiating lines crossed by others concentrically disposed.

The concentric lines are very irregularly disposed, being much more closely arranged
and indistinctly marked as the shell increased in size, at first they are not more numerous
than the radiating lines. Length about 3J inches, basal diameter 2J inches, diameter
through both the valves, 13 lines. In Gloucestershire, it occurs only in the upper division
of the Inferior Oolite.

Localities. In the slaty Oolite of Easton and Collyweston, Northamptonshire, and in
Lincolnshire ; in the Cave Oolite of Yorkshire.

TRICHITES, Lhwyd, 1699.

TEICHITES, Plot, 1676; Lhwyd, 1699; Guettard, 1750; Defrance, 1828;

Pietet, 1845; Lycett, 1850; Deahayes, 1851.
TESTA INCEKTI GENEKIS, Woodward, 1723.
PINNIGENE, Deluc, 1799.
CATILLUS, Sp., Pusch, 1836.
PINNA, Sp., Deshayes, 1835.
PlNNIGENA, D'Orbigny, 1851.

Gen. Char. Shell of fibrous structure, thick, inequivalve, inequilateral, subquadrate,
the valves anteriorly forming a prominent and somewhat pointed apex curved obliquely
forwards. The left or larger valve convex and very thick, its apicial extremity hollowed
internally, and forming with the corresponding portion of the other valve a funnel-like
cavity, which is more or less open at its extremity; the right valve is thinner and
flattened, or sometimes somewhat concave ; the margins of the valves are very irregular
and sinuated, but fit closely together all round, and there is always a large flexure upon
the posterior side of the shell, forming a wide depression in that portion of the larger
valve and a corresponding elevation in the smaller valve. The hinge border is very
irregular and sinuated, it is nearly horizontal, lengthened, and internally without teeth, or
any testaceous thickening. The interior side of the larger valve is much thicker than the
other, its border is excavated beneath the apex, and is somewhat corrugated. The
muscular impression is single, large, subcentral, and strongly impressed, its circumference
has concentric step-like ridges. Ligament probably linear and subinternal, as in Pinna.

The individuals of a species vary much in the convexity of the valves and in the

BIVALVIA. 33

character of the surface, so that species are not easily discriminated; the costse, nodules, or
other elevations which are occasionally present upon the surface, become indistinct or
even vanish altogether; but their broad flexure upon the posterior side and their irregular
sinuous hinge border are invariably conspicuous.

The structure of the test consists of closely-packed perpendicular fibres of a columnar
aspect, which are traversed transversely by calcareous laminae of extreme tenuity, parallel
to each other, and sometimes of a colour different from the rest of the shell ; they occur
at very uncertain distances, appearing in the sections as so many fine lines, these thin
laminae give both to the external and internal surfaces of the valves a perfectly smooth
appearance, and in some sections a dozen or more of them may be counted, they indicate
successive additions of thickness to the test during the growth of the animal. The
muscular impression exhibits the mode of growth in a very clear manner, the necessary
addition of perpendicular fibres around its circumference producing a sudden elevation, or
step like surface at the border of every successive zone of increase. The position of the
muscular impression is rather posterior to the centre of the valves, or nearer to the posterior
and superior border ; there may also usually be observed upon the inner surface of the
flat valve, at a little distance from the anterior border and parallel to it an elongated
swelling, or rounded prominence, having exactly the contour of the outer border, and
exhibiting the appearance of having formed the outer border at a former stage of growth,
a feature precisely similar to that which is observed in certain oysters. The irregular
swellings upon the surfaces of the valves do not coincide with the surface of the interior,
sections of the thicker specimens often exhibit this circumstance in a very striking manner,
and likewise a general irregularity and inequality in the thickness of the test ; the inner
surfaces of the valves, though smooth, are singularly uneven, and it is not uncommon to
observe an occasional thickness in the test of seven or eight lines, terminate towards the
posterior border in a considerable degree of tenuity and delicacy. It would seem that the
transverse laminae, whatever may have been their original structure, impeded fracture
only to a very limited extent, for we find that in most cases the fracture is directly across
all the laminae, occasionally indeed the fracture has been arrested at the surface of one of
the laminae, and has followed the plane of its surface for some distance, an indication that
its structure was lamellar. The fibrous structure then was very fragile, in the fossil state,
fracture in the direction of the fibres takes place upon any slight concussion, however thick
maybe the test; and with the living shells the same circumstance seems to have obtained,
for in the majority of instances, Trichites acquired its fossil state in the condition of fragments
only, and these occur in such numbers, both in the Great and Inferior Oolite, as to
indicate that this genus occupied a very prominent position amongst the marine fauna
of the lower Oolitic epoch. The valves of Trichites (more especially the older and thicker
specimens), are perforated, and sometimes literally honeycombed with little crypts of
Lithopliagida, in which, occasionally, the valves of the shells may be discovered ; these
perforations are a constant feature pertaining to Trichites, from whatever formation or bed

5

84 MOLLUSCA FROM THE GREAT OOLITE.

it is obtained, and a little search discloses the crypts in such extraordinary numbers, as to
indicate that the Lithophagidce then existed in a force which would not have been expected
from the small number of instances in which their tests are preserved. In the shelly beds
of the Great Oolite, the convex valve of Trichites is usually covered, and even loaded with
small adherent oysters; but through these masses the perforations of the Lithophagida are
found to have passed, a sufficient proof that the operations of the latter mollusks com-
menced posterior to the occupation of the adherent shells, and leading to an inference
that the latter may have pertained to the living examples of Trichites. Our Great Oolite
examples of the genus convey but a very inadequate idea of the magnitude which it
sometimes attained ; the upper division of the Inferior Oolite has disclosed sections of the
valves upwards of two feet in length, and two inches in thickness. A shell imbued with
such peculiar fragility, must have been unfitted to exist upon the bed of a littoral deposit
exposed to the attritions and accidents to which such a position must have been incident,
but in which, nevertheless, we find their remains ; it seems more probable that they lived
like the Myadae, buried and defended in mud or sand, and that it was only by the
denuding action of currents that their shells became exposed, and rolled with other
fragmentary bodies.

In seeking for the generic forms allied to Trichites, we are reminded of the Catilli ;
the structure of the shell is alike in both genera, and the general figure is not very dissimilar,
but the regularity of one contrasts with the irregularity of the other ; the character of the
surface more especially is distinct, the regular concentric folds of the Catilli have no
affinity with the nodose and laminated surface of Trichites, nor can the recurved solid
umbones and thick crenulated hinge plate of the former genus find any similitude with
the Pinna like termination of Trichites. But if the character of the apex be allowed to
resemble that portion of Pinna, we may search in vain for any other point of affinity
with that genus; the structure of the shell in each differs materally; in Pinna it consists
of two distinct layers, the external one of which is fibrous, but the internal is that of
ordinary shell or nacreous, a structure tending to obviate the fragility which pertains to
the fibrous structure of the outer layer, and very much resembling a method practised in
the mechanical arts, for giving increased strength to thin layers, in substances whose
fibres pass in different directions ; by this contrivance, a shell very thin is made to possess
a considerable degree of elasticity and strength; the other particulars, in which Pinna
differs from Trichites, embrace every remaining generic character, as the equivalve form,
its regularity, the gaping truncated posterior extremity, and lastly, the muscular impres-
sions, of which Pinna has two. The preceding comparison with Pinna has been made in
consequence of several authors, who confessedly had acquired only a very imperfect
knowledge of Trichites, having classed the Pinniyenc of Deluc, with Pinna, under the
name of Pinna Saussurei.

It is now known that Trichites is abundant in the Oolitic rocks of England, and is
found over extensive areas, but it is not confined to one of the Oolitic formations merely, as

BIVALVIA. 35

there are other species which are nearly unknown to science; these circumstances, it is
trusted, will sufficiently incite the industry of local collectors, and that ere long our knowledge
of this obscure form will be augmented. On referring to the earliest notice of Trichites, we
find that it dates even to the period when fossil shells were regarded as mere sports of
nature, as the product of a supposed plastic power possessed by inorganic matter. Dr. Plot,
in his 'Natural History of Oxfordshire, 1676,' applied the term Trichites to fragments of
these shells, and figured a specimen in pi. 7, fig. 7 ; these he regarded merely as mineral
curiosities. To Lhwyd is due the merit of having discovered their true position in the
animal kingdom, and their distinctness from all known shells of Mollusca. He described
in his ' Lithophylacii Britannici,' several species from the Coralline Oolite of Oxfordshire,
a fact the more remarkable, when it is remembered that more than a century afterwards
the majority of systematic writers omitted the genus altogether from their works, or
confessed their imperfect acquaintance with it. In Woodward's ' Catalogue of British
Fossils, 1723,' it seems to have been confounded with the Catilli of the cretaceous rocks,
and is placed with the " Testae incerti generis." Guettard recognised it in the Oolite
rocks of Normandy, and mentioned it under the name of Trichites.

Deluc, in the great work of Saussure, ' Voyages dans les Alpes,' i, p. 192, made it a new
genus, under the name of Pinmgene, and figured a species which has not been recognised
in this country; he does not seem to have been aware of the identity of Pinnigene with the
Trichites of Lhwyd. The article Trichites, in the ' Dictionnaire des Sciences Naturelles,'
torn. Iv, contributed by Defrance, contains a digest of all the information which had been
acquired respecting this obscure form. Deshayes, in the 2d edition of Lamarck, ' Anim. s.
Vert./ torn, vii, p. 68, refers Deluc' s species to Pinna, under the name of Pinna Saussurei,
but states however that he had never seen a perfect specimen. Pusch, in his ' Polens
Paleontologie, 1835,' page 45, offers some remarks upon fragments which he had detached
from the rocks of the middle Oolite at Brzegi and Koritrice, but having no knowledge of
the entire form, he refers the fragments to Catillus. Pictet, in his ' Traite Elementaire de
Paleontologie,' allows the generic value of Trichites, and reproduces the figures of Deluc
reduced in size. Lastly, the reader is referred to a notice of this genus in the ' Annals
and Magazine of Natural History for 1850,' p. 347, by one of the authors of this
monograph.

TRICHITES NODOSTJS, Lycett. Tab. Ill, fig. 11.

TRICHITES NODOSUS, Lycett. Ann. and Mag. of Nat. Hist., 1850, p. 347, t. 10.
Bronn. Leth. Geog., p. 221, t. 20, f. 1, 1851.

Testa subquadratd, convexd, valvis valde intequalibus, valvd sinistrd convexd, valvd
dextrd concavd; valvis varicibus subradiantibm irregularibm inter dum dichotomis. Valvd
minord nodis nonnullis irregularibus. Apices valvarum attenuate et obliqua.

Shell subquadrate, convex, the valves very unequal, the left valve being very convex or

36 MOLLUSCA FROM THE GREAT OOLITE.

gryphoid, the right valve somewhat concave ; the valves ornamented with irregular varices,
sometimes dichotomous, and imperfectly radiating. The smaller valve has a few unequal
nodules upon the varices. Apices of the valves oblique and attenuated.

The thickness of the larger valve is moderate, the smaller valve is rather thin ;
specimens vary much in the convexity of the larger valve and in the varices, the latter
being sometimes not distinguishable; the apices are much produced, attenuated, and
curved forwards, more especially that of the larger valve. The almost constant manner in
which the larger valve is loaded with adherent shells is a considerable obstacle to the
determination of species, this, together with some variation in the figure of the valves,
suggests doubts which are only to be removed by a comparison of numerous specimens.

Height, 5^ inches ; opposite diameter, 4 \ inches ; diameter through both the valves,
2f inches.

Localities. Minchinhampton Common, where it is not unfrequent; Scar Hill, near
Nailsworth, in the freestone of the Inferior Oolite, where it occurs very rarely.

In the Great Oolite of Comb Down, near Bath. (Museum of Practical Geology, pre-
sented by Mr. S. P. Pratt.)

MYTILUS, Linn., 1758.
MYTILCS et MODIOLA, Auct.

Gen. Char. Shell longitudinal, oblique ; umbones terminal or subterminal. Hinge
lateral, linear, and without teeth, ligament marginal and somewhat internal, muscular
impression elongated, club shaped, and placed somewhat laterally; anterior impression
very small.

MYTILUS SOWERBYANUS, D'Orb. Tab. IV, fig. 1.

MYTILUS SOWEEBYAKUS, D'Orb. Prod. Pal. i, p. 282, 1850.
MODIOLA SOWEUBYANA, Bronn. Leth. Geog., p. 233, t. 15, f. 13, 1851.
— PLICATA, Sow. Min. Con., t. 248, f. 1, 1819.

Zeiten. Petref., t. 59, f. 7, 1835.
MYTILUS PLICATCS, Goldf. Petref., p. 175, t. 130, f. 12, 1840.

Testa elongatd, soleniformi, antice angmtd, obtusd, postice dilatatd, angulo obliquo
tenui bipartitd, parte inferior e et anticd Icevigatd, superiore et posticd arcuatim plicatd.

Shell elongated, pod-shaped, anterior part narrow and obtuse, posterior dilated, divided
into two portions by a thin oblique angle, inferior and anterior part smooth, superior and
posterior part with numerous curved folds.

The hinge margin is very much elongated and slightly curved, the inferior border is
slightly concave and acute. The short costse upon the superior border are parallel, oblique,
and are impressed with numerous densely-arranged curved lines, which upon the lower
portion of the shell are parallel with the inferior border.

BIVALVIA. 37

Our Great Oolite specimens must be considered as a variety of this well-known shell,
they are much attenuated at the anterior extremity, and unusually expanded and com-
pressed at the posterior extremity. It occurs rarely in the Stonesfield Slate, and has not
been observed in the shelly beds of the Great Oolite.

Localities. In the slaty beds at Minchinhampton Common ; Stonesfield, Oxfordshire.
Also in the Upper Marly deposits of the Great Oolite at Felmersham, Bedfordshire, and
Blisworth, Northamptonshire.

M. D'Orbigny has changed the generally known name given to this species by Mr.
Sowerby, as Gmelin had previously described a recent species under the name of
Mytilus plicatus.

MYTILUS (MODIOLA) TENUISTRIATUS, Munst. Tab. IV, fig. 6.

MYTILUS TENCISTBJATUS, Goldfuss. Petref., t. 131, f. 5, 1840.

Buckman. Geol. Cheltenham, p. 69, t. 3, f. 3.

Testa ovato-cordatd, fornicato tenuissime concentrice striatd, umbonibus terminalibus
arcuatis, margine cardinali recto, brevissimo, dorso alto angusto, latere inferiore cordato,
antice subventricoso. (Goldfuss.)

Shell ovately cordate, short, very convex ; umbones terminal acute and curved forwards,
hinge border straight and short, dorsal surface very much elevated and narrow, inferior
border sinuous, its anterior portion rather ventricose ; concentric striations regular, fine, and
closely arranged.

This is a short, obtuse shell, and the convexity of the valves is so considerable that the
diameter through them, when in apposition, is nearly equal to their length ; the striations
are very delicate, and the test thin.

Locality. For this pretty species we are indebted to the kindness of Professor
James Buckman, who collected it in a bed of yellow Clay at Sevenhampton, together
with numerous other testaceous relics, which though numerous in species, are for the
most part badly preserved. It is probable that this stratum, which can be traced for
two miles and upwards, is a subordinate local deposit of the Great Oolite ; at Seven-
hampton, it is situated 22 feet above the Stonesfield Slate.

MYTILUS TUMIDUS. Tab. IV, fig. 5.

Testa arcuatd, inflatd, striatd concentrice rugosd, margine cardinali curvato, margine
inferiore concavo, umbonibus terminalibus obtusis, crassis.

Shell curved, inflated, with rugose concentric stria3, hinge margin curved, inferior
margin arched or concave, umbones terminal, obtuse, and thick.

The dorsal surface is very elevated, narrow anteriorly, and more flattened posteriorly;
the convexity of the valves is so considerable that the diameter through both is equal to

38 MOLLUSCA FROM THE GREAT OOLITE.

half the length of the shell, and is greater than the height ; the general form is therefore
narrow, very convex, and curved elliptically.

It occurs very rarely in the shelly beds of the Great Oolite.

Locality. Minchinhampton Common.

MTTILTJS PTJLCHERRIMUS, Roemer, var. Tab. IV, fig. 12, 12 a.

MODIOLA PDLCHEERIMA, Roemer. Verst., p. 34, t. 4, f. 14, 1836.

Koch and DunJcer. Beitr. Oolith., t. 6, f. 7, 1837.
MTTILTJS PTJLCHERKIMUS, Goldfuss. Petref., p. 177, t. 131, f. 9.

Testa ovato-fornicatd, umbonibus postmedianis return, margine cardinali recto, later e
inferiore convexo, postice sudretuso, lineis radiantibus crebris superne crassioribus con-
eentricis decussatis.

Shell ovate, with an elevated dorsal ridge, umbones postmesial, extended backwards,
hinge margin straight, inferior side convex, with radiating lines closely arranged upon the
superior side, and decussated by very fine concentric lines, which form knots where they
cross the longitudinal elevations.

The general figure is subquadrate, the height being equal to hah0 the length, and the
diameter through both valves is a little less than the height ; the usual length is about
four lines ; the test is delicate and fragile.

Localities. All our specimens have been obtained in the bed of the soft Shelly Oolite,
which at Minchinhampton Common underlies the planking. It is moderately rare.
Ancliff, Wiltshire, (Mr. J. D. C. Sowerby's Collection.)

MYTILUS SOLENOIDES. Tab. IV, fig. 4.

Testa prcelongd, ettipticd, concentrice rugoso striatd, antice vix angustatd, obtusd,
postice paulum depressd et dilatatd ; margine cardinali subrecto, margine inferiore in
media subsinuato.

Shell elongated, elliptical, gibbose, with rugose concentric striae, anterior extremity
rather narrow and obtuse, posterior extremity more depressed and dilated, hinge margin
nearly straight, inferior margin sinuated.

The general aspect has a considerable resemblance to Mytilus plicatus, but it is much
more gibbose, the diameter through both the valves being upwards of one third of the
length, and it is destitute of the posterior plicae, which distinguish that species; the con-
centric striae are very prominent and irregular.

Modiola elongata, Koch and Dunker, which is probably Modiola scalprum, Sowerby,
is also less gibbose.

Locality. The Slaty Oolite of Minchinhampton Common, rare.

BIVALVIA. 39

MYTILUB SOLENOIDES, var. SUBRENIFORMIS. Tab. IV, fig. 11.

Testa crassd subdepressd aut subreniformi, lavigatd, umbonibus obliquis terminalibus,
margine superiore arcuato, margine inferiore excavato aut subsinuato, plicis incrementi
paucis irregular ibus.

Shell thick, rather depressed, or kidney-shaped, smooth, umbones oblique, depressed,
terminal, superior margin curved, inferior margin excavated or somewhat sinuated, folds of
growth few and irregular.

The two extremities of the shell are nearly equally rounded and convex, an obscure
and obtuse dorsal ridge extends in a curved direction from the umbones to the posterior
and inferior extremity; the superior side of the shell has a considerable convexity, and the
inferior or ventral side is compressed.

We have only obtained two specimens of this species, which occurred in the soft
shelly Oolite which underlies the planking.

Height, 6 lines ; length, 14 lines ; diameter, through both the valves, 6 lines.

Locality. Minchinhampton Common.

MYTILUS FURCATUS, Goldf., var. BATHONICOS, nob. Tab. IV, fig. 9, 9 a.

MYTILCS FURCATUS, Goldfuss. Petref., t. 129, f. 6.

Roemer. Nordd. Ool., p. 33, t. 18, f. 38.
?MODIOLA ASPEKA, Phillips. Geol. York., t. 11, f. 9.

Testa ovato-acutd, injlatd, umbonibus acutis, margine cardinali subrecto obliquo, latere
inferiore abrupto, costis crebris subpapittosis interdum dichotomis, lineis incrementi paucis
magnis irregularibus.

Shell ovately acute, very convex, with terminal acute umbones ; hinge border straight,
or rather oblique, anterior border steep and excavated ; costae numerous, closely arranged
and indented with concentric striations, producing a papillary surface, the costse are waved
and occasionally dichotomous. The specimens rarely show the imbricated costae.

The larger and indented costse distinguish it from M. asper, Sow. It is not
uncommon in the shelly beds of the Great Oolite, and varies in length from 3 to 16 lines.

Locality. Minchinhampton Common.

MYTILUS ASPER, Som. Tab. IV, fig. 8.

MODIOLA ASPEUA, Sow. Min. Con., t. 212, f. 3, 1818.

Testa cuneatd gibbosd, arcuatd longitudinaliter striatd, lineis numerosis radiantibus
furcatis, imbricatis ; umbonibus incurvis subacutis, margine cardinali arcuato, posterior^
subrecto.

An elongated arched gibbose and longitudinally striated shell, with rather small and
curved beaks ; striae numerous, furcate, and minutely imbricated.

40 MOLLUSCA FROM THE GREAT OOLITE.

Mr. Sowerby remarks, " the small and nearly flat posterior lobe leaves the beaked end
of this Modiola so small as to give it much of the contour of a Mytilus, the depth of
the two valves together is greater than the width, and the length is twice the depth.
The roughness of the striae proceeds from minute elevated scales, that are most conspicuous
near the margin of the shell, and are nearly obliterated towards the beaks."

It occurs somewhat rarely in the shelly beds of the Great Oolite, and likewise in the
marl bed of the Inferior Oolite in the Cotswolds.

Localities. Forest Marble of Wiltshire ; upper marly beds of Great Oolite, at
Felmersham, Bedfordshire; Blisworth, Northamptonshire, &c.; Minchinhampton Common,
in the Great Oolite ; near Nailsworth and Cheltenham in the Inferior Oolite.

MYTILUS LONSDALEI. Tab. IV, fig. 3.

Testa ovato-oblongd, Icevigatd; antice latd, subdepressd, postice convexiore, angulo
obliquo formante ; umbonibusgracilibmincurvis, margine cardinali obliquo, curvato, margine
inferiore subsinuato ; laminis incrementi conformibm tenuibus,

Shell ovately oblong, smooth ; anteriorly wide and depressed, posteriorly more convex,
divided from the anterior portion by an oblique and obtuse angle, which passes from the
umbo to the infero-posterior extremity; umbones slender, incurved; hinge border oblique
and curved, inferior border slightly sinuated ; the surface has numerous delicate irregular
laminae of growth.

The general figure has some resemblance to Modiola sub&quiplicatd, Roemer, Verst.,
tab. v, fig. 7, but the latter shell has greater convexity, the umbones are less attenuated
and the oblique angle formed by the anterior depressed surface is less distinct. It has
also some resemblance to M. imbricata, Sow., but is distinguished by the posterior
portion being less expanded and the general form more elongated.

Length, 16 lines; height, 7 lines; diameter, through both the valves, 6 lines.

Localities. Sapperton railway tunnel, in the Great Oolite. In the Cornbrash of Wilt-
shire it is abundant.

MYTILCS COMPRESSTJS, Goldf. Tab. IV, fig. 7.

MYTILUS COMPRESSUS, Goldfuss. Petref., t. 131, f. 11.
MODIOLA COMPKESSA, Portlock. Geol. Report, p. 122.

Testa ovatd subconvescd, concentrice striatd; umbonibus subanticis, compressis, margine
cardinali recto, latere inferiore convexo-plano, postice subcompresso prorsum rotundato.

Shell ovate, rather convex, concentrically striated ; the umbones subterminal and com-
pressed, hinge margin straight; inferior side moderately convex, posterior side rather
compressed and rounded.

The anterior extremity is narrow and somewhat compressed, the posterior much

BIVALVIA. 41

wider and more expanded, the concentric striae are very numerous and distinct, the folds
of growth are few and irregular.

Height, 7 lines ; length, 1 1 lines ; diameter, through both the valves, 4 lines.

Localities. It occurs rarely in the shelly beds of the Great Oolite, at Minchinhampton,
and more frequently in the slaty or clay beds of the formation, as in the Bradford clay,
near Cirencester, and the Stonesfield slate of Oxfordshire.

MYTILUS IMBRICATUS, Sow. Tab. IV, fig. 2.

MODIOLA IMBKICATA, Sow. Min. Con., t. 212, f. 1, 3, 1818.

Testa ovato-reniformi convexd concentrice striatd, umbonibus subterminalibus arcuatis,
dorso antice angusto, postice planiusculo, margine cardinali recto, parte anticd lateris infe-
rioris brevi ventricosd.

Shell ovately reniform, convex, concentrically striated, uinbones subterminal, curved,
the dorsal convexity is narrow towards the anterior part, and more expanded posteriorly;
the hinge border is straight, its length rather exceeding one third that of the entire shell.
The concentric lines are very numerous, irregular, strongly marked and imbricated, those
near to the posterior side being the most conspicuous.

Proportions of a medium sized specimen: Length, 21 lines; height, 10 lines;
diameter, through both the valves, 9 lines. The largest specimens acquire dimensions
one half greater.

This is by very much the most abundant Mytilus of the shelly beds of the Great
Oolite, but the greater number of examples do not exceed 12 lines in length, and the
valves are constantly disunited.

Localities. Great Oolite, at Minchinhampton ; Stonesfield slate of the same district ;
Bradford Clay and Forest Marble, near Cirencester ; also in the upper marly beds of the
Great Oolite, in Northamptonshire, Bedfordshire, and Lincolnshire.

MVTILUS SUBLJEVIS, Sow. Tab. IV, fig. 19.

MYTILUS SUBL^VIS, Sow. Min. Con., t. 439, f. 3, 1823.

Bronn. Leth. Geog., p. 236, t. 19, f. 14.

Goldf. Petref. ii, p. I/O, t. 129, f. 3.
? MYTILCS JURENSIS, Roemer. Oolith., p. 89, t. 4, f. 10.
? EDCLIS, Young and Bird. Geol. Yorksh., t. 7, f. 10.

Testa arcuato-cuneiformi, lasvigatd, umbonibus terminalibus, acutis, dorso antice angusto
et convcxo, postice expanso, margine superiore arcuato, inferiore concavo.

Shell curved and cuneiform, smooth, umbones terminal, acute, the back of the shell
anteriorly narrow and convex, posteriorly expanded, superior margin curved, inferior
margin concave with steep sides; lines of growth few, distant, regular, and strongly
marked.

6

42 MOLLUSCA FROM THE GREAT OOLITE.

The hinge border is curved, and equal to half the entire length of the shell, the
terminal umbones are remarkably acute, without any expansion upon the lower side. It
is tolerably abundant in the shelly beds of the Great Oolite.

Dimensions of a medium sized specimen : Length, 23 lines ; height, 12 lines ; diameter,
through both the valves, 9 lines.

Locality. The whole of the Minchinhampton district ; Felmersham, Blisworth, &c. ;
in the marly deposits belonging to the upper portion of the Great Oolite.

MYTILUS BINFIELDI. Tab. IV, fig. 10.

Testa ovatd subarcuatd concentrice striatd, umbonibus obtmis, dorso fornicato, moraine
cardinali recto, latere inferiore abrupto antice convexo.

Shell ovate, superior side compressed, inferior side elevated, with terminal obtuse
umbones, hinge margin rather oblique, the greatest convexity is about the middle of the
valves, the lower margin is straight, and the general aspect of the shell is smooth.

It occurs rarely in the shelly beds of the Great Oolite.

Locality. Minchinhampton Common.

Named in compliment to Mr. W. R. Binfield, who has assiduously collected the fossils
of the Oolite.

LITHODOMUS, Cuvier, 1817.

•

Gen. Char. Shell elongated, subcylindrical, anterior extremity rounded and convex,
posterior extremity more attenuated, margins of the valves close all round ; umbones
anterior, terminal, pointed ; hinge without teeth, ligament internal linear, and placed in a
lengthened groove.

Lithodomus perforations are extremely common in the shelly beds of the Great Oolite ;
they are not, however, confined to the surface of any particular bed, but occur indifferently
throughout a considerable thickness of shelly rock, and the more massive bivalves often
exhibit their perforations, more especially Trichites and Astarte subquadrata ; the number
of these perforations proves that the Litliodomi existed in great profusion, and contrasts
singularly with the paucity of the specimens preserved ; we may infer from this fact, that
a very qualified degree of dependence should be placed in the number preserved of certain
thin and fragile bivalves, as representing the actual number of individuals which existed in
the seas of the Oolitic period. The valves which occur in the shelly detritus are well
preserved, others which remained in the hollow oval crypts are uniformly very tender and
imperfect, they can scarcely be said to be fossilized ; the crypts themselves are for the
most part empty, or contain only a little hardened mud ; when, however, the crypts are
filled with calcareous spar, it is probable that the living animals themselves were
entombed in the deposit.

BIVALVIA. 43

LITHODOMUS INCLUSUS, Phil. Tab. IV, fig. 13, 13 a.

MODIOLA INCLUSA. Phil. Geol. York., i, t. 3, fig. 20, 1835.

Deslongchamps. Mem. Soc. Linn, de Normand, 1838, pi. 9,
f. 39, 40.

Testa parvd, subellipticd, convexd, umbonibus subanticis, margine poslico compresso,
producto et curvato, striis concentricis tenuissimis irregularibus, lineis incrementi paucis,
distantibus.

Shell small, delicate, subelliptical, tumid, umbones anterior, nearly terminal, posterior
margin compressed, produced, and curved ; concentric striae fine and irregular ; lines of
growth few, and distant.

This delicate little shell occurs in all the shelly beds of the Great Oolite, more
especially in the beds of soft Oolite which underlies the planking, where the numerous
cylindrical crypts sometimes contain it; the cavities themselves filled with calcareous
spar, elongated and pyriform, are not uncommon; the general figure is much more
tumid than is observed in the Lithodomi generally. The diameter through both the
valves somewhat exceeds the height, and is equal to two thirds of the entire length, which
latter rarely exceeds six lines.

Localities. Minchinhampton Common; Bisley Common; Ancliff, Wiltshire. It
occurs also in the Coralline Oolite of Yorkshire (Phillips).

LITHODOMUS PARASITICUS, Deslotiffchamps , Sp. Tab. IV, fig. 15, 15 a.

MODIOLA PAEASITICA, Desl. M6m. Soc. Linn, de Normand., 1838, t. 9, f. 44 — 46.
LITHODOMUS PAEASITICUS, VOrbigny. Prod. Paleont., p. 312, 1850.

Testa parvd, tenui, obliqud, costis radiantibus magnis paucisque ornatd, interstiis
angustis, umbonibus terminalibus acutis.

Shell small, thin, oblique, lengthened, with terminal acute smooth umbones, the middle
and posterior portions of the shell are ornamented with a few large radiating costa3, the
interstitial spaces narrow and deeply depressed ; the absence of decussating plications, and
the acute apex readily distinguishes it from Mytilus pulcherrimus, the only contempo-
raneous allied species. It has occurred very rarely both in the shelly Great Oolite and
Stonesfield Slate.

Localities. Minchinhampton ; Langrune, Normandy.

Professor E. Deslongchamps records a curious fact connected with the occurrence of
this species in Normandy : in a block of stone containing about twenty individuals, each
of them occur within the valves of another species, the Modiola (Lithodomus) inclma,
which had previously effected their perforations in the limestone. The Rev. H. Jelly
has described a somewhat analogous case, as occurring in the Bath Oolite, in which two
or three individuals of a species of Modiola lie encased in the valves of a Lithodomus, that
had perforated a coral.

44 MOLLUSCA FROM THE GREAT OOLITE.

ARCA, Linn., 1758.

ARCA RUDIS, Sow. Tab. V, fig. 12.

eucuLL.EA B.UDIS, Sow. Min. Con., t. 447, f. 4, 1824.

Testa oblongd, subcylindricd, umbonibus magnis antemedianis approximatis, margins
cardinali elongato, marginibus aliis arcuatis, costis radiantibus numerosis anticis et
mediants acutis, posticis magnis irregularibus subdistantibus, nodosis, lineis concentricis
decussatis.

Shell oblong, subcylindrical, umbones large, contiguous, and placed anterior to the
middle of the valves, hinge border elongated, the other margins rounded ; radiating costae
acute, elevated upon the anterior and middle portions of the valves, much larger, irregular,
more distant and nodose upon the posterior side, decussated by numerous concentric
lines.

The posterior side of the shell is rather compressed, and has four or five very promi-
nent irregular knotted costae ; the concentric lines are very fine, and for the most part
indistinct. It occurs rarely in the shelly beds of the formation.

Height, 6 lines ; length, 1 2 lines ; diameter through both the valves, 6 lines.

Localities. Minchinhampton and Bisley Commons ; Ancliff, Wiltshire.

ARCA PULCHRA, Sow. Tab. VI, fig. 6.

AKCA PULCHBA, Sow. Min. Con., t. 4/3, f. 3, 1824.

Testa ovato-oblongd, convexd, umbonibus antemedianis subdistantibus, margins cardinali
elongato, margine in/era parattelo, area angustd, latcribus costalis radiantibus crcbris sub-
(equalibus, slriis concentricis tenuissimis indentatis.

Shell ovately oblong, convex, umbones anterior, separated, hinge margin elongated,
with the inferior margin of the valves parallel to it, area narrow ; the sides of the valves
are ornamented with densely arranged radiating little ribs, these are rather unequal in
size, but radiate in every direction, and are indented by fine closely arranged concentric
striations.

The example of this species figured in the 'Mineral Conchology,' represents the
immature stage of growth in which the concentric striations are scarcely distinguishable,
and the general form has not acquired the full degree of convexity. In the description
of Area pulchra, Mr. Sowerby states that it is " nearly twice as wide as long ; the striae are
very uniform and close together; the valves are rather flat in the middle;" and further
remarks — "Although there is hardly any appearance of a sinus in the margin, this is
placed as an Area because it has no transverse elongated teeth in the hinge, those nearest
the extremities being longitudinal; it is, however, one of the links that unite the two
genera."

BIVALVIA. 45

Localities. The shelly beds of the Great Oolite throughout the Minchinhampton
district ; Ancliff, Wilts ; Ponton, Lincolnshire.

••

ARCA KILVERTI. Tab. V, fig. 10.

Testa oblongd aut subrhomboidali, umbonibus medianis contiguis ; lateribus compressis ;
basi arcuatd ; superficie bipartitd sulco lato ; costulis radiantibus (circa 50) subnodosis,
lineis concentricis crebris decussatis.

Shell oblong or subrhoraboidal, umbones moderately large, mesial, and contiguous ;
the sides of the shell compressed, the lower margin curved ; the surface divided into two
parts by a wide superficial sulcation ; radiating lines or costae (about 50) slightly nodose,
and decussated by fine, closely arranged concentric lines.

Upon the sides of the shell the costae are more widely separated, and the interstitial
spaces sometimes disclose a smaller rib. It ranks as one of the more rare Great Oolite forms,
the figure nearly agrees with Area bipartita, Roemer, ' Nordd. Ool.,' tab. 14, fig. 12 ; but
that species is destitute of the concentric lines.

Height, 3 lines ; length, 6 lines.

Locality. Minchinhampton Common.

Named in compliment to Mr. Kilvert, of Bath.

ARCA TENUITEXTA. Tab. V, fig. 9.

Testa pared, ovatc-oblongd, umbonibus obliquis antemcdianis subdistantibus ; marginibus
rotundatis; dorso convexo, superficie mediano sulco lato impressd; lineis radiantibus crebris
minutis aliift concentricis decussatis.

Shell small, ovately oblong, umbones oblique, anterior to the middle of the valves, and
separate ; hinge margin of moderate length, its extremities rounded, base slightly sinuated
by a wide but superficial sulcation which descends from the umbo ; the entire surface is
covered with radiating, closely arranged, depressed, very fine lines, crossed by others
concentric and closely arranged.

The general figure has a considerable degree of convexity, and the hinge margin is
very short; the radiating and concentric interstitial spaces are so minute that they
resemble fine punctuations. It ranks as one of the smallest and most rare of the Great
Oolite Arcacea -, it is found in the planking and contemporaneous white stone of
Bussage.

Localities. Minchinhampton and Bisley Commons.

ARCA PRATTII. Tab. V, fig. 3.

Testa subrhomboided, umbonibus antemedianis contiguis, area anguslatd; latere antico
maraine rotunda, latere postico producto, angulo obliquo declivi ; costulis radiantibus

46 MOLLUSCA FROM THE GREAT OOLITE.

tenuissimis crebris, costulis posticis majoribus subnodosis ; lineis incrementi panels
di&tantibus.

Shell subrhomboidal, umbones compressed, placed anterior to the middle of the valves,
and contiguous; area narrow; anterior portion with the margin rounded, posterior side
more lengthened, with an angle passing obliquely from the umbones to the infero-
posterior extremity ; radiating costse very fine and closely arranged, the costse posterior to
the angle are larger and nodose ; lines of growth few and distant.

The usual figure is compressed, and the posterior angle is acute, but there is much
variation in the convexity of the valves. The Area funiculosa, Goldfuss, tab. 121, fig. 13,
has a general resemblance to it, but differs in having regular distinct concentric lines.

It is the most common Area in the Great Oolite, and occurs throughout all the shelly
beds.

Height, 8 lines ; length, 15 lines; diameter through both the valves, 6 lines.

Localities. Minchinhampton, in the Great Oolite ; Ancliff, Wiltshire. Leckhampton
Hill near Cheltenham, in the shelly free stone of the Inferior Oolite ; also in the Oolite
of Ponton, Lincolnshire.

This species is dedicated to S. P. Pratt, Esq., F.R.S.

ARCA EUDESII. Tab. V, fig. 6, 6 a.

Testa oblonyd, subcompressd ; umbonibm obliquis, acutis, antemedianis distantibus, area
latd ; latere antico margine rotunda ; latere postico producto carinato longitudinaliter pli-
cato, plicis 3 lafis profundis; dor so costulis radiantibus crebris ineequalibus nodosis ; striis
concentricis frequenter obsoletis ; basi recta.

Shell oblong, rather compressed, umbones oblique, acute, anterior to the middle of the
valves, and distant ; area large ; anterior side with the margin rounded, posterior side
with an obtuse carina more produced, and having upon the surface posterior to the carina
three large strongly-marked longitudinal plications ; the dorsal surface has very fine
radiating costse densely arranged, knotted, and unequal; concentric striae very faintly
traced ; inferior margin straight.

The less convex form will distinguish it from Area trisulcata, Goldfuss, the figure is
nearly that of his Area fracta, but that shell is destitute of the posterior longitudinal
plications, it is scarcely so wide as Area lata, Dunker, and more compressed upon the
dorsal surface ; that species would likewise seem to want the large posterior folds. It
occurs very rarely in the shelly beds of the Great Oolite.

Height, 7 lines ; length 14 lines ; diameter through both the valves, 7 lines.

Localities. Minchinhampton Common ; Langrune, Normandy.

This species is dedicated to Professor Eudes Deslongchamps, of Caen, who has
obligingly forwarded to us, for comparison, many interesting shells from the Great Oolite
of Normandy.

BIVALVIA. 47

ARC A JGMULA, PML Tab. V, fig. 17.

AECA ^MULA, Phil. Geol. Yorksh., i, t. 3, f. 29, 1835.

Testa subrhomboided, vel oblongd, ineequilaterali, convexd, umbonibus odliquis anteme-
dianis distantibus; latere antico convexo, latere postico elonyato, obtusi carinato et
compresso ; superficie sulco lato mediano ; basi subrectd; lineis radiantibus crebris minutis
nodosis, plicis concentricis panels interruptis : superficie posticd excavatd, plico unico
obliquo mediano et sulcis duobm conformibus parallelis.

Shell subrhomboidal or oblong, inequilateral, convex, umbones oblique, placed anterior
to the middle of the valves and separated by a moderately wide area ; anterior side convex,
posterior side elongated, obtusely carinated and compressed; the dorsal surface with a
wide and slightly oblique depression which is not always distinct ; basal margin straight ;
radiating lines closely arranged, fine, minute, and knotted, interrupted by a few concentric
plications; the surface posterior to the obtuse carina is concave, has a mesial oblique
plication which is bounded upon each side by a sulcation.

The greater number of examples have not preserved the lines which ornament the
surface, but the posterior plications are always distinctly shown. In the Great Oolite of
Minchinhampton, the species occurs in a dwarfed or rather in an immature form, which
would scarcely be identified, but for the aid of specimens from other localities ; it occurs
well preserved in the shelly roe stone of Leckhampton Hill, and likewise in the Ponton
Oolite, at both of which places it attains its full dimensions.

Localities. Minchinhampton and Bisley Commons. Ponton, Lincolnshire.

ARCA JEMCLA, Phil. var. TRANSVERSA. Tab. V, fig. 8.

A shell which we consider to be only a variety of A. amula requires a separate notice,
it is more elongated and subcylindrical, the mesial or oblique depression upon the dorsal
surface is usually distinctly marked, and the shell never acquires the dimensions of the
typical form, the length of the largest specimens not exceeding 10 lines.

The more mesial position of the umbones will serve to distinguish this shell from young
examples of Macrodon Hirsonensis, to which in other respects it has a considerable resem-
blance ; it is more elongated and cylindrical than any other of the contemporaneous Arcacea.

It occurs not uncommonly throughout the shelly beds of the Great Oolite, but the
delicate features of its surface are seldom well preserved.

Localities. Minchinhampton and Bisley Commons.

ARCA RUGOSA? var. of ARCA PRATTII. Tab. V, fig. 2.

Testa subrhomboided, convexd, antice rotunda, postice compressd, angulo obliquo actito ;
umbonibus depressis approximatis, antemedianis lineis radiantibus crebris undulatis subno-
dosis et imbricatis ; plicis concentricis ruyis, irreyularibm subundulatis ; basi subsinuatd.

Shell subrhomboidal, convex, anterior side rounded, posterior side much compressed,

48 MOLLUSCA FROM THE GREAT OOLITE.

with an oblique sloping acute angle; umbones depressed, approximate, placed anterior
to the middle of the valves, radiating costae closely arranged undulated, slightly nodulated
and imbricated; concentric folds numerous, rugose irregular and somewhat undulated ;
base sinuated.

This species is exceedingly irregular both in its general figure and convexity, the portion
of the shell posterior to the carina is excavated and compressed, the lines upon its surface are
much* knotted; Area Prattii approximates to it but is less convex, and in that species the
lines are not nodose, neither has it the concentric undulating plications and sinuous base
which distinguishes the Area rugosa. It occurs somewhat rarely in the shelly beds of the
Great Oolite.

Localities. Minchinhampton and Bisley Commons.

ARCA MINUTA, Sow. Tab. V, fig. 11 a ; Tab. VI, fig. 19.

CUCBLLEA MINDTA, Sow. Min. Con., t. 447, f. 3, 1824.

Testa parvd trapeziformi, convexd, wmbonibus acutis submedianis, subdistantibus, area
mat/no, Icevigatd obliqud; lateribus striis crebris radiantibus plicis incrementi interruptis.

Shell small trapeziform, convex, with acute and rather distant umbones, area large,
smooth, sloping obliquely, the sides of the valves with densely arranged radiating striations,
broken by the concentric plications of growth.

The figure of this little shell varies considerably in the size of the area, and in the
general convexity, the posterior angle is strongly marked, rather acute and slightly
concave ; the striations are only visible under a magnifier ; from two to ten lines appear
to be the amount of variation in length. It is not common, and is usually badly preserved,
its range is throughout the Great Oolite and Bradford clay of Gloucestershire.

Localities. Minchinhampton ; Ancliff, Wiltshire ; Langrune, Normandy.

Sub-Genus — MACRO DON, Lycett.

MACEODON, H. E. Strickland and J. Buckman. Geol. of Chelt., 1845, p. 98.

Testa subrhomboided, umbonibus anticis subremotis, area cardinali modice laid laviffatd,
margine cardinali redo valde elongato ; latere antico convexo crasso, latere postico com-
pressiusculo, tenui et subtruncato; margine inferiori corrugato, sinuato et hiante. Cardo
linearis, deniibus (5 — 7), anticis, angmtis parallelis et obliquis; dentibus posticis plerumque
duobus, anffustis, longitudinaliter elongatis ad extremitatem po&ticam testa productis.
Impressio muscularis, anticus elevatus (ut in Cuculltea instructa,) posticus obsoletm.

Shell subrhomboidal, umbones anterior, rather distant, cardinal area moderately wide,
smooth, hinge line straight, and much elongated ; anterior side rounded and thick, posterior
side rather compressed, somewhat truncated and thinner, inferior margin corrugated in
its middle part, sinuated and gaping. Hinge linear, teeth (5 — 7), situated anteriorly,
narrow, parallel, and oblique; posterior teeth usually two, narrow, elongated longitudinally

BIVALVIA. 49

extending nearly to the posterior extremity of the hinge line. Of the muscular impressions
the anterior one is elevated upon a raised internal projecting ledge, as in Cuculltsa,
the posterior impression is indistinct. The general figure is that of Byssoarca, the
umbones which are rather small, are placed near to the anterior extremity of a very
lengthened hinge line, the corrugation in the ventral border and hiatus are strong
points of resemblance to that genus. The dental characters present an approach to
those of Cucullesa, but in lieu of diverging from the central or subumbonal portion of
the hinge line, as in that genus, they are ah1 turned in one direction inclining posteriorly.
Another external feature should be noticed, which it possesses in common with some
other of the Arcacea, viz. : there is a depression upon the back of the shell, extending
obliquely from the umbo to the middle of the lower border. In generic value, this
form will take rank with Cuculltea and Byssoarca, but whether the two latter should
be regarded, of generic or only of subgeneric value, as considered by some authors, is
a subject which we will not discuss ; Palaeontologists, however, will perceive the conve-
nience of separating the present form from others of the Arcacea.

MACRODON HIRSONENSIS, D 'Archiac, Sp. Tab. V, fig. 1, la, b, c.

CUCULL^A ELONGATA. Phil. Geol. York., i, t. 11, f. 43, 1835.

Goldfuss. Pet., t. 123, f. 9, 1840.
HIRSONEXSIS, D' Archiac. Me"m. Soc. Geol. Fr., t. v, t. 27, f. 5, 1843.

Testa in atate juniori costatd, costis radiantibus, regularibiis, et imbricatis, eetate pro-
gredient? costis plerumqiie obsoletis, cum laminis increments maynis, paucis et rugis.

Shell in the young state costated ; costse radiating, elevated, regular and imbricated ;
with increase of growth the costae gradually disappeared, and the surface was rendered
rugose by large folds or laminae of growth, which are usually few and distant ; they
become corrugated near to the hiatus in the lower border, as in Byssoarca.

The aspect of this shell changed so much during the progress of growth, that without
a regular series for comparison, the larger and smaller specimens would probably be
separated into distinct species ; the figure given in the ' Geology of Yorkshire,' Pt. 1, 1. 11,
fig. 43, accurately represents the shell in its young state ; the costse are then sharply
defined, perfectly regular, and it has not acquired the laminae of growth which subse-
quently disarranged the regularity and continuity of the costae ; the figure of Goldfuss,
t. 12, fig. 9, is rather more elongated than is usual, it is of middle size, and the costae
are still visible; the figure of D'Archiac, t. 27, fig. 5, though beneath the middle size,
represents the stage of more advanced growth, in which the costae are obliterated, and
the lower border becomes corrugated. Sometimes, however, traces of the costae are
visible even upon shells of the largest size, and on the other hand, small shells may be
found smooth. The cast figured under the name of Macrodon ruyosus, by Professor
Buckman, in the ' Geology of Cheltenham,' plate 5, fig. 5, appears to represent another
species which has a few distant and strongly-marked radiating costae.

7

50 MOLLUSCA FROM THE GREAT OOLITE.

Localities. It occurs abundantly in the Minchinhampton district, but is chiefly
found in the planking of Minchiuhampton Common ; it occurs likewise more rarely in the
Inferior Oolite of the same district. Ponton, Lincolnshire.

Height of the largest example, 2J inches ; length of the hinge line, 5 inches.

Sub-Genus — CUCTJLL^A, Lam., 1801.

*

Gen. Char. Shell inequilateral ventricose; umbones large, distant, separated by a
ligamental area. The posterior surface with an oblique angle more or less prominent ; the
margins of the valves close all round. Hinge linear straight, teeth radiating obliquely
from beneath the umbones. Muscular impressions two, of which the anterior one is
supported by an elevated plate or ledge, projecting from the side of the shell; the
posterior impression is rounded and faintly marked.

Cuc0LL.SA CONCINNA, Phil. Tab. V, ffg. 7.

CUCULL^EA CONCINNA, Goldfuss. Petref., t. 123, f. 6? 1840.
Phil. Geol. York., i, t. 5, f. 9, 1835.
?CUCULLJEA SUBLJEVIGATA, Zieten. Wurtt., p. 75, t. 56, f. 3, 1834.

Testa ovato-rhomboided, convexd, umbonibus antemedianis magnis depressis approxi-
mates ; latere antico brevi margine rotunda ; latere postico acute-carinato obliquo dcclivi ;
superfaie striis concentricis regularibus crebris ; lateribus costis radiantibus panels et
prominentibiis.

Shell ovately rhomboidal, convex, umbones anterior to the middle of the valves, large,
depressed, and nearly touching each other ; anterior side short, its margin rounded ;
posterior side with an acute carina sloping obliquely ; the surface has closely arranged,
regular and very fine concentric striations ; the sides of the shell have a few radiating
prominent costse, those upon the anterior side are four, elevated and distant.

Our specimens agree with the figure of Phillips, but differ somewhat from that of
Goldfuss, which has fine radiating lines ; it is probable, therefore, that the latter is a
distinct species.

It occurs not uncommonly in the shelly beds of the Great Oolite.

Localities. Minchinhampton and Bisley Commons.

CUCULL<EA GOLDFUSSI, Roemer. Tab. V, fig. 4, 4«.

CUCULL^A GOLDFUSSII, Roemer, 183C. Nordd. Ool., p. 104, t. 6, f. 18.

Testa trapeziformi convexd, concentric^ subruyosd, antice rotundatd, angustatd, posterius
angulo rotunda cordato-compressd margine postico oblique truncate ; umbonibus crassis
prominulis incurvis, area lanceolatd 5 — 6 striatd. (Roemer).

BIVALVIA. 51

Shell trapeziform convex, the surface with irregular concentric rugose plications,
anterior side short,, con vex, its margin rounded, posterior side with an oblique obtuse
angle, the side posterior to the angle compressed and truncated ; umbones large, incurved,
and almost touching each other ; area lanceolate, of moderate size, with 5 or 6 striae.

This species has some resemblance to Cucullaa oUonga, Phillips, but it is less
elongated, the umbones are more compressed, and it is destitute of all radiating lines ;
the more oblique form, compressed umbones, and longer posterior side, will distinguish it
from Cuculleea cucullata, when the surface markings of that species are not distinguishable.

Height, 16 lines; length, 21 lines; diameter through both the valves, 14 lines.

Localities. Minchinhampton and Bisley Commons, where it occurs in all the shelly
beds.

CUCULLATA, Goldfuss. Tab. V, fig. 5.

CUCULL^A CUCULLATA, Goldfuss. Petref., p. 148, t. 123, f. 7, 1840.

Testa ovato-rhomboided, ventricosd, umbonibus antemedianis approximatis, later e postico
compresso-declivi, concavo, carinato Itevi ; lineis concentricis confertis et radiantibus
subtillissimis. (Goldfuss.)

Shell ovately rhomboidal, ventricose, umbones placed anterior to the middle of the
shell, oblique, and somewhat separated ; posterior side with an oblique obtuse carina,
posterior to which is a flattened or slightly concave surface ; the inferior margin is curved >
the lines both radiating and concentric are closely arranged, very fine, but irregular and
unequal, the part posterior to the carina or angle being destitute of lines ; the plications
of growth are faintly marked, few, and distant.

The finely reticulated surface is usually most distinct in young specimens, those of
more advanced growth being nearly smooth. It occurs throughout the shelly beds of the
Great Oolite, but is not abundant. It likewise occurs in the middle division of the Inferior
Oolite at Leckhampton, and near to Nailsworth in Gloucestershire.

Locality. Minchinhampton Common.

NUCULA, Lam., 1801.

Gen. Char. Shell transverse, inequilateral, ovately oblong ; hinge linear, separated
in the middle by a fossa or oblique channel ; teeth numerous, elevated, narrow, or frequently
comb-like ; umbones contiguous, curved posteriorly ; ligament partly internal, inserted in
the central fossa or canal.

NUCULA VARIABILIS, Sow. Tab. V, fig. 13, 13«.

NUCULA VARIABILIS, Sow. Min. Con., t. 475, £. 2, 1824.

Phil. Geol. York., vol. i, t. 9, f. 11, 1835.
NUCULI SUBGLOBOSA, Roemer. Verst. Oolith., t. 6, f. 7, 1836.

52 MOLLUSCA FROM THE GREAT OOLITE.

Testa parvd, Iteviusculd, ovatd, convexd, obliqud, umbonibus anticis, latere antico
brevissimo, latere postico, oblique declivi, basi ellipticd curvatd, lineis concentricis irregu-
laribus tenuissimis.

Shell small, smooth, ovate, convex, oblique, umbones anterior, anterior side very short,
posterior side lengthened, its border obliquely sloping, base curved elliptically, lines con-
centric, irregular, and very fine.

This small shell is common throughout the shelly beds of the Minchinhampton district,
where its figure is much less variable than in the specimens from Ancliff, which are figured
in the ' Mineral Conchology,' so that it is not easily mistaken for any other contempo-
raneous species.

Localities. Ancliff and Minchinhampton.

NTJCULA WALTONI, Tab. V, fig. 14.

Testa parvd ovatd subcompressd, umbonibus acuminatis, anticis, latere antico rotunda,
postico elongato et subrostrato.

Shell small, ovate, rather compressed, umbones acute and anterior ; anterior side short
and rounded, posterior side elongated and somewhat rostrated.

The figure has some resemblance to N. acuminata, but the anterior side is much more
produced, the posterior extremity more pointed; there is a kind of obtuse ridge, extending
posteriorly from the umbo to the inferior and posterior extremity, and the junctions of the
valves posteriorly are compressed, and the surface is very smooth. It is very common in
the Clays of the Fullers-earth and likewise in the Bradford Clay, having the valves in
apposition ; in the shelly beds of the Great Oolite it occurs very rarely, and the valves
are disunited.

Localities. The Cotswold Hills, at various localities in the Fullers-earth; the
Tetbury Road Railway Station, in the Bradford Clay ; Minchinhampton Common, in the
Great Oolite.

This species is dedicated to that indefatigable collector, Mr. Walton of Bath.

LEDA, Schumacher, 1817.

NUCULA (pars), Lam.
LEMBULUS, Risso, 1826.
DACKOMYA. Agass., 1840.

Gen. Char. Shell inequilateral, umbones small, contiguous, anterior side convex, its
margin rounded ; posterior side attenuated, posterior slope lengthened, and excavated ;
teeth numerous parallel, separated in the middle by a fossa, structure of the test fibro-
lamellar.

BIVALVIA. 53

LEDA MUCRONATA, Sow., Sp. Tab. VI, fig. 7.

NUCULA MUCRONATA, Sow. Min. Con., t. 476, f. 4, 1824.

Testa parvd subrhomboidali, rotundatd, convexd-concentrice sukatd, postice mucronatd.

Shell subrhomboidal, rounded, convex, concentrically sulcated, posteriorly mucronated.

Two thirds as long as wide, very minute ; the posterior side is drawn out in the form
of a flattened spine, and is distinguished from the other portion of the shell by being
flatter. (Sowerby.)

The figure of this shell is copied from the one given in the ' Mineral Conchology.'

Locality. Ancliff, Wiltshire.

LEDA LACHRYMA, Sow., Sp. Tab. V, fig. 15, 15<z.

NUCCLA LACHRYMA, Sow. Min. Con., t. 476, f. 3, 1824.

Phil. Geol. York., i, t. 11, f. 14, 1835.

Goldfuss. Petref., t. 125, f. 10, 1840.

NUCULA CAUDATA, Koch and Dunker. Beit. Xord. Ool., p. 31, t. 2, f. 7, 1837.
? LEDA ACASTA, D'Orb. Prodrom. Paleont., i, p. 275, 1850.

Testa ovato-subtriqnetrd ventricosd, antice inflatd, postice elongatd attenuatd, umbonibus
antemedianis, lunuld declivi ellipticd, marginaid, angulo cardinali obtuso ; lateribus striis
concentricis remotiusculis interdum obsoletis.

Shell ovately subtriquetral, ventricose, anterior side inflated, posterior side lengthened
and attenuated, umbones anterior to the middle of the shell, lunule elliptical, sloping
obliquely and marginated, the cardinal angle obtuse ; the sides of the shell with regular
concentric striations, rather remote, and faintly impressed, sometimes undistinguishable.

The few specimens which have been obtained agree with the figure in the ' Mineral
Conchology,' rather than with that of Goldfuss, which is more produced posteriorly ; the
apparent absence of striations in the specimen figured by Sowerby has induced D'Orbigny
to regard the striated figure of Goldfuss as distinct, but whoever has examined the half-
obliterated striations of the Great Oolite specimens will be convinced of the fallacy of such
a distinction. The figure 150 represents the smooth variety from Ancliff, which has been
kindly lent to us for comparison by Mr. J. D. C. Sowerby.

Localities. Minchinhampton and Bisley Commons; Ancliff; it is rare.

LIMOPSIS, Schacci, 1827.

TRIGONOC.ELIA, Nyst, 1834.
PECTUNCULINA, D'Orbigny, 1850.

Gen. Char. Shell smooth, transverse, ovately oblong or subquadrate, umbones mesial
depressed, contiguous ; hinge curved, teeth raised, numerous, minute, placed in a parallel
series, which is separated in its middle portion by a triangular depression. Ligament

54 MOLLUSCA FROM THE GREAT OOLITE.

nearly internal, placed in the trigonal fossa beneath the umbones, margins of the valves
entire.

The smooth valves, mesial cardinal fossa, subquadrate form, and entire margins
distinguish it from Pectunculus. The general character of the hinge presents an approxi-
mation to Limea, Goldfuss, both in the curvature of the series and form of the teeth ; the
latter genus may in fact be regarded as a representative of Limopsis amongst the Limae.
In Nucula the series of teeth form an angle, they are narrow and raised like a comb.

LIMOPSIS OOLITICUS, D'Archiac, Sp. Tab. V, fig. 16, 16a.

PECTUNCULUS OOLITICUS, D'Archiac. M£m. Soc. Geol. Fr., t. v, t. 27, f. 6, 1843.
? OBLONGUS, Sow. Min. Con., t. 472, f. 6, 1824.

? MINIMUS, Sow. Ibid., t. 472, f. 5.

Testa Ifevigatd oblongd, convexo-pland, subcompressd in&quilateratd, umbonibus pro-
minulis, obliquis, lateribus oblique truncatis.

Shell smooth, oblong, more or less transverse, convex but somewhat flattened,
inaequilateral, umbones prominent, oblique, the sides obliquely truncated, the lower
margin lengthened and curved.

This species, which is very abundant, occurs under several varieties of aspect ; the hinge
line may be nearly straight and angular, or rounded ; the figure may differ much in the
degree of convexity, and in the length transversely ; all the specimens are larger than the
Ancliff shells which were figured in the ' Mineral Conchology' under the specific names
P. minimus and oblongus, but which, nevertheless, we are disposed to regard as only varieties
of the present species, and to these we might add another variety, which together with a
short superior or hinge border, has several irregular folds upon the surface, giving it a
rugose aspect. Owing to the great abundance of the species, we are at any time
enabled to compare these varying forms, the test being thick, always well preserved, and
never compressed. It occurs indifferently in all the shelly beds, and is one of the most
common shells of the formation.

The Limopsis Dammariensis of Buvignier, ' Geol. dela Meuse,'p. 20, pi. 16, f. 26 — 29,
has some resemblance to our species, but has greater convexity and less angularity of
figure.

Localities. The entire formation in the Minchinhampton district ; Ancliff, Wiltshire.
Eparcy, Langrune, France.

TRIGONIA, Bruguiere, 1791.
TEIGONIA, Lam., 1804. Park, 1811. Sow., 1815. D'Orbiffny,\850.

HlPPOCEPHALOIDES (NUCLEUS), Plot., 1676.

LYRIODON, Bronn, 1836. LYKODON, Goldfuss, 1838.
Gen. Char. Subtrigonal, rounded anteriorly, truncated posteriorly with an oblique

Hsn-Y

^M.^UV02S^

BIVALVIA. 55

flattened, or excavated area, which extends posteriorly from the umbo to the infero-posterior
extremity, and is separated from the dorsal surface by a ridge or angle, and by a similar
division from a small lanceolate space upon the other side, the anterior part of which
supports the ligament; umbones recurved, contiguous, usually angulated ; the dorsal
surface is ornamented with longitudinal or concentric rows of costse or tubercles. The
hinge has four oblong compressed diverging teeth in one valve, the sides of which are
grooved transversely, and two similar teeth in the other valve; ligament external,
muscular impressions two in each valve, elliptical, and deeply impressed.

In the descriptions of species, we use the term marginal carina to indicate the ridge
which bounds the area from the other surface of the shell ; inner carina, the ridge which
separates the area from the lanceolate space ; the median carina is a ridge or line of
tubercles which passes longitudinally along the middle of the area.

TRIGONIA SUBGLOBOSA. Tab. V, fig. 21.

Testa suborbiculari, convexd, umbonibus prominulis recurvatis; margine anteriore et
inferiore rotundato, margine posteriore brevi et concavo ; area brevi, laid transverse striatd,
carinis tribus ornatis, carinis tuberculosis, carina marginali tuberculis majoribus ; costis
numerosis per series angulatis dispositis, postice magnis et tuberculatis, antice laevigatis
crebris inter dum obsoletis.

Shell subglobose, umbones prominent and recurved, the anterior and inferior margins
rounded, the posterior margin short and somewhat concave ; area short and wide, striated
transversely, and ornamented with three tuberculated carinse, of which the marginal
carina has the larger tubercles ; the space between the inner carinse is smooth and short ;
the other portion of the shell has numerous closely-arranged oblique tuberculated costse
which form a series of angles upon the middle of the shell, the' angles being usually greater
than right angles. The anterior portions of the costse pass obliquely downwards to meet
the posterior portions, they are smooth, usually undivided, and towards the lower part of
the shell become nearly obsolete ; their posterior portions are large, forming irregular
varices, which are very prominent. It is nearly allied to Trigonia Goldfussii in the
character of its surface, the chief distinction consisting in the fewer costse and less acute
angle of the latter species ; but the figure of the two species is very different.
T. Gohlfmsii is much more flattened and less elongated posteriorly, the umbones are not
recurved, the figure of the area altogether is more lengthened and straight, and it likewise
attains to a larger size than T. subglobosa.

Our species occurs rarely both in the shelly beds of the Great Oolite and in the upper
part of the middle division in the Inferior Oolite.

Localities. Minchinhampton Common, in the Great Oolite ; Nailsworth, or Scar Hill,
in the Inferior Oolite.

56 MOLLUSCA FROM THE GREAT OOLITE.

TRIGONIA GOLDFUSSII, Agass. Tab. V, fig. 18, 18#.

LYKODON LITTEKATUM, Goldfuss. Petref., t. 136, f. 5, 1840.
TBIGONIA GOLDFCSSI, Agaz. Mem. sur les Trigonees, p. 35.
? — CUSPIDATA, Sow. Min. Con., t. 507, f. 4, 5, (junior.)

Testa plano-convexd, ovato-triffond, antice et in/erne rotundatd, postice truncatd ;
tuberculis per series undulatas dispositis, ad carinam marginalem crassissimis ; carind
marginali tuberculis ornatd; area cardinali transversim striatd; tuberculis nonnullis in
carind internd, (Agassiz, pro parte.)

Shell with a moderate convexity, ovately trigonal, the anterior and inferior borders
rounded, the posterior border truncated ; umbones not prominent, nearly straight, costae
few, tuberculated, disposed in a series of rows which anteriorly are slightly curved, passing
obliquely downwards, posteriorly the eostse are larger, and are curved upwards at a con-
siderable angle ; the area is flattened, transversely striated in the young state, but nearly
smooth in the adult ; the inner carina is slightly tuberculated, and the tubercles upon the
marginal carina are more distinct.

The series of costse posteriorly, which at first are tuberculated and moderately curved,
afterwards gradually become large, irregular compressed varices, which are directed nearly
perpendicularly downwards, and form a considerable angle at their junction with the
posterior portions of the costse. The inner carina is small and indistinctly tuberculated;
the marginal carina is much larger, but has likewise indistinct tubercles, which disappear
altogether in the adult state of growth ; the area is divided into two parts by a slight
longitudinal furrow.

The examples of this species are moderately numerous and of every stage of growth,
so that ample materials are afforded for comparison. The surface markings underwent
a continuous change throughout the life of the Mollusk; in the earliest condition, when
the length is only 6 or 7 lines, the surface has a few regular curved and smooth costse,
which form an angle or prominence as they pass over the marginal border (or position of
the carina), to the area which they cross, forming so many large plications ; when about
seven costse have been perfected, those which succeed begin to have their posterior
extremities more curved and indented to form tubercles, the plications upon the area have
then degenerated into striations ; ultimately these latter become indistinct, and the
portion of the area last formed is nearly smooth ; the posterior extremities of the costse
gradually become large varices, which are directed nearly perpendicularly downwards,
and are imperfectly united to the anterior portions. The minute shell from Ancliff,
figured in the ' Mineral Conchology' under the name of Trigonia cuspidata, Sow., is
probably the present species in its earliest stage of growth.

It will also be perceived, that the young shell very nearly resembles the same stage
of Trigonia Moretoni the only distinction residing in the more prominent costse of T.
Goldfussii. The Great Oolite shells never attain to the magnitude of those figured by

BIVALVIA. 57

Goldfuss, and the small example figured by him, tab. 136, fig. 5 a, appears to be another
species altogether unlike the young examples of our shell. Trigonia litter ata
of Phillips, ' Geol. Yorksh.,' i, tab. xiv, fig. 11, from the Lias of Robin Hood's Bay,
is likewise a distinct species, and having the priority, that specific name must be
retained for it. Trigonia Goldfussii, and more especially young specimens, occur not
unfrequently in the coarse bed of planking forming part of the shelly beds of the
formation. Trigonia undulata from Fromberg, of which M. Agassiz has given two
very different figures, would appear to be nearly allied to our species, more especially
the shell figured by him, (Etudes Mol. Trigouees, tab. vi, fig. 1,) which exhibits small
tubercles upon the carinae.

Locality. Minchinhampton Common.

TRIGONIA MORETONI. Tab. V, fig. 19, 19«.

1 TKIGONIA CONJDNGENS, Phillips. Geol. Yorkshire, i, p. 122.

Testa ovato-triyond, plano-convexd, umbonibus obtusis recurvis, area angustd, trans-
versim plicatd ; plicis magnis irregularibus ; carind marginali et internd depressis irregu-
lariter subnodulosis ; cost is per series numerosis ((state juniori arcuatis, adulto subanffulatis,}
et tuberculatis, tuberculis posticis magnis crebris confuse dispositis.

Shell ovately trigonal, rather depressed, umbones obtuse, recurved, anterior border
rounded, posterior border lengthened and slightly excavated; area narrow, transversely
plicated, plications large and irregular ; marginal and inner carina? depressed, rather
obscure, (more especially in adult specimens,) irregularly undulated ; costa3 disposed in a
numerous series (about 16), which in the young state are regularly curved, but subse-
quently become somewhat angulated ; they are tuberculated, the posterior tubercles being
the larger, closely arranged and much confused or irregular.

In the earliest stage of growth the aspect is so dissimilar that it requires a separate
notice, the shell is rather compressed, the costae are prominent, regular, and smooth, the
plications upon the area appearing like continuations of the costse, which they nearly
equal in size, and the oblique divisional line upon the area which replaces the median
carina is perceptible.

It is only when five or six costse have been perfected, that they become indented,
the indentations becoming more strongly marked with succeeding costee, and at length
forming distinctly rounded tubercles ; during a series of five or upwards, the tuberculated
costas continue to have a regular graceful curvature, but subsequently they become irregular
and confluent ; posteriorly the tubercles are large, and the costa3 are at that part usually
bent upwards at a considerable angle. Thus in the adult stage of growth, the surface
is always irregular and varies in every individual, even more than is usual in the tuber-
culated TrigonicR. It would seem to be more nearly allied to T. impressa than to any
other British species, but it is twice or thrice as large, has greater convexity, the apex is
more obtuse, the area has much larger and more distantly arranged plications, neither has

8

58 MOLLUSCA FROM THE GREAT OOLITE.

it the distinct and regularly tuberculated marginal carina of that species ; the arrangement
of the rows of costae is similar, but the tubercles are larger, and the adult condition more
confusedly disposed in our shell.

It occurs in the shelly beds of the Great Oolite, in which small specimens are
abundant, but adult forms are comparatively rare. The species is respectfully dedicated
to Lord Moreton, who has assiduously cultivated geological science.

Localities. The Minchinhampton district in general. Stonesfield slate, Oxfordshire.

TRIGONIA COSTATA, Sow., Far. PULLUS. Tab. V, fig. 22, 220.

CURVIROSTRA NGN RUGOSA, Luid. Lithoph. Brit., t. 9, No. 714, 1760.
DONACITES COSTATUS, Schoth. Petref., i, p. 193, 1820.
LYRIODON COSTATUM, Bronn. Leth. Geog., t. 20, f. 4, 1836, 1851.
LYRODON COSTATUM, Gold/. Petref., ii, t. 137, f. 3, 1840.
TEIGONIA PULLUS, Sow. Min. Conch., t. 508, 1826.

COSTATA, Lamarck. An. s. Vert., vi, p. 64, 1819.

Parkinson. Org. Rem., iii, t. 12, f. 4, 1811.

Zeiten. Wurtt., p. 78, t. 58, f. 5, 1834.

Roemer. Oolith., p. 97, 1835.
— Agassiz. Mem. sur les Trigonees, p. 35, t. 3, f. 12 — 14, 1840.

Testa subtrigond, umbonibus prominentibus recurvix, acutis, area magnd, plicata et
carinatd.

In (state junior i, carina marginali acutd et Itevigatd, carind media et internd denticulatd.

jffitate adulto area in valvd sinistrd carind marginali magnd rotundatd et indentatd ;
carind media et internd distinctd et denticulatd sed pared; superficie inter carinis plicis
longitudinalibus densis interdum spinis acutis instructis ; area in valvd alterd sine carind
media plicisque longitudinalibus magnis, paucis intertiisque latis et profundis. Costis
dorsalibus magnis, lavigatis, elevatis et curvatis, carind marginali separatis.

Shell subtrigonal, umbones prominent, acute, recurved ; area large, longitudinally
plicated and carinated, dorsal surface costated. In the young state, the marginal carina
is acute and smooth, the inner and mesial carinse are denticulated. In a more advanced
stage of growth, the area in the left valve has a marginal carina large, rounded, and deeply
indented, the median and inner carina3 are distinct and denticulated, the spaces between
the carinae have numerous longitudinal plications, which are not unfrequently covered
with asperities, or acute spinous elevations. In the right valve, the surface of the area is
different ; it is divided into two portions, the posterior portion being more depressed than
the other, there is no distinct median carina, but the anterior portion of the area has two
large indented plications, separated by wide interstitial spaces, ultimately two other
plications are added. The longitudinal costae are large, smooth, and gracefully curved,
separated from the marginal carina by a smooth sulcus ; the lanceolate space between the
inner carinse has a surface very similar to that of the area. Notwithstanding the frequency

BIVALVIA. 59

with which this species has been figured and described, the foregoing definition will be
found to differ from all which have previously been given ; it is founded, however, upon
observation of the form in its varieties and stages of growth without stint of examples.
It is distinguished from other allied costated species, by characters which are chiefly
supplied by the posterior slope, and which are constant and of importance. When from
six to eight costse have been perfected, the marginal carina acquires large denticulations,
and subsequently continues to be indented transversely. The distinctly elevated median
carina and finely reticulated surface of the left valve are very different from the correspond-
ing parts of the right valve, the area of which has in its middle a longitudinal divisional
line which separates the surface into two portions, the posterior portion being more
depressed than the other; at first, there appears a kind of median carina, which subse-
quently is not to be distinguished from the other plications ; these large plications do not
occupy the entire surface of the area, but have between them, and more especially
separating them from the marginal carina, wide and depressed interstitial spaces.
Goldfuss states, that the apex of the right valve is more recurved, or advances before the
other ; this feature has occasionally been observed in specimens from the Cotswolds, it may
therefore be regarded not as an accidental but as an occasional feature, which certainly
is absent in the majority of specimens. Neither is this character altogether peculiar to the
present species of Trigonia. A rigid comparison of specimens proves that the minute
Trigonia pullus of the ' Mineral Conchology' from Ancliff, is only the germ of Trigonia
costata, not of the typical large Inferior Oolite shell, but of a much smaller variety, which
is abundant in the Great Oolite ; adult specimens of this variety, which may be called
pullus, have an equal number of costa3 with the typical form, but the figure is less convex ;
the anterior border is not truncated, both that and the inferior border being regularly
rounded. The linear dimensions never attain to half of the large Inferior Oolite form, an
inconsiderable number only exceed an inch in length, but specimens of half an inch, or
even less, are much more abundant. The peculiar features of the cardinal area above
described are persistent in all the varieties of the species, and furnish a ready means
of distinguishing it from allied costated forms, such as Triffonia similis of Bronn,
T. Meriani, monilifera, denticulata, papillata, and suprajurensis of Agassiz; T. costata
of Pusch, ' Polens Palscont.,' taf. vii, figs. 1 , 2, is regarded by Agassiz as a distinct species, for
which he proposes the specific name of zonata. Trigonia costata would appear to have
very frequently been confounded with an abundant Kimmeridge clay species, but in the
latter shell the area is alike in both valves, the marginal carina has not large denticu-
lations, the general form is more elongated, the umbones much less recurved, the marginal
carina is nearly straight, and the costse are much more oblique. In the Minchinhampton
district the pullus variety of T. costata is exceedingly abundant, surpassing in numbers
those of the other Trigonias combined ; the valves are usually disunited, and internal
casts are never obtained; a length of 20 lines upon the marginal carina appears to be its
utmost limit in size.

60 MOLLUSCA FROM THE GREAT OOLITE.

Localities. Everywhere in the shelly beds of the Minchinhampton district ; in the
Forest Marble of Wiltshire and Dorsetshire.

TRIGONIA COSTATA, Sow., var. ELONGATA. Tab. V, fig. 23.

Somewhat rarely an elongated variety of this well-known form occurs in the shelly
beds of the Great Oolite ; it is somewhat more convex than T.pullus, the marginal carinais
remarkable for its general straightness and prominence, the costse are less curved and are
disposed with greater obliquity than in the other varieties, and the character of the area
has nothing peculiar. It is not distinguishable from a shell from Cutch, figured and
described by Mr. Sowerby in the ' Geological Transactions,' 2d ser., vol. v, pi. 21.

TRIGONIA FLECTA. Tab. V, fig. 20.

Testa ovato-trigond, subcompressd, area elongatd, planatd, transverse striatd ; carinis
ejusdem swbnullis, superficie costis angustis, Jiorizontalibus rectis, postice angulo Jlectis,
angulo costarum subrecto.

Shell ovately trigonal, or oblong, rather compressed, area elongated and flattened,
transversely striated ; carinse scarcely distinguishable, the middle portion of the area with a
longitudinal furrow ; the other portion of the shell with narrow straight nearly horizontal
costae, which at their posterior portions are suddenly bent upwards at a right angle, and
become nodose, forming short perpendicular varices.

It differs from T. angulata, Sow., in the absence of tuberculated carinas upon the area,
in its flatness and in the costse, which are more closely arranged, and have not the elegant
curvature of the Inferior Oolite shell. The general figure is more oblong than T.
Goldfussii and T. undulata, Agassiz, to both of which it has a certain resemblance in the
character of its surface. It would seem to be rare ; we have only met with a single
example, which occurred in a rock too hard to permit the perfect exposure of the shell ; its
position is a bed somewhat shelly and situated a little beneath the Bradford clay.

Locality. The Tetbury Road station of the Great Western Railway.

TRIGONIA DUPLICATA, Sow. Tab. VI, fig. 2.

TBIGONIA DUPLICATA, Sow. Min. Con., t. 237, f. 4, 1819.

Testa ovato-trigond antice rotundatd, postice productd et rostratd, umbonibus obtusis
sub-recurvis ; area angustatd transversd striatd, media sulco longitudinali, -carinis parvis
tuberculis minimis instructis ; costis serratis ornatis ; costulis prioribus concentricis et
regularibus, aliis obliquis nonnunquam dichotomis.

Shell ovately trigonal, moderately convex, anterior extremity rounded, posterior
extremity produced and rostrated, superior border rather concave ; umbones mesial,

BIVALVIA. 61

obtuse, slightly recurved ; area narrow, transversely striated with a mesial longitudinal
furrow ; carinae small, with densely arranged minute tubercles ; costae serrated ; the first
few costae are regular and concentric, the others are directed obliquely downwards from
the marginal carina to the lower border, they are nearly straight, some few are dichotomous
and slightly waved, the serrations are irregular or unequal, which gives to the costae a
knotted aspect.

This species is not uncommon (more especially the external moulds), in the bed called
Triffonia grit, a member of the upper division of the Inferior Oolite ; in the Great Oolite
it is very rare.

Localities. Minchinhampton Common, in the Great Oolite. The Cotswold hills
generally, in the Inferior Oolite.

TRIGONIA IMPRESSA, Sow. Tab. V. fig. 24.

TKIGONIA IMPRESSA, Sow. Zool. Journal, iii, t. 11.

Prevott. Ann. Scien. Nat., iv, t. 18, f. 22, 23.
Morris. Catal. Brit. Foss., p. 103, 1843.

Testa ovato — trigond subcompressd, antice productd rotundald, postice recta, obliqud ;
umbonibus submedianis acutis ; costis per series numerosis Iceviter arcuatis, subundulatis et
tuberculatis, costis, anticis, obliquis, anguntis, subrectis dense serratis, posticis curvatis,
tuber culls parvis crebris ; area angustd, transversim striatd, striis tenuibus crebris ; carind
marginali nodulis parvis regularibus ornatis, carind internd transversim plicatd ; carind
media sulco longitvdinali.

Shell ovately trigonal, rather compressed, anterior side produced and rounded,
posterior side straight, oblique, and compressed, umbones nearly mesial acute and very
slightly recurved ; costse disposed in a numerous series which are moderately curved,
little elevated, somewhat angulated and tuberculated. The anterior portions of the costae
are narrow and but little prominent ; they are nearly straight, but are directed obliquely
downward, and are more or less distinctly serrated or indented, but do not form distinct
tubercles ; posteriorly the costaB are more curved or rather angulated ; they rise upwards
to meet the marginal carina at a right angle and are distinctly tuberculated, the tubercles
being small and closely arranged. The area is rather narrow and distinctly bounded by
two carina? ; the marginal carina is small, it has regular elevated tubercles which are
rather distantly arranged, the inner carina is plicated, an oblique furrow or line replaces
the median carina, the surface of the area has at first a few prominent transverse plications,
but these soon degenerate into striations which are fine and densely arranged ; the
lanceolate space between the inner carinse is elongated and smooth.

The aspect of this little shell is peculiar, and its features are very persistent — few
exceed an inch in length, and from this size to half an inch is its most frequent dimensions ;
they were eminently gregareous, and are numerously scattered over the thin laminae of

62 MOLLUSCA FROM THE GREAT OOLITE.

Stonesfield slate, at very many localities, but have not hitherto been discovered in the
shelly beds of the Great Oolite.

Localities. Stonesfield, Eyeford, and generally throughout Oxfordshire and Glouces-
tershire, where the Stonesfield slate is present.

TRIGONIA PHILLIPSI. Tab. VI, fig. 1.

Testa ovato-triffond, convexd, umbonibus submedianis obtusis, subredis, area parvd
planatd ; carind marainali angustd, tuberculis parvis, crebris ornatd, carind intend vari-
cibus subdistantibus ; superjicie inter carinis plicis crebris transversis et sulco obliquo mediano
instructo ; valvis lateribus costis concentricis regularibus crebris elevatis, tuberculis parvis
dense dispositis.

Shell ovately trigonal, convex, anterior border produced and rounded ; posterior border
truncated, umbones nearly mesial, obtuse, nearly straight and scarcely recurved, marginal
carina nearly straight, narrow, and little elevated, ornamented with minute closely
arranged' tubercles, inner carina with a few prominent rather distantly placed varices ;
lanceolate space between the inner carinse wide and smooth ; the surface of the area
between the carinse is flattened, traversed transversely by prominent closely arranged
plications, and divided in its middle part by an oblique furrow ; the sides of the valves
have very numerous elevated narrow concentric regular costse, which are ornamented with
small, equal, densely arranged tubercles.

This elegant shell possesses a considerable general resemblance to Tngonia striata,
Sow. ; like that shell the costs are regular, concentric, elevated, and are furnished upon
their upper surfaces with small tubercles ; but the figure is essentially different ; T. striata
has the umbones recurved and -pointed, the hinge margin posteriorly much excavated,
the marginal and inner carinse have a graceful curvature, and the posterior side of the
shell is considerably produced ; none of these features are observable in our species, the
hinge margin of which is scarcely concave, the umbones obtuse, not prominent and
recurved ; the posterior side is likewise so short that the umbones appear to be nearly
mesial ; the costse in our species are nearly twice as numerous, equally elevated, and the
minute tubercles upon them are rounded and much more densely arranged, so that a little
distance from the eye the tubercles are scarcely distinguishable. This comparison can
only be made between the specimens themselves, for it happens that nearly all the figures
hitherto published of Trigonia striata are very unsatisfactory, with the exception only of
that in the Petrefacten of Goldfuss, which is excellent, and represents the adult condition
of that species.

Triyonia Phillipai occurs in soft Oolite, in the vicinity of Stamford and Denton,
Lincolnshire, and has not been recognised in the Great Oolite of Gloucestershire.

Dedicated to Prof. John Phillips, whose philosophic researches have greatly contributed
to the advancement of geological science.

BIVALVIA. 63

TRIGONIA IMBRICATA, Sow. Tab. VI, fig. 8, 8a.

TRIGONIA IMBBICATA, Sow. Min. Con., t. 507, f. 2, 3.

Under this name, Mr. Sowerby has figured apparently an immature or young state
of a species of Trigonia from Ancliff, of which the adult specimens have scarcely been
recognised ; this small form is shewn in the figure Sa ; we believe, however, that the shell
represented by fig. 8 belongs to a more advanced stage of growth ; the peculiar imbrication
of this species noticed by Mr. Sowerby appears to arise from the erosion of the concentric
spinose tubercles which ornament the shell.

The young stage of this shell is described in the 'Mineral Conchology,' as being
" Transversely oblong, depressed ; with five or six concentric, dentated, subimbricated
keels upon the rounded anterior side ; posterior side obliquely truncated, ribbed. The
carinee upon the surface of this little shell resemble terraces one above the other ; each is
divided into four or five angular lobes."

Localities. Minchinhainpton, (fig. 8, in the British Museum Collection ;) Ancliff,
Wiltshire.

CARDIUM, Linn. 1758.

Gen. Char. Shell equivalve subcordiform, umbones prominent, contiguous. Hinge
with two cardinal and two lateral teeth in each valve ; the cardinal teeth are approximate,
oblique, crucially inserted, one with the other, lateral teeth remote.

CARDIUM SEMICOSTATUM, Lycett. Tab VII, fig. 6, 6«, 6.

CAKDIUM SEMICOSTATUM, Lycett. Annals Nat. Hist., 1850.

Testa parvd, ovato-orbiculari, convexd, umbonibus magnis, mediants, concentrice et tenuis-
sime striatis ; latere postico compresso, costulis crebris radiantibus decussatis.

Shell small, ovately orbicular, convex, umbones large, mesial ; concentric striaj regular
and faintly impressed ; the posterior side is compressed, its concentric strise are crossed
by radiating closely arranged ribs.

The figure of this little species is wide towards the ventral border and narrow towards
the umbones, the lunule is small or nearly obsolete ; the convexity of the valves is
moderate, and the flatness of the posterior side produces at its junction with the dorsal
surface a well-defined oblique angle. It would seem to be rare in the shelly beds of the
Great Oolite, but the Bradford clay of Wiltshire produces numerous casts of a Cardium,
which we believe to belong to this species, and which attained a much greater development
of growth ; casts of this shell are also abundant adjacent to the Tetbury Road Railway
station, a locality which is very prolific of the fossils of the Bradford clay.

The height and lateral diameter are about equal, varying from 2i to 5 lines.

Locality. Minchinhampton Common in the Great Oolite. It occurs likewise in the
middle division of the Inferior Oolite of the same district.

64 MOLLUSCA FROM THE GREAT OOLITE.

CARDIUM STRICKLANDI. Tab. VII, fig. 5, 5a.

CAKDIUM STRIATUM. Geol. Chelt., J. Buckmann and H. E. Strickland, 1845, p. 97.

Testa suborbiculari aquilaterali, ventricosd, umbonibus mediants, contiguis, marginibus,
arcuatis ; latere postico lineis radiantibus crebris ; dorso lineis concentricis crebris regu-
laribus.

Shell suborbicular, equilateral, ventricose ; umbones, mesial and contiguous, margins of
the valves regularly rounded ; surface ornamented with concentric regular small ridges,
posterior portion with radiating closely arranged lines.

This small species is very abundant in the shelly beds of the Great Oolite, the con-
centric lines are most elevated and conspicuous in the smallest specimens, in those of
the largest size which have a diameter of 1 0 lines, the lines are nearly or quite obsolete.

Height and lateral diameter equal, diameter through both the valves one third less.

Localities. Every Great Oolite quarry in the Minchinhampton district.

CARDIUM BUCKMANI. Tab. VII, fig. 2.

CABDIUM L^EVIGATUM, Lycett. Annals Nat. Hist., p. 422, 1850.

Testa subltevi ovato-suborbiculari convexd, umbonibus medianis prominulis incurvis, latere
antico rotunda, postico obliquo, sed rotundo, basi arcuatd ; striis concentricis tenuissimis
irregularibus.

Shell smooth, ovately orbicular, convex, umbones mesial, prominent, and incurved,
anterior side rounded, posterior side oblique and rounded, base curved symmetrically ;
dorsal surface, with a few very fine and irregular concentric striae.

The substance of the test is very thin, and its bad state of preservation together with the
variety of the species render it difficult to exemplify it from any one specimen ; much
finer and more perfect specimens have been procured in the shelly freestone of Leckhampton
hill, by the Rev. P. B. Brodie.

Height 22 lines ; lateral diameter 24 lines ; diameter through both the valves 1 5 lines.
It has occurred in more than one of the shelly beds.
Locality. Minchinhampton Common.

CARDIUM SUBTRIGONUM. Tab. VII, fig. 3.

Testa subtrigond, convexd, umbonibus acuminatis contiguis anticis, latere postico
elongato oblique declivi, lineis radiantibus undulatis ; dorso striis tenuissimis concentricis
irregularibus.

Shell subtrigonal, convex; umbones pointed, prominent, contiguous and anterior;
posterior side elongated, sloping obliquely with radiating and waved lines ; dorsal surface
with very fine, concentric, irregular striaa. An ill-defined obtuse angle passes obliquely

BIVALVIA. 65

from the umbones to the posterior and inferior angle, and forms a boundary to the radiating
posterior lines. The posterior side is not excavated or flattened, as in some other trigonal
species, but is rather convex.

It occurs very rarely near to the base of the Great Oolite, in a band of hard whitish
argillaceous rock, but has not been found in the shelly beds.

Locality. The southern boundary of Minchinhampton Common.

CARDIUM-PES-BOVIS, D'ARCHIAC. Tab. VII, fig. 4, 4«.

CAHDIUM PES-BOVIS, D' 'Archiac. Mem. Soc. Geol. Fr., torn, v, t. 27, f. 2, 1843.

Testa nucleo subtrigond, convexd ; umbonibus magnis incurvis, dorso fornicato, angulo
obliquo, acuto carinato ; lunuld magnd cor data ; latere postico angusto, excavato ; dorso
lineis longitudinalibus tenuissimis perpendicularibus ornatis.

Shell with the nucleus subtrigonal and convex ; umbones large, incurved, dorsal
surface with a ridge forming an oblique and acute angle ; lunule large, cordate ; posterior
side narrow and excavated ; dorsal surface with longitudinal, fine, perpendicular lines.

The large excavated lunule, fine perpendicular lines, and more erect mesial umbones,
distinguish this from our C. concinmtm, which latter is a much smaller species. It occurs
very rarely in a whitish argillaceous rock near to the base of the Great Oolite.

Height, 30 lines; lateral diameter, 28 lines; diameter through both the valves,
22 lines.

Locality. The southern side of Minchinhampton Common.

CARDIUM CONCINNTJM. Tab. VII, fig. la, b, c.

1 CARDIUM MINUTUM, D'Archiac. Mem. Soc. Geol. Fr., v, t. 27, f. 4.
? — PES-BOVIS, junior.

Testa ovato-orbiculari, obliqud, umbonibus anyulatis incurvis, latere antico rotundo
brevi, lunuld parvd, latere postico compresso aut excavato, angulo obliquo obtuso carinato ;
dorso costulis radiantibus rotundis crebris, striis concentricis decussatis.

Shell ovately orbicular, oblique; umbones large, angulated, and curved forwards,
anterior side rounded, short ; lunule small, moderately excavated ; posterior side flattened
and excavated, bounded by an oblique and obtuse angled carina ; dorsal surface with little
ribs radiating, closely arranged, rounded, and decussated by regular, numerous, concentric
striae.

The posterior surface is ornamented in a manner similar to the other part of the shell,
but so much more faintly marked that, in ordinary or not well preserved specimens, it appears
smooth. The general figure has a considerable resemblance to the large Cardium pes-bovis,
but the latter species is much higher, and more nearly equilateral.

Height, 9 lines; lateral diameter, 10 lines; diameter through both valves, 7 lines.

Localities. Minchinhampton Common, Bisley Common.

9

66 MOLLUSCA FROM THE GREAT OOLITE.

ISOCARDIA. Lam. 1799.

Gen. Char. Cordiform, regular, ventricose; umbones prominent, distant, diverging,
involute ; hinge with two compressed cardinal, and one compressed lateral tooth in each
valve ; ligament external, bifid, diverging in the direction of the umbones.

ISOCARDIA TENERA, Sow. Tab. VII, fig. 1, la.

ISOCAKDIA TENERA, Sow. Min. Con., p. 494, t. 295, f. 2, 1821.

— Deshayet. Traite Elementaire de Couch., ii, p. 27, t. 24, f. 6, 7.

CEEOMYA TENEKA, Agassiz. Etud. Cat., t. 8 — e, f. 1 — 12, p. 34.
? Var. ISOCAKDIA TCMIDA, Phil. Geol. Yorksh., i, t. 4, f. 25, 1835.

Testa nucleo subtrigono, inflate ; umbonibws mediants, altis antrorsum incurvis ; latere
antico lato, striis concentricis subtillissimis.

Shell with the nucleus subtrigonal, inflated; umbones mesial, elevated, and curved
forwards and inwards ; anterior side very wide, rather flattened, giving somewhat a three-
sided figure to the nucleus ; surface of the test with fine concentric striae.

The convexity of the valves is so considerable that the diameter through both is almost
equal to that of the height and length, but the length varies with the stages of growth, the
younger forms being more produced laterally and less convex ; the posterior side is always
rather compressed, and usually exhibits an angle, which passes obliquely from the umbones
backwards, but in the more inflated specimens it is obsolete ; the valves appear to fit
closely at their circumference, and the ventral border is regularly and elliptically curved.
The anterior side is very wide, and somewhat flattened, giving a three-sided aspect to the
general figure. The nuclei do not display any concentric striae, and we have never found
the test preserved.

Locality. It occurs somewhat rarely in the upper beds of the Great Oolite, two miles
east of Minchinhampton, but has not been found in the shelly beds of the same
formation.

LUCINA, Bruff. 1791.

Gen. Char. Inequilateral, orbicular, posterior side short or truncated, anterior side
more produced. Hinge usually with two small cardinal, and two lateral teeth in one valve,
one lateral tooth in the other; ligament external, but deeply excavated. Muscular
impressions two in each valve, the anterior one narrow and lengthened, the posterior
somewhat rounded ; impression of the mantle not sinuated.

BIVALVIA. 67

LUCINA BELLONA, If Orb. Tab. VI, figs. 18, 18 a.

LUCINA LIRATA, var. TRANSVERSA, TfArchittc. Mem. Soc. Geol. France, v, t. 26, f. 3.
BELLOXA, d Orb. Prod. Paleont., 1, p. 309.

Testa transversd, ovato-orbiculari, plano-convexd, antice rotundatd, postice subsinuatd,
umbonibus mediants acutis, margine cardinali subrecto, oblique declivi, lunuld pared exca-
vatd; superficie plicis concentricis magnis irregularibus, striis densissimis impressis.

Shell transverse, ovate, rather flattened, anterior margin rounded, posterior margin
sinuated ; umbones mesial and pointed ; hinge margin lengthened, straight, and oblique ;
concentric folds rather irregular, elevated, and impressed with longitudinal, densely
arranged, and very fine striations. An obscure elevation passes obliquely from the
umbones to the inferior and posterior border. This shell presents considerable variety in
its form and markings ; young specimens are much more compressed, and then* borders
are very acute, the general outline is nearly orbicular, and the concentric plications are
very distinct and regular : the adult shell becomes either of a suborbicular and convex, or
of a transverse and more depressed form, and in both varieties the concentric elevations are
placed at unequal distances ; the suborbicular variety has a more excavated lunule, and the
umbones are more directed forwards or oblique. The shell figured by M. D'Archiac, belongs
to the transverse variety to which our Great Oolite specimens belong, but we are not without
examples of the other form. It is absent in the shelly beds of the Great Oolite, being found
only in mudstones, or a fine calcareous muddy sediment which has become limestone. It
occurs very abundantly in the middle division of the Inferior Oolite in Gloucestershire,
associated with Nerincea, and a numerous suite of other Mollusks, but is almost absent
when the organic fades consists of Terebratula . It reappears in the upper beds of the
Great Oolite, forming a numerous colony in a compact marly rock, about one hundred
feet above the Fuller's earth, where it is seldom that specimens much better than nuclei
can be disengaged.

Dimensions. Transverse variety: — lateral diameter, 31 lines ; height, 25 lines; diameter
through both valves, 13 lines. Suborbicular variety: — lateral diameter, 26 lines; height,
24 lines; diameter through both valves, 13 lines.

Localities. In Great Oolite, two miles east of Minchinhampton. In Inferior Oolite,
along the outer escarpment of the northern and middle Cotswold hills. Also near Stam-
ford, and in other localities in Lincolnshire.

LUCINA BELLONA, var. Dcpressa. Tab. VI, fig. 15.

Testa transversa, subeequilaterd, orbiculatd, compressd et leevigatd ; margine superiori
antice subhorizontali postice recto declivi, striis concentris irregularibus.

Shell transverse, subequilateral, orbicular, compressed and smooth, superior margin
anteriorly produced, and nearly horizontal, posterior margin straight and sloping ; base
regularly elliptical.

68 MOLLUSCA FROM THE GREAT OOLITE.

The lateral diameter, in regard to the height, is as eleven to nine ; the umbones are
nearly mesial, and pointed, but depressed ; the concentric striae are very slightly impressed,
which gives to the shell a smooth and depressed aspect. It is not very common, but
occurs in more than one of the shelly beds of the Great Oolite.

Localities Minchinhampton and Bisley Commons.

LUCINA ORASSA, Sow. var. Tab. VI, fig. 13.

LUCINA CRASSA, Sow. Min. Con., t. 557, f. 3, 1827.

Testa crassd, suborbiculari, plano-convexd, lateribus sub&qualibus ; umbonibus acutis
mediants, cardine marffinali recto, obliquo declivi ; lunuld parvd obliqud; basi arcuatd,
Jineis concentricis crebris irrcffularibus.

Shell convex, suborbicular, the sides nearly equal ; umbones acute, mesial ; hinge
margin straight, oblique, and sloping ; lunule small, oblique ; base regularly rounded,
concentric lines closely arranged and irregular.

The umbones are mesial and curved forwards, so that the anterior side of the shell is
less produced than is usual with the genus ; the degree of convexity near the umbones is
moderate, and less than in L. obliqua. It occurs very rarely well preserved in the
planking beds of the Great Oolite.

The specimen figured is contained in the collection of the British Museum.

Worn specimens of this species, of which the shell has become thin, and the exterior
markings obliterated, are difficult to distinguish from what we consider a distinct species,
L. rotundata, and which may prove to be only a variety.

Locality. Minchinhampton Common.

LUCINA ROTUNDATA, Roemer, sp. Tab. VI, figs. 14, 14 a.

?ASTARTE ROTUNDATA, Roemer. Vers. Oolith., t. 6, f. 12, 1836.

Testa subtransversd, ineequilaterd, oblique orbiculari, concentrice lineatd, convexd, antice
xubproductd, complanatd ; umbonibus parvis incurvis.

Shell somewhat transverse, inequilateral, obliquely orbicular, concentrically lineated
convex, anterior side rather produced ; umbones small, incurved.

Specimens vary both in the degree of convexity, and in the proportions between the
lateral diameter and the height, but the former measurement always exceeds the latter.
The concentric lines or plications are very irregular and faintly marked, so as to give
a general smoothness to the surface.

It occurs somewhat rarely in the shelly beds of the Great Oolite, and has also been
recognised in the upper ragstones of the Inferior Oolite.

Localities. Minchinhampton Common in the Great Oolite ; Rodborough Hill in the
Inferior Oolite.

BIVALVIA. 09

The figure showing the hinge has been copied from a specimen in the British
Museum collection.

LUCINA DESPECTA, Phil. Tab. VI, figs. 16, 17.

LUCINA DESPECTA, Phil. Geol. Yorksh., i, t. 9, f. 8, 1835.

CARDIOIDES, D'Archiac. Mem. Soc. Geol. France, torn, v, t. 25, f. 6.
DESPECTA, junior, tab. nost. vi, f. 16.

Testa suborbiculari, obliqud, convexd ; umbonibus parvis acutis, postmedianis, later e
antico producto, postico brevi ; superftcie lineis concentricis crebris irregularibus.

Shell suborbicular, oblique, convex, anterior side produced, posterior side short ;
umbones small, acute, situated posterior to the middle of the valves, and curved forwards ;
the surface with closely arranged, irregular concentric lines.

Having had the advantage (through the kindness of Mr. Bean) of comparing the original
specimen (fig 17) figured in the 'Geology of Yorkshire,' we are enabled to affirm that
Lucina cardioides, D'Archiac (Mem. Soc. Geol. Fran., vol. v, tab. xxv, fig. 6), represents the
young of this species (Tab.VI, fig. 16); in that condition the shell is somewhat more convex,
the concentric lines are prominent and less irregular than in the adult condition. Lucina
obliqua, Goldfuss, (Petref., tab. 146, fig. 14,) is probably another synonym of the same
species ; these synonyms having been occasioned by the figure in the ' Geology of York-
shire,' unaccompanied by any description not having been fully recognized.

The numerous specimens which we have examined present a considerable diversity in
figure, depending chiefly upon the varying amount of obliquity ; the substance of the test
is thick, and in the ultimate stage of growth the concentric plications become both pro-
minent and closely arranged. In the shelly beds of the great Oolite the greater number
of specimens are diminutive ; in the upper portion of the Inferior Oolite they are much
larger.

Localities. Minchinhampton Common in the Great Oolite; Ponton, Lincolnshire;
near Nailsworth, in the Inferior Oolite.

CORBIS, Cuvier, 1817.

IDOTJEA, Schumacher, 1817.

Gen. Char. Shell transverse equivalve, umbones submesial, incurved, contiguous ;
surface ynbricated or cancellated. Hinge, with two narrow triangular teeth, in each valve
of which one is bifid, and two lateral teeth, the anterior of which are approximate, the
posterior teeth remote. Muscular impressions lunulate, pallial impression simple.

CORBIS LAJOYEI, D' Archiac. Tab. VII, fig. 12, I2a, b.

COEBIS LAJOYEI, D'Archiac. Mem. Soc. Geol. Fr., torn, v, t. 27, f. 1, 1843.
Testa crassd, convexd, transverse elonyatd, umbonibus maynis medianis ; antice sub-

70 MOLLUSCA FROM THE GREAT OOLITE.

horizontali producto, postice subrostrato, attenuate ; margins cardinali subrecto, oblique
declivi ; costis concentricis crebris imbricatis ; margine inferno integro.

Shell thick, convex, transversely elongated, umbones large mesial ; anterior side pro-
duced subhorizontal ; posterior side more attenuated, slightly rostrated ; hinge border
nearly straight, elongated, and sloping obliquely; concentric costse densely arranged,
regular imbricated ; inner margins of the valves smooth.

A very rare shell readily distinguished from other contemporaneous species by the
finer and more densely arranged costse.

Height 16 lines; length 25 lines; diameter through both the valves 13 lines.

Locality. Minchinhampton Common, where it occurs in the bed of coarse planking.

CORBIS LAJOYEI, Far. cingenda. Tab. VII, fig. 11.

Testa ovato-rotundatd concentrice costatd ; costis magnis subdistantibus prominulis
lamelliformibus ; latere antico brevi, marginibus rotundis.

Shell ovately rounded, convex, concentrically costated ; costae rather distant, regular,
prominent, lamellar, anterior side short, margins rounded.

The figure is less elongated than in the preceding species, more especially the anterior
side ; the costse are much more distantly arranged.

Height, one inch ; length, an inch and a quarter ; rare.

Locality. Minchinhampton Common, in the bed of coarse planking.

CORBIS ASPERA. Tab. VII, fig. 13, 13«.

CORBIS ASPERA, Lycett. Ann. Nat. Hist., Dec. 1850, pi. 11, f. 7.

Testa ovato-elonffatd, convexd, umbonibus subacutis prominulis, costis concentricis
subacutis regnlaribm distantibus.

Shell ovately elongated, convex, umbones prominent, mesial, rather acute ; concentric
costse regular, distinctly arranged, and rather acute.

Compared with C. cingenda, the figure is more elongated, the umbones more pointed,
and the costas are more elevated and distantly arranged.

Height, 8 lines, length, 1 1 lines ; but larger specimens occur in the Inferior Oolite.

Localities. Minchinhampton Common, in the Great Oolite ; the vicinity of Nailsworth,
in the Inferior Oolite.

-
Sub-Genus, SPH^RA, Sow.

Shell thick, subaequilateral, equivalve, globose, umbones large, contiguous, directed
forwards, lunule small, but slightly excavated, ligament external, surface smooth, or
impressed only with the folds of growth. Hinge, massive, with two cardinal teeth in the
right valve, these are thick and united beneath the umbo ; the posterior one is prominent,
and placed transversely to the hinge plate, the anterior one is oblique and elongated

BIVALVIA. 71

forwards, having a pit above it to receive the anterior lateral tooth of the other valve. Left
valve with two cardinal teeth, of which the anterior one is prominent, somewhat conical,
and disunited from the other, there is also a small approximate anterior lateral tooth.
Each valve has likewise a distant posterior lateral tooth, which is not very prominent.

As SphoRra has a considerable general resemblance to Corbis : we will concisely indicate
the features whereby they are distinguished. In Corbis, the anterior side is the most
prominent ; Sphcera, is equilateral and oblique. The surface of Corbis is always cancellated
having a denticulated inner border ; Spheera, has its surface smooth, or is marked only
with the lines of growth, and the inner margin is acute and smooth. The hinge in the
right valve of Corbis consists of two narrow triangular teeth placed like the sides of the
letter V, the angle being at the umbo, the anterior lateral tooth being separate and
distinct ; in Sphcera, the cardinal teeth are thick, not angular or pointed, and the anterior
one forms a thickened oblique, lengthened process, before which there is no lateral tooth.
In the left valve the arrangement of the teeth is likewise different ; in Sp/tesra, the anterior
and larger cardinal tooth is obtusely conical and projecting ; in the other genus it is
trigonal and depressed, and the anterior lateral tooth is differently situated with respect to
the teeth of the other valve. Allowing, then, that SpAcera is nearly allied to Corbis, there
would appear to exist sufficiently distinctive characters to demand their separation sub-
generically.

SPH.ERA MADRIDI. Tab. VII, fig. 14, 14a, b, c, d.

CARDIUM MADRIDI, D'Archiae. Mem. Soc. Geol. Fr., torn, v, pi. 25, f. 7, 1843.

CORBIS MADRIDI, If Orb. Prodome Paleont., i, p. 309.

? CARDIUM INCERTUM, Phil. Geol. York., i, t. 11, f. 5, 1835.

Testa crassd subglobosd, umbonibus magnis oUiquis et contiguis. Valms in atate
juniori Icevigatis subdepressis ; in estate adulto globoso plicis incrementi rugis, concentricis et
irregularibus.

Shell thick, subglobose ; umbones large, directed obliquely forwards, and contiguous.
In the young state the valves are rather depressed and smooth ; in the adult state they
become much more globose, and acquire concentric, irregular, and prominent folds of
growth.

Considerable variation occurs in the figure of this species, the more globose specimens
have the height and length of the valves almost equal, those which are more depressed
have a greater length laterally and are nearly smooth ; the latter characters are exhibited in
specimens from the Inferior Oolite of Leckhampton Hill, where it occurs somewhat rarely.
Our species ranks as one of the most abundant shells of the shelly beds of Great Oolite in
the Minchinhampton district, and we have also detected it at several positions higher in
the series, even to 120 feet above the Fuller's earth.

Localities. Minchinhampton and Bisley Commons, in the Great Oolite ; in the shelly
roe stone of the Inferior Oolite of Leckhampton Hill ; and in the Forest Marble, near Frome.

72 MOLLUSCA FROM THE GREAT OOLITE.

Genus UNICARDIUM. IfOrbigny, 1847.

Shell thin, convex, ovately oblong ; umbones contiguous, depressed ; hinge margin
elongated, nearly horizontal ; margins of the valves rounded, not close fitting, but without
any regular aperture. Hinge ligamentary, the ligament being external, supported by a
thin shelly lamina, which is partly internal, and extends posteriorly the length of the hinge
margin ; beneath the umbo is a small depressed tooth in each valve, but these are nearly
obsolete, and in the greater number of specimens cannot be distinguished. Muscular
impressions elliptical; pallial impression simple. The external surface is destitute of
ornament, but has large, concentric, irregular plications ; the substance of the test is very
thin.

The three species which we give as examples of Unicardium, belong to an extensive
series of shells, several of which M. Agassiz has figured and described as Mactromyae, but
which are in fact perfectly distinct from another portion of the same genus, for which the
name Mactromya may perhaps be retained ; these latter are Mactromya mactroides
striolata, tenuis, and brevis ; these shells are distinguished by well-marked features,
externally they have an oblique posterior angle, internally they have an anterior, oblique,
elongated rib, and a large sinus in the palleal impression.

Three other species of the same author, viz., M. globosa, aqualis, and rugosa, have a
figure much more convex, without any posterior angle ; internally they are destitute of
the anterior rib, and their palleal impression is simple ; the latter group should therefore
be removed from the Myada. M. D'Orbigny, (' Prodrome de Paleontologie,') has referred
this group, together with other shells, to his new proposed genus Unicardium, the type
of which is Corbula cardioides, of Phillips. Unicardium is described as resembling
Cardium, but having only a single cardinal tooth in each valve.

Unicardium comprises a numerous group of species, several of which are so nearly allied
in form as to be with difficulty distinguished. They occur throughout the Lias, the lower,
the middle, and the upper Oolitic rocks of Europe, and it is probable that many species
remain undescribed ; they occur indifferently in beds of clay, in lias limestone, and in
shelly oolite, in the latter case the valves are always disunited, but in the lias and other
clays, and argillaceous limestones, the valves are invariably in apposition. Their habits
were not gregareous, but, on the contrary, they always occur sparingly, and from the
thinness of the test, have often sustained fracture or compression. From the borders of
the valves not being close fitting, and perhaps from a considerable amount of lateral motion
which the kind of union in the valves would permit, one valve frequently overwraps
the other, producing a mistaken appearance of inequality in the valves, which may have
led to the species first figured in the ' Geology of Yorkshire/ having been assigned to
Corbula.

We regard Unicardium as presenting a considerable resemblance to certain species of
Lucina, and would arrange it in the Malacological series near to that genus.

BIVALVIA. 73

UNICARDIUM VARICOSUM, Sow., Sp. Tab. VIII, figs. 7, la, b ; 8a, b.

VENUS VARICOSA, Sow. Min. Con., t. 296, 1819.

? UNICAEDIUM COEBISOIDEUM, D'Orbigny. Prod, de Pal^ont., i, p. 309, 1850.
VARICOSUM, D'Orbigny. Ibid., p. 310.

Testa subylobosd, umbonibus magnis, medianis antrorsum incurvis, lateribus brevibus,
postice subtruncato, marginibm rotundis, plicis concentricis tenuibus irregularibm.

Shell very thin, subglobose ; umbones large, mesial directed forwards ; sides of the
shell short, more especially the posterior side, which, differing from the usual form of the
genus, is somewhat shorter than the other side ; the margins of the valves are rounded
and slightly irregular ; the concentric plications are not prominent.

The nuclei of this species are impressed with one or more strongly -marked grooves,
which pass downwards from the umbones towards the inferior border in each valve.
Mr. Sowerby remarks that this species is " not remarkable for anything but the furrows
that occur along the middle of the specimens, all of which are casts in a light-coloured
limestone ; the furrows are two upon each valve, one of them much larger than the other,
and terminated before reaching the edge by a deep hollow ; corresponding ridges must
have existed inside the shell, but whether they were visible externally cannot now be
discovered ; the concentric furrows that are strongly marked upon some specimens would
seem to indicate a thin shell. It is nearly globose, but not so deep as long ; the line of
the hinge is two thirds as long as the shell, and nearly straight ; other characters of the
hinge are not discoverable; the beaks are much incurved." (Min. Con., vol. iii, p. 173.)

Localities. Casts occur in the upper marly deposits of the Oolite at Telmersham,
Blisworth, Kingsthorpe, Oundle, &c. The shells occur rarely in the Great Oolite of
Minchinhampton Common.

UNICARDIUM IMPRESSUM. Tab. VIII, fig. Qa, b, c.

Testa ovato-obliqua nut subquadratd, convexd ; umbonibus contiguis submedianis, de-
pressis, latere antico brevi, margins ejusdem rotundato, latere postico magis producto margine
oblique declivi, margine superiori subJiorizontali recto, basi curvatd, plicis concentricis
magnis irregularibus.

Shell obliquely ovate, or subquadrate, convex ; umbones submedian, contiguous, and
depressed ; anterior side short, its margin rounded ; posterior side more lengthened, its
margin sloping obliquely ; superior border nearly horizontal and straight, gaping slightly ;
lower border curved ; concentric plications large and irregular.

In its young state this species is very delicate, more transverse or oblong, and depressed,
its surface is nearly smooth. It is only in a very advanced stage of growth that the
surface acquired large concentric folds, and the figure becomes subglobose, but the degree
of obliquity and convexity varies very much even with individuals of the same size. The

10

74 MOLLUSCA FROM THE GREAT OOLITE.

ligamental area is elongated, smooth, and lanceolate, its margins are not in contact, but
have between them a distinct elongated aperture, which is beneath the cushion of the
ligament. It occurs very frequently in a crushed or imperfect condition, a circumstance
which seems to indicate that it was not habitually a mud living species.

It is met with somewhat rarely throughout the shelly beds of the Great Oolite, and
likewise in the middle division of the Inferior Oolite in Gloucestershire.

Compared with U. fflobosum, Ag., it is more elongated, depressed, and oblique ; as the
test is always preserved, and the valves disunited, we are precluded from examining the
characters of the internal casts.

Localities. Minchinhampton and Bisley Commons in the Great Oolite ; Leckampton
and Selsley Hills in the Inferior Oolite.

UNICARDIUM PARVULUM. Tab. VIII, fig. 6, 6a.

Testa parod subdepressd, ovato-oblongd ; umbonibus subanticis acuminatis, later e antico
brevi, postico elongato ; bad curvatd, lined cardinis horizontali, subrectd; superficie sub-
compresso plicis concentricis irregulariltus.

Shell small, rather depressed, ovately oblong ; umbones anterior and acute, anterior
side short, posterior side elongated, base curved elliptically ; hinge border lengthened,
horizontal, and straight; surface somewhat compressed with irregular concentric pli-
cations.

This little species has less convexity, and is more oblong than is usual with this genus;
the hinge border is nearly horizontal, but rounded at its extremity, and the valves do not
gape perceptibly at the ligamental area ; in many specimens there is an obscurely defined
angle directed from the umbo to the antero- ventral border, and in common with other species
there is much variation in the degree of obliquity and convexity. One of our specimens,
a portion of which exposes the internal cast, has a very fine radiating striae, of which there
is no trace upon the external surface of the shell. It occurs not uncommonly in the shelly
beds of the Great Oolite, and has also been recognised in the upper portion of the
formation.

Height, 7 lines; length, 9 lines.

Locality. Minchinhampton Common.

CYPRICARDIA. Lam. 1801.

Gen. Char. Shell equivalve, inequilateral, oblique, transverse, anterior side short ;
hinge with two or three cardinal teeth in each valve, and one lateral tooth. Muscular
impressions two in each valve ; ligament external.

BIVALVIA. 75

CYPRICARDIA BATHONICA, D'Orb. Tab. VII, fig. 8, 8«, b, c.

CYPEICAEDIA BATHONICA, D'Orbiyny. Prodrome de Pale"ont., p. 308, 1850.

Testa ovato, transversd, incequilalerd, turgidd, cordiformi, postico angulatd et elongato
lavigatd; umbonibus magnis obliquis recurvis, cardine bidentato dentibus lateribus distan-
tibus elongatis ; margine integro postice subsinuato.

Shell ovate, transverse, inequilateral, ventricose, heart-shaped, posterior side angulated,
elongated and smooth ; umbones large, oblique, slightly recurved ; hinge with two large
cardinal teeth and one distant elongated posterior lateral tooth ; margin of the valve entire,
slightly sinuated posteriorly.

This species approaches near to C. cordiformis, Deshayes, but it is more oblique or
lengthened posteriorly ; it occurs rather abundantly in the bed of coarse planking.

Height, 21 lines; length, 27 lines; diameter through the valves, 17 lines.

Localities. Minchinhampton Common ; Ponton, Lincolnshire ; in the Fuller's earth
of Box Tunnel, near Bath.

CYPRICARDIA ROSTRATA, Sow. sp. Tab. VII, fig. 9, 9a, 6.

ISOCAEDIA EOSTRATA, Sow. Min. Con., t. 295, f. 3, 1819.

Goldf. Petref., p. 210, t. 140, f. 12, 1840.

Morris. Cat., p. 88, 1843.

? CAEDIUM BEAUMONTI, IfArchiac. Mem. Soc. Ge"ol. Fr., torn, v, t. 26, f. 4, (nucleus,)

1843.

Testa subtriffond, convexd ; umbonibus angulatis, antemedianis, prominulis ; lunuldparvd
excavatd ; latere antico rotun do, postico truncato angulo obliquo carinato ; dorso leevigato ;
lineis incrementi paucis, irreffiilaribus.

Shell subtrigonal, convex; umbones angulated, prominent, anterior, and incurved;
lunule small, excavated; anterior side rounded, posterior side truncated and somewhat
concave, its inner border forming a prominent and obtuse angle ; the surface of the shell
is smooth, and marked only with a few faintly impressed lines of growth.

The hinge line posteriorly is nearly horizontal, forming an angle with the posterior
sloping margin, the margin itself forming an acute angle with the inferior borders.

Height, 10 lines; lateral diameter, 11 lines; diameter through both the valves usually
about 8 lines, but the latter measurement varies in individuals.

It occurs abundantly in the form of nuclei in the upper portion of the Great Oolite, and
very rarely with the test preserved, in the shelly beds of the formation. The figure of
D'Archiac has a greater height than is exhibited by our specimens, and the umbones are
less inclined forwards, but looking at the great varieties of figure which the nuclei assume,
we do not see any sufficient reason to regard it as a distinct species.

Localities. Minchinhampton Common ; Oxfordshire ; Northamptonshire.

76 MOLLUSCA FROM THE GREAT OOLITE.

CYPRICARDIA NUCULIFORMIS, Roemer, sp. Tab. VII, fig.10, 10a, b..

CYBENA NDCULIFORMIS, Roemer. Verst. Oolith., t. 9, f. 13, 1836.

Testa subtrigond aut cuneiformi, incequilaterd ; umbonibus anticis confirms, marline
antico rotunda, postico elongato et recto, basi curvatd, subsinuatd, cardine bidentato dentibus
lateribus magnis.

Shell subtrigonal or cuneiform, very inequilateral ; umbones anterior, contiguous ;
anterior margin rounded, posterior margin elongated and straight ; base curved, slightly
sinuated ; hinge with two cardinal teeth in each valve and a large lateral tooth placed at
some distance from the others. The general form is rather compressed ; the concentric
plications are distinct, but not very prominent.

It occurs somewhat rarely in the shelly beds of the formation, also occasionally in the
upper beds in the form of casts.

Height 8 lines; length, 12 lines; diameter through both the valves, 5 lines.

Locality. Minchinhampton Common.

*

HIPPOPODIUM, Sow. 1819.

A solitary specimen of this genus has been found by us in the Stonesfield slate of
Oxfordshire ; unfortunately it is in too imperfect a condition for description or comparison,
but it bears a general resemblance to some specimens of H. ponderosum, Sow., and we
have recorded the fact of its occurrence with the view of drawing further attention to the
subject.

MTOCONCHA, Sow., 1824.

Gen. Char. Shell equivalve, transverse, very inequilateral, umbones small, depressed,
subterminal ; hinge border lengthened, straight, having an external elongated groove
parallel with it, and extending from the umbo posteriorly to the extremity of the shell,
ventral margin entire, not sinuated, and parallel with the hinge border. Hinge, with an
elongated cardinal tooth in the right valve, situated beneath the umbo, and which is
received into an elevated cavity in the other valve ; there is also in each valve a lengthened
posterior thickened plate or rib, serving to support the ligament, which is external.
Muscular impressions, two in each valve, of which the anterior are rounded, and bounded
internally by an elevated and thickened plate which projects from beneath the cardinal
tooth ; posterior impression expanded ; palleal impression not sinuated.

MYOCONCHA CRASSA, Sow. Tab. Ill, fig. 16, 160.

MYOCONCHA CRASSA, Sow. Min. Con., t. 467, 1824.

— Bronn. Leth. Geog., p. 237, t. 20, f. 15, 1851.
MYTILUS SULCATCS, Gold/use. Petref., t. 129, f. 4, 1840.

B1VALVIA. 77

Testa subellipticd, fornicatd, concentrice striatd, lineis radiantibusirregularibus, tenuis-
simis undulatis, scepissime obsoletis ; umbonibus parvis ; sulco elongate postico semper
notato.

Shell subelliptical, ridged, concentrically and irregularly striated, with very fine
longitudinal waved lines, frequently obsolete ; umboues small ; posterior elongated,
external groove always visible.

The few Great Oolite examples of this well-known shell are of much smaller dimensions
than those which are so abundant in the lower or Ammonitiferous beds of the Inferior
Oolite at Dundry, they are likewise more compressed ; they have only a moderate degree
of thickness, and the fine lines radiating from the umbones can rarely be discovered ;
these variations are such as might be expected to occur in a species which possesses so
considerable a geological range, and they are moreover precisely similar to those which
the species presents when it is found in the middle or freestone division of the Inferior
Oolite, in Gloucestershire.

Dimensions of the larger Great Oolite specimens : —

Height, 14 lines; longitudinal diameter, 27 lines; diameter through both the valves,
8 lines.

Localities. Minchinhampton Common ; Barnack, Northamptonshire ; Ponton, Lin-
colnshire.

MYOCONCHA ACTION, D'Orbigny. Tab. Ill, fig. 17, 17«.

MYOCONCHA ACTION, D'Orbigny. Prodrome de Paleeont., p. 312, 1850.

Testa ovato-oblongd subdepressd, marginibus superioribus et inferioribus parallelis, margine
postico subrecto, umbonibus parvis, depressis, plicis concentricis paucis irregularibus.

Shell ovately oblong, the superior and inferior borders straight and nearly parallel,
the posterior border nearly square; the umbones very small and depressed, posterior
sulcus distinct ; concentric plications few and irregular.

On comparison with MyoconcJia crassa, this shell is more depressed, less pointed at the
extremities, the posterior border more especially being quadrate ; the superior and inferior
borders are more nearly straight or parallel, and no radiating lines are visible upon the
surface.

Length, one inch and three quarters ; height, one inch.

Locality. Minchinhampton Common, where it occurs in the bed of coarse planking.

MYOCONCHA ELONGATA. Tab. Ill, fig. 18.

Testa soleniformi, clongatd, subdepressd, umbonibus parvis contiguis depressis, latere
antico angusto, postico latiore et compresso, marginibus superioribus et inferioribus rectis,
parallelis, plicis incrementi paucis tenuibus.

Shell pod-shaped, elongated, rather depressed ; umbones small, contiguous, depressed ;

78 MOLLUSCA FROM THE GREAT OOLITE.

anterior side, narrow, posterior side wider and more compressed, upper and lower margins
straight and nearly parallel, concentric plications few and delicate.

A species unusually elongated and compressed posteriorly; it appears to be destitute
of radiating lines, judging from three examples which are the whole that have passed under
our notice.

Height, 8 lines; length, 21 lines; diameter through both the valves, 6 lines.

Localities. Minchinhampton Common, in the Great Oolite ; it occurs also in the
Inferior Oolite of the same district.

PACHYRISMA, Morris and Lycett, 1850.

PACHYRISMA, Deshayes, 1851.

Testa oblongd, cordiformi, cequwalm, valde inte'quilaterali, crassissimd, laviusculd aut
concentrice striatd ; umbonibus magnis angulatis contiguis et involutis, antice recurvis ;
carind obtusd, dorsali, posticd ; ligamento externo, crasso, subelliptico, umbones versus
bifurcate. Dente et foved cardinali unicd in utrdque valvd ; dente magno, obtuso, irregu-
lariter conico lateribus compressis, et dente parvo accessorio in valvd dextrd ; impression-
ibus muscularibus duabus ; posticd obliqud in lamina internd sitd ; untied oblongd excavatd
processu dentiformi superne instructd.

Shell oblong, cordiform, equivalve, very inequilateral, thick, with large, angulated,
contiguous, and involute umbones diverging anteriorly ; an obtuse-angled posterior dorsal
keel divides the surface into two portions ; ligament large, external, somewhat elliptical
and bifurcated towards the umbones, to the apices of which a groove passes for its recep-
tion, as in Isocardia. Hinge massive, consisting of a single large, obtuse, conical tooth
in each valve, compressed laterally ; and a pit by the side of it to receive the corresponding
cardinal tooth of the other valve ; the right valve has, in addition, a small accessory tooth
placed upon the anterior margin of the cardinal pit. Muscular impressions two, the pos-
terior one is supported upon a raised projecting plate, which descends from beneath the
hinge obliquely backwards, the position of which is marked upon the external surface by a
slight furrow ; anterior impression deeply excavated, of an oblong form, and with a small
tooth upon its upper margin.

This genus has some affinities with Isocardia, Opis, and Megalodon, the latter of which
it appears to represent in the Jurassic period, and with it may constitute a family
" Megalonidce." It is distinguished from Megalodon by the cardinal tooth in the right
valve not having been divided as in the latter genus. Megalodon has the anterior mus-
cular impression upon a somewhat raised or larnelliform plate ; but the posterior raised
plate of Megalodon presents a near approximation to that of Packi/rixma. From Opis it is
sufficiently distinguished by the characters of the dentition. The dichotomous ligament
resembles that of Isocardia, and when viewed anteriorly, it reminds us of the recent
Isocardia cor., with its large and graceful diverging umbones. Pachyrisma, then, may be

BIVALVIA. 79

described as a Megalodon-like shell, the dental characters of which, however, are peculiar,
combined with the external figure of Opis and Isocardia.

A detailed description of this genus and its affinities will be also found in the valuable
and useful work of Mons. G. P. Deshayes, the ' Traite Elementaire de Conchologie.'

PACHYRISMA GRANDE, Lycett. Tab. VIII, figs. 1 — 5.

PACHYKISMA GRANDE, Morris and Lycett. Journal of the Geol. Society, 1850, p. 401.
Deshayes. Traite Elementaire de Conch., ii, p. 187, pi- 326i«,
f. 1—3.

Testa cordatd, elongatd; carind obtusd, dorsali, posticd, later e antico brevi ; latere
postico profunde depresso ; striis numerosis, concentricis, irregularibus.

Shell cordate, with an obtuse, prominent, posterior, dorsal keel ; posterior side deeply
excavated, with a mesial oblique furrowj forming with that of the other valve a cordiform
surface ; striae numerous, concentric, and irregular.

In young specimens the form is less gibbous, the small dental processes are very
distinct, but the large tooth has little of the prominence which it afterwards attains, it not
having acquired the conical projecting form as in the adult state.

The massive character of the hinge, umbones, and anterior side of the shell, presents a
striking contrast with the attenuation of the posterior side ; this latter portion is conse-
quently very rarely well preserved, although the internal projecting oblique plate must
have contributed to strengthen this part ; the small dentiform processes bordering the
anterior muscular impression are just in contact when the valves are closed, that of the
left valve being received into a small depression above the corresponding process of the
right valve, the tooth of the right valve resting within the muscular impression of the
opposite one. The thickness of this portion of the test is such that in an individual
which measured six inches across, it was upwards of three quarters of an inch.

Our shell nearly resembles a figure published by Catullo1 of a cast of a shell named
Cardium triquetum, by Wolfen,2 from the Jurassic strata of Antello, near Cardonino. The
shells figured by Pusch, (Polens. Palseont., t. vii, figs. 8, 9,) under the names Isocardia
exaltata, and I. ventricosa, have some affinity with our shell, and may belong to the same
genus.

Geological position. This species occurs near to the base of a series of hard cream-
coloured limestone beds which extend from Minchinhampton to Cirencester, the base line
of which has at one locality been ascertained to be forty-five feet above the Fuller's earth ;
the position is therefore higher than the shelly weatherstones of Minchinhampton Common,
and near to the middle of the formation. The limestones have, in the aggregate, a very
considerable thickness, but become browner and more sandy upwards. It is impossible
to disengage the crystalline tests from the hard limestone, but an accidental seam of softer

1 'Saggio di Zoologia Fossile,' de T. A. Catullo, t. 1, f. D, E, F, f. 2 A ; Padua, 1827.

2 'Abhandl. von Karnthenschen pfaueuschen. Helmintholith.,' p. 48.

80 MOLLUSCA FROM THE GREAT OOLITE.

and less homogeneous rock has enabled us to disclose the interior of the valves in many
instances. The valves occur of all sizes, both in conjunction and disunited ; the habits of
the species were gregareous to the almost entire exclusion of other Mollusks, a few casts of
Purpuroidea and Natica, however, accompany it. Pachyrisma occupies a vertical thickness
of only half a yard, and its horizontal extension would likewise appear to have been very
limited ; hitherto it has been found only at two localities of the same neighbourhood.
Locality. The vicinity of Minchinhampton and Chalford.

OPIS. Defiance, 1825.
CARDITA, Sp., Sow., 1819.

Gen. Char. Shell subtrigonal or cordate, thick, the valves convex, arched, the posterior
side being separated from the anterior by an angle or carina ; umbones prominent, large,
curved spirally outwards and forwards ; lunule large, cordiform, sometimes deeply exca-
vated. Hinge massive, the right valve with a large obliquely pyramidal tooth compressed
laterally, posterior to which is a narrow and deep cavity, with parallel sides ; the left valve
with a large subquadrate cavity to receive the tooth of the other valve, and a small
accessory tooth extending along the posterior margin. Ligament external. Muscular
impressions strongly marked and rounded ; palleal impression simple.

OPIS LUNULATUS, Sow. var. Tab. VI, figs. 3, 3 a, b, c.

CABDITA LUNULATA, Sow. Min. Con., p. 55, t. 232, f. 1, 2, 1819.
OPIS LUNULATUS, Morris. Catalogue, p. 96, 1843.

Blainville. Malacol., t. 70 bis, f. 1,

Testa triffond, ventricosd, concentrice lineatd ; umbonibus maynis involutis, carind dorsa/i
subacutd, elevatd, latere postico abrupte-plano ; lunuld cordatdprofundd, maryinibm actili*.

Shell trigonal ; umbones large, angular, terminal, and curved outwards, the posterior
side bounded by a prominent and acute angled carina ; anterior side with closely arranged
regular concentric lines ; posterior side flattened or slightly excavated, smooth, or with
faintly-marked oblique lines ; lunule smooth, cordate, large, deep, its margins acute.

This thick shell, with the valves disunited, is one of the most abundant bivalves of the
Great Oolite shelly beds ; the size of the lunule varies very much, as likewise does the
number and prominence of the concentric lines ; occasionally, indeed, the surface appears
to have become quite smooth in the more advanced stage of growth.

The height and lateral diameter are of equal dimensions ; the diameter through both
the valves is one third less.

Upon comparison with the typical form from Dundry, this variety is observed to be
smaller, less elongated, the lunule usually larger, and its margins more acute, but we do
not regard these differences of more importance than might be expected to occur in shells
procured from a different stratum and locality.

Localities. The whole of the Minchinhampton district in the Great Oolite ; Ponton,
Lincolnshire.

BIVALVIA. 81

OPIS SIMILIS, Sow., sp. Tab. VI, figs. 4, 4a.

CAHDITA SIMILIS, Sow. Min. Con., p. 56, t. 232, f. 3, 1819.
OPIS SIMILIS, Morris. Catal., p. 96, 1843.

Testa subrhomboided, fornicatd, concentrice lineatd, umbonibus terminalibus incurvis,
carind dorsali acutd, latere postico abrupto, lunuld pland. (Goldfuss.)

Shell nearly rhomboidal or cordiform, elongated ; umbones terminal, rather augulated
and incurved ; dorsal surface with an elevated acute angle ; the lunule is very small and
cordiform, its borders rounded ; the anterior portion of the surface has concentric lines,
which pass over the carina, and are soon lost upon the flattened posterior surface.

The height, measured along the dorsal carina, very much exceeds the lateral diameter,
the shell being much produced and pointed at the posterior and inferior extremity ; it is
associated with Opis lunulatus in the shelly beds of the Great Oolite, but is much less
common ; compared with that species it is much more lengthened and oblique, the lunule
minute, and the lines are much more delicate and closely arranged.

Localities. Minchinhampton and Bisley Commons in the Great Oolite; Ancliff,
Wiltshire ; Ponton, Lincolnshire. Cloughton Wyke, Yorkshire. (Phillips.)

OPIS DESHAYESII. Tab. VI, figs. 5, 5a.

Testa dongatd, angustd, trapeziformi, concentrice costatd, antice depressd, postice acute-
carinatd, sublcevigatd, subsinuatd ; costis regularibus depressis ; lunuld magnd excavatd,
marginibus rotundis ; umbonibus elutis, angustis, incurvis.

Shell elongate, narrow, trapeziform, the sides concentrically costated; anterior side
depressed, truncated ; posterior side acutely carinated, the carina separating a posterior
depressed and smooth area from the costated portion of the shell ; the posterior margin of
the shell forms an angle at its middle part ; lunule large and deep, its margins rounded ;
umbones elevated, angulated, and compressed at the sides.

The general figure is compressed, elongated, and attenuated, irregularly pentagonal, the
anterior side being the most wide. The absence of an anterior angle is sufficient to
distinguish it from Opis 'cardissoides, Goldfuss ; but the two species which approach most
nearly to it are the Opis Archiaciana and 0. Michelinea, figured and described by
M. Buvignier in his work on the ' Geology and Palaeontology of the Department of the
Meuse -.' but in neither of the latter species does the convexity of the valves equal that of
our shell ; they are comparable to it in the elevation and attenuation of the umbones, but
are destitute of the regular concentric costae.

Height, 5j lines ; opposite diameter, 3J lines ; diameter through both the valves, 4 lines.
Rare.

Localities. Quarhouse, Bisley Common, and Minchinhampton Common ; Ancliff,
Wiltshire.

11

82 MOLLUSCA FROM THE GREAT OOLITE.

ASTARTK. SOW., 1817.

Gen. Char. Shell equivalve, inequilateral, thick, the surface usually concentrically costated,
the margins of the valves close, and internally crenulated. Hinge with two diverging cardinal
teeth in each valve, those of the left valve being elongated and nearly equal, those of the
right valve unequal, the anterior one being small. Muscular impressions two ; ligament
external.

ASTARTE SQTJAMULA, D'Archiac. Tab. IX, fig. 9.

ASTARTE SQUAMULA, D'Archiac. M6m. Soc. Geol. Fr., vol. v, pi. 25, f. 5.

Testa ovato-orbiculari, subdepressd, umbonibtts mediants acutis, lunuld ovato-lanceolatd,
costis concentricis, crebris, irregularibus et depressis, nonnunquam obsoletis.

Shell ovately orbicular, rather flattened ; umbones mesial, prominent, and acute ; lunule
ovately lanceolar, and but little excavated; hinge margin lengthened and rounded; concentric
costae numerous, irregular, and depressed, sometimes obsolete.

The valves of this little depressed species occur in considerable numbers throughout the
shelly beds of the formation in the Minchinhampton district ; in the greater number of
instances the surface is smooth, probably by erosion. The lateral diameter is one fifth
greater than the height, and in the largest examples does not exceed six lines.
Individuals vary moderately, both in the outline and the convexity of the valves, but a
considerable number can easily be obtained for comparison.

Localities. Minchinhampton. Eparcy, France.

ASTARTE MINIMA, Phil. Tab. IX, fig. 100, b.

ASTARTE MINIMA, Phil., Geol. Yorksh., t. 9, f. 23.
?ASTAETE PULLA, Roomer, Nordd. Ool., p. 113, t. 6, f. 26.

Testa convexd, ovato-orbiculari; umbonibus submedianis ; costis regularibus convexis,
interstiis eequalibus (circa 14).

Shell convex, ovately orbicular; umbones nearly mesial; costae (about fourteen in number)
regular, rounded, elevated, and equal in breadth to the interstitial spaces.

This little shell is not associated with any other at all resembling it, but from its
minuteness, it is probably often unnoticed ; it does not appear to be abundant (at least in
the Minchinhampton district, from which our specimens have been obtained).

The lateral diameter exceeds the height by about one third, and rarely equals 4
lines.

Localities. Minchinhampton Common, in the soft beds of Oolite beneath the planking ;
Ponton, Lincolnshire ; Scarborough, in the grey limestone of the Great Oolite.

BIVALVIA. 83

ASTARTF, PUMILA, Sow. Tab. IX, fig. 13a, b.

ASTAKTE PTJMILA, Sow. Min. Con., t. 444, f. 2, p. 64.
— ? Gold/us*. Petref., t. 134, f. 16.

Morris. Catal. Brit. FOBS., 1854, p. 187.

Testa parvd, convexd, ovatd, umbonibus acutis, postmedianis, antrorsum incurvis, lunuld
parvd, mediocre depressd, costulis regularibus, oblusis, crebris, intersliis angustioribus.

Shell small, convex, ovate ; umbones acute, postmesial, but directed somewhat forwards ;
lunule small, moderately depressed ; concentric costas regular, obtuse, closely arranged, the
interstitial spaces very narrow.

The height is always greater than the lateral diameter, a character which differs from
the shell figured by Goldfuss, the latter probably being a different species ; the depression
of the lunule varies in different individuals, but never has the deep concavity figured by
Goldfuss. The height is usually about 3 lines ; it is somewhat rare.

Localities. Ancliff and Minchinhampton.

ASTARTE EXCENTKICA. Tab. IX, fig. 8a, b.

Testa parvd, ovato-orbiculari convexd, umbonibus medianis acutis, lunuld minima ; plicis
incrementi paucis, magnis et irregularibus ; costis crebris depressis, interstiis angustioribus ;
costis superioribus subundatis, excentricis, inferioribus semel subundulatis sed concentricis.

Shell small, ovately orbicular and convex ; umbones mesial and pointed ; lunule very
small ; folds of growth few, strongly marked, and irregular ; costaa very densely arranged,
depressed, the interstitial spaces very narrow ; the superior costa3 are slightly undulated,
and are excentric, passing across the surface of the valves very slightly inflected ; the inferior
costse are concentric, but are likewise slightly undulated.

The finely ornamented surface of this little shell is scarcely visible except under a
magnifier ; the costse are flattened, and so closely arranged that the interstitial spaces are
mere striae ; there is also about the borders of the costse a kind of obscurely wrinkled
appearance, or as though they were slightly crenulated ; the superior or excentric costse
occupy a surface less than the inferior ones, and the two kinds are separated by a
prominent fold of growth. Our little species does not appear to be very abundant, it
occurs with other small shells of the same genus in the beds of soft shelly Oolite which
underlie the planking.

Height and lateral diameter equal, or about 4 lines.

Localities. Minchinhampton and Bisley Commons.

84 MOLLUSCA FROM THE GREAT OOLITE.

ASTARTK ROTUNDA. Tab. IX, fig. 12.

ASTAKTE ORBICULAEIS, Sow. Min. Con., t. 520, f. 2.
— EOTUNDA, Morris. Catal. Brit. FOBS., p. 187.

Testa crassd orbiculatd, convexd, umbonibus submedianis acutis, margine cardinali
obliquo, elongate, subrecto, lunuld magnd lanceolatd, plicis incrementi paucis, irregularibus ;
costis depressis, crebris et irregularibus.

Shell thick, orbicular, convex ; umbones nearly mesial, prominent, acute ; hinge margin
oblique, lengthened, and nearly straight ; lunule large and lanceolate ; folds of growth few
and irregular ; costse depressed, small, closely arranged, and irregular.

The general figure has a considerable degree of convexity ; the umbones are small,
pointed, and curved forwards, and are placed somewhat nearer to the anterior than
posterior side of the valves ; the extremity of the lengthened hinge border forms an angle
with the inferior margin. It is rare.

Height nearly equal to the lateral diameter, which is 2£ inches ; the diameter through
both the valves is \\ inch.

Locality. Minchinhampton Common, in the planking.

ASTARTE? RHOMBOIDALIS, Phil., sp. Tab. IX, fig. 20.

ISOCAKDIA RHOMBOIDALIS, Phil. Geol. York., 1, t. 3, f. 28.
HIPPOPODIUM LUCIENSE, D'Orb. Prod. Paleont., p. 308.
BAJOCIENSE, D'Orb. Ib., p. 277.

Testa crassd convexd, subquadratd, vel oblongd, umbonibus anticis obtusis, margine
cardinali elongato, subJiorizontali, hinuld magnd, excavatd, margine inferiore subrecto et
sinuato, marginibus internis integris, superjicie plicis incrementi paucis, magnis, distantibus ;
striis concentricis tenuissimis regularibus crebris. JEtate senili striis concentricis obsoletis,
plicis rugis magnis irregularibus.

Shell thick, convex, subquadrate, or oblong ; umbones anterior, obtuse ; hinge margin
elongated, subhorizontal, but slightly arched ; lunule large, elliptical ; inferior margin
nearly straight, parallel to the superior border, and slightly sinuated ; internal margins of
the valves plain, acute ; folds of growth few, large, and distant ; concentric striations regular,
delicate, and closely arranged. In an advanced stage of growth the concentric striations
disappear, and the surface became rugose with the irregular plications of increase. An
oblique prominence or obscure angle extends downwards posteriorly, and becomes promi-
nent in specimens which are short and have the superior border much arched. The Great
Oolite examples are very numerous, and for the most part rather flattened arid rugose with
adherent shells, the largest specimens not unfrequently having been perforated or grooved
by the Lithophagidae ; the substance of the test is very thick, and the muscular im-
pressions are deeply excavated ; the cardinal teeth are remarkably large and massive.

BIVALVIA. 35

Localities. The vertical range of this remarkable species is very considerable ; it occurs
in the Inferior Oolite of the Cotteswolds, the Great Oolite of Minchinharnpton, the
Coralline Oolite of Malton, and we have seen fine casts from the Kimmeridge Clay of
Wilts. The Hippopodium Luciense and H. Bajociense, D'Orb., are probably identical with
this species.

ASTARTE EXCAVATA, Sow., Var. COMPRESSIUSCULA. Tab. IX, fig. 18, 19.

ASTABTE EXCAVATA, Sow. Min. Con., t. 233.

COMPLANATA, Roemer. Nordd. Oolith., t. 6, f. 28.

Testa ovatd, transversd, compressd, umbonibus parvis anticis depressis, margine cardinali,
elongate, carvato, subhorizontali, margine inferiore elliptico, lunuld angustd excavatd,
margine aculo. Costis externis concentricis depressis irregularibus interdum confertis aut
enim obsoletis. JEtate juniori testa planatd et fragili, costis paucis latis prominulis.

Shell ovately transverse, compressed ; umbones small, anterior, and much depressed ;
hinge border elongated, nearly horizontal, and curved ; lower border regular, elliptical ;
lunule deeply excavated, its margins acute; concentric costae depressed, irregular, some-
times nearly obsolete. In the young state the shell is flattened, very delicate, pellucid, and
has a few distinct broad concentric costae near to the umbones.

In the shelly beds of the Great Oolite, the young delicate shells occur abundantly from
8 to 6 lines in length. Adult specimens are much more rare, and few exceed 20 lines in
length.

The tenuity of the test is considerable ; and this feature, together with the greater
flatness, will serve to distinguish it from the typical form, A. excavata, Sow., which is a
much larger and thicker shell. Notwithstanding its tenuity, flatness, and the small
dimensions, we believe this to be only a variety of the well-known Inferior Oolite shell,
induced by peculiarities of the stratum in which it occurs. The same change of aspect takes
place in the freestone beds of the Inferior Oolite ; but the form again attains its pristine
dimensions and thickness in the upper ragstones higher in the series.

Localities. Minchinhampton Common in the Great Oolite ; Nailsworth Hill, in the
freestone beds of the Inferior Oolite.

The typical shell occurs abundantly at Dundry and at Rodborough Hill.

ASTARTE DEPRESS A, Gold/. Tab. IX, fig. 11.

ASTARTE DEPKESSA, Goldfuss. Petref., p. 192, t. 134, f. 14.

Testa compressd, transversim ovato-orbiculari ; umbonibus mediants obtusis ; lunuld
ellipticd, angustd, coslis convexis interstiisque concent-rice striatis. (Goldfuss.)

Shell compressed, transverse, ovately orbicular ; umbones median, prominent, obtuse ;

86 MOLLUSCA FROM THE GREAT OOLITE.

lunule elliptical, narrow ; cardinal margin nearly straight, oblique ; concentric costae convex,
irregular, with fine interstitial concentric striae.

The lateral diameter is one fifth greater than the height ; the smaller specimens arcs
those which display the characters of the species most distinctly ; with increase of growth
the shell acquired some additional convexity, and the costse became less distinctly
elevated.

Locality. It occurs somewhat rarely in the shelly beds of the formation at Minchin-
hampton, and likewise in the middle division of the Inferior Oolite of the same district.

ASTARTE ANGULATA. Tab. IX, fig. Yla, b.

Testa crassd transversd, subtetragond, aut cuneiformi ; umbonibus anticis promi-
nentibus ; margine antico rotundato, postico elongato, subrostrato, dorso oblique subinflexo ;
striis concentricis crebris, irregularibus.

Shell thick, transverse, somewhat triangular or wedge-shaped ; umbones prominent and
anterior ; anterior margin short and rounded ; posterior margin elongated, slightly curved,
and rostrated ; dorsal surface slightly bent by an obscure angle, which passes obliquely
downwards to the posterior extremity; striae concentric, closely arranged, and irregular.

A sulcus borders the posterior side of the shell throughout its length ; it is smooth,
and the margin separating it from the dorsal surface is acute. This character will readily
distinguish it from contemporaneous species of the genus.

This small shell is not very common : it occurs with other small Veneridae in the soft
Oolite which underlies the planking.

Locality. Minchinhampton Common.

ASTARTE ELEGANS, Sow. Tab. XIV, fig. 14.

ASTARTE ELEGANS, Sow. Min. Con., t. 137, f. 3.

Phil. Geol. York., 1, t. 11, fig. 41.
Goldf. Petref., t. 134, f. 12.

— Zeiten. Petref., t. 61. f. 4.

— Morris. Catal., 1854, p. 186.

Testa ovato-obliqud plano-convexd, crassd; umbonibus antemedianis prominentibus ;
lunuld excavatd, marginibus rotundis ; lateribus plicis concentricis magnis elevatis subacutis,
plerumque regularibus ; marginibus internis denticulatis.

Shell ovately oblique, with a low convexity; test thick ; umboues prominent, anterior,
and curved forwards ; lunule excavated ; border of the valves rounded ; surface with large,
elevated, and rather acute, usually regular concentric plications ; inner margins of the
valves denticulated.

Specimens vary much in the degree of obliquity and convexity.

BIVALVIA. 87

This very common Inferior Oolite species occurs rarely in the Great Oolite, but it is
absent in the shelly beds of the formation in Gloucestershire.

Geological position and localities. Minchinhampton and Scarborough in the Great
Oolite ; the Cotteswolds, Dundry, Yeovil, and Brora in the Inferior Oolite ; Malton in
the Coralline Oolite.

ASTARTE INTERLINEATA., VttT. LyC., Sp. Tab. IX, fig. 14, 15fl, 6.

HIATELLA ? INTERLINEATA, Lycett. Anu. and Mag. Nat. Hist., 1850, p. 421.

Testa pared subquadratd vel oblongd, convexo-pland ; umbonibm acutis, parvis, ante-
medianis; lunuld excavatd; margins superiori et inferiori parallelis subrectis, antico
rotunda, postico truncato , angulo obliquo; costis longitudinalibm magnis, postice in
angulo flectis et trinodulosis ; striis interstitialibus tenuissimis instructis.

Shell small, subquadrate or oblong, slightly convex ; umbones acute, small, depressed,
and placed anterior to the middle of the valves ; lunule excavated ; superior and inferior
margins parallel, horizontal, and straight ; anterior border rounded ; posterior border
truncated ; longitudinal costse few, somewhat irregular, large, and rounded in the Great
Oolite variety, bent posteriorly upwards, forming an acute angle ; their posterior portions
have also in this variety three rather obscure nodules ; the interstitial spaces have very fine
longitudinal striations.

This species presents itself under two varieties of aspect, one of which occurs in the
middle portion of the Cotteswold Inferior Oolite. This latter and more smooth variety
has the figure somewhat shorter, the costae rather more distant ; they are also more narrow
and acute ; and posteriorly they have not the nodules of the other variety. It must not,
however, be inferred that these distinctions are preserved in all specimens ; on the contrary,
the posterior nodules are uncertain in their distinctness ; the number of costa? and their
size are equally variable. The test is delicate.

Height, 3 lines ; length, 4i lines ; diameter through both the valves, 2 lines : but the
greater number of specimens have smaller dimensions. .

Geological position and localities. Astarte interlineata occurs in the shelly freestone of
the Inferior Oolite of Leckhampton and of the Minchinhampton, and likewise in the shelly
Great Oolite of the latter locality.

ASTARTE WILTONI. Tab. IX, fig. 16.

Testa ovato-subangulari planatd, umbonibus anticis acutis ; costis apicialibus concentricis
paucis, magnis.

Shell ovately subangular or subquadrate, flattened ; umbones anterior, acute ; the
surface with a few acute concentric costae near to the apex ; the other portion of the
surface nearly smooth.

88 MOLLUSCA FROM THE GREAT OOLITE.

The surface ornaments nearly resemble A. striato-costata, Munster, Goldf. Pet.,
tab. 134, fig. 18; but the latter shell has much larger dimensions, is somewhat more
convex, and has not the subquadrate figure of our species. It is somewhat rare. The
name from John Wilton, Esq., of Gloucester, who has investigated the minute anatomy of
the univalve Mollusca.

Lateral diameter, 6 lines ; height, 5 lines.

Locality. Minchinhampton Common, in a bed of soft Oolite, which underlies the
planking.

ASTARTE RECONDITA, PML, sp. Tab. XII, fig. 10.

Syn. PULLASTRA RECONDITA, Phil. Geol. York., 1, t. 9, f. 13.

Testa parvd, ovato-oblongd, subdepressd ; umbonibus obtusis, anticis ; margine cardinali
subhorizontali, basi ellipticd curvatd, superficie striis concentricis paucis magnis ; lunuld
excavatd.

Shell small, ovately oblong, rather depressed ; umbones obtuse, anterior ; hinge border
elongated, nearly horizontal ; basal margin curved elliptically ; lunule excavated ; the
surface near to the umbones has a few large obscure concentric striations, which disappear
towards the middle of the shell.

In figure, this little shell bears some resemblance to the young of Astarte rhomboidalis,
but it is more flattened, and is destitute of the posterior angle of that species ; the few
rugose striations near to the umbones is another distinctive feature.

Locality. Ponton, Lincolnshire, where it has occurred rather sparingly in the coarse
Oolite. In "Yorkshire, Professor Phillips records it in the Great Oolite of Cloughton
Wyke.

CYPRINA. Lam.

Gen. Char. Shell equivalve, inequilateral, transverse, subglobose or subovate ; umbones
curved obliquely ; ligament external ; hinge with three diverging cardinal teeth, and a
remote laminar or lateral tooth in each valve ; muscular impressions, two, lateral ; pallial
rapression slightly angulated posteriorly; margins of the valves close, smooth internally.

CTPKINA LOWEANA. Tab. XIII, fig. 2 2« — d

Testa transvers im ovali, Icsvi, convexd; umbonibus antemedianis crassis ; lunuld ova fa
parvd, area lanceolatd, latere postico subcompresso, inferne subangulato ; striis concentricis
tenuissimis irregularibus frequenter obsoletis.

Shell transversely ovate, smooth, convex ; umbones anterior, thick, and large ; lunule
ovate, but slightly excavated ; area lanceolate ; anterior side rounded ; posterior side rather
compressed, and slightly angulated at its inferior extremity ; the surface has very fine
irregular concentric striations, which in the greater number of instances are obsolete.

BIVALVIA. 89

In none of the Oolitic forms do we find a greater variety of figure than in this species,
and without ample materials for comparison, its examples would probably be regarded as
pertaining to more than one species; these variations, which are irrespective of growth, refer
to the degree of convexity, the extent to which the valves are produced posteriorly, and the
more or less compressed and angulated, or, on the other hand, rounded and convex figure
of the posterior side of the shell. The valves occur in such considerable numbers, and so
fully illustrate all these minor variations of figure, as to remove all doubt that they belong to
the same species, even though we place together two examples of very dissimilar aspect.
The shell is rather thin, always very fragile, except at the umbones, which are not un-
frequently the only portions preserved when the shelly beds are more than usually detrital
in their character. The valves rarely occur in contact ; but when this happens the ligament
is preserved.

The subjoined proportions must be regarded as representing the median figure of the
species. Height, 13 lines; lateral diameter, 15 lines; diameter through both the valves,
10 lines. It ranks as one of the most abundant of the bivalves in the Minchinhampton
district, and ranges throughout the shelly beds. Named after J. G. Lowe, Esq., who has
assiduously collected an interesting series of fossils from the middle Oolite.

Localities. Minchinhampton Common ; Bisley Common.

CTPRINA TRAPEZIFORMIS, et var. SUBROTUNDA. Tab. XIII, fig. 5, 5a, c.
VENUS TBAPEZIFORMIS, Roemer. Verst. Nordd. Oolith., t. 7, fig. 14.

Testa orbiculato-subtrapezif ormi, convexo-pland ; antice rotundatd ; postice subproductd,
angulo acuto carinato-depresso ; umbonibus anticis incurvis.

Shell orbicular or subtrapeziform, moderately convex ; anterior side rounded ; posterior
side somewhat produced, forming a depressed angle ; umbones anterior, incurved.

This small species occurs abundantly throughout the shelly beds of the formation at
Minchinhampton, with the valves disunited. When well preserved, its surface exhibits
concentric, irregular, and very fine striations ; it is shorter and more convex than C. Loweana.
The form which we have designated as a variety has greater convexity, and the posterior
side has not the angulated outline of the typical form.

Dimensions of this variety: height, 8 lines; lateral diameter, 9 lines; diameter through both
the valves, 7 lines. Another line added to the lateral diameter will represent the typical form.

Localities. Minchinhampton Common ; Bisley Common.

CYPRINA JTJRENSIS, Gold/., sp. Tab. XIII, fig. 3.

VENUS JUKENSIS, Goldfuss. Petref., p. 245, t. 150, fig. 1 7.

Testa parvd suborbiculari ; wnbonibus mediants minutis ; lunuld ovatd ; area
lanceolatd.

12

90 MOLLUSCA FROM THE GREAT OOLITE.

Shell small, smooth, nearly orbicular, rather depressed ; umbones mesial and small ;
lunule ovate ; area lanceolate.

The nucleus figured by Goldfuss from the Coral Rag of Nattheim, agrees in form with
our little species, and they are probably identical.

Height, 5^ lines ; lateral diameter, 7 lines.

Localities. Bisley Common, at Eastcombs, and Bussage.

CTPRINA DEPRESSIUSCULA. Tab. XIII, fig. 4.

Testa suborbiculari, leevi, convexo-pland ; umbonibus medianis parvis acutis ; lunuld
subexcavatd ; margine postico curvato ; basi arcuatd.

Shell suborbicular, smooth, and slightly convex; umbones mesial, small, and
pointed ; lunule slightly excavated ; hinge margin curved ; base regularly rounded.

The smooth, rather depressed surface, the mesial pointed umbones, and absence of all
angularity in the outline, are the leading characters of this shell, which appears to be rare.
Its position is the soft shelly Oolite, about the middle of the shelly beds.

Height, 8 lines ; lateral diameter, 9| lines.

Locality. Minchinhampton Common.

CTPRINA NUCIFORMIS, Lycett. Tab. XII, fig. 4.

CYPKINA NUCIFOKMIS, Lycett. Journ. Geol. Soc., 1853, vol. 9, p. 340, pi. 14, fig. 3.

Testa subnuciformi, convexd ; umbonibus magnis curvatis ; marffinibus rotundis ; latere
postico angulo obtuso obliquo ; lunuld excavatd.

Shell subcordiform or nut-shaped, convex; umbones large, prominent, and curved
forwards ; margins of the valves rounded ; posterior side with an oblique, obtuse angle ;
lunule large, slightly excavated.

A very convex species, with large umbones, less oblique and more convex than Venus
trapeziformis, Roemer.

Height and length equal ; convexity of the valves one third less.

Localities and position. In Gloucestershire it occurs in the middle portion of the
Inferior Oolite ; our specimens are from the Great Oolite of Ponton, in Lincolnshire.

Genus — TANCREDIA. Lycett, 1850.

TANCKEDIA, Lycett. Ann. Nat. Hist., 1850, p. 407.

HETTANGIA, Terquem, 1852. Buvignier. Statistique Geologique, Mineralogique et

Paldontologique du Departement de la Meuse ; Atlas, p. 14.
Terquem, Bull. Soc. Giol. de France, 10. p. 368.

Gen. Char. Shell equivalve, subaequilateral, smooth, somewhat flattened, transverse,
donaciform; umbones nearly mesial, small, contiguous, flattened; anterior extremity
usually pointed ; no lunule ; posterior side more convex, with an oblique angle more or
less conspicuous, the extremity truncated, and more or less gaping; ligament short,
external, placed in a small depression; basal margin lengthened, curved, or elliptical;

BIVALVIA. 91

hinge with an obtuse cardinal tooth in each valve, which is received into a corres-
ponding cavity in the other valve; occasionally in the right valve there is a small
anterior, and in the left a small posterior accessary tooth or prominence upon the
margin of the cavity ; lateral teeth are large, posterior, and approximate in each valve, that
of the left valve projecting and received into a depression of the tooth or callosity of the
other valve. Muscular impressions oval ; pallial impressions simple, faintly marked. There
is no lunule ; the margin of the right valve anterior to the umbo forms a thickened projecting
fold, which covers the tooth of the other valve, and is received into a corresponding receding
portion of the margin of that valve ; so that the junction of the valves anterior to the umbo
has a sinuous flexure.

In the typical species, T. donaciformis, which is an Inferior Oolite shell, the lateral teeth
are remarkably large; and they are nearly equally conspicuous in the Hettangia
Deshayesea, Terquem, and H. Broliensis, from the Lias of the Moselle and the Meuse, figured
by M. Buvignier ; but the other Liassic species described by that author, coincide in their
dental characters more nearly with our Great Oolite species of this genus. In these, the shells
are more delicate, the hinges are smaller and more elongated, the teeth are less projecting,
and the cardinal tooth of the left valve is elongated forwards, somewhat upon the anterior
border ; the lateral teeth are variable in their prominence, and not uncommonly the tooth
of the right valve is indistinct or obsolete. When the valves are much flattened, the posterior
aperture becomes narrow or not distinguishable. The figure of Tancredia varies according
as the anterior or posterior sides are the most produced ; but more commonly the posterior
side is the shorter one, and when it is much truncated, the figure then nearly resembles that
of the recent Donaces. All the species at present known are destitute of ornament ; they are
smooth, and exhibit but indistinctly the lines of growth. The margins of the valves are
smooth, and, independently of the posterior aperture, there is a general irregularity in the form
of the margins, so that they are not close fitting along their extent. In England, Tancredia
has only hitherto been noticed in the lower Oolitic rocks. M. Buvignier and M. Terquem
have recognised eleven species in the Lias of France, and Dr. Dunker one from Halber-
stadt. To the geologist a knowledge of this form is of importance, as the species appear
to be very limited in their vertical range, and hitherto it has not been discovered that any
one of them is common to two formations. The profuseness with which T. brevis is
distributed in the shelly beds of the Minchinhampton Great Oolite, and the young of
T. donaciformis in the shelly freestone of the Leckhampton Inferior Oolite, is such, that
each becomes the most abundant bivalve of their respective localities ; the valves are always
disunited, and casts are unknown.

In looking to the affinities of this genus, we discover a near approximation — almost an
actual passage — into a group of Oolitic forms, which are as yet very imperfectly known,
and of which Corbis Items, Sow., and Corbis deprcssa, Buvig., are examples. Three
other species have been obtained from the Inferior Oolite of the Cotteswolds, and one from
the Coralline Oolite of Malton. In all of these a smooth surface is coincident with a

92 MOLLUSCA FROM THE GREAT OOLITE.

compressed, elongated figure, and a hinge, the dentition of which differs materially from
that of the better known forms of Corbis. The shells, likewise, are rather thin, the margins
not toothed, and the posterior side is always the larger of the two.

TANCREDIA TRUNCATA, Lycett. Tab. XIII, fig. 11.

TANCKEDIA TRUNCATA, Lycett. Ann. and Mag. Nat. Hist., 1850, pi. 11, f. 10.

Testa subtrigond, ovato-cuneatd; umbonibus posticis ; latere postico, brcvi, truncato; antico
elongato, margine superiore ejusdem recto, oblique-declivi ; margine inferiore subrecto.

Shell subtrigonal, or ovately wedge-shaped ; umbones posterior ; posterior side short,
truncated ; anterior side elongated, its superior margin straight, sloping obliquely down-
wards, the extremity rounded ; basal margin nearly straight.

The short posterior side slopes suddenly downwards, it is bounded by an obscure
angle or ridge.

Height, 6£ lines; length, 13 lines; diameter through both the valves, 5 lines. Its
position is the shelly beds of the Great Oolite, in which it is somewhat rare.

Localities. Minchinhampton and Bisley Commons.

TANCRKDIA BREVIS. Tab. XIII, fig. 8.

Testa joarvd subtrigond ; umbonibus submedianis ; latere postico brevi, angulo producto ;
marginibus acuminatis, margine inferiore ettiptico.

Shell small, subtrigonal; umbones submesial, depressed; posterior side sloping obliquely,
and having a prominent angle, which passes obliquely from the umbo to the postero-
inferior border; margin of the valves pointed at both extremities, the inferior margin
curved elliptically.

Compared with T. axiniformis this species is much more short and convex, and it
always forms a prominent angle upon the posterior side, posterior to which the surface is
flattened, or even slightly excavated, the extremities of the valves being pointed. In its
geological range it accompanies the two other species ; it is everywhere common, and
certain layers of soft shelly Oolite beneath the planking of Minchinhampton Common are
entirely covered with its valves ; undoubtedly it is the most abundant bivalve in the district.

Length, ?i lines ; height, 4| lines.

The Tancredia donaciformis, Lycett, 'Ann. and Mag Nat. Hist.,' 1850, vol. vi, pi. xi,
fig. 8, approximates so nearly to our species that it is necessary to discriminate between
the two forms. The T. donaciformis is more lengthened, the umbones are mesial, but the
anterior side is more attenuated, its marginal slope being slightly concave, and its extremity
more pointed, so that the posterior side appears to be larger than the other ; it occurs in
the shelly free stone of the Inferior Oolite, Leckhampton Hill, in an abundance rivalling
our Great Oolite species.

Locality. The whole of the Minchinhampton district.

BIVALVIA. 93

TANCREDIA CURTANSATA, Phil., sp. Tab. XIII, fig. la, 6.

COEBDLA CCRTANSATA, Phil. Geol. York., 1, t. 3, f. 27.

Testa ovato-elongatd ; umbonibus mediants, parvis ; antice compressd, acuminatd, postice
convexd; margine antico oblique declivi concavo ; basi ettipticd curvatd.

Shell ovately elongated ; umbones small, mesial ; anterior side compressed, its
extremity pointed ; posterior side moderately convex, its margin slightly rounded ; antero-
superior border obliquely sloping and concave ; base elliptically curved.

This is the largest of the Great Oolite species of this genus, it is moderately abundant
in the shelly beds ; specimens vary much in the convexity of the valves.

Height, 10 lines; length, 15 lines; diameter through the valves, 7 lines.

Localities. Minchinhampton, in the Great Oolite ; Malton, in the Coralline Oolite.

TANCREDIA AXINIFORMIS, Phil., sp. Tab. XIII, fig. 6a, 6.

NCCULA AXINIFORMIS, Phillips. Geol. York., 1, t. 11, f. 13.

TANCBEDIA EXTENSA, Lycett. Ann. and Mag. Nat. Hist., 1850, pi. 2, f. 9.

AXINIFORMIS, Morris. Journ. Geol. Soc., 1853, v. 9, p. 341, pi. 14, f. 4.

Testa ovato-trigond elongatd, convexo pland ; umbonibus mediants ; latere postico convexiore,
angulo oblique subacuto ; margine anteriore et posteriore rectis, oblique declivibus ; bam,
ellipticd curvatd.

Shell ovately trigonal, elongated, rather depressed, pointed at the extremities ; umbones
mesial, depressed, small, and pointed ; the posterior side the more convex, with a subacute
oblique angle separating a space posterior to it, which is slightly concave ; anterior and
posterior margins straight, and sloping obliquely downwards; lower margin curved
elliptically.

Specimens of this species present a considerable amount of variability in their
figure ; those from Lincolnshire are usually more convex posteriorly, and have the angle
more acute, the space posterior to it being somewhat concave; the Minchinhampton
specimens are flatter, the umbones scarcely so much elevated, the posterior angle more
obtuse, the space adjoining it being flattened. These differences at first induced us to regard
the two as distinct species, and the first description of T. extensa, published in the 'Annals
of Nat. Hist/ for 1850, was deduced from Gloucestershire specimens, as compared with
the acute angle and otherwise distinct figure given in the ' Geology of Yorkshire ;' but an
examination of numerous specimens, and more especially of those from Lincolnshire, have
satisfied us that at the utmost, those of the North of England can only be considered as a
variety of the more common form seen in Gloucestershire.

Tancredia angulata is a higher shell, with a shorter posterior, and more attenuated
anterior side.

Length, 1 1 lines ; height, 6 lines.

94 MOLLUSCA FROM THE GREATO OLITE.

Geological position and localities. T. axiniformis occurs in the Inferior Oolite of
Yorkshire, and in the Great Oolite of Ponton, Lincolnshire, and of Minchinhampton, in
the shelly beds.

TANCREDIA PLAN ATA. Tab. XIII, fig. lOa, b.

Testa ovatd, planatd ; umbonibus submedianis parvis acuminatis ; antice compressd;
postice plano-convexd ; margine postico oblique-curcato ; antico recto oblique declivi ; basi
curvatd.

Shell ovate, flattened ; umbones nearly mesial, small, and acute ; anterior side com-
pressed, its extremity rounded ; posterior side rather more convex ; the posterior margin
has an oblique curvature ; the anterior margin is straight, and slopes obliquely ; the base is
curved elliptically.

A delicate, smooth, and flattened shell, the anterior extremity of which is much less
acuminated, and the posterior less truncated than is usual in this genus. It is moderately
abundant in the shelly beds of the formation, and varies considerably both in its outline
and degree of convexity.

Height, 9 lines ; length, 13 lines.

Localities. Minchinhampton and Bisley Commons.

TANCREDIA ANGULATA, Lycett. Tab. XIII, fig. 9a, b.

TANCREDIA ANGULATA, Lycett. Journ. Geol. Soc., 1853, vol. 9, p. 341, pi. 14, f. 5.

Testa ovato-triffond ; umbonibus elatis, medianis, acutis ; latere antico compresso ; postico
angulum obliquum formante ; margine cardinali brevi, recto horizontali ; basi curvatd.

Shell ovately subtrigonal ; umbones elevated, mesial, acute ; anterior side compressed ;
posterior side with an oblique angle separating a flattened posterior portion ; ligamental
margin short, horizontal ; basal margin with a considerable curvature.

This species, which is smaller than T. curtansata, is distinguished from that form by
the flattened and angulated posterior side, and by the more erect and acute umbones ; and
from the Inferior Oolite T. donaciformis, by the more erect, acute umbones, and more
lengthened form ; the basal margin has also a more considerable curvature.

Height, 9 lines ; length, 14 lines.

Geological position and localities. Ponton, Lincolnshire, and Minchinhampton ; at
both places in the Great Oolite.

CORBIS. Sub-genus — CORBICELLA.

Testa inornatd, ovato-elongatd, subcompressd ; umbonibus plerumque antemedianis
depressis, contiguis ; margine superiore elongate, subrecto, obliquo ; ligamento externo

BIVALVIA. 95

brevi ; basi ellipticd curvatd. Cardo dentibus cardinalibus duobus subtrigonis, et lamina
testaced posticd, elongatd, cum dente laterali postico remoto obtuso in utrdque valvd.
Impressiones musculares ut in Corbis ; valvium marginibus interni integri.

Shell destitute of ornament, ovately elongated, rather compressed ; umbones contiguous
and depressed, and placed a little anterior to the middle of the valves ; superior or ligamental
border lengthened, nearly straight, and sloping obliquely ; ligament external, short, and
contained in a groove ; basal margin curved elliptically. Hinge with two cardinal sub-
trigonal teeth, a lengthened posterior lamina, and a remote, obtuse, posterior lateral tooth
in each valve. Muscular impressions as in Corbis, the anterior impression being small and
oval, the posterior larger and more rounded, the inner margins of the valves plain. Casts
of a large Inferior Oolite species exhibit an oblique anterior sulcation, which passes down-
wards immediately behind the anterior impression, and is obliterated towards the lower
border ; this sulcus indicates the presence of an oblique rib upon the interior of each of
the valves. The character of the hinge is shown in Tab. XII. fig. 13, 13<z.

This group of shells, of which the Great Oolite contains a small species, consists of six or
more Oolitic species, which all agree in their characteristic features ; their external aspect is
sufficiently distinct from the typical group of Corbis, their surface is destitute of ornament,
and the greater development of the posterior side indicates a distinction, which is confirmed
by an examination of the hinge characters. The anterior lateral tooth is always absent,
and the internal ridge, which in the typical form of Corbis descends from it anterior to the
impression, passes in our group posterior to the impression, as is clearly shown by the groove
in the cast. The stratigraphical position of the known species of this group is as follows.
The Inferior Oolite of the Cotteswolds has two species ; our Great Oolite shell is the third ;
a large elongated shell in the Coralline Oolite of Malton is the fourth ; the Corbis depressa,
Desh., from the department of the Meuse, is the fifth ; and another, probably, is the
Psammobia Moreana, Buvig., 'Pal. de la Meuse' Atlas, pi. iv, figs. 8 — 10 ; the latter form
nearly resembling our Great Oolite species. The number of these species, and their general
accordance in form, surface, and hinge characters, indicate a distinctness worthy of con-
sideration. M. Buvignier, in his description of Corbis depressa, Desh., ' Pal. de la Meuse,'
p. 1 2, has, we believe, correctly indicated the natural affinities of this group ; he regards it
as establishing a passage between Corbis and Hettangia (Tancredia). Adopting this view,
we would likewise place it intermediate to Corbis and the latter genus.

CORBIS (CORBICELLA) BATHONICA. Tab. XIII, fig. 14.

Testa ovato-elongatd subcompressd tenui ; umbonibus antemedianis ; latere antico rotunda,
postico elongate, subtruncato, angulo obliquo obtuso ; basi curvatd ; lateribus plicis incremenh
panels, irregularibw.

Shell ovately elongated, rather compressed, the test thin ; umbones small, anterior to

96 MOLLUSCA FROM THE GREAT OOLITE.

the middle of the valves; anterior side rounded, posterior side elongated, the superior
border being nearly straight, and sloping obliquely, the posterior extremity is rather
truncated ; an obscure and obtuse angle descends obliquely upon the posterior side ; the
sides of the shell have a few irregular folds of growth ; the base is curved elliptically.

A delicate species, which varies considerably in its figure, and in the distinctness of its
lines of growth ; the dental characters are minute, and can rarely be exposed. It is nearly
allied to a much larger and more stout Inferior Oolite species, in which the figure is usually
more elongated, and the dental characters much more conspicuous. The relative dimensions
in this shell vary so much that measurements have little value, but the umbones are always
anterior to the middle of the valves. It occurs rather commonly throughout the shelly
beds of the formation.

Locality. Minchinhampton.

QUENSTEDTIA.

Testa (equivalvi, sub&quilaterd, oblongd et planatd ; umbonibus parvis, contiguis, com-
pressis ; ligamento externo ; foved ligamenti angustd et elongatd ; margine anlico rotunda,
postico compresso, subquadrato ; superficie plicis longitudinalibus plus minusve instructd.
Cardo dente cardinali unicd obtusd et transversd in valvd sinistrd, valva dextra fossa
cardinali unicd transversd sub umbone sitd. Impressiones musculares postici rotundi, antici
elongaii et sinuati ; impressio pattealis sinu brevi.

Shell equivalve, subequilateral, oblong, and flattened ; umbones small, contiguous, and
compressed ; ligament external, placed in a narrow elongated groove ; anterior margin
rounder ; posterior margin compressed and subquadrate ; the surface with irregular longi-
tudinal plications more or less conspicuous. Hinge with one obtuse transverse cardinal
tooth in the left valve, which is received into a corresponding pit in the opposite valve.
Posterior muscular impressions rounded ; anterior impression elongated and sinuated ;
siphonal scar with a small sinus. (Tab. XV, fig. 12. Tab. IX, fig. 4«. 6.)

A genus approximated to Psammobia in the general figure of the valves, but dis-
tinguished from it in the position of the ligament, which is placed in a narrow fossa,
instead of upon the raised nymphal plate of Psammobia ; the single transverse tooth is
another distinctive feature, and reminds us of Myoconcha ; the sinus in the siphonal scar
is much smaller than in Psammobia or Sanguinolaria.

QCENSTEDTIA oBLiTA, var. Tab. IX, fig. 4, 4<z, b., and Tab. XV, fig. 12.

Syn. PULLASTRA OBLITA, Phillips. Geol. York., I, tab. 11, fig. 15.

Testa ovato-oblongd compressd ; umbonibus parvis medianis ; antice rotundatd, postice
comprcssd, subtruncatd. angulo obliquo declivi obtuso ; latere postico plicis longitudinalibus
irregularibus.

BIVALVIA. 97

Shell ovately oblong, compressed ; umbones small, mesial, compressed, rather pointed ;
shell with the sides anteriorly rounded, posteriorly compressed, truncated, and forming an
obtuse angle, which slopes obliquely downwards to the infero-posterior extremity ; the
posterior side has some irregular longitudinal plications, which disappear towards the
middle of the shell.

The Great Oolite variety of this species is many times smaller than that of the Inferior
Oolite, and it is rather more elongated, but it presents no real specific difference. The
test is delicate.

This shell was referred to Pullastra, by Professor Phillips, from its external form only,
and we believe that only one or two specimens were at his disposal. The figure in the
' Geology of Yorkshire,' unaccompanied by any description, appears to have misled
Professor Quenstedt, who has figured the hinge of Tancredia donaciformis, Lye., for his
exemplification of Q. oblita. The Panopcea Lebruncsa, Buvig. ' Paleont. de la Meuse,'
Atlas, pi. 7, fig. 6, 7, is nearly allied to our species, but is more elongated and less trun-
cated posteriorly. The arrangement of the longitudinal ridges is very similar.

Localities and position. Quenstedtia oblita has occurred in the Inferior Oolite of Blue
Wick, Yorkshire, and in the upper portion of the same formation at Rodborough Hill,
Cotteswolds. The shelly Great Oolite of Minchinhampton Common has afforded our
smaller variety ; but the species appears to be rare at each locality.

Dimensions. Our largest Inferior Oolite specimen has a length of 2i inches, and is
12 inch in height, the greater number of specimens being about 2 inches in length; but
the Great Oolite variety is only 6 lines in length, and 3 in height.

CORBULA, Bruff. 1791.

Shell ovately trigonal, convex, inequivalve, the left valve being the smaller ; a single
cardinal tooth in each valve projecting, that of the left valve being compressed ; there is
likewise a pit in each valve contiguous to the tooth, which is destined to receive the
ligament ; the ligament is internal, inserted in the pit of the right valve, and in the cavity
of the tooth of the left valve ; depression of the mantle posteriorly angulated.

CORBULA INVOLUTA, Goldf. Tab. IX, fig. 6.

CORBULA INVOLCTA, Goldfuss. Petref., t. 151, f. 14.

„ STRIATA, Buckman. Geol. of Cheltenham, 2d edit. p. 97, pi. 3, f. 4.

Testa parvd convexd, conccntrice striatd; umbonibus submedianis ; latere postico rostrato,
carinato, excavato ; latere antico rotundato.

Shell small, convex, concentrically striated ; umbones nearly mesial ; posterior side
rostrated and slightly excavated ; anterior side rounded.

13

MOLLUSCA FROM THE GREAT OOLITE.

An acute angle passes from the umbo obliquely backwards, separating a narrow area
from the remainder of the surface ; the concentric stria? are continued upon the flattened
posterior area. This little shell is one of the most abundant in the formation ; its con-
centric stria? are very frequently not preserved, and the valves are never found in opposition.
The test is thick, and the characters of the hinge strongly marked.

Height, 3 lines ; lateral diameter, 4 lines.

Localities. Minchinhampton Common, and Eyeford, Gloucestershire.

IBBETSONI. Tab. XII, fig. 9.

IBBETSONI, Morris. Geol. Soc. Journ., 1853, p. 341, pi. 14, fig. 6.

Testa subglobosd, pyriformi, subaqtiivalvi, striatd ; umbonibus maynis submedianis ;
latere antico rotunda ; postico producto, bicarinato, subrostrato ; basi curvato ; lateribus
plicis regularibm inconspicuis ; nucleo Icevi.

Shell subglobose, pyriform, subequivalve, striated; umbones large, rounded, mesial;
anterior side rounded ; posterior side produced, attenuated, and bicarinated, the anterior
carina acute ; lower margin curved ; the sides with regular, slightly marked plications ;
nucleus smooth.

A very convex and nearly equivalve shell, with an acutely marked angle upon the
posterior attenuated slope ; anterior side rounded. The nucleus has the posterior extremity
compressed, short, and truncated. It ranks as one of the most rare productions of the
Lincolnshire beds.

Height, 9 lines; length, 11 lines; diameter through both the valves, 8 lines.

Localities. Danes Hill ; Essendine, and Ketton quarries. Dedicated to Capt. L. B.
Ibbetson, F.R.S., in whose company it was first noticed, much compressed in the clays
above the Ketton Oolite.

Family — MYAD.E.

Previously to stating our views upon this extensive family, we desire to record our
obligations to Agassiz, for his important work, ' Etudes Critiques,' which exhibits a large
amount of patient research, of critical sagacity, and original views. The author has,
however, candidly admitted that his work is imperfect in certain of the details — that facts
are sometimes wanting or insufficiently known, and consequently that the genera proposed
by him are probably not all of equal value. The subject, indeed, is connected with
difficulties of more than one kind, and of such a nature, that subsequent observers might
be expected to differ in their estimates of the value of the several generic distinctions pro-
posed by M. Agassiz, and might even determine to discard some of them altogether. The
length of time which has elapsed since the publication of the ' Etudes Critiques' has been
sufficient for the accumulation of many additional facts tending to render our theoretical

BIVALVIA. 99

views more precise and conclusive. The considerable opportunities afforded us for in-
vestigation, and the interest with which we have long viewed this obscure family, combine
to impart to our language a degree of confidence which we should not otherwise venture
to express. The numerous arid varied series of these fossil forms all agree in having their
test of great tenuity and delicacy, so that not unfrequently we are reduced to derive our
knowledge from an examination of their internal casts ; or, should the tests be preserved,
it is very rarely that we are enabled to expose sufficiently their hinges or other internal
characters. In this family we also lose another important aid in the determination of the
genera, inasmuch as the dental characters of the hinge are reduced almost to nothing,
the Oolitic Myadae being altogether destitute of hinge teeth, properly so called, and
possessing only a shelly lamina, variously modified in form, and extending internally
posteriorly to the umbones, and supporting the cushion of the ligament ; but this lamina
never forms an elevated nymphal collosity, as in certain recent genera.

At the period of the publication of the ' Etudes Critiques/ the internal hinge characters
of certain of the genera had not been fully ascertained. They were known only from
appearances upon the external moulds or internal casts ; and in more than one instance the
author was induced to rely upon the observations of others, although these were opposed
to his own experience. These uncertainties have since gradually been diminished, not,
indeed, without the perpetration of other errors, and it will be found that in the presen t
Monograph, we have been induced to adopt certain modifications of, and other changes
in, several of the genera, although our exemplifications of the Myadse constitute only a
subordinate position in the testacea of the Great Oolite.

In discriminating the fossil Myadae, it will be found that certain features, which are
only of subordinate importance in shells of the symmetrical acephala, generally become the
principal, and, indeed, sole aids upon which we have to rely ; fortunately, however, these
features, which are included in the terms general figure and ornaments of the surface,
acquire in the Myadsc an increased degree of importance from their invariable persistence
and distinctness of design, in a similar ratio that the hinges and their characters have
degenerated in value.

The thin flexible coverings of the fossil Myadse have a much more intimate relation to
the forms of the enclosed Mollusks than is possessed by the shells of other families of
bivalves ; the shell does not form a mere compact rigid cyst, but rather a thin sheath or
tegument, which conforms to the figure of the Mollusk itself, and varies somewhat
according to the circumstances in which the animal was placed with relation to the
surrounding ground, or to contiguous organisms. The entire family have large, irregular,
longitudinal folds or ridges, which are, for the most part, but imperfectly distinguishable
upon the internal casts. The genera of Myadae, proposed by Agassiz, are the following.
Pholadomya, Homomya, Corimya, Ceromya, Cercomya, Goniomya, Myopsis, Pleuroniya,
Arcomya, Platymya, and Mactromya. Pholadomya had previously been established, and
remains uncontroverted.

100 MOLLUSCA FROM THE GREAT OOLITE.

Corimya is the Thracia of Leach, the latter author having the priority ; Tellina incerta,
Thurm., is an English Oolitic example.

Mactromya has, we believe, justly been dismembered by D'Orbigny, the forms which
Agassiz regarded as typical having been separated from the Myadae to constitute the genus
Unicardium of the former author, and has been previously described in this Monograph.
Three remaining species, referred by Agassiz to Mactromya, are too imperfectly known to
justify us in pronouncing their true position with any confidence.

Ceromya may now be considered as sufficiently established ; the hinge characters, which
were imperfectly known to Agassiz, have been fully described byM. Buvignier, 'Bull. Geol.
Soc. Fr.,' 1850 ; for, although the shell upon which the latter author founded his description
is a Gresslya, we have ascertained that the hinges of the two genera are altogether alike.
M. d'Orbigny (' Prodrome de Paleontologie ') and M. Buvignier (' Paleont. Dep. de la
Meuse ') have merged Gresslya in Ceromya, but we consider that Agassiz was justified in
regarding them as distinct, their figures are essentially different ; the Ceromyse are all
ventricose, with incurved equal subspiral umbones ; they are equivalve, for although there
is much irregularity in this respect, and occasional inequality of the valves, these variations
are altogether accidental, and resulted probably from the position which the Mollusk
occupied in the ground, or its proximity to other bodies ; their surface has regular ridges
which are not altogether smooth, they are concentric, or in other species they take an
oblique direction ; or, again, they suddenly change their direction and are reflected after
the manner of the Goniomyai. Gresslya, on the contrary, is never perfectly equivalve, the
right valve being always larger, and its umbo higher than the other ; the form is much
more compressed, the umbones more pointed, the surface is destitute of the peculiar ridges
of Ceromya, but possesses a different kind of ornamentation ; the outer layer consists of a
very delicate pellucid semicorneous test, with densely arranged radiating lines of granules,
the lines usually slightly undulate, and the granules, which are regular, are densely arranged,
and so minute as scarcely to be visible to the unassisted eye. M. Agassiz was not
acquainted with this fact, which we have ascertained by an examination of a large number
of examples in a good state of preservation. Cercomya has been shown by M. d'Orbigny
to be identical with Anatiua, of which it possessed the usual vertical fissure beneath the
umbones and the granulated surface ; but the aspect of the two forms differs in other
particulars, for Oolitic species are compressed, the posterior side is remarkably elongated,
and the anterior side has large longitudinal ridges. These features indicate a distinction
which we regard as of subgeneric value. We would, therefore, place Cercomya as a
sub-genus of Anatina.

Goniomya is a form which we believe to be entitled to a separate generic rank, not-
withstanding M. d'Orbigny and M. Buvignier have reunited it to Plioladomya; the ridges
upon the sides are strongly impressed upon the internal casts, and are very different from
the costse of Pholadomya; and it lias, moreover, a granulated surface, the granules, as in
Gresslya. being radiating and linear.

BIVALVIA. 101

There yet remain a very numerous and varied series of the fossil Myadae, which have
been separated by Agassiz under the names of Myopsis, Pleuromya, Arcomya, Platymya,
and Homomya. These forms are found in the Muschelkalk, and throughout all the
Secondary rocks ; one or more species likewise occur in the older Tertiary rocks of England.
M. Agassiz believed that Myopsis was distinguished from the others by the presence of a
tooth in the hinge (Jide D'Orbigny), although he had never been able to detect its
presence, and also by its possessing a surface ornamented by radiating lines of granules.
We have been enabled to ascertain that the most abundant of the British Myopsides
(Mya dilata, Phil.) is destitute of any cardinal tooth, and that the granulated surface,
which M. Agassiz relied upon as distinguishing Myopsis, is possessed also in a manner
more or less modified by Arcomya, Platymya, Pleuromya, and Homomya.

There remains, therefore, between these proposed genera little more than the distinction
of figure ; and even this feature, although sufficiently remarkable and distinct in certain
selected typical species, approximates so nearly in others, that in very many instances it is
only possible to separate them as distinct groups by an arbitrary and uncertain arrangement.
The test of these shells is very thin, and a depression more or less distinct exists upon the
anterior side of the valves, extending from the umbones to the inferior border.

The Myopsides are usually elongated posteriorly ; their siphonal aperture is large, and
their radiating lines of granules are distantly arranged, and large upon the posterior side :
Mya dilata, Phil., is a well-known English example. Arcomya is more rhomboidal or
subquadrate ; the anterior side is compressed ; the posterior has an oblique prominence
the syphonal aperture is elongated and narrow. Pleuromya, with more tumid umboues,
has its superior border slightly concave, and the posterior third of the shell is attenuated
with a small aperture. Platymya resembles Myopsis, except that the umbones are placed
nearer to the middle of the valves ; the figure is more compressed, and the siphonal
aperture is small. Homomya resembles the more elongated of the Pholadomyas. The
umbones are large and usually but little compressed ; but, with this exception, there is
nothing to distinguish the figure from one or other of the preceding types, insomuch that
M. Agassiz, in the absence of a knowledge of the test, was sometimes unable to allocate
them to either of his proposed genera. Certain of the shells which Agassiz would refer to
Homomya possess a feature which tends to approximate them to the true Pholadomyas,
viz., the presence of a few faintly marked radiating costas upon the umbones. These,
however, are uncertain, and sometimes vanish altogether. Such species appear to form a
true passage, connecting the more elongated Pholadomyas with the Panopaeas. The
granulated surface which distinguishes this great series of fossil Myadse presents several
modifications of character, and tends to separate more fully the several species. The first
modification has the granules rather large, placed upon lines which are slightly elevated
and distantly arranged : some of the larger Myopsides and Arcomyae present examples.
The second modification has the lines of granules distinct ; but the granules are minute,
and both these and the rows are very closely arranged : the Pleuroniyee have usually this

102 MOLLUSCA FROM THE GREAT OOLITE.

kind of surface. The third modification has the entire surface covered with granules so
minute as to be nearly or altogether invisible to the unassisted eye. They are so dense
that the linear arrangement cannot be recognised : the Hornomyae have this kind of surface.
In the present state of our knowledge, it would not appear that the figure of the
shell affords any certain guide to the character of the granules which adorn its surface, a
general resemblance of form being sometimes coincident with a very different kind of
surface, and in the fossil Myadse, wherein the figures of the individuals present much
variability, and consist more commonly only of casts, the presence of a small portion of
the outer granulated tegument will in some instances serve as a sure guide to distinguish
species for which the casts alone would not have sufficed. It is owing to the absence of
the test that so many of the figures of the 'Etudes Critiques' of Agassiz afford only doubtful
guides to the correct knowledge of the species.

The foregoing observations will prepare the reader for the conclusion at which we have
arrived, viz., that Myopsis, Pleuromya, Arcomya, Platymya, and Homomya cannot claim
to be regarded as distinct genera, and that it is very difficult, or perhaps not practically
possible, even to separate them into so many sections or sub-genera. They seem rather to
constitute a single very extensive and varied series of forms, which, although individually
resembling in certain of their features either Pholadomya or Panopa3a, are nevertheless
sufficiently separated from both of these genera, and possess a generic entirety which is
rather strengthened than otherwise by these resemblances.

The hinge exactly resembles that of Pholadomya, except that the subligamental lamina
is more stout, and the test at that part of the shell is generally more thickened. It is
therefore destitute of the sharp tooth of Panopaea ; but even this feature is not without
exceptions, for M. Buvignier has figured an Oolitic species, which has a distinct tooth, and
we have ourselves discovered a tooth slightly defined in an Inferior Oolite shell, other
examples of which present no trace of this feature.

The hinge then generally resembles that of Pholadomya, and some few species or rather
individuals of these species, by possessing a few delicate radiating costsc upon the umbones,
present another feature which tends to approximate them to the same genus. To
Panopsea other examples are allied by the occasional presence of a projecting cardinal tooth,
and by a universal flattening or depression upon the anterior third of the valves. The
granulated surface, however, removes it equally from Panopa3a and Pholadomya. In the
figure of the muscular impressions we recognise a close resemblance to those of Pholadomya,
the anterior impression being very narrow, pyriform, and so much elongated upwards as to
reach nearly to the umbo. In Panopsca the figure of this impression is irregular and
different. The siphonal flexure is always very great, whatever may be the figure of the
posterior side of the shell. Briefly to recapitulate these analogies and differences : our
group is allied to Pholadomya, in the features of the hinge and of the muscular im-
pressions, but differs from it in the absence of costse, in the presence of radiating lines of
trramilcs upon the surface, and in the vertical depressions upon the sides of the shell. It

BIVALVIA. 103

resembles Pauopaea in the depression upon the middle or anterior side, and by the
presence of an occasional cardinal tooth in the hinge ; but these affinities are neutralized
by the differing figure of the anterior muscular impression, by the usually edentulous
hinge, and by the granulated surface. We regard, therefore, Myacites (Schlot.) as a
genus intermediate and connecting Pholadomya with Panopsea.

The genus Myacites, Schlotheim, was founded upon certain Muschelkalk shells, which
belong to our great group of granulated Myadae, and have that kind of figure which
belongs to the Pleuromyae and perhaps to the Homomyae of Agassiz. Schlotheim, who had
no knowledge either of the hinge or of the test, characterised his genus in the following terms .-
" Testa transversa, incequilatera, subhians, olovatavelovalis, ventricosa l<svis, concentrice
striuta ; umbones anteriores."

The meagreness and insufficiency of this description would render the genus valueless,
in the absence of other and more precise knowledge ; but as the Muschelkalk shells are
well known, Schlotheim has a claim to priority in the generic designation, and as the five
genera proposed by Agassiz must necessarily be referred to the same group, those of the
latter author must be discarded as superfluous. Our arrangement of the fossil Myadee
will be as follows :

Pholadomya.

Anatina, Sub-gen. Cercomya . . . Genus, Cercoraya, Ag.

Goniomya . . „ Goniomya, Ag. .

Ceromya . . . . „ Ceromya, Ag.

Gresslya . . „ Gresslya, Ag.

Thracia . . . „ Corimya, Ag.

Myacites . Myopsis, Pleuromya, Platymya, Arcomya, and Homomya, Ag.

GRESSLYA, Ag.

Shell ovate, rather compressed, very inequilateral, sub-equivalve ; umbones anterior,
contiguous, compressed, acute, and incurved ; lunule excavated ; anterior side convex, its
border rounded; posterior side more attenuated, sometimes rostrated; superior border
rather convex, sloping obliquely downwards ; lower margin curved elliptically, borders of
the valves close, or with a very small posterior aperture ; ligament external, short ; hinge
line externally somewhat sinuous ; the shell is not perfectly equivalve, the unibo of the
right valve being a little higher in the other ; the test is extremely delicate, with fine
longitudinal plications, and with very densely arranged radiating rows of minute granules.
Hinge edentulous, but having an elongated lamina in each valve, that of the left valve
being inserted beneath the outer lamina of the other valve, as in a groove ; there is also
in the right valve an oblique internal rib, which extends posteriorly, and is only visible

104 MOLLUSCA FROM THE GREAT OOLITE.

upon the casts, a feature similar to that in Ceromya ; the muscular impressions are very
faintly marked, as is likewise the pallial impression, the flexure of which appears to be
short. This genus, having been reunited to Ceromya by M. d'Orbigny, and M. Buvignier
having figured and described the hinge of a Gresslya, named by him Ceromya Deshayesi,
in a very complete manner, it has become necessary to institute a close comparison between
the two generic forms, and to weigh carefully their affinities and differences

Istly. Form. Ceromya is usually larger thau Gresslya, and always more ventricose,
the urabones are more prominent, those of Ceromya approaching to the form of Isocardia ;
Gresslya, with its acute umbones and more compressed figure, approaches to that of
Cardinia : Gresslya is also very constantly slightly insequivalve, the right valve exceeding
the other in height ; in Ceromya they are equal, and any irregularity of form which may
sometimes occur to give the semblance of inequality in the valves is altogether accidental,
and depends, apparently, upon the portion of the shell during its growth.

2dly. Character of the Surface. The sculptured surface of Ceromya is quite unlike
that of any other of the Myadts, the longitudinal grooves being more or less visible upon
the casts, but the casts of Gresslya are smooth, and the granulated surface of the test is
altogether different from that of Ceromya.

3dly. Hinge Characters. In Ceromya, as in Gresslya, the casts of the right valve
exhibit a groove posterior to the umbones which has been impressed by a corresponding
prominence or internal rib in that valve ; in Ceromya, however, this groove is likewise
visible upon the exterior of the test, but not in Gresslya ; the internal hinge larninre are
precisely alike in both genera ; but this is a feature which in the fossil Myadce has but
little value in generic affinity or distinction. Whatever value the Palaeontologist may be
disposed to attach to the foregoing distinctions when viewed singly, it must, we think, be
admitted that in the aggregate they are of considerable importance, and it is necessary to
neglect none of them in forming a fair estimate of the two forms.

Gresslya was eminently gregareous, Ceromya not so, and for the most part it occurs
much more sparingly ; both lived in the same beds ; the valves of Ceromya are frequently
disunited, in Gresslya they are invariably in contact.

GRESSLYA CARDIT^EFORMIS. .

Testa ovalo-depressd; umbonibusprominentibussubplanis, latere antico produclo rotundato,
basi curvatd, latere postico abrupte declivi, lineis incrcmenti paucis, irregularibus.

Shell ovate, depressed ; umbones prominent, rather compressed ; anterior side produced
and rounded ; base curved ; posterior side sloping abruptly ; lines of growth few and distant.

This species possesses a general resemblance to Gresslya Saussuri, the Venus Saussuri
of Brongniart and Goldfuss, but our shell has much less convexity ; in both species the
outline has a considerable resemblance to that of a Venus, but an examination of the hinge
border has proved that it is edentulous.

BIVALVIA. 105

The extreme tenuity of the test will account for its uniformly bad state of preservation
and rareness. It occurs in a bed of soft shelly Oolite, which is situated about the middle
of the shelly beds, and abounds with valves of Tancredia.

Length, 2j inches; height, If inches; diameter through both the valves, 7 lines.

Locality. Minchinhampton Common.

GRESSLYA PEREGRINA, var. ROSTRATA. Tab. X, fig. 7.

GRESSLYA ROSTRATA, Agasziz. Etud. Crit., t. 126, fig. 7, 8.

Testa ovato cuneiformi, antice rotundatd, postice elongatd et acuminatd, basi subrectd.

Shell ovate or somewhat cuneiform, rounded anteriorly, produced and pointed
posteriorly ; basal margin nearly straight.

The posterior side is somewhat compressed, forming an angle which extends obliquely
from the umbones to the infero-posterior extremity, and there forms a pointed termination.

Height, 13 lines ; lateral diameter, 19 lines ; diameter through both the valves, 10 lines.

Locality, The southern side of Minchinhampton common, where small openings in
the Stonesfield slate have afforded a few of the internal moulds. The genus never occurs
in the shelly beds of the formation. Marls of the Ostrea acuminata (fuller's earth).

CEROMYA, Ag.

Shell corcliform or oval, very inequilateral, ventricose ; umbones large, contiguous,
incurved, involute ; lunule excavated ; anterior side convex, its border rounded ; posterior
side elongated and more flattened, its border either closed or having a slight aperture ;
ligament narrow, external. The surface is ornamented with one or more series of ridges
and sulcations, which are longitudinal but not always concentric. In certain species a
change in the direction of the ridges occurred at a certain period of the growth ; substance
of the test thin, almost papyraceous. Hinge edentulous ; a lengthened lamina beneath the
ligament in the left valve is received into a groove beneath the lamina of the opposite
valve ; there is also in the right valve an obliquely elongated posterior rib or internal
depression, which, unlike that of Gresslya, is visible upon the surface of the test ; muscular
and pallial impressions rarely distinguishable ; the anterior impression is pyriform, elongated
upwards, and jagged or fringed irregularly, as in Pholadomya and Gresslya.

The variety of figure in Ceromya is very considerable ; Ceromya similis, Lye., in its
elongated and compressed form approaching to that of Gresslya ; the opposite figure is
exemplified by C. Bajociana, D'Orbigny, which has the short ventricose aspect of hocardia,
between these there is every gradation of figure. Ceromya occurs rarely in the shelly
beds of the Great Oolite, the valves being most commonly disunited, the tests are then
preserved ; in other situations without shelly detritus the valves are united, but the tests
have disappeared.

14

106 MOLLUSCA FROM THE GREAT OOLITE.

CEROMYA SYMONDSII. Tab. X, fig. 4a, b.

Testa ovato-ventricosd, umbonibus magnis obliquis incurvis, latero antico convexo, postico
subcompresso et elongato, basi curvato ; plicis concentricis regularibus tenuibus non nunquam
obsoletis.

Shell ovately ventricose ; umbones large, oblique, incurved ; anterior side convex ;
posterior side rather compressed and elongated ; base curved ; concentric plications regular,
very delicate, not unfrequently indistinct.

The general figure approaches C. concentrica, but it is more elongated, the umbones
being more oblique and anterior; the concentric plications are more delicate, and are
curved with a larger ellipse, they become undistinguishable near to the umbones. The
substance of the test is extremely delicate, so that the fine plications are frequently visible
upon the nucleus. The height of the shell is rather greater than the diameter through
both the valves, and one fifth less than the longitudinal diameter, a slight aperture exists
at the posterior extremity of the valves.

Localities. Nuclei occur rather commonly in the upper portion of the Great Oolite
two miles east of Minchinhampton, but examples with the test preserved are very rare in
the shelly beds of Minchinhampton Common ; it also occurs in the Inferior Oolite of the
same district.

The name in compliment to the Rev. W. S. Symonds, the Founder and President of
the Malvern Naturalist's Field Club.

CEROMYA UNDULATA. Tab. IX, fig. 1, la, b.

Testa ovato-oblonffd, tumidd ; umbonibus anticis elongatis sub-terminalibus, involutes;
latere antico anyusto, brevissimo ; postico lato, elongato ; margins superiore convexo, interdum
subundulato carind dorsali oblique instructo ; margine postico truncate ; inferior e subrecto ;
latcribus lineis obliquis, excentricis crebris regularibus tenuissimis ct undulatis ; basi et
margine postico plicis concentricis paucis irrec/ularibus.

Shell ovately oblong, tumid ; umbones anterior, elongated, subterminal, and involute ;
anterior side narrow, very short ; posterior side much wider and elongated ; superior
margin convex but irregular, sometimes rather undulated, a keel or angle passes obliquely
from the umbones posteriorly nearly parallel to the superior border; the posterior margin
is truncated, the lower margin straight. The sides of the shell are covered with densely
arranged undulating fine lines, which are directed obliquely or excentrically from the
umbones towards the wide posterior border, but do not reach it, being decussated by a
few irregular concentric plications, which in advanced growth occupy the inferior and
posterior margins of the valves ; the supero-posterior angle separates the sides from a
narrow posterior surface which is destitute of the excentric lines.

BIVALVIA. 107

The tenuity of the test is extreme, and the fine radiating lines are usually visible upon
the internal casts. The figure varies even more than is usual in the Ceromyae. It has
some resemblance to Ceromya inflata, Agassiz, but in that shell the character of the
plications and their direction is altogether different, the size, likewise, never attains to that
of our species.

In the greater number of specimens there is a wide depression, which extends from the
region of the umbones to the inferior border, giving a compressed aspect to the anterior
and inferior portion of the shell.

It occurs not unfrequently in the upper beds of the Great Ooolite in beds of buff-
coloured hard sandstone, situated about 95 feet above the fuller's earth, but always
in the form of casts ; in the shelly beds of the formation it occurs very rarely, the test is
then preserved, and the valves disunited.

The form of Ceromya undulata presents the greatest possible contrast to Gresslya, but
it is not easy to describe the distinctive features however striking.

Height, "17 lines; length, 20 lines; diameter through both the valves, 16 lines.

Locality. Minchinhampton.

CEROMYA PLICATA, Ag., var. Tab. X, fig. la, b, fig. 2.

CEROMYA PLICATA, Ag. Etud. Cret. Myes., tab. Sd, 1842.
CAKDITA V-COSTATA, Buckman. Geol. Chelt., 2d edit., p. 97, 1845.

Testa ovato-oblongd, inflatd ; umbonibus anticis depresses, involutis ; later e antico
brcvissimo, tumido, truncate ; latere postico lato, aperturd ejusdem magnd et elonyatd;
maryine superiore elato ; inferiore subrecto et subundulato ; lateribus fastis/Us longitudinalibus
crebris, subundulatis, superne acutavyulo reflectis, ((etate progrediente} aliis concentricis
decmsatis ; lateribus semel in media sulcis radiantibus obscuris notatis.

Shell ovately oblong, much inflated about the middle of the valves ; umbones involute,
anterior and depressed ; anterior side very short, truncated and tumid ; posterior side wide,
its aperture large and lengthened ; superior margin much elevated, and rather compressed ;
inferior margin lengthened, nearly straight, and sometimes slightly undulated ; the sides
of the valves with closely arranged longitudinal ridges, which slightly undulate, and
towards the superior and posterior border are suddenly reflected anteriorly, forming acute
angles ; in progress of growth these reflected ridges are nearly effaced, and a second series
of concentric ridges are formed, which cross the others obliquely towards the inferior
border ; lastly, in adult specimens, there may be distinguished a few obscure radiating
sulcations about the middle of the valves. This shell, in the young condition, is a pretty
species ; the longitudinal ridges are very distinct, and their V-like angle towards the
superior border is clearly defined ; in adult shells the figure is more ventricose, the superior
angle formed by the ridges is nearly effaced ; the second, or concentric series of ridges, are
formed, and some few radiating sulcations may be traced.

108 MOLLUSCA FROM THE GREAT OOLITE.

Collectors have very generally mistaken this species for Ceromya excentrica, a shell which
is stated to occur abundantly in the upper or Portlanclian Oolite of Switzerland, at Porrentroy,
and in a similar parallel in the Jura of Soleure ; C. plicata has not heretofore been
adequately figured or described ; the specimens figured by M. Agassiz represent adult and
even aged shells, not well preserved, and in which the V-hke angle of the ridges has
nearly disappeared ; his description is likewise more than usually meagre, and, in the
absence of other evidence, the reader would be inclined to believe that the author had
unnecessarily separated this shell from C. excentrica, but an examination of specimens in
several stages of growth has convinced us of the propriety of the specific distinctions which
are given in the ' Etudes Critiques ;' the general figure is near to C. excentrica, except that
in the adult forms the superior border is more compressed and elevated, and the posterior
aperture is much larger ; the change in the direction of the ridges upon the surface is not
peculiar to C. excentrica, but occurs in other species of the same genus, neither is it a
regular and constant feature in any species, or rather, we should say, that it is never found
in the young condition of any species. All the specimens known are casts, the delicate
and very perfect markings in young examples is a sufficient indication that the test must
have been of extreme tenuity, and the partial obliteration of these features with advance of
growth, evidences a corresponding change in the character of the test. In the specimen
figured by Agassiz the angles of the reflected ridges are less acute.

Dimensions. Our largest specimen is in length 3 \ inches ; in height, 2| inches ;
the diameter through both the valves being 2| inches.

Localities and position. We have observed this species in the upper beds of the
Inferior Oolite in Gloucestershire jn the fuller's earth it has occurred over the Sapperton
tunnel of the railway, from which deposit a specimen has kindly been forwarded to us by
John Wilson, Esq., of Gloucester ; we have ourselves obtained it from certain hard lime-
stone beds near to the base of the Great Oolite in the Minchinhampton district, and
Professor Buckman has recorded a specimen which he obtained in a bed of clay at
Sevenhampton, which appears to be a little higher in the series ; it is, however, rare
at each of these localities.

CEROMYA CONCENTRICA, Sow., sp. Tab. X, fig. 8a, b.

ISOCARDIA CONCENTRICA, Sow. Min. Con., tab. 491, fig. 1.

Phil. Geol. York., 1, pi. 1 1, fig. 40.

Morris. Catal. Brit. Foss., 1st. Ed. p. 88. 1843.

Testa ventricosd, ovato-obliqud, umbonibus magnis incurvis subanticis, latere antico
convcxo,postico subcompresso, basi curvato, lateribus fastiffiis tenuibus concentricis regularibus
crebris.

Shell ventricose, ovately oblong ; umbones large, incurved, anterior to the middle of

BIVALVIA. 109

the valves ; anterior side convex ; posterior side more elongated and compressed ; base
curved ; the sides of the shell with regular closely arranged concentric and fine ridges.

The umbones are prominent and elevated, more especially by comparison with C. Symondsii
and C. Northamptoniensis, the two contemporaneous forms which most nearly approach to
it ; owing to this prominence, the superior border is rendered slightly concave. The valves
fit closely, except at the posterior extremity, which has a slight aperture. The test is
never preserved. It is liable to be confounded with a larger and magnificent Inferior
Oolite species, which occurs in the neighbourhood of Stroud, and has the test preserved ;
this latter, which we believe to be the Ceromya Bajociana of D'Orbigny, 'Prodrome
de Paleontologie,' p. 275, and, probably, the Isocardia concentrica of Phillips ; in this shell
the umbones are very large, and curve gracefully forwards ; they are more median and less
oblique ; the general form is more ventricose, and the posterior side is shorter than in the
true Ceromya concentrica.

Ceromya concentrica does not occur in the shelly beds of the Great Oolite, it occurs in
the upper portion of the formation associated with C. Symondsii in the Minchinhampton
district, and also near to Nymphsfield, it is also abundant in the Marl bed of the Inferior
Oolite, and in the upper division of the same formation.

Dimensions of a Great Oolite specimen. Height, 16 lines; length, 20 lines ; diameter
through both the valves, 14 lines.

Localities. The neighbourhood to the east of Minchinhampton, and at Nymphsfield, in
the Great Oolite ; the escarpment of the Cottesvvolds generally in the Inferior Oolite.

CEROMYA SIMILIS. Tab. XII, fig. 12.

CEROMYA SIMILIS, Lycett. Geol. Soc. Journ., 1853, p. 340, pi. 14, fig. 2.

Testa ovato-oblongd, convexd ; umbonibus anticis incurvis ; latere antico brevissimo,
convesoo, postico elongato mediocriter attenuate ; margine superiori et inferiori parallelis,
subrectis ; striis concentricis magnis regularibus et crebris.

Shell oblong, elongated, convex; umbones anterior, incurved, anterior side convex,
very short, its margin rounded ; posterior side elongated, superior and inferior borders
nearly parallel, horizontal, and slightly curved ; the lunule is excavated ; the sides of the
valves have regular, strongly impressed, and closely arranged longitudinal striations, which
nearly vanish as they approach the superior border.

The form of this elegant species is intermediate between Ceromya concentrica and C. ex-
centrica, some examples approaching more nearly to the former, others to the latter shell, the
striations are strongly marked, rather larger than in C. concentrica, and there exists a
slight vertical depression upon the middle of the valves ; the umbones are rather depressed,
scarcely rising higher than the elongated superior border.

Height, 15 lines; length, 22 lines; diameter through both the valves, 14 lines.

Locality. Ponton, in the shelly beds ; also in the lower strata of Stamford, Morcot, &c.

110 MOLLUSCA FROM THE GREAT OOLITE.

f

THRACIA, Leach.

COHIMYA, Agassiz.

Shell subtrigonal, inequivalve, inequilateral, rather flattened ; cardinal area distinctly
marked, the hinge margin forming a sudden declivity posterior to the umbones; the
area is separated from the sides by a carina more or less visible ; the left valve is always
smaller than the right, its umbo is flatter or less elevated; the surface has concentric
plications more or less prominent; the substance of the test is extremely thin, more
especially in the smaller valve ; the valves do not gape, or but very slightly, and the hinge
is destitute of teeth. From Tettina it is distinguished by the absence of teeth, and by its
wanting the lateral flexion which distinguishes that genus.

THRACIA STUDERI. Ag. sp.

TELLINA INCEKTA, Thurm, Roemer, Verst. Nordd. Ool., p. 121, tab. 8, fig. 7.

_ _ Gold/. Petref., tab. 146, fig. 14.

COEIMYA STUDEKI, Ag. Etud. Crit., p. 267, tab. 35.

Testa subaquivalvi obovatd, convexd-pland, antice convexd ; margine curvato ; latere
postico abrupte compresso ; umbonibus medianis in&qualibus, compressis ; lateribus plicis
concentricis irregularibus.

Shell subequivalve obovate, moderately convex, anterior side convex, its margin
curved, posterior side compressed, attenuated, and separated from the other portion of the
shell by an obtuse angle (sometimes imperfectly defined). The urabones are mesial and
contiguous, but not prominent nor large, the margins of the valves are close fitting ; the
sides of the valves have numerous irregular concentric plications.

This species is more elongated, and has the posterior side more produced than our other
Great Oolite species ; the Cornbrash specimens have considerable variety of figure, with
respect to their height and to the distinctness of the posterior angle, irrespective of acci-
dental compression.

Geological position and localities. In England it occurs in the Cornbrash of Wilts,
and in the Great Oolite of Northamptonshire. M. Agassiz states that it is abundant in
the Portlandian beds of Porrentroy, Jura. Goldfuss records it in the upper oolite of
Hanover.

THRACIA CURTANSATA. Tab. XIII, fig. la, b.

Testa convexo-pland, subtrigond, subaquilaterali, et laviyatd ; umbonibus submedianis,
inoRaualibus incurvis ; latere postico abbreviate ; valvd sinistrd subpland, umbone parvo ;
plicis concentricis tenuissimis irregularibus.

BIVALVIA. Ill

Shell depressed but convex, subtrigonal, nearly equilateral and smooth; umbones
nearly mesial, unequal, and incurved ; posterior side short ; left valve compressed, its umbo
small ; surface with concentric, closely arranged, very fine, and irregular plications.

The surface is very smooth, the posterior side is scarcely so much attenuated as is
usual in this genus, and the cardinal area is very obscurely defined. The general figure
approaches the Corimya tenuistriata of Agassiz, but that shell has a smaller longitudinal
diameter, and the umbones are not so nearly mesial. It would appear to be very rare,
but has occurred both in the lower or shelly, and upper portions of the Great Oolite.

Locality. Minchinhainpton.

MYACITES, Schlot.

Syn. MYOPSIS, Ag. PLEDROMYA, Ag. ARCOMYA, Ag.
PLATYMA, Ag. HOMOMYA, Ag.
PANOP^EA, sp. Buvignier. PANOP^EA, sp. TfOrbigny.

Shell elongated, umbones anterior to the middle of the valves, contiguous, depressed,
anterior border rounded, posterior border either rounded or truncated, both extremities
gaping, sometimes equally so, or the posterior aperture is the more expanded, and some-
times slightly reflected ; a depression more or less distinct extends from the umbones to
the inferior border ; ligament external and short ; test delicate, with irregular longitudinal
plications, and ornamented with a pellucid outer tegument, having granules disposed in
radiating lines. Hinge without teeth, with an elongated horizontal thickened plate, which
extends posteriorly to the umbones, and supports the ligament; muscular impressions
usually indistinct, but resembling those of Pholadomya, pallial impression with a very
large posterior flexure.

Under the comprehensive term Myacites, we arrange a very extensive series of forms
which have been referred to Amphidesma, Lutraria, Sanguinolaria, Myopsis, Arcomya,
Pleuromya, Hoinomya, and Platymya; commencing in the Muschelkalk, their numbers
increased in the Lias, and they continued to hold a very prominent position throughout
the oolitic and lower portion of the Cretaceous rocks.

From others of the Myada? which have granulated surfaces, as Gresslya, Goniomya,
and Anatina, they are distinguished by features which will be found under those genera.

We regard Myacites as a form which connects Panopaja with Pholadomya, by means
of the more elongated forms of the latter species, and more especially by the hinge, which
differs from Pholadomya solely by the greater thickness and strength of the former.

MYACITES VEZELAYI. Lajoye, Sp. Tab. XI, fig. 5, 5#.

Syn.

MYA VEZELAYI, D'Archiac. Mem. Soc. Geol. Fr., vol. v, tab. 24, fig. 4.
HOMOMYA GIBBOSA, Ag. Etud. Cret. Myes., pi. 18.

112 MOLLUSC A FROM THE GREAT OOLITE.

Testa nucleo elongato, umbonibus parvis anticis depressis, latere antico brevissimo,
compresso, postico ventricoso, aperturd ejusdem valde elongatd, margins superiore concavo,
inferiore curvato ; lateribus plicis longitudinalibus magnis et irregularibus.

Shell with the nucleus elongated, ventricose about the middle portion, and compressed
towards the two extremities ; umbones anterior, rather small, and depressed ; posterior
aperture of moderate breadth, but very much lengthened upon the superior margin, which
is concave ; the inferior margin is curved and nearly parallel to the superior, it has a
narrow antero-basal aperture. The sides of the valves have large irregular longitudinal
plications, and near to the umbones are some traces of a few radiating lines or costse.

The aspect of this species is so much compressed from above, and tumid laterally, that
the diameter through both the valves exceeds the height of the shell, and exceeds half its
length ; there is a superficial depression which extends downwards obliquely to the middle
of the lower border, and coincides with the extent of the basal hiatus ; the figure altogether
is more ventricose and depressed than any other example of Homomya hitherto figured.
M. Agassiz appears to have mistaken this species for H. gibbosa, the Lutraria gibbosa of
the 'Min. Con.,' tab. 42 and 211 ; but the latter shell differs from it very considerably in
figure, it is less depressed, has much larger umbones, is less ventricose in its middle
portion, is destitute of the flattening of the anterior side, and likewise of the large longi-
tudinal plications of H. Fezelayi.

We are not aware that the test of M. Vezelayi has ever been found preserved, the
prominence of the plication indicates that it was very thin ; we have not seen any traces of
the muscular or palleal impressions.

Localities and position. It is abundant in the clays of the fuller's earth throughout
the Cotteswolds, and we have obtained several specimens a little higher in beds of hard
sandstone, near to the base of the Great Oolite, on the southern side of Minchinhampton
common, associated with several other of the Myadse.

MYAOITES CRASSIUSCULUS. Tab. IX, fig. 3.

Testa crassd, ovato-elongatd, antice etposticesubcompressd, in media ventricosd, umbonibus
anticis subcompressis, latere antico brevi, margine rotunda ; latere postico elongato, aperturd
angustd, sed elongatd ; margine superiori et inferiori subrectis et parallclis ; lateribus
plicis longitudinalibus crebris irregularibus ; area ligamenti magnd, latd.

Shell thick, ovately elongated, umbones anterior, moderately large, and compressed
laterally ; anterior side short and compressed, its margin rounded ; posterior side elongated
and attenuated, its aperture narrow and elongated upwards, the middle portion of the
shell obliquely ventricose; superior and inferior borders parallel, nearly straight and
horizontal ; the cardinal area is large and distinctly circumscribed ; the surface has closely
arranged irregular longitudinal plications. The internal surface of the left valve has a
curved projecting rib placed a little anterior to and beneath the umbo.

BIVALVIA. 113

From Mactra ffibbosa, Sow., this species is distinguished by the less elevated and
compressed umbones, by the more straight and horizontal superior and inferior borders,
and more especially by the very marked depression of the anterior side, which in M.
ffibbosa is convex. The test upon the anterior side and near to the umbones has a
considerable degree of thickness ; the rib of the left valve deeply indents the cast. The
surface of the test, although identical in character with that of other species of Myacites,
has never exhibited any distinct portion of granulated surface ; had the granules been large,
they could scarcely have failed to have been preserved equally with the surfaces of other
species in the same bed. Indications of a few radiating lines, near to the umbones, are
sometimes obscurely visible upon the test.

Dimensions of a small Great Oolite specimen. Height, 1 \ inch, length, 2^ inches,
diameter through both the valves, 1 inch ; but the examples from the Inferior Oolite of the
Cotteswolds are not uncommonly more than double these dimensions.

Geological position and localities. Ponton, Lincolnshire, in the Great Oolite ;
Rodboro'-hill, near Stroud, in the gryphite grit of the Inferior Oolite; at the latter
locality the test is preserved ; it also occurs not uncommonly in the form of casts
throughout the Cotteswolds, in the same stratum ; but it has usually been confounded with
Mactra gibbosa, Sow., a shell whose test is rarely preserved, and which does not occur so
low as the gryphite grit.

MYACITES CALCEIFORMIS, Phil. sp. Tab. XI, fig. 2.

MYA MARGAK1T1FERA, Young and Bird. Geol. York. Coast, pi. 7, fig. 2.
MYA CALCEIFORMIS, Phil. Geol. York., 1, t. 1 1, fig. 3.

Testa elongatd, compressd, antice subconvexd, postice compressd et attenuatd, costd
unicd obscurd ab umbone ad basin instructd, lateribus plicis longitudinalibus irregularibus,
testa delicatissima, granulis radiantibus crebris minutis.

Shell elongated, somewhat compressed ; umbones acute, anterior to the middle of the
valves ; anterior side rather convex, its margin rounded, and the aperture narrow ; posterior
side compressed, lengthened, and somewhat pointed, its aperture small ; superior margin
sloping obliquely, nearly straight; inferior margin nearly straight; a single obscure
elevation extends from the umbo to the inferior border, and there is, occasionally, posterior
to it, a wide superficial depression; the longitudinal plications are numerous, fine, and
irregular ; the test is of extreme tenuity, and covered with lines of very minute radiating
granules.

Specimens are usually destitute of the delicate test, but well preserved portions of it
are occasionally found. It is nearly allied to Myopsis marginata, Ag., 'Etud. Grit. Moll.,'
tab. 30, fig. 1, 2, but the species of Agassiz has a shorter anterior side, less rounded, and
the convexity of the valves is more considerable ; it is also higher and shorter than the

15

114 MOLLUSCA FROM THE GREAT OOLITE.

Panopcea longa, Buvig., ' Geol. de la Meuse, Atlas,' pi. 7, fig. 1, 3, to which, in other
respects, it has a general resemblance.

The Arcomya calceiformis, Ag., 'Etud. Grit. Myes.,' p. 176, tab. 9, fig. 7, 9, from the
ferruginous Oolite of Moutiers, is a different species of the same group or sub-genus, and
must be distinguished from our shell, which has the priority of name.

Height, 21 lines ; length, 43 lines ; diameter through both the valves, 14 lines.

Position and localities. The geological range of this species is considerable ; in the
Cotteswolds it occurs in the upper beds of the Inferior Oolite, in the fullers' earth, also
in hard pale coloured sandstone near to the base of the Great Oolite ; it occurs also in
the Cornbrash of Chippenham, Malmesbury, and Cirencester ; and at the latter three
localities it is not uncommon. Professor Phillips records it in the Inferior Oolite of Blue
Wick, and in the Kelloway rock of Scarborough.

MYACITES DILATUS, Phil. sp. Tab. X, fig. 5 a, b.

MYA DILATA, Phil. Geol. York., 1, tab. 11, fig. 4.

— Morris. Catal. Brit. Foss., p. 92.

SANGUINOLAKIA (?) DILATA, Buckman and Strickland. Geol. Chelt, pi. 6, fig. 1.
PANOPCEA DILATATA, If Orb. Prodr. de Paleont., 10 etag. No. 216.

Testa elongatd, antice compressd, postice subcylindricd, dilatd ct truncatd ; umbonibus
antemedianis, parvis, compressis ; aperturd untied angustd ; posticd magnd superne
elongatd; margine superiori concavo, inferiore subrecto ; lateribus plicis irregularibus
magnis, angulo postico flecto ; superficie granulis regularibus serialibus radiantibus
dispositis.

Shell elongated, anterior side compressed, posterior side nearly cylindrical, dilated and
truncated at the extremity; umbones anterior to the middle of the valves, small, and
compressed ; anterior aperture narrow ; posterior aperture large, suborbicular, but ex-
tending along the superior border almost to the ligament ; superior border concave ;
inferior border nearly straight ; the sides of the shell with a few large irregular longi-
tudinal plications, which are bent upwards posteriorly at a considerable angle; the
radiating lines of granules are rather large, and most conspicuous upon the posterior side.

The compressed anterior side of the shell is strikingly contrasted with the posterior
expansion. Much variation exists in the proportions of its posterior elongation, and the
latter border is sometimes reflected, the more aged specimens being the most elongated :
the figure in the ' Geology of Cheltenham' represents the most shortened phase of form.
The Great Oolite specimens are small ; they have not occurred in the shelly beds, but in
some imperfectly slaty deposits near to the base of the formation. The species also occurs
in the fullers' earth, and in the upper portion of the Inferior Oolite, the latter rock
producing by much the finer specimens. The punctations upon the granules appear to
resemble those of the recent Anatina Mspidula, and in like manner probably gave in-

BIVALVIA. 115

sertion to as many corneous prickles ; but we have not been able to trace this feature in
all specimens.

The species most nearly allied are Sanguinolaria ? rotunda, ' Geol. Chelt.,' pi. 6,
fig. 3, and Panopaa Guibaliana, Buvignier, 'Geol. de la Meuse,' Atlas, pi. 8, fig. 8 — 5,
but it is more trumpet-shaped and less elongated than the former, and less compressed
than the latter.

Localities. Small excavations on the southern slope of Minchinhampton Common,
in the Great Oolite ; also in the Cotteswolds generally in the fullers' earth and Inferior
Oolite ; Glaizedale, Yorkshire.

MYACITES TERQUEMEA, Suv. sp. Tab. XII, fig. 6.

Syn. PLEUROMYA TENUJSTKIA, Ag., 1848, pi. 24.

PANOP^EA TENUISTRIA, If Orb., 1850, Prod., 1, etag. 10, No. 242, (non Buv.)
Non LCTRARIA TENUISTRIATA, Munst. in Gold/., pi. 153, fig. 2.
PANOPJEA TERQUEMEA, Buvig. Paleont. Dep. de la Meuse, Atlas, p. 7.

Testa obovatd, ventricosd ; umlonibus subacutis, antemedianis, latere antico cordato-
declivi, subdepresso, postice attenuate, aperturd parvd ; plicis longitudinalibus tenuibus.

Shell obovate, ventricose mesially ; umbones rather acute, anterior to the middle of the
valves ; anterior side rather compressed, its border rounded ; posterior side attenuated,
its border slightly gaping ; lower margin curved ; longitudinal plications delicate.

The greatest diameter through the valves is a little anterior to the umbones, which gives
a somewhat ventricose aspect to the figure.

Length, 16 lines; height, 10 lines; diameter through both the valves, 8 lines.

Geological position and localities. Our specimens are from the shelly beds of Minchin-
hampton Common, where it is very rare. Agassiz and Goldfuss have recorded it in the
lower Oolitic rocks of France and Germany.

MYACITES UNIONIFORMIS. Tab. X, fig. 6.

Testa tumidd, ovato-clongatd ; umbonibus magnis, subcompressis ; margine antico et
postico rotunda ; margine superiori concavo, lateribus l&vigatis •, sulco lato superficiali ab
umbone ad marginem inferiorem producto.

Shell tumid, ovately elongated ; anterior side short ; posterior side elongated ; both
anterior and posterior margins rounded ; the posterior margin gapes but slightly ; the hinge
margin is elongated and concave ; the area is lengthened, lanceolate, or narrow, and
distinctly marked ; the ventral margin is somewhat rounded ; a wide, superficial depression
extends from the umbo obliquely to the inferior border, and renders the anterior side
nearly as much compressed as the posterior ; the surface is smooth with faintly-marked
irregular concentric plications.

116 MOLLUSCA FROM THE GREAT OOLITE.

The species which approach nearly to the present form, are the Homomya gracilis
Agassiz, 'Etud. Grit.,' p. 162, tab. 20, f. 1—2, and Mya Vezelayi of D'Archiac,
'Mem. Soc. Geol. Fr.,' tom 5, pi. 25, fig. 4; but compared with the former shell, the
figure is more compressed laterally and less elongated : the concavity of the superior border
and larger umbones are other points of distinction. The species described by D'Archiac
is very much more ventricose, and the umbones are more nearly terminal ; the posterior
aperture is likewise much more considerable.

Besides these there is another large undescribed species found in the upper division of
the Inferior Oolite of the Cotteswolds, which resembles more nearly the present species than
either of those before mentioned ; but it is of thrice the linear dimensions, somewhat more
elongated, and the superior border is not concave ; the test and ligament, which are very well
preserved, enable us to affirm its distinctness both from the Great Oolite species, and from
Homomya gracilis, to which perhaps it is still more nearly allied. We possess two
specimens, which occurred in the bed of soft shelly Oolite which overlies the Weather-
stones : it would, therefore, appear to be very rare.

Height, 13 lines; longitudinal diameter, 26 lines; diameter through both the valves,
12 lines.
Locality. Minchinhampton Common.

MTACITES COMPRESSUS. Tab. XII, fig. 11.

Testa ovato-rkomboided ; umbonibus prominentibus compressis ; latere antico brevi,
compresso, margine ejusdem subrecto declivi ; latere posteriors medocre elongato, convexo,
margine truncate ; margine cardinali, subrecto, oblique, declivi ; margine inferiore sinuato ;
lateribus sulco lato superficiali ab umbone margine inferiore producto.

Shell ovately rhomboidal ; umbones prominent and compressed ; anterior side short,
its margin nearly straight, sloping obliquely, and somewhat rostrated at the inferior ex-
tremity ; posterior side moderately elongated, convex, its margin truncated ; hinge border
nearly straight, but sloping obliquely downwards; inferior margin sinuated; the sides
with a wide and superficial depression directed from the umbones to the inferior
margin.

The general contour of this species is remarkable for the anterior compression of the
valves and of the umbones, which are prominent and very oblique ; the height of the valves
is so considerable, that it equals two thirds of the length. The straight anterior slope dis-
tinguishes it from Arcomya Couloni, Agassiz, which in other respects it nearly resembles.
From our M. tumidus it is separated by the greater height of the valves and oblique slope of
the hinge margin, which is also shorter ; the anterior side is likewise more compressed,
and its margin straighter. The granulated surface is- not preserved in our specimen.

Height, 21 lines; length, 33 lines; diameter through both the valves, 16 lines.

Locality. Minchinhampton Common.

BIVALVIA. 117

MYACITES TUMIDUS. Tab. IX, fig. 2 a, b,

Testa subrhomboided, valvis in media tumidd, latere antico brevi, compressiusculd ; postice
elongato et truncato ; margins ventrali subrecto et sinuosd; margins cardinali subrecto
et horizontali ; valvis Icevigatis ligamentwn magnum; lateribus lineis increments confertis
et irregularibus.

Shell subrhomboidal, its middle portion tumid ; anterior side short and compressed ;
posterior side elongated and somewhat truncated ; ventral margin nearly straight and
somewhat sinuous ; hinge margin straight and almost horizontal ; the valves smooth ;
ligament large ; series of growth numerous and irregular.

An obtuse and very tumid surface extends obliquely from the umbones to the inferior
and posterior border, which renders that part of the shell more convex than is usual in this
genus. The anterior border slopes obliquely, but is somewhat rounded, and is moderately
compressed. There can scarcely be said to be a hiatus at the anterior border, and the
posterior border, which is somewhat truncated, has only a narrow opening. The entire
form is short, as much so as Ar corny a brevis of Agassiz. The shortness, together with
the greater convexity of the middle portion of the valves, serves to distinguish it from
Arcomya quadrata of the same author. This species of Myacites is represented by one
specimen only : it has the ligament preserved, which is prominent, but not much
lengthened.

Height, 16 lines; length laterally, 27 lines; greatest diameter through both the valves,
15 lines.

Locality. Minchinhampton Common.

ANATINA, Lam. CERCOMYA, Agassiz.

Shell elongated; urnbones mesial, small, and depressed; anterior side rounded and
produced ; posterior side attenuated, having a lengthened and strongly defined posterior
area, which has two longitudinal furrows upon its surface ; no lunule. The surfaces of
the valves are covered with large longitudinal ridges, which are strongly marked anteriorly,
but are faintly traced posteriorly. There exists two depressions, more or less marked, upon
the side of the shell, which, originating at the umbo, diverge obliquely, and are directed
to the inferior border, causing that margin to undulate. These depressions, although
superficial, influence the direction of the longitudinal folds, make them to deviate from
their normal direction, and sometimes efface them altogether. The extremities of the
valves gape, more especially at the posterior extremity.

M. Agassiz, judging from the contorted figure of the casts and the absence of anything
like a fracture, thinks that the test must have possessed considerable flexibility.

118 MOLLUSCA FROM THE GREAT OOLITE.

M. d'Orbigny regards this group as identical with Anatina. He believes that the
furrows upon the area are impressed by carina?, which were destined to support the
spoon-shaped processes of the hinge, and states that he has observed a chink or cleft at
the summit of the umbo, left by the spoon-shaped processes and by the internal osselet
of Anatina.

M. Agassiz admits that these features would indicate an affinity with Anatina, but
directs attention to the elongated posterior side, to the cardinal area, and to the large
longitudinal ridges upon the sides of the valves. These characters, which are wanting
in Anatina, have induced him to retain his genus Cercomya.

One character of the genus has not been alluded to by M. Agassiz. It possesses
an external semicorneous layer of test, which is furnished with radiating lines of tubercles,
as in Goniomya, Myacites, Gresslya, and in the recent Anatina.

Anatina has not been found in the shelly beds of the Great Oolite. It occurs in
beds near to the base of the formation, in pale argillaceous buff-coloured limestones
and sandstone ; it has also been found in the upper portion of the formation, associated
with Goniomya.

M. Agassiz has sufficiently indicated the features which distinguish externally Cercomya
from Anatina. The interiors of the valves of the fossil species have not been seen, but
there is every reason to believe that they do not differ from Anatina.

ANATINA PLIUATELLA. Tab. XI, fig. 6, 6 a.

Testa transverse- elongatd, convexiusculd, later e postico elongate; plicis concentricis
crebris inconspicuis, postice obsoletis.

Shell transversely elongated, convex; anterior side rather short, its upper border
sloping obliquely from the uinbo ; posterior side more lengthened. Lateral longitudinal
plications closely arranged, distinct upon the anterior side of the shell, but disappearing as
they recede from it, so that the greater portion of the surface is nearly smooth. The very
delicate plications and general convexity of the valves are sufficient to distinguish it from
contemporaneous species.

Height, 13 lines; length, 25 lines; diameter through both the valves, 9 lines.

The figure nearly resembles that of C. antica, Agassiz, tab. lla, fig. 14, 15 ; but the
plications of that species are much larger and more continuous upon the sides.

Locality. It occurs very rarely in Stonesfield Slate, on the south side of Minchin-
hampton Common.

ANATINA UNDULATA, Sow. sp. Tab. XI, fig. 4.

SANGUINOLARIA UNDULATA, Sow. Min. Con., t. 548, f. 1, 2.
— — Phil. Geol. York., 1, t. 5, f. 1.

BIVALVIA. 119

Testa elongatd, convexd ; umbonibus mediants, area magnd, marginibus depressis, lateribus
plicis longitudinalibus magnis, striis longitudinalibus dense impressis.

Shell elongated convex ; umbones mesial, area large, its margins faintly marked, the
sides with very large regular plications, which are impressed with very fine densely ar-
ranged longitudinal striae.

The length of the posterior side slightly exceeds the other ; its extremity is slightly
curved upwards, it is rarely preserved or perfectly represented upon the internal moulds ;
the lines of radiating tubercles cannot be distinguished upon the moulds. Height 9 lines ;
lateral diameter, 22 lines; diameter through both the valves, 8 lines.

Locality. Minchinhampton.

GONIOMYA, Ag.

Shell very thin, cylindrical and ventricose, or ovate and flattened, gaping at both the
extremities, more especially the posterior extremity ; anterior extremity rounded, posterior
truncated ; umbones mesial or a little anterior to the middle of the valves, contiguous and
not very prominent ; costae large and curved, their anterior portions are directed obliquely
backwards towards the inferior border, the posterior portions are directed in a similar
manner forwards, so that the extremities of the costae meet each other near to the middle
of the shell at an angle more or less acute. The costse are crossed and indented by
closely-arranged concentric plications. The substance of the test has two layers, of which
the outer one is semi-corneous, and is furnished with minute tubercles which are arranged
in lines radiating from the umbones. Hinge edentulous ; muscular impressions faintly
marked ; ligament external.

GONIOMYA LITTERATA, Sow. sp. Tab. XI, fig. 3.

GONIOMYA LITTERATA, Agassiz. Etud. Crit., p. 18, t. 16, f. 13-16.
MYA LITTERATA, Sow. Min. Con., t. 224, fig. 1.
LYSIANASSA LITTEKATA, Gold/. Petref., t. 154, f. 8.

Testa ovato-clongatd, convexd; umbonibus ante-medianis, margine cardinali subhorizontali
aut concavd, margine antico oblique declivi; costis anticis angustis subundatis; posticis magnis
curvatis ultimis evanescentibus ; plicis concentricis crebris decussatis; angulo costarmn acuto,
obliquo margine postico producto; margine inferiore subrecto.

Shell ovately elongated, convex, umbones placed anterior to the middle of the valves,
superior margin elongated, nearly horizontal, or even slightly concave, anterior margin
sloping obliquely, inferior margin nearly straight ; costae anteriorly narrow, nearly straight,
and slightly undulated, posterior costae larger, curved but become obscure towards the
extremity of the series ; the costae are decussated with closely arranged regular concentric
plications ; costal angle acute, and directed obliquely towards the infero-posterior
border.

120 MOLLUSCA FROM THE GREAT OOLITE.

Our specimens agree more nearly with the figures of Agassiz than with those of
Goldfuss ; in the latter, the posterior side is not so much raised, so that the hinge margin
slopes downwards in a manner similar to that of the anterior border, and the costal angle
is not directed obliquely backwards ; so that, judging from the figure alone, it might be
regarded as a distinct species. Compared with Goniomya v. — scripta, our shell has much
less prominent umbones, and the entire figure of the shell is more elongated or sub-cylin-
drical, the umbones being likewise more anterior ; the posterior side of the shell is more
lengthened, its superior margin being nearly horizontal. It is comparatively rare ; we have
obtained it in thin layers of pale or buff-coloured argillaceous limestone, about 100 feet
above the fullers' earth, also in a much lower position, in a similar description of rock ; but
the genus has not been found in the shelly beds of the formation. Height and diameter
through both valves equal, or half the longitudinal diameter.

Locality. Minchinhampton.

GONIOMYA HEMICOSTATA. Tab. XII, fig. 3.

Testa ovato-clongatd, convexd ; umbonibus ante-medianis magnis subcompressis, margine
antico obhque-declivi, postico subhorizontali, concavo-hiante ; superfaie in media oblique,
depresso, costis crebris biangulatis aut trapeziformis instructis; costis inferioribus
evanescentibus.

Shell ovate, elongated, convex, gaping posteriorly with a considerable aperture;
umbones anterior to the middle of the shell, large, elevated, but somewhat compressed ;
anterior border sloping obliquely downwards, posterior border lengthened nearly horizontal
and concave ; the middle portion of the shell has a wide depression which passes from the
umbo directed slightly backwards and vanishing towards the inferior border ; the superior
and middle portion of the surface has numerous closely arranged costae directed upon each
side obliquely downwards towards the other, but connected with it by a horizontal straight
costa ; the lower half of the shell and the two extremities are altogether smooth. Outer
or granulated layer of the test unknown.

A single well-preserved cast with the valves in contiguity is our only authority. The
several features of this remarkable species clearly separate it from any other of the British
Goniorayse, the general figure with its elevated broad umbones, concave superior border,
gaping and slightly reflected posterior extremity combined with the wide mesial depression,
present no inconsiderable resemblance to a diminished figure of the great Panopcea
Aldrovandi; the trapeziform direction of the costse is governed by the mesial depression,
and exists in those species only of the Goniomya3 in which this depression is well marked,
thus in Pholadomya trapezina, Buv., Lutraria trapezicostata, Pusch., and Goniomya inflata,
Ag. the horizontal costaa extend, with the depression, even to the lower border of the valve ;
in the present species they extend, with the depression, about half the depth of the valve,
and in others, such as G. Dubois, Ag. G. v. — scripta, and G. liiteraia, the depression and

B1VALVIA. 121

horizontal costae only exist upon the umbo. Unfortunately our specimen has no portion
of the granulated outer surface preserved.

Length, 19 lines ; height, 12 lines; diameter through both the valves, about 8 lines.

Locality. — Blisworth, Northamptonshire.

PHOLADOMYA, Sow.

Shell thin, insequilateral, ventricose, oval or oblong ; the borders of the valves more or
less gaping, especially at the posterior extremity ; the umbones are large, contiguous, the
apex of the one slightly impressing the other ; the ligament external, and placed in an oval
depression, the surface is ornamented with costse radiating from the umbones, which are
regular and equal or irregular and unequal, smooth and rounded, or deeply notched and
nodulous ; the entire surface has concentric plications which vary in their regularity,
size, and prominence. The hinge is without teeth, but has an elongated lamina situated
beneath the ligament.

The costae are very commonly more numerous and prominent in the right valve than
in the left.

The muscular impressions are faintly marked and cannot usually be distinguished ;
the anterior impression is pyriform and elongated upwards towards the umbones, the
posterior muscle is rounded, the syphonal scar has a considerable flexure.

PHOLADOMYA ACUTICOSTA, Sow. Tab. XIII, tig. 13.

PHOLADOMYA ACUTICOSTA, Sow. Min. Con., t. 546, f. 1, 2.

Testa ovato-elongatd ; umbonibus crassis, antemedianis, latere antico brevi rotundato,
posteriore producto angustato, costis elatis acutis, anticis magnis remotiusculis et
irreyularibus ; posticis numerosis crebris et tenuibus ; striis concentricis decussatis.

Shell ovately elongated ; umbones thick, placed anterior to the middle of the valves ;
anterior side short and rounded ; posterior side more produced and narrow; costae elevated,
acute ; the anterior costae large, rather remote, unequal, and placed at irregular intervals ;
the costae posteriorly are less elevated, numerous, and very closely arranged, gradually
decreasing in distinctness towards the posterior extremity of the shell ; the costae are
decussated by concentric striations.

Our species is distinct from Pholadomya acuticosta, Rcemer, tab. ix, fig. 15 ; and from
Goldfuss, tab. cxxxvii, fig. 4 ; these, and likewise P. multicostata, Agassiz, tab. ii, figs. 3, 4,
have the anterior costac regular and less prominent than in our species ; the P. multicostata
varies very considerably in its length, but our species is nearly uniform in figure.

Localities. — The upper beds of the Great Oolite, near Minchinhampton ; the slate of
Stonesfield.

16

122 MOLLUSCA FROM THE GREAT OOLITE.

PHOLADOMYA SOCIALIS. Tab. XI, fig. 7, la.

Testa nucleo mediocre magnitudini, ovato ventricosd, latere antico brcvi et gibboso,
latere postico elongate, attenuate, et hiante ; umbonibus anticis magnis ; area cardinali
elongatd et planatd ; marginibus anticis et posticis curvatis ; plicis longitudinalibus magnis
irregularibus ; costalis radiantibus (circa 6) obscuris, aut evanescentibus.

Shell with the nucleus moderately large, ovately ventricose ; anterior side short and
gibbose ; posterior side elongated, attenuated, and gaping, with a lengthened but narrow
aperture extending upon the superior and posterior border to its junction with the hinge
border ; upon the anterior border there is scarcely any perceptible aperture. The umbones,
which are placed anteriorly, are moderately large ; the cardinal area is lengthened and
rather flattened; both the anterior and posterior extremities are rounded, and pass
insensibly into the superior and inferior borders. The longitudinal plications are large
and irregular, with deep furrows between them, but they become less prominent, and are
almost lost as they approach the posterior extremity. The radiating little costse are
distinct only upon the umbones ; they are about six in number, but not unfrequently they
are absent altogether.

This species presents its full share of variations of figure, not unfrequently the anterior
side appears compressed, and forms an obscure angle or rib, extending from the umbones
to the inferior border ; we have never seen the test preserved, but the nuclei display all the
more delicate features of the shell ; there are no traces of muscular or pallial impressions.
It was eminently gregareous, and occurred in a bed of bufl-coloured calcareous sandstone,
situated nearly 100 feet above the fullers' earth, and associated with Lucina Orbigniana,
Ceromya Symondsii, Ceromya undulata, and other characteristic forms.

The examination of a large number of specimens has enabled us to affirm its distinctness
from the P. laeviuscula, Agassiz ; a shell which is not so much elongated and attenuated
posteriorly, and whose radiating costa3, though delicate, are visible over the sides of the
shell, even to the inferior border. The large plications and more ventricose form distinguish
it from Pholadomya inornata, Sow., ' Geol. Trans.' 2d ser., vol. v, pi. xxi ; other species are
more distantly allied.

Localities. — Small road side excavations two miles east of Minchinhampton ; Blisworth,
Northamptonshire.

PHOLADOMYA OVULCM, Ag. Tab. XIII, fig. 12.

Testa ovatd; umbonibus magnis anticis subdcpressis, latere antico brevi, convexo, margine
rotunda, latere postico elongate et attenuate ; aperturd parvd, margine ligamenti oblique
declivi, inferiore curvato; lateribus costis radiantibus distantibus paucis, plicis longitudinalibus
impressis.

BIVALVIA. 123

Shell ovately elongated ; convex anteriorly, attenuated posteriorly ; anterior side short,
its border rounded ; posterior side lengthened and attenuated, its aperture small ; ligamental
border nearly straight, sloping obliquely downwards, lower border curved ; radiating costs:
(about 7) distant, equal, spreading over nearly the whole of the shell, and rendered nodulous
by sOrne large longitudinal plications ; the costoe of the left valve more prominent than those
of the right. The convexity of the valves is considerable towards the anterior side ; the
umbones, though large, are but little elevated, and these features, together with the few
distant and large knotted costa3, will serve to distinguish it from the Inferior Oolite
Pholadomya ovulum, Ag., and Pholadomya ovalis, Sow., to both of which species it has
some affinities ; from the Pholadomya Murchisoni from Srora, it is distinguished by having a
more elongated form, and much more distantly arranged costae, so that only a small
portion of the test is without them.

Dimensions. — Length, 2 inches; height, 1| inch; diameter through both the valves,
1 inch.

Geological position and localities. — We are not aware that this species has occurred
except in the Great Oolite of the North of England ; the specimens forwarded to us are
from Scarborough, and from the vicinity of Stamford.

PHOLADOMYA S^EMANNI. Tab. XI, fig. 1, et Tab. XV , fig. 3.

Testa ovato sub-compressd ; umbonibus elatis magnis ; latereantico brevi, rotunda ; postico
sub-compresso, brevi ; aperturd angustd ; costis radiantibus, 7-8 depressis, subrectis subaequali-
bus, et remotis ; plicis longitudinalibus impressis.

Shell ovate, rather compressed ; umbones elevated and large ; anterior side short,
rounded, posterior side rather compressed and short, gaping, with a narrow aperture;
radiating costa3 7-8 depressed, nearly straight, equal, regular, and remote; decussated but
not much impressed by the longitudinal plications. The lateral diameter is somewhat less
than the height, and exceeds considerably the diameter through both valves ; but there is
some variation in these proportions, the specimens which have the least convexity being
usually less regularly ovate and rounded at their borders, so that they might, perhaps, be
divided into two varieties.

From P. solitaria it is distinguished by the compressed posterior extremity, by
the smaller convexity of the valves, and by the character of the cost®, which are less
elevated and diverge so much more considerably that they nearly occupy the surface of the
valves.

Localities. — Small openings or pits in the Great Oolite near to its base, and in the
vicinity of the village of Avening. Scarborough, in the Great Oolite.

124 MOLLUSCA FROM THE GREAT OOLITE.

PHOLADOMYA SOLITARIA. Tab. XII, figs. 2, 5 ? var. of P. producta, Sow.

Testa ovato-subfflobosd ; umbonibus magnis, latis, medianis ; lateribus brevibus, postice
lavi, aperturd angustd ; costis (7) perpendicularibus elatis approscimatis, eequalibus, laemter
impressis -, plicis concentricis tenuibus.

An ovately globose large species, with elevated median and broad umbones ; the sides
of the shell are short, the posterior side being destitute of costa3, its aperture is incon-
siderable ; the costa? (7 in number) are large, equal, but little divergent, and only slightly
indented by the concentric plications, which latter are not conspicuous.

The height always exceeds the lateral diameter, and that through both the valves, the
two latter measurements being nearly equal.

The combination of broad umbones, with equal little impressed perpendicular costae
only slightly radiating, together with the short but not truncated sides, will suffice to
distinguish it from contemporaneous species.

Geological position and localities. — All our specimens are from the Minchinhampton
district, they have been procured at several localities in oolitic sandstone a little higher
than the fullers' earth, and obtained by well sinkings, they were unaccompanied by any
other fossil.

PHOLADOMYA HERAULTI, Ag. Tab. XV, fig. 4, var. Tab. XII, fig. ] .

PHOLADOMYA MUECHISONI, Ag. Etud. Crit., p. 79, t. 4c, f. 5, 7.

Roemer. Nordd. Ovl., p. 128, t. 15, f. 7.
HERAULTI, Ag. Etud. Crit., Appendice, 1845.

Testa ovato-ylobosd ; umbonibus magnis anticis, serratis ; area cardinali magnd, elongatd,
laiere postico modico hiante, latere antico brevi, costis (circa 9) obliquis, elevatis plicis
longitudinalibus impressis ; costdprimd obscurd, costd secundd majord et elevatd.

Shell ovately globose ; umbones large, anterior, and serrated ; cardinal area large and
depressed, posterior side gaping with a lengthened and moderately large aperture, anterior
side short, slightly truncated ; the radiating costse, (usually 9 in number,) are large and
elevated, the posterior ones are oblique ; the first is only slightly marked, the second is the
largest and most elevated; they are strongly impressed or rendered nodulous by the
longitudinal plications ; the two extremities of the shell arc destitute of costa3.

This shell is more elevated, and the prominence of the second rib will suffice to separate
it from P. Murchisoni, with which it has been confounded.

Geological position and localities. — Pholadomya Heraulti occurs not unfrequently in
certain sandstone beds of the Great Oolite, in Gloucestershire ; also at Blisworth, North-
amptonshire, but the dimensions of these specimens are usually small ; in the Inferior
Oolite it appears to range throughout the extent of that formation in this country, in
which it attains its full dimensions, and is very common.

BIVALVIA. 125

HINNITES ABJECTUS, Phil, sp. Tab. IX, fig. 7, and Tab. XIV, fig. 3.

PECTEN ABJECTUS, Phil. Geol. York., 1, t. 9, f. 37.

Morris, Cat. Brit. FOBS., 1854, p. 175.

Testa suborbiculari convexd ; auricula anticd productd lineatd, posticd subobsoletd; cos-
tellis rddiantibus numerosis (SO ad 100) irregularibus incequalibus nodulosis et transverse
striatis ; interstitialibus interdum lineisque tenuissime notatis ; valvd prope mediant costellis
2 vel 3 elevatis acutis sed nodulosis instructd. Valvd alterd planatd, delicatissimd lineis
tenuissimis et undulatis non nunquam obsoletis.

Shell, when not distorted, sub-orbicular and convex ; the umbones small and depressed ;
the anterior auricle produced, the other usually indistinguishable ; the radiating little
costae are very numerous, (from 80 to 100,) irregular, unequal, nodulous, and transversely
striated ; the interstitial spaces have likewise more minute costse or lines, which are also
nodulous, unequal in size, and uncertain in number ; the auricle has these fine irregular
lines ; there will also constantly be noticed, towards the middle of the valve, two or three
costse, which are larger and more elevated than the others, they are acute but nodulous,
and will alone at once serve to distinguish the species from Hinnites velatus, to which the
general character of the surface offers a considerable resemblance. The figure of the
latter and smaller species, however, is more fan-shaped or less orbicular and less convex.
The other valve, which is very rarely seen, is extremely delicate and flattened, its surface
has numerous very fine waved radiating lines, which are occasionally indistinct.

The numerous examples which we have obtained of this imperfectly known species
exemplify its extreme irregularity of contour and convexity, not one is altogether regular ;
the test is thin, and there can be no doubt that it readily assumed the figure of any surface
to which the flat valve was attached. In young examples the two or three more elevated
costae form a conspicuous feature which becomes less remarkable with the increase of the
dimensions. Our largest example is upwards of four inches across.

Geological position and localities. — Hinnites abjectus is found in the Coralline Oolite of
Malton, in the Great Oolite of Whitwell, and in the Inferior Oolite of Glaizedale,
Yorkshire ; it is also not uncommon in the upper division of the Inferior Oolite of
Gloucestershire, but it has only occurred very rarely in the Great Oolite of the Minchin-
hampton district.

PHOLAS. Linn. 1758.

Shell elongated, sub-cylindrical, gaping at both the extremities; umbones incurved and
contiguous. Hinge thickened, reflected to form a plate which covers the umbo in each
valve ; internally it has a curved spatulous tooth which projects in each valve.

126 MOLLUSCA FROM THE GREAT OOLITE.

PHOLAS OOUTICA. Tab. IX, fig. 21.

Testa pared ovatd, antice convexd, postice compressd, dorso in media sulco profundo ;
costulis radiantibus acutis, anticis magnis distantibus, posticis crebris ; plicis longitudinalibm
regularibus imbricatis.

Shell small, ovate, anterior side convex, posterior side rather compressed and attenuated ;
the dorsal surface with a deep mesial depressed line, which extends from the umbo to the
inferior border ; radiating costse acute, elevated, and distant upon the anterior side, less
elevated and more numerous posteriorly ; they are indented by longitudinal plications, or
lamellae, which are regular and imbricated.

The test of this small species is very delicate ; in adult specimens the umbones are
placed one third from the anterior extremity ; the convexity at that part is equal to the
height, or about half of the length ; young examples are shorter in proportion, and the
mesial furrow is more strongly marked. The Pholas crassa, of Deslongchamps, ' Mem.
Soc. Linn, de Normandie,' 1839, pi. ix, figs. 1, 3, 5, 7, has a similar or perhaps shorter figure ;
it has prominent but fewer imbricated folds, and it would appear to be destitute of the
radiating costaB which ornament our species.

Length of our largest specimen, 10 lines; height and diameter through both the
valves, 5^ lines.

Localities. — Minchinhampton and Bisley Commons, Gloucestershire.

YORKSHIRE SHELLS.

OSTREA MARSHII, Sow. Tab. XIV, fig. 2, 2 a.

OSTEEA DiLtrviANA, Park. Org. Rem.,3, t. 15, f. 1-

Zeiten. Petref., t. 46, f. 1.
MAKSHII, Gold/. Petref., t. 73.

— Roemer. Verst. Ool., p. 58.
— SULCIFEEA, Phil. Geol. York., 1, t. 9, f. 35, junior.

Testa subsolitarid sub&quivalvi, ovato-trigond, convexo-pland, crassa, pliciu radiantibus,
magnis incEqualibus acutis subimbricatis. (Roemer.)

Shell subequivalve, either ovately oblong or fan-shaped ; umbones small, terminal ; the
dorsal surface near to the umbones, has a mesial elevated smooth longitudinal ridge fringed
upon each side with acute radiating plications, towards the lower border.

BIVALVIA. 127

The central ridge divides into several very elevated acute costae ; the interstitial spaces
of which, form acute angles with them ; the substance of the test is thick. The Ostrea
sulcifera, Phil., of which we have a specimen from Whitwell, Yorkshire, is only the germ
of this large species, in which the central longitudinal smooth ridge has not divided to form
the great posterior denticulate plications, the latter change having taken place at a subse-
quent period of its growth. In the adult condition the figure is sometimes a lengthened
oval or oblong as in 0. sulcifera, but, in other instances, which probably represent the
final stage, the lower and larger plications spread out laterally, giving the shell a fan_
shaped contour.

Geological position and localities. — We have received 0. Marshii from the grey lime-
stone of the Great Oolite near Scarborough ; we have collected it in the Cornbrash near to
Malmesbury, and it occurs not uncommonly in the upper division of the Inferior Oolite in
the Cotteswolds. Ostrea sulcifera is from the Great Oolite of Whitwell, Yorkshire.

GRTPH^A MIMA, Phil. Tab. XIV, fig. 5.

GRYPH^EA MIMA, Phil. Geol. York., 1, t. 4, f. 6.

Testa parvd obliqud, subglobosd, valvd convexd, rugis concentricis magnis ; area adherenti
magnd, alterd convcxo-pland.

Shell small, oblique, subglobose, the larger valve convex, rugose, with large concentric
folds ; the adherent surface subterminal, large ; the smaller valve more smooth, slightly
convex.

More globose than Ostrea rugosa, Sow., and destitute of the marginal plications ; in
other respects it much resembles that little species.

Height, 6 lines ; lateral diameter, 5 lines ; diameter through both the valves, 3 lines.

PECTEN DEMISSUS, Phil. Tab. XIV, fig. 7.

PECTEN DEMISSUS, Phil. Geol. York., 1, t. 6, f. 5.
Goldf. Pet., p. 74, t. 99, f. 2.

Testa suborbiculari planatd; umbonibus parvis acutis; auriculis parvis aquaUbm, valvd
dextrd subpland, valvd sinistrd convexio; lateribus cequalibus marginibus rotundis; superficii
glabro lineis tenuissimis concentris, aliis subobsoletis radiantibw decussatis.

Shell suborbicular, depressed, smooth and shining ; umbones small, acute ; auricles
small, equal, rising slightly at their extremities, their outer borders curving obliquely
downwards ; the margin of the valves slope downwards from the umbones nearly at an
equal angle on each side, (about 40° to the axis of the valves) and the margins and base
are regularly rounded ; the right valve has only a very slight convexity, and sometimes is
traversed on each side obliquely by a slight furrow diverging from the umbo ; the left

128 MOLLUSCA FROM THE GREAT OOLITE.

valve is somewhat more convex ; the shining surface of the valves discloses closely ar-
ranged, very delicate and unequal concentric lines, which are decussated by radiating lines,
equally dense, but slightly waved and knotted when viewed under a magnifier; the auricles are
densely striated. The auricles are so small, that the length of their superior border is less
than a third of the height of the shell, the measurement of the lateral diameter being equal
to the height. The specimen forwarded to us from Yorkshire, is only 14 lines across, and
agrees with small examples from the Inferior Oolite of the Cotteswolds, in which latter rock
the species attains to thrice this measurement.

Geological position and localities. — The Coralline Oolite of Malton, the Kelloway rock
of Scarborough, the Cornbrash of Gristhorpe, the Great Oolite or grey limestone at Cloughton,
and the bed called Trigonia Grit, in the Inferior Oolite of the Cotteswolds ; it would appear
to be abundant in each of these positions.

PERN A RUGOSA, Gold/, var. Tab. XIV, fig. 16, et antea, Tab. Ill, fig. 1.

PEBNA QUADRATA, Phil. Geol. York., t. 9, f. 21, 22.
Gold/. Pet., t. 107, f. 12.

Testa ovato-sigmoided convexo-pland, in ulam brevam productd ; umbonibus acutis promi-
nentibus ; margine cardinali obliguo, canaliculis (8 — 12) piano concavis. (Goldfuss.)

A subquadrate thick shell, with a lengthened and large series of hinge-grooves ; the apex
is pointed, and projects forwards, beneath which the anterior border is concave and in-
crassated, the lower border is rounded, the posterior side of the shell is thin, and its border
nearly straight. The surface has irregular concentric plications, which, however, are not
very prominent.

Aged specimens acquire a very considerable degree of elongation, the opposite measure-
ment upon the hinge border having but little increase, usually the figure is more quadrate
or less sigmoidal than is represented by Goldfuss.

Geological position and localities. — In Yorkshire, P. rugosa, var. quadrata occurs in the
grey limestone of the Scarborough Great Oolite ; in the Cotteswolds, we have examples
both from the lower and upper division of the Inferior Oolite.

PTEROPERNA PLANA. Tab. XIV, fig. 4.

Testa obliqud, alatd, lined cardinali recto elongato, postico valde producto, valvis
xubaequalibus, depressis, inornatis ; plicis conccntricis irrcgularibus.

Shell oblique, winged ; unibones small, acute, curved forwards, and placed near to the
anterior extremity of the hinge-line, above which they are scarcely elevated ; hinge border
lengthened, produced posteriorly into an extended and pointed wing; the valves are
nearly equally flattened, the left valve being a little more convex than the other; they are

BIVALVIA. 129

destitute of ornament, and have only irregular concentric plications. The anterior border
beneath the short anterior wing is but little excavated, its aperture being very narrow ; the
lower side of the shell has not much obliquity, and its border is regularly rounded.
Two ribs extend the length of hinge border immediately beneath it, as is usual in the
Pteropernee.

In size it equals the larger specimens of our P. costatula, but it is less oblique than
that species : the left valve is much less convex, and the anterior sinuation is much less
considerable; the umbones are smaller, and are much less elevated above the hinge
border ; the anterior auricle is nearly upon the same plane as the posterior, but in P.
costatula it is directed obliquely downwards and forwards.

Geological position and locality. — The Grey Limestone of the Scarborough Great
Oolite.

AVICULA MUNSTERI, Goldf. Tab. XIV, fig. 6.

Testa (valva major) ovatd, obliqud, subconvexd, aid untied acutd, posticd falciformi;
costis radiantibus (3-4) acutis lineisque interstitialibus inaqualibus.

Shell very oblique and convex, inequivalve ; anterior auricle acute ; posterior auricle
more lengthened and falciform; the larger valve with regular equal radiating slightly
knotted costae (about 1 6 in number) ; in the middle of each interstitial space is an
elevated line, with one or more delicate or more faintly marked, upon each side of it ; the
auricles are ornamented in a similar manner.

An elegant shell, with convex prominent umbones, narrow but well marked costae,
which slightly project at the inferior border.

Geological position and locality. — The Great Oolite of Scarborough, in dark grey
argillaceous sandstone.

AVICULA BRAAMBURIENSIS, Sow. Tab. XV, fig. 7, var. fig. 6.

AVICULA BRAAMBUEIENSIS, Sow. Geol. Trans, vol. ii, p. 323.
— BRAAMBDEIENSIS, Phil. Geol. York., l,t. 6, f. 6.

Testa ovato obliqua, aid anticd rotundatd, posticd obtusianguld, valvd majord convexd,
lineis radiantibus confertis minoribus alternis, interstiis angmtis tegulatis. Valvd minord
convexo-pland Icevigatd, lineis radiantis paucis distantibus subobsoletis.

Shell ovately oblique ; anterior auricle small, rounded, posterior auricle forming an
obtuse angle ; the larger valve convex, with numerous radiating lines, alternating with
others which are smaller and indistinctly marked ; the interstitial spaces narrow and
indistinctly tegulated. The smaller valve slightly convex, smooth, with a few (7)
radiating lines faintly marked.

17

130 MOLLUSCA FROM THE GREAT OOLITE.

The figure is remarkable for the smallness of the auricles and lengthened outline ; the
convexity is less than is usual in other of the ornamented aviculse of the Lower Oolites.

It would appear to be nearly allied to a species which occurs in the Inferior Oolite of
the Cotteswolds, from which it is distinguished by the shorter hinge border, less convex
form, and fewer radiating costse ; it is not, however, quite certain that the Inferior Oolite
shell may not be only a variety.

Locality. — Scarborough, in the bed of Grey Limestone.

•

PINNA CANCELLATA, Bean, MSS. Tab. XIII, fig. 20«, b.

Testa ovato-lanceolatd, quadriquetrd, antice convexd plicis magnis concentricis ; postice
compressiusculd ; striis transversis crebris et lineis radiantibus angustis nodosis distantibus
decussatis.

Shell ovately lanceolate, straight, quadriquetral, anterior side convex, with large densely
arranged irregular, concentric plications ; middle and posterior side more compressed, with
fine irregular striations crossed by a few (about 12) longitudinal radiating knotted lines.

The single valve at our disposal does not exemplify the convexity and figure of the
posterior aperture. It appears most nearly to resemble Pinna Hartmanni, Goldfuss, but
it is more straight, with much fewer radiating lines, none of which are visible upon the
anterior slope.

Locality. — Scarborough, in the Grey Limestone.

LIMA PUNCTATA, Sow., sp. Tab. XV, fig. Qa, b.

PLAGIOSTOMA PUNCTATUM, Sow. Min. Con., t. 113, f. 1, 2.
LIMA PUNCTATA, Gold/. Petref., p. 81, t. 101, f. 2.
PLAGIOSTOMA PUNCTATUM, Morris. Catal., 1843, p. 117.

Testa ovato-obliqud, convexo-pland ; margine antiore subrecto, elongato, abrupte truncato ;
lunuld excavatd ; auriculis parvis intequalibus ; margine posteriore et inferiors rotunda •,
superficie Icevi striis angustis, numerosis sub-flexuosis, dense punctatis.

Shell ovately oblique, rather flattened; anterior margin nearly straight, truncated,
elongated; lunule large, excavated; auricles small, unequal; the posterior and inferior
borders of the valves regularly rounded ; the surface is smooth, with very numerous,
narrow, slightly waved, and densely punctated striations, crossed by a few irregular folds
of growth.

The smooth shining surface, densely arranged striations which cover the entire surface
of the shell, and flattened elongated form, readily serve to distinguish it from other
species of the lower oolites.

Localities. — The specimen forwarded to us from Yorkshire is from the hard Grey
Limestone of Scarborough. In the Cotteswolds it occurs abundantly in the Inferior
Oolite ; but it has not occurred in the Great Oolite of the latter district.

BIVALVIA. 131

HINNITES ABJECTUS, Phil. Tab. XIV, fig. 3, vide antea, p. 125.
MITILUS (MODIOLA) CUNEATUS, Sow. Tab. XIV, fig. 9.

MODIOLA CUNEATA, Sow. Min. Con., t. 248, f. 2.

Phil. Geol. York., 1, t. 5, f. 28.

Testa ovato elongatd, convexd ; umbonibus subterminalibus parvis curvalis, acutis ; margine
antico subsinuato ; margine cardinali oblique declivi, curvato, dorso obtuse fornicato, antice
subdepresso, superficie ; lineis concentricis tenuissimis irregularibus.

Shell ovately elongated, convex ; umbones nearly terminal, acute, and incurved ; hinge
margin sloping obliquely and curved; anterior margin nearly straight, but slightly
sinuated ; dorsal surface obtusely ridged, most elevated about the middle of the valve,
forming a depressed surface anteriorly and obliquely to it ; the surface with fine irregular
concentric lines or striations.

The acute umbones, depressed and wedge-shaped anterior side, and slight obliquity of
the entire form, serve to distinguish it from other species of the Lower Oolites.

Geological position and localities. — At Scarborough, in the Great Oolite ; Somerset-
shire, in the Inferior Oolite.

MYTILUS (MODIOLA) LECKENBII. Tab. XIV, fig. 8.

Testa ovato, arcuatd, convexd, acutd et oblique fornicatd ; antice angusto postice lato ;
umbonibus subterminalibus acutis ; dorso fornicato, latere anteriore sulcato et sinuato ;
superficie striis tenuissimis, crebris, irregularibus.

Shell curved, ovate ; anterior extremity rounded but narrow, posterior extremity wide
and curved obliquely ; umbones nearly terminal and acute ; dorsal surface with an elevated
narrow ridge, anterior to which is a depressed and sinuated surface, the anterior border of
which is much excavated, and its lower extremity rather pointed; the hinge margin is
lengthened, sloping downwards obliquely, and but very slightly curved ; the surface has
closely arranged very fine concentric striations.

The great obliquity of the valves, the deeply sinuated anterior border, the pointed
inferior extremity, and the flattened but raised posterior surface, will serve to distinguish
it from Mytilus (Modiola} bipartita, to which its acute dorsal ridge presents a resemblance.

Length, 16 lines ; opposite diameter, 8 lines ; diameter through both the valves, 8 lines.
The name is in complement to John Leckenby, Esq., of Scarborough, to whom we are
indebted for the loan of the specimen.

Geological position and locality. — The Great Oolite of Scarborough, in a bed of hard
grey ferrugino-micaceous sandstone.

132 MOLLUSCA FROM THE GREAT OOLITE.

MVTILUS (MooioLA) UNGULATES. Tab. IV, fig. 5 (M. tumidus}. .

M. UNGULATA, Young and Bird. Geol. Yorksh., pi. 7, f. 10.
M. TCMIDUS, antea, p. 37, pi. iv, f. 5.

This species has been previously figured under the name of M. tumidus, p. 37, but it is
not distinct from the Yorkshire shell, and the latter name cannot therefore be retained.

CUCULL^A CANCELLATA, Phil. Tab. XIV, fig. 12.

CUCULLEA CANCELLATA, Phil. Geol. York., 1, t. 9, f. 24, t. 11, f. 44.
OBLIQUA, Lycett. Ann. and Mag. Nat. Hist., 1850.

Testa ovato-rhomboided perobliqud ; umbonibus antemedianis contiguis, latere antico brevi,
latere postico fornicato oblique declivi et producto ; superficie lineis radiantibus minutis
crebris aliis concentricis decussatis.

Shell ovately rhomboidal, very oblique ; urabones placed near to the anterior extremity
of the hinge line, and contiguous ; anterior side short, its margin rounded, posterior side
with an oblique ridge, obtuse, and much elongated posteriorly ; the surface with very
densely arranged, equal, regular, radiating lines, decussated by others concentric and
equally densely arranged ; the lines are smooth, and the angles produced by the junction
of the decussating lines have a punctated appearance ; upon the anterior side of the shell
the radiating lines are rather less densely arranged.

The surface of this species has a considerable resemblance to Cucullaa cncullata,
Goldfuss, but the latter shell is more convex and is less elongated, the area being likewise
larger.

Geological position and localities. — At Scarborough, in the hard grey limestone of
the Great Oolite; in Gloucestershire, it occurs in the middle division of the Inferior
Oolite.

UNICARDIUM GIBBOSUM. Tab. XIV, fig. 11.

Testa ovato subglobosd ; umbonibus magnis mediants, curvatis; margine cardinali brevi,
subrecto, et subhorizontali ; marginibus aliis curvatis; superficie plicis may vis irregularilus
et ineegualibus.

Shell ovately sub-globose ; umbones large, mesial, prominent, and curved forwards ;
hinge margin short, nearly straight, and horizontal, its posterior extremity rather angulated,
the other margins of the valves regularly rounded ; the surface is covered with large,
irregular, and unequal concentric plications ; the thickness of the test is moderate.

The umbones are more nearly mesial than U. depressum and U. impressum; they also
project more, and therefore more nearly resemble U. varicowm, but the anterior side is

BIVALVIA. 133

less produced, and the height is much less than in that shell ; it is more nearly allied to,
but is more oblique, than a large lias species which is not uncommon in Gloucestershire
and Oxfordshire. Height and diameter through both the valves equal, lateral diameter
one fourth more. The specimen forwarded to us from Yorkshire is much smaller than
several which we have obtained in the Cotteswolds, in one of which the lateral diameter
exceeds two inches.

Geological position and localities. — The Great Oolite of Scarborough ; also in the
middle or freestone beds of the Inferior Oolite in Gloucestershire ; but it has not occurred
in the Great Oolite of the same county.

UNICARDIUM DEPRESSDM, Phil. sp. Tab. XIV, fig. 10.

COEBDLA DEPRESSA, Phil. Geol. York., 1, t. 9, f. 16.

Testa ovato subglobosa ; umbonibus rnagnis, subanticis incurvis, margins cardinali oblique
declivi subrecto, basi et lateribus rotundis ; plicis concentricis crebris irregularibus et
incequalibus.

Shell ovately globose, oblique ; umboues large, depressed, anterior to the middle of the
valves ; hinge border sloping obliquely downwards and nearly straight, its posterior ex-
tremity rounded ; the margins of the valves, basal, anterior, and posterior, rounded ; the
general figure tumid, excepting near to the hinge border, where the surface is more de-
pressed ; the surface is covered with closely-arranged concentric plications which are irregular
and unequal.

The substance of the test is of greater thickness than is usual in this genus ; it is most
nearly allied to U. varicosum, p. 73, tab. 8, figs. 7 — 8 ; but it is much more oblique and
of greater length, the dimensions being, height, 14 lines ; length, 17 lines ; there is some
amount of variation in the obliquity of the valves and we have specimens which exhibit
greater obliquity than the example from Yorkshire.

Geological position and localities. — The grey limestone of the Great Oolite at Scar-
borough. In Gloucestershire it has occurred only in the Inferior Oolite in the bed called
Trigonia Grit.

TRIGONIA DECORATA, Lye. Tab. XV, fig. 1.

TRIGONIA DECOKATA, Lycett. Ann. and Mag. Nat. Hist., 1853, vol. xii, pi. 11, f. 1.

Testa ovato trigona, subcowpressa, umbonibus obtusis, non recurvatis, area cardinali laid
pland tripartitd; carind internd tuberculis in varicis elongatis instructus, carind media et
marginali tuberculis minimis crebris ornatd : lateribus tuberculis per series arcuatis
concentrice dispositis.

Shell ovately trigonal, somewhat depressed ; umbones obtuse, not recurved ; anterior

134 MOLLUSCA FROM THE GREAT OOLITE.

and inferior borders rounded, posterior border lengthened and nearly straight ; area wide,
flattened, finely striated transversely, and divided into three portions by as many faintly
traced carinse, or rather as many lines of minute closely-arranged equal and regular tuber-
cles, those of the inner carina, being elongated into as many varices or plications ; there is,
likewise, a median divisional groove, which is immediately adjacent to and parallel with the
tubercles of the median carina. The clavellated portion of the shell has a numerous series
of rows of concentric closely-arranged but not very prominent tubercles, the larger tuber-
cles being towards the middle of the curvature ; they are distinct, usually rounded, closely-
arranged (15 or more being contained in a row), the number of rows in adult shells being
about 20, the whole of which are distinctly tuberculated ; the lines of growth upon the
sides of the shell are fine and distinct. The dimensions are equal to the largest examples
of the clavellated Trigoniae. The species which approximate most nearly to our shell are
T. perlata, Ag. T. Bronnii, Ag. T. muricata, Goldf. and T. clavellata, Sow., it having
usually been mistaken for the latter shell.

T. perlata has the umbones more recurved ; the tubercles upon the carinae are much
larger, and those of the median carina have in addition a series of transverse varices which
are absent in T. decorata. T. Bronnii has the apex more elevated, it is destitute of the
inner varices upon the area ; the sides of the shell have a less numerous series of rows of
tubercles, the tubercles being larger.

T. muricata has the area much smaller and more narrow ; the lanceolate post ligamen-
tal space is smooth ; the costae upon the sides of the shell are distinctly elevated, the tu-
bercles being more prominent and more distantly arranged in the rows.

T. clavellata has the figure more elongated and rostrated posteriorly ; the umbones are
much more recurved ; the superior border of the area is distinctly concave ; the lanceolate
space is of great size, and the inner carina is destitute of varices ; the sides of the valves
have the rows of tubercles fewer, the tubercles more elevated and more distantly arranged
in the rows ; the general convexity of the valves being greater than in T. decorata.

The specimen forwarded to us from Yorkshire, is rather more elongated, and the costae
are somewhat more prominent than obtains in specimens from Gloucestershire ; but there
appears to be no essential difference between them.

Geological position and localities. — The Great Oolite of Scarborough ; it is abundant
likewise in the bed called Trigonia Grit of the Inferior Oolite in the Cotteswolds.

ASTARTE MINIMA, Phil. Tab. XIV, fig. 15.

ASTAKTE MINIMA, Phil. Geol. York., 1, t. 9, f. 23.

— Williamson. Geol. Trans., 2(1 ser., vol. v, pt. 1, p. 240.

Testa parvd ovato-acutd convexd; umbonibus prominulis obliquis ; superficie apice
1(sviffato; dorso striis concentricis magnis irrcffidaribus.

Shell small, ovately acute, convex ; umbones prominent, pointed, oblique ; margins of

BIVALVIA. 135

the valves rounded ; the surface smooth near to the apex, the remaining portion with large
concentric irregular striations.

Locality. — This small species is not uncommon upon the slabs of Brandsby slate, and near
Scarborough ; it has not been identified in Gloucestershire. Mr. Williamson records it both
in the Great and Inferior Oolite of Yorkshire.

ASTARTE ELEGANS, Sow. Tab. XIV, fig. 14, vide antea, p. 86.
CYPRINA ? DOLABRA, Phil., sp. Tab. XIII, fig. 19.

CYTHEHEA DOLABEA, Phil. Geol. York., 1, t. 9, f. 12.

Testa parvd ovato-orbiculari, plano-convexa lavigata ; umbonibus subacutis mediants
elevatis ; marginibus rotundis ; lunuld magnd excavatd.

Shell small, ovately orbicular, rather flattened, smooth ; umbones mesial, rather acute,
and elevated ; margins of the valves rounded ; lunule large and excavated.

The depressed figure, elevated acute mesial umbones, and large lunule, separate it
from other small contemporaneous species of the Cyprinae.

Height, 4 lines ; length, 5 lines ; diameter through both the valves, a line and a half.

Locality. — Scarborough, in the Great Oolite.

ISOOARDIA CORDATA, Buck. Tab. XV, fig. 5.

ISOCAEDIA CORDATA, Buchiiun. Geol. of Chelt., p. 98, t. 7, f. 1.

Testa ovato orbiculari convexd, umbonibus magnis obliquis antemedianis antrorsum
curvatis et separatis ; area ligamenti magnd, sulco elongato, marginibus rotundis et integris ;
superficie laevi, striis concentricis tenuibus et irregularibus instructis.

Shell ovately orbicular or cordiform ; very convex near to the umbones, but rather
compressed at the margins, which are regularly rounded and entire ; umbones large,
curved forwards, and separated by a large and lengthened ligamental area, upon each side
of which is a groove which extends nearly to the posterior extremity, and is bounded
above by an angle which may be traced to the extremities of the umbones ; the surface is
smooth, with fine irregular concentric striations ; test very delicate.

Dimensions of the Yorkshire specimen ; height, 18 lines; length, 21 lines; diameter
through the valves, 15 lines.

Localities. — Scarborough, in the Great Oolite ; larger examples, some of which have
the test preserved, occur in the Inferior Oolite of the Cotteswolds, but it is unknown in
the Great Oolite of Gloucestershire.

Q.UENSTEDTIA L^EVIGATA. Tab. XIV, fig. ] 3.

PSAMMOBIA L.EVIGATA, Phil. Geol. York., 1, t. 4, f. 5.

Testa ovato-elongatd, cowpressd, Icevigatd ; umbonibus depressis, mediants; antice

136 MOLLUSCA FROM THE GREAT OOLITE.

rotundo, postice subtruncato, angulo obliquo obtuso imtructo ; margine cardinali subhorizon-
tali, inferiors parallelo ; lateribus striis irregularibm tenuibus.

Shell ovately elongated, compressed and smooth ; umbones depressed, mesial ; anterior
border rounded, posterior border somewhat truncated ; an oblique obtuse angle descends
from the umbo posteriorly; hinge border horizontal, lower border parallel, the surface
with fine irregular longitudinal striations.

Compared with Quenstedtia oblita, this species is more elongated, the umbones
more nearly mesial, and the longitudinal plications are much more delicate, producing a
general smoothness of the surface. Length, 2 inches ; height, 1 inch.

Geological position and localities. — Specimens have been forwarded to us from the
Grey Limestone bed of the Scarborough Great Oolite ; it also occurs in the Inferior Oolite
of Blue Wick upon the same coast, and in the upper division of the Inferior Oolite of the
Cotteswolds ; we have also obtained a specimen in the Great Oolite of Minchinhampton,
but it appears to be rare at each of these localities.

MYACITES BEANII. Tab. XV, fig. lla, b.

Testa ovato-oblonffd subcompressd, umbonibus depresses ; antemedianis, area liyamenti
angustd, parvd ; margine postico rotundo ; hiante basi et margine anteriore curvato ; superficie
tsulco lato, superficiali instructo ; plicis longitudinalibus maynis irregularibus.

Shell ovately oblong, rather short and compressed ; umbones antero-mesial, depressed ;
ligamental area small and narrow, the margin posterior to it nearly horizontal ; the
extremities of the valves rounded, the anterior extremity being almost closed, the posterior
extremity with a lengthened and moderately large aperture ; a superficial and vertical wide
depression passes downwards from the umbones crossing the longitudinal plications, which
are large and irregular.

This species is not without a considerable resemblance to Homomya compressa, Ag.,
but as the latter shell has the anterior side less produced, with a distinct aperture, together
with umbones more elevated, we prefer to consider them distinct species ; the short form,
depressed small umbones, and fully developed nearly entire anterior border, will also
serve to distinguish it from other of the British Myada?. Length, 2j inches; height,
1 j inch ; diameter through the valves, 1 inch.

Locality. — Scarborough .

MYACITES SECURIFORMIS, Phil., sp. Tab. XIII, fig. 15.

AMPHIDESMA SECTJRIFORME, Phil. Geol. York., 1, t. 7, f. 10.
PLECKOMYA SECURIFORME, Ag. Etud. Crit., p. 232.

BIVALVIA. 137

Testa elongatd, securiformi, comprcssiusculd, umbonibus submedianis parvis, margine
antico et postico oblique-declim, basi ettiptico curvato ; valvis in medio subdepresso, plicis
longitudinalibus magnis distantibus, lunuld nulld.

Shell elongated, subtrigonal or hatchet-shaped, umbones antero-mesial and small,
anterior and posterior borders sloping obliquely downwards, the anterior slopes have the
greater angle, lower margin curved elliptically ; the extremities of the valves , rounded, and
no distinct aperture ; the sides of each of the valves with a large superficial perpendicular
mesial depression caused by a few large and distant longitudinal plications. The general
figure is more compressed, the umbones more nearly mesial, and the extremities of the
valves are more completely closed than is usual in this genus, there is also more or less
degree of inequality in the valves. Numerous as are the forms of this genus, we have
seen none which are likely to be confounded with the present species ; some of the shorter
specimens of Pleuromya elongata, Ag., resemble it in outline only, but the posterior aperture
and greater convexity will at once distinguish the species of Agassiz.

Height, 13 lines ; length, 22 lines; diameter through both the valves, 8 lines.

Localities. Myacites securiformis occurs abundantly in the Cornbrash both of
Yorkshire and Wiltshire.

Mr. Bean has kindly forwarded us a fine specimen from the Great Oolite of Scarborough,
which we have figured.

MYACITES DECURTATUS, Phil. Sp. Tab. XV, fig. 10«, b.

Syn. AMPHIDESMA DECURTATUM, Phil. Geol. York., 1, t. 7, f. 11.
PLEUROMYA DECCRTATA, Ag. Etud. Crit. Myes., p. 232.
LUTRARIA DECURTATA, Goldf. Petref., t. 153, fig. 3.

Testa ovato-elonffatd, umbonibus anticis elevatis, latere antico brevi, abrupte truncate,
postico dongato, attenuato et hiante ; margine superiori oblique declivi, basi curvato,
later ibus plicis longitudwalilus irregular ibw.

Shell ovately elongated, umbones anterior, elevated ; anterior side short, truncated, with
a superficial vertical depression ; posterior side elongated and attenuated, superior margin
sloping obliquely downwards, the extremity with an aperture of moderate size and elon-
gated, lower border curved elliptically ; the sides of the valves with longitudinal irregular
plications.

Compared with its congeners, the elevated umbones, short anterior side, and lengthened
attenuated posterior side, will usually serve to distinguish it ; the middle portion of the
shell is moderately tumid, the two extremities being somewhat compressed ; the posterior
aperture extends both upon the superior and inferior borders ; we have not seen the outer
granulated layer of the test.

Height, 11 lines ; length, 20 lines; diameter through both the valves, 9 lines.

18

138 MOLLUSCA FROM THE GREAT OOLITE.

Locality. Myacites decurtatus occurs in the Cornbrash both of Yorkshire and of
Wiltshire ; we have also been favoured by Mr. Bean, with a specimen from the Great
Oolite near Scarborough.

MYACITES SCARBURGENSIS, Phil. Sp. Tab. XV, fig. 13.

Syn. LUTEAKIA GIBBOSA, Phil. Geol. York., 1, t. 9, f. 6.

Testa ovato-elongatd, compressiusculd, umbonibus antemedianis parvis, margins antico
rotunda, producto, postico elongato, hiante; lasi elliptico curvato, margins supcriori sub-
horizontali, concavo; lateribus compressis, plicis irregularibus magnis longitudinalibus.

Shell ovately elongated, compressed ; urnbones anterior to the middle of the valves,
small and not much elevated ; anterior side produced, its margin rounded ; posterior side
lengthened, and gaping with a moderately large aperture ; base curved elliptically ; the
sides of the valves are compressed, and have large irregular longitudinal plications ; the
ligamental area is large and excavated, the posterior aperture extending upon the horizontal
superior border nearly to the ligament.

A species somewhat resembling Myopsis Jurassi, Ag., but less tumid, or more com-
pressed in its middle part.

Height, 17 lines ; length, 31 lines; diameter through both the valves, 12 lines. The
specimen figured is the original one drawn by Professor Phillips.
Locality. Scarborough. Mr. Bean's Collection.

MYACITES GIBBOSUS, Sow. Sp. Tab. XII, fig. 14, (junior.)

Syn. PANOP.EA GIBBOSA, Sow. Min. Con., t. 211.

AGASSIZII, Falenc. Arch, du Mus., 1, p. 31.
MYACITES GIBBOSUS. Morris. Catal. 2d edit., 1854, p. 213.
MYA GIBBOSA, D'Jrchiac. Mem. Soc. Geol. Fr., vol. 5, pi. 26, f. 1, 184.5.
— MODICA, Bean. MSS. (junior.)

Testa ovato-oblongd, ventricosd, umbonibus rotundis, magnis, clevatis ante medianis,
latere antico brevi, margins rotunda, latere postico compresso, margins aperturd angustd, basi
elliptico curvato; margins swperiori concavo; area ligamenti magnd, ellipticd ; lateribus
striis irreffularibus tenuissimis.

Shell ovately oblong, veritricose ; umbones rounded, large, elevated, and placed anterior
to the middle of the valves ; anterior side short, convex ; its margin rounded, gaping with
a small aperture; posterior side compressed, its extremity with a narrow lengthened
aperture ; base elliptically curved ; superior margin rather concave ; ligamental area large,
elliptical, depressed ; sides of the valves with fine irregular longitudinal striations.

The small specimen forwarded us from the Great Oolite of Scarborough, is the young

BIVALVIA. 139

condition of the large and well-known Panop&a gibbosa, Sow., a species in which the test
has not been observed, and which in the Cotteswolds and West of England, is procured in
the upper portion of the Inferior Oolite; our small example is more than usually elongated, but
the species differs very much in this particular, and we possess examples from the Inferior
Oolite in which the posterior side is fully as much elongated. The large elevated umbones and
tumid anterior side of the shell, serves to distinguish it from another Inferior Oolite species
hitherto undescribed, and for which it has not unfrequently been mistaken ; the older or
fully developed specimens of Myacites gibbosus are invariably shorter and more ventricose.
The shell figured by d'Archiac represents a specimen of medium size ; the Homomya gibbosa,
Ag., ' Etud. Grit. Myes/ pi. xviii, is our Myacites Vezelayi, a shell which never occurs in
the Inferior Oolite.

Dimensions of the small Yorkshire example. Height, 13 lines; length, 25 lines;
diameter through both the valves, 1 1 lines.

Locality. Scarborough.

MYACITES ^QUATUS, Phil. Sp. Tab. XII, fig. 15.

MYA JJQUATA, Phil. Geol. York., 1, t. 11, f. 12, (junior.)

Testa ovato-tumidd, umbonibus magnis, elevatis antemedianis, latere antico producto,
postico attenuate ; margine superiore concavo, declivi ; basi elliptico curvato.

Shell ovate, tumid ; umbones large, elevated, slightly compressed, and placed anterior
to the middle of the valves ; anterior side produced, middle portion ventricose, posterior
side rather compressed and attenuated ; lower border curved elliptically ; the sides of the
valves have fine irregular striations. Our species possesses some general resemblance to
Pleuromya tenuistria, Ag., but it is more lengthened, and the posterior side is more
attenuated, the superior border having a greater declivity.

We believe that the small shell figured by Phillips under the name of Mya cequata, is
the young condition of the larger specimen we have figured, in which the posterior side
has with increase of growth become somewhat more elongated.

Height, 12 lines; length, 20 lines; diameter through both the valves, 10 lines.

Locality. Scarborough, in the Grey Limestone.

GRESSLYA PEREGRINA, Phil. Sp. Tab. XV, fig. Ba, b.

Syn. UNIO PEREGIUNUS, Phil. Geol. York., 1, t. 7, f. 12.

GRESSLYA ERYCINA, Ag. Etud. Grit. Myes., p. 214, t. 14, f. 1—9.
GRESSLYA CONCENTRICA, Ag. Etud. Grit. Myes., p. 213, t. 14, f. 10 — 15.
PEREGRINA, Morris. Cat. Brit. Foss., 2d ed., 1854, p. 203.

Testa ovato-cordiformi, tenui, umbonibus antemedianis subdepressis, anticc productd et

140 MOLLUSCA FROM THE GREAT OOLITE.

tumidd, lunuld magnd, excavatd; postice compressd, margins cardinali curvato, oblique
declivi; plicis incrementi magnis, paucis, irregularibus. Superficie granulis dense, ornatis>
granulis in lineis radiantibus minutis serialibus regularibus instinctis.

Shell ovately cordiforra, the test very thin, anterior side very convex and produced
posterior side attenuated and compressed ; umbones depressed, placed at about one third
from the anterior margin, lunule large, excavated ; hinge border curved and sloping
obliquely downwards, its posterior extremity rounded. The sides of the valves have large
irregular but distant plications.

The entire surface is very densely ornamented with minute granules disposed in closely-
arranged fine radiating lines, the lines being distinctly raised and uniting the granules
at their bases.

Agassiz has not noticed the Unio pereyrinus, but his tab. XIV contains numerous and
truthful exemplifications of its phases of aspect under the names of Gresslya erycina and
G. concentrica.

The most prominent distinguishing feature of Gresslya per egrina, consists in the great
development of the anterior side, and the compression of the posterior, so that when placed
upon its side, the anterior border and lunule faces the spectator.

Some specimens of Gresslya latirostris, Ag., from the Inferior Oolite of the Cotteswolds,
much resemble our species in their general outline, but the more considerable diameter
through the valves upon the anterior side of G.peregrina, will always distinguish it, together
with the more compressed and shortened figure of the posterior side.

From Gresslya abducta (Unio abductus, Phil.), it is readily distinguished by the more
elevated umbones and shorter anterior side of the latter species.

Geological position and localities. Gresslya peregrina occurs both in the Cornbrash,
and in the Grey Limestone of the Great Oolite, near Scarborough.

GONIOMYA V-SCRIPTA, Sow. Sp. Tab. XIII, fig. 16.

Syn. MYA V-SCRIPTA, Sow. Min. Con., t. 224, f. 2 — 5.

GONIOMYA V-SCRIPTA, Ag. Etud. Crit. Myes., t. 15, f. 17 — 19.
GONIOMYA V-SCRIPTA, Morris. Catnl. 2d edit., 1854, p. 203.

Testa ovato-subtrigond, umbonibus submedianis, margine antico rotunda, postico sub
truncato, costis angulis acutis verticalibus, extremitate postico lavi.

Shell ovate, somewhat subtrigonal ; umbones nearly mesial ; anterior border rounded ;
posterior border somewhat truncated, lower margin nearly straight ; from the umbones the
anterior and posterior margins slope obliquely downwards, the posterior side, which is
slightly the longer, having its slope at a smaller angle than the other ; costae numerous,
their angle acute, and directly perpendicularly downwards, or a little backwards ; the

BIVALVIA. 141

posterior extremity is destitute of costae ; the costae nearly of equal size upon both the sides
of the shell.

The Lysianassa v-scripta of Goldfuss, Pet., t. cliv, fig. 6, is the Mya literata of
Sowerby, Phillips, and Agassiz.

Geological position and localities. Great Oolite, Scarborough ; Kelloway Rock, Wilts ;
Cornbrash, Bedford ; Inferior Oolite, Brora ; Claydon, and the Cotteswolds.

PHOLADOMYA OVALIS, Sow. Tab. XV, fig. 14.

PHOLADOMYA OVALIS, Sow. Min. Con., t. '226.
? PELAGTCA, Ag. Etud. Grit. Myes., p. 105, t. 2, f. 5—7.

NANA, Phil. Geol. York., 1, t. 9, f. 7, (junior.)

Testa elongato-ovatd, antice ventricosd brevi, postice elongate, anyusto, vix, hiante ;
umbonibus magnis, elevatis ; lateribus plicis longitudinalibm irregularibus et costis (circa 9)
distantibus angustis, subperpendicularibus.

Shell ovately elongated ; anterior side ventricose, its margin closed ; posterior side
attenuated and elongated, its aperture small ; umbones large, elevated ; superior border
nearly horizontal, and sinuated, base curved elliptically ; the sides of the valves with
irregular longitudinal plications, crossed by costae, which are narrow, distant (about nine in
number), nearly of equal size, and are nearly perpendicular ; the anterior and posterior
sides are without costae.

Of the costaj five or six are prominent, and are distinct to the lower border, the others
are less elevated, and are gradually lost upon the surface. P. pelagica, Ag., and
P. decemcostata, Roemer, have the costae more oblique, but we think that the species is
subject to some variability in this respect, and that they cannot be separated ;
Pholadomya nana, Phillips, we also regard as a young example of the same species ; we
have arrived at this conclusion from a comparison of the original specimen figured in the
' Geology of Yorkshire,' and placed at our disposal by Mr. Bean.

Height, 14 lines; length, 25 lines; diameter through both the valves, 12 lines.

Localities. The specimen forwarded to us is from the Grey Limestone of Scarborough ;
it also occurs in the Cornbrash of the same locality.

PHOLAS PULCHRAUS, Bean. MSS. Tab. XIII, fig. 17.

Testa subcylindricd, media constricto, lateribus convexis hiantibus, costellis paucis
intequalibus radiantibus, umbonibus mediants depressis, et sulco mediano perpendiculariter
instructo, laleribus semel plicis longitudinalibus subundulatis et crebris.

Shell subcylindrical, short, compressed in the middle portion, and convex towards the
two extremities, each of which gapes with a considerable aperture ; umbones mesial and

142 MOLLUSCA FROM THE GREAT OOLITE.

depressed; a narrow sulcation passes nearly perpendicularly from the uinbo to the
inferior border ; the sides of the valves have numerous closely arranged and nearly regular
but depressed plications; the plications towards the extremities are crossed by a few
radiating and rather irregular costae, which are most prominent upon the anterior side,
but upon each side the costae become indistinct which are nearest to the middle of the
shell.

Lateral diameter, 13 lines; height, 9 lines.

Geological position and locality. The specimen kindly forwarded to us by Dr. Murray
of Scarborough, is from the Grey Limestone of the Great Oolite.

PHOLAS COSTELLATA. Tab. XIII, fig. 1 8.

Testa parvd, ovatd, antice convexd, costettatd, postice attenuatd sub-lcevigatd ; umbonibus
magnis ante mediums, compressis ; valvis in media sulco obliquo ; costellis prominentibus
subacutis irregularibus ; laminis concentricis crebris depressis.

Shell small, ovate ; anterior side convex, with radiating, irregular, subacute costae ;
posterior side nearly smooth ; the middle of the valves is depressed, with a groove which
passes obliquely downwards and backwards ; the umbones are placed anterior to the middle
of the valves, they are large and compressed ; the extremities of the valves are nearly
closed ; the concentric lamellae upon the sides of the shell are fine, and closely arranged,
nearly disappearing upon the posterior half of the valves. The calcareous crypt, which
contains the shell, is obtuse anteriorly.

Compared with Pholas Oolitica the costae are more distinct and numerous upon the
anterior half of the valves ; the concentric lamellae are more numerous, closely arranged,
and much less conspicuous, so that they scarcely impress the radiating costse ; the mesial
sulcus is more oblique, and the general figure of the shell is less cylindrical ; the crypt is
less ovate, or more nearly pyriform, the anterior extremity being more obtuse. The
posterior extremity of the shell is somewhat embedded in the crypt, and is not sufficiently
exposed to enable us to give the dimensions with accuracy ; the costse upon the anterior
half are about 12 in number, and nearly straight ; the anterior extremity does not exhibit
any distinct apertures.

Locality. Scarborough.

CEEOMTA CONCENTRICA. Tab. XV, fig. 3, antea, p. 108.
GERVILLIA ACUTA. Tab. XIV, fig. 1, la, antea, p. 20.
Trigonia conjungens is probably a variety of T. angulata.

NOTE. — We are indebted to the liberality of Mr. J. Leckenby and Mr. W. Bean, of (Scarborough, for the
loan of the specimens above described from the Oolite of Yorkshire.

142*

ADDENDA.

PHOLADOMYA OBLITA. Tab. XII, fig. 5.

Shell ovately ventricose, umbones large, elevated ; anterior side tumid, posterior side
produced, compressed, its extremity gaping with a narrow aperture; superior border
concave, inferior border curved elliptically ; sides of the shell with very numerous, fine
radiating lines, which are effaced towards the lower borders, and are absent towards the
two lateral extremities.

The shell which most nearly resembles the present species is the well known
Pholadomya Jidicula, Sow., from which it is distinguished by the shorter and more
ventricose figure, by the much larger and more elevated umbones, by the considerable
curvature of the lower border, and by the surface, which, in lieu of the acute elevated
costac of P. Jidicula, has very much more numerous, fine, lines, which vanish towards the
lower border. Pholadomya oblita has occurred rarely in sandstone at the base of the
Great Oolite, and also in the Inferior Oolite of the Cotteswolds.

Localities. Minchinhampton Common, in the Great Oolite. Selsley and Frocester hills,
in the Inferior Oolite.

18*

TAB. I.

Fig.

1, la.

Ostrea

acuminata, page 3.

2.

33

gregarea, var.,p. 4.

3, 3 a.

>3

Sowerbii, jo. 4.

4.

jj

rugosa, jo. 2.

5, 5 «.

)3

costata,j5. 3.

6, 6 a.

33

sub rugulosa,jo. 4.

7.

Exogyra auriformis, p. 5.

8, 8 a.

Placunopsis Jurensis, jo. 6.

Sb.

Interior of Ditto, showing muscular impression.

9, 9 a.

Placunopsis socialis,jo. 7.

10.

33

radians, p. 7.

11, 11 a.

33

ornatus,j>?. 7.

12, 12 a.

Pecten

vagans, p. 8.

13.

33

annulatus.jo. 12.

14.

3)

peregrinus,jo. 9.

15, 15 a.

33

retiferus, p, 9.

16.

3)

hemicostatus, p. 10.

17, 17 a.

33

personatus, jo. 11.

18.

33

arcuatus.jo. 11.

19, 19 a.

33

clathratus, p. 13.

20.

JJ

Woodwardii, p. 8.

Tab I

i'rmtfii t'.v !''">'-l *• Wr«l

TAB. II.

Fig.

1, la. Pecten lens, p. 11.

2, 2#. Hinnites velatus. p. 14.

3, 3 a. ,, tegulatus, p. 14.

4, Plicatula tuberculosa, j». 15.

5, „ fistulosa, p. 15.

6, Qa. Avicula costata,jy. 15.

7, 7 a, 6. „ echinata.jo. 16-

Pteroperna costatula, young of, showing the costated
surface, p. 18.

9. Gervillia crassicosta, j». 23.

10. Pteroperna emarginata, />. 19.

11. 11 a. „ pygmaea, p. 19.

12. 12«. Gervillia ovata, p. 22.

1 3 . Pteroperna costatula, p . 1 8 .

13 a. Interior of ditto, showing muscular impression and

hinge area, p. 18.

14. 14 a, 6. Gervillia monotis, jo. 22.

15. „ Bathonica, p. 21.

7/iinim

lit

•

'

.,

TAB. III.

Fig.

1, Perna rugosa, p. 25.

2, 20. Lima cardiiformis, p. 27.

3, 3 a. „ semicircularis, p. 29.

4, „ Luciensis, p. 28.

5, 5 «. „ ovalis, p. 29.

6, 6 a. „ duplicata, p. 26.

7, 7 a. „ gibbosa,/i. 28.

8, 8 a. „ impressa, p. 29.

9, 9 a. „ bellula,jO. 30.

10, Hinge area of Gervillia crassicosta, p. 23.
11- Trichites nodosus, p. 35.

12, 12 a. Gervillia acuta, p. 20.

13, 13 a, b. „ subcylindrica, p. 21.

14, Inoceramus Fittoni, p. 24.

Tat. MI.

Pi-mi.. 1 by K.-nl It West

TAB. IV.

Fig.

1. Mytilus Sowerbyanus, p. 36.

2. „ imbricatus, p. 41.

3. „ Lonsdalei, p. 40.

4. „ solenoides, p. 38.

5. „ tumidus, p, 37. (/^'U^

6. „ tenuistriatus, p. 37.

7. „ compressus, p. 40.

8. „ asper, p. 39.

9. 9 a. „ furcatus, p. 39.

10. „ Binfieldi, p. 42. /•* iU

11. „ subreniformis, p. 39.

12. 12«. „ pulcherrimus, p. 38.

13. 13 a. Lithodomus inclusus, p. 43.

14. Pinna ampla, p. 31.

15. 15 a. Lithodomus parasiticus, p. 43.

16. 16 a. Myoconcha crassa,/). 76.

17. „ actseon,j». 77.

18. „ elongata, p. 77.

19. Mytilus sublaevis.jo. 41. M (F^.-^.1^-

lot.

a*.

Achilles, lei etlith

ft-inteiliy forl

TAB. V.

Fig.

1. 1 b. Macrodon (Area) Hirsonensis, p. 49.

1 a. ,, young state of ditto, p. 49.

»

2. Area rugosa, p. 47.

3. „ Prattii,j». 45.

4. 4 a. Cucullaea Goldfussi, p. 50.

5. „ cucullata, jo. 51.

6. Area Eudesii, p. 46.

7. Cucullaea concinna, p. 50.

8. Area semula, var. transversa, p. 47.

9. „ tenuitexta, p. 45.

10. „ Kilverti,jo. 45.

11. „ minuta, p. 48.

12. „ rudis, p. 44.

13. 13 a. Nucula variabilis, p. 51.

14. „ Waltoni,jo. 52.

15. 15«. Leda lachryma, j». 53.

15a. „ „ the smooth variety of ditto, p. 53.

16. 16 a. Limopsis ooliticus, p. 54.

17. Area aemula, p. 47.

18. 18 a. Trigonia Goldfussi,^. 56.

19. 19 a. „ Moretoni.jo. 57.

20. „ flecta,j5. 60.

21. „ subglobosa, p. 55.

22. 22 a. „ costata, var. pullus, p. 58.

23. „ „ var. elongata, p. 60.

24. „ itnpressa, p. 61.

Tab ';

1 i,

TAB. VI.

Fig.

1. Trigonia Phillipsii,j». 62.

2. ,, duplicata, p. 60.

3, 3 a, b, c. Opis lunulatus, p. 80.

4, 4<7, b. ,, similis, p. 81.

5, 5 a. ,, Deshayesii, p. 81.

6. Area pulchra, p. 44.

1 '• Leda mucronata, ^.53.

8, 8 a. Trigonia imbricata, j>?. 63.

9. Lima pectiniformis, p. 26.

10. Gervillia radians, p. 23.

11. Pinna cuneata, j». 32.

12. Inoceramus obliquus, p. 24.

13. Lucina crassa, p. 68.

14. 14 a. „ rotundata, p. 68.

15. „ Bellona, var. depressa, p. 67.

16. „ despecta,jy. 69.

17. „ „ var. cardioides, p. 69.

18. 18 a. „ Bellona,^. 67.

19. Area minuta,jo. 48.

TAB. VII.

.

Fig.

1, 1 a. Isocardia tenera, p. 66.

2. Cardium Buckmani, p. 64.
»iTT-.C<w/^3. „ subtrigonurn, p. 64.

4,4(2. „ pes-bovis, j». 65.

5, 5 a. „ Strickland!, p. 64.

6, 6a, £. ,, senricostatum, />. 63.

7, la, b, c. „ concinnum, p. 65.

8, 8 a, b, c. Cypricardia Bathonica, p. 75.

9, 9 a, b. „ rostrata, p. 75.

10, 10 a, b. „ nuculiformis, p. 76.

11. Corbis Lajoyei, var. cingenda, p. 70.
12,12M- „ „ jo. 69.

13, 13 a. „ aspera, p. 70.

14, 14 a, b, c, d. Sphaera (Corbis) Madrid!, p. 71.

Tab.VIl

^5 L

TAB. VIII.

Fig.
1.

2.
3.

4.
5.

6, 6 a.

7, 7 a, b.

8, 8 a, b.

9, 9 a, b, c.

Pachyrisma grande, anterior view, p. 79.

posterior view, showing ligamental area, p. 79.
„ hinge area of right valve, p. 79.

„ hinge area of left valve, p. 79.

„ side view, p. 79.

Unicardium parvulum, p. 74.
„ varicosum, p. 73.
„ „ nucleus of ditto, p. 73.

„ impressum, p. 73.

Ta.t\ •;][

TAB. IX.

Fig.

la, 6. Ceromya undulata, p. 106.

2a, b. Myacites tumidus, p. 117.

3. Myacites crassiusculus, p. 112.

4. Quenstedtia oblita, p. 96.
4a, b. Hinge of ditto.

5. Nucula variabilis, p, 51.

6. Corbula involuta, p. 97.

7. Hinnites abjectus, p. 125.
8a, b. Astarte excentrica, p. 83.
9. „ squamula, p. 82.

1 Go, b. „ minima, p. 82.

11. „ depressa, p. 85.

12. „ rotunda, p. 84.
13a, b. „ pumila, p. 83.

14, 15a, b. „ interlineata, p. 87.

16. „ Wiltonii, p. 87.

17a, b. „ angulata, p. 86.

18,19. „ excavata var. compressiuscula, p. 85.

20. „ rhomboidalis, p. 84.

21. Pholas Oolitica, p. 126.

PI IX

Ford l.West Imp.

TAB. X.

Fig.

la, b. Ceromya plicata, p. 107.
2. ditto. p. 107.

3a, b. Ceromya concentrica, p. 108.
4a, b. Ceromya Symondsii, p. 106.
5a, b. Myacites dilatus, p. 114.

6. Myacites uniomformis, p. 115.

7. Gresslya peregrina, var., p. 105.

Pl.X.

TAB. XL

Fig.

1. Pholadomya solitaria, p. 123.

2. Myacites calceiformis, p. 113.

3. Goniomya literata, p. 119.

4. Anatina undulata, p. 188.

5. 5a. Myacites Vezelayi, p. 111.

6. 6a. Anatina plicatella, p. 118.

7. 7 a. Pholadomya socialis, p. 122.

Tab. XI.

x- -'-•

Cha. R AchiHea

TAB. XII.

Fig.

1. Pholadomya Heraulti, p. 124.

2. Pholadomya oblita, p. 243.

3. Goniomya hemicostata, p. 120.

4. Cyprina nuciformis, p. 90.

5. Pholadomya oblita, p. 143.

6. Myacites Terquemea, p. 115.

7. Tancredia axiniformis, p. 93.

8. Tancredia angulata, p. 94.

9. Neaera Ibbetsoni, p. 98.

10. Astarte recondita, p. 88.

11. Myacites compressus, p. 116.

12. Ceromya similis, p. 109.

14. Myacites gibbosus, p. 138.

15. Myacites sequatus, p. 139.

Ta"b XII.

TAB. XIII.

Fig.

1, 10, b. Thracia curtansata, p. 110.

2, 2a, c. Cyprina Loweana, p. 88.

2d. „ „ var. elongata.

3, Cyprina Jurensis, p. 89.

4, Cyprina depressiuscula, p. 90.

5, 5a, b, c. Cyprina trapeziformis, p. 89.
6a. Tancredia axiniformis, p. 93.
Qb. Hinge of ditto.

la. Tancredia curtansata, p. 93.

lb. Hinge of ditto.

8. Tancredia brevis, p. 92.

9a, b. Tancredia angulata, p. 94.

100, Tancredia planata, p. 94.

10£, Hinge of ditto.

1J . Tancredia truncata, p. 92.

12. Pholadomya ovulum, p. 122.

13. Pholadomya acuticosta, p. 121.

14. Corbis (Corbicella) Bathonica, p. 95.

15. Myacites securiformis, p. 136.

16. Goniomya V-scripta, p. 139.

17. Pholas pulchralis, p. 140.

18. Pholas Oolitica, p. 140.

19. Cyprina dolabra, p. 135.
200, b. Pinna cancellata, p. 130.

Tab-

I

'

K>a

K,,i »'«.,» Inf.

TAB. XIV.

Fig.

1. la. Gervillia acuta, p. 20.

2. Ostrea Marshii, p. 126.

2a. Young of ditto (0. sulcifera), p. 127.

3. Hinnites abjectus, p. 125.

4. Pteroperna plana, p. 128.

5. Gryphsea mima, p. 127.

6. Avicula Munsteri, ? p. 129.

7. Pecten demissus, p. 127.

8. Mytilus (Modiolci) cuneata, p. 131.

9. Mytilus (ModiolafLeckenbyi, p. 131._

10. Unicardium depressum, p. 133.

11. Unicardium gibbosum, p. 132.

12. Cucullsea cancellata, p. 132.

13. Quenstedtia Isevigata, p. 135.

14. Astarte elegans, p. 86.

15. Astarte minima, p. 134.

16. Perna rugosa, p. 128.

P.U1V

>.V..,t Imp.

TAB. XV.

Fig.

1. Trigonia decorata, p. 133.

2a, b. Ceromya concentrica, p. 108.

3. Pholadomya Ssernanni, p. 123.

4. „ Heraulti, p. 124.

5. Isocardia cordata, p. 135.

6. 7. Avicula Braamburiensis, p. 129.
8a. Gresslya peregrina, p. 13j>fcf
8d. Portion of surface, magnified.
9«. Lima punctaturn, p. 130.

9b. Portion of surface.

lOa. Myacites decurtatus, p. 137.

105. Portion of surface.

11 a. Myacites Beanii, p. 136.

lib. Surface of ditto.

12. Cast of Quenstedtia oblita, p. 96; showing muscular im-

pressions, &c. (from Mr. J. G. Lowe's collection).

13. Myacites Scarburgensis, p. 138.

14. Pholadomya ovalis, p. 139.

P1.XV

INDEX

or

SPECIES RETAINED IN THE SECOND PART OF THIS WORK.

PAGE

ANATINA plicatella

. 118

AVICULJ

undulata . .

. ib.

ARCA aemula .

. 47

car. transversa

. ib.

Eu de-si i .

. 46

CARDIC

Kilverti .

. 45

Prattii .

. ib.

? car. rugosa

. 47

rudis

. 44

tenuitexta

. 45

(sub-genus) MACEODON Hirsonensis

. 47

CEROMI

(sub-genus) CCCULLEA concinna

. 50

cucullata

. 51

Goldfussii

. 50

ASTARTE angulata

. 86

depressa

. 85

COHBIS

elegans

. 86

excavata

. 85

excentrica . ' .

. 85

interlineata

. 87

minima

. 82

COKBUI

pumila

. 83

CYPRIC

recondita

. 88

rhomboidalis .

. 84

rotunda

. ib.

CYPHIN

squamula

. 82

Wiltoni

. 87

AVICULA costata

. 15

echinata

16

(sub-genus) PTEROPEKNA costatula

. 18

AVICULA, (sub-genus) PTEROPERNA emarginata

pygmeea .

concinnum
pes-bovis
semicostatum .
Stricklandi
subtrigonum
ITA concentrica
plicata
similis
Symondsii
undulata
aspera
Lajoyei
var. cingenda

(sub-genus) SPHJERA madridi
(sub-genus) CORBICELLA Bathonica
LA involuta
JAHDIA Bathonica
nuculiformis
rostrata

IA depressiuscula
jurensis
Loweana
nuciformis
subrotunda
trapeziformis .

PAGE
19
ib.

64
65
ib.
63
64
ib.
108
107
109
106
ib.
70
69
70
71
95
97
75
76
75
90
89
88
90
89
89

144

INDEX.

GERVILUA acuta

Bathonica .

crassicosta

monotis

ovata

radians

subcylindrica .
GONIOMYA litterata

hemicostata .
GRESSLYA carditeeformis
peregrin a

HINNITES tegulatus
velatus

INOCERAMUS? Fittoni
obliquus
ISOCARDIA tenera

LEDA lachryma
mucronata
LIMA belula .
cardiiformis
duplicata
gibbosa
impressa
Luciensis
ovalis .
pectiniformis
semicircularis
LIMOPSIS ooliticus
LITHODOMUS inclusus .
parasiticug

LUCINA Bellona, var. depressa
Bellona
crassa, var.
despecta
rotundata

MYACITES calceiformis
compressus
crassiusculus

PAGE

PACK

20

MYACITES dilatus

114

21

Terquemea

113

22

tumidus

117

ib.

Vezelayi

111

ib.

unioniformis .

115

20

MYOCONCHA actaeon

77

21

crassa

76

119

elongata

77

120

MYTILUS asper

39

104

furcatus

ib.

105

Sowerbyanus

36

sublsevis

41

tumidus

37

14

(sub genus) MODIOLA Binfieldi

42

ib.

compressus

40

imbricatus

41

Lonsdalei

40

24

pulcherrimus

38

ib.

solenoides

ib.

66

var. subrenifonnis

39

tenuistriatus

37

53

ib.

NE^RA Ibbetsoni

98

30

NUCDLA variabilis

51

27

Waltoni

52

26

28

29

OPIS Deshayesii

81

28

lunulatus

80

29

similis ....

81

26

OsTREA acuminatn

3

29

costata

3

54

gregarea

4

43

rugosa ....

2

ib.

Sowerbyi

4

67

subrugulosa

ib.

ib.

(sub-genus) EXOGYRA auriforrais

5

68

69

68

PACHYRISMA grande

79

PECTEN annulatus

12

arcuatus

11

117

cl nth rat us

13

116

hemicostatus

10

112

lens ....

11

INDEX.

145

PECTEN peregrinus
personatus
retiferus
vagans

PEENA rugosa
PHOLAS oolitica
PHOLADOMYA acuticosta
Heraiilti .
Srcmanni .
socialis
solitaria .
ovulum
PINNA ampla .
cuneata

PLACUNOPSIS Jurensis .

ornatus

radians

socialis

PLICATULA fistulosa

tuberculosa .

QUENSTEDTIA oblita

TANCEEDIA axiniformis .
angulata
curtansata .
brevis
planata
truncata
THEACIA curtansata

Studeri

TEICHITES nodosus
TEIGONIA costata, var. pullus
var. elongata
duplicata
flecta
Goldfussi
imbricata
impress^
Moretonis
Phillipsi
subglobosa .

UNICAEDIUM impressum
parvulum .
varicosum .

PAGE

YORKSHII

9

11

ASTAETE elegans

9

minima

8

AVICULA Braamburiensis

25

Munsteri

126

121

CUCULLJIA cancellata

124

obliqua

123

CYPRINA dolabra

122

124

GONIOMYA V-scripta

122

GEESSLYA peregriua

31

32

HINNITES abjectus

6

7

ISOCAEDIA cordata

ib.

ib.

LIMA punctata

15

ib.

MYACITES aquatus

Beanii

96

decurtatus

gibbosus

93

Scarburgensis

ni

securiformis .

94

MYTILUS cuneatus

92

Leckenbyi

94

ungulatus

92

110

OSTREA Marshii

ib.

35

GEYPHEA mima

58

60

PECTEN demissus

ib.

PEENA rugosa

ib.

PHOLADOMYA ovalis

56

PIIOLAS costellata

63

pulchralis

61

PTEEOPEBNA plans

57

62

QUENSTEDTIA levigata .

55

TKIGONIA decorats

73

74

UNICARDIUM depressum

73

gibbosum

PAGE
. 135
. 134
. 129
. ib.

. 132
. 132
. 135

. 140
. 139

131, 125
. 135
. 130

. 139

. 136

. 137

. 138

. 138

. 136

. 131

. ib.

. 132

. 126

. 127

. 127

. 128

. 141

. 142

. 141

. 128

. 135
. 133

. 133
132

19

INDEX OF SYNONYMS.

Amphidesma decurtatum
securiforme
Anomia Jurensis
Astarte orbicularis

pulla .

rotundata
Avicula ovata .

polyodon

Cardita lunulata
similis
var. costata
Cardium Beaumonti
incertum
leevigatum
Madrid!
tninutum
striatum
Corbis Madridi
Corbula curtansata
depressa
striata
Cucullsea elongata

Hirsonensis
minuta
rudis

sublaevigata
Cyrena uuculiformis
Cytherea dolabra

Donacites costatus

PAGE

. 127

Gervillia costatula

. 136

lanceolata

6

siliqua

. 84

Gresslya concentrica

. 82

erycina

. 68

rostrata

. 21

. 18

Hippopodiura Bajociense

LuciensU .

. 80

. 81

. 107

? Inoceramus amygdaloides

. 75

Isocardia rhomboidalis .

. 71

. 64

. 71

Leda? ncasta .

. 65

Lima alternicosta

. 64

proboscidea

. 71

Lucina cardioides

. 93

lirata, var. transversa

. 133

Lutraria decurtata

. 97

Lyrodon costatum

. 49

litteratum

. "ib.

. 48

. 44

Modiola aspera

. 50

parasitica

. 76

Sowcrbyana

. 135

Mytilus amplus

edulis

Jurensis

. 58

plicatus

PAGE
18

20
29

138
ib.

105

84
ib.

24

84

53
20
ib.
69
67
137
58
56

39
43
36
31
41
ib.
36

INDEX.

147

MytUus sulcatus

tumidus

Mya calceiformis

dilata

Vezelayi

margaritifera

litterata

Nucula axiniformis
caudata
lachryma
raucronata
subglobosa

Ostrea complanata

Knorrii

obscura

palmetta

pectiniformis
Ostracites pectiniformis

Panopcea dilatata
tenuistria
Terquemea
Pecten obscurus
sulcatus
velatus

Pectunculus minimus
oblongus
minimens

PAGE
76
132
113
114
111
113
119

93
53
ib.
ib.
51

85
3
5
4

26
ib.

114

115

ib.

12

8

14

54

ib.

ib.

Plagiostoma cardiiforme
duplicata .
ovalis

pectinoides .
punctata
semicircularis
Pholadomya Murchisoni
nana
pelagica
Perna quadrata
Pleuromya decurtata
Psammobia Isevigata
Pullastra recondita
oblita

Sanguinolaria dilata

undulata .
Spondylus velatue

Tancredia extensa
Trigonia conjungens

cuspidata

pullus

Unicardium corbisoideum

Venus Jurensis

trapeziformis
varicosa

PAGE

27

26

29

26

130

29

124

140

ib.

126

137

135

88

96

114

118

14

93
57
56

58

73

89
ib.
73

PRINTED BY J. K. ADLARD, BARTUOLOMKW CLOSB.

CORRIGENDA.

Part I, p. 27,/or "Purpuroidea Moreausia," read "P. Morrisii, Buv. ;" Purpura Moreausia, is considered

by M. Buvignier to be a distinct species,
p. 48, for "Eulima pygraeea," read "Eulima vagans (junior)."
p. 93, for "Patella nana," read " Patella cingulata (junior)."
Part II, p. 24, for " Inoceramus Fittoni, Tab. iv," read "Tab. iii."

p. 48, sixth line from the bottom, erase the four words within the parenthesis.

p. 49, second line, erase the last three words. The raised ledge which supports the anterior

muscular impression in Macrodon separates it from other sub-genera of Area ; in Cuculleea the

ledge is posterior.
p. 75. Both Cypricardie: Bathonica, d'Orb. and C. cordiformis,Desh., occur in the Inferior Oolite of

the Cotteswolds but in different beds, further observations have induced us to regard them as

only varieties of the same species induced by peculiarities of the beds in which they occur.

SUPPLEMENTARY MONOGRAPH

ON THE

MOLLUSCA

FROM THE

STONESFIELD SLATE, GREAT OOLITE, FOREST
MARBLE, AND CORNBRASH.

BY

JOHN LYCETT, M.D.

LONDON :

PRINTED FOR THE PAL^ONTOGRAPHICAL SOCIETY.
1863.

J. E. ADLARD, PRINTER, BARTHOLOMEW CLOSE.

INTRODUCTORY EXPLANATION.

THE introduction to the first part of the 'Monograph of the Great Oolite Mollusca'
contained an intimation that, with increasing knowledge of the testacea of the Cornbrash
and Forest Marble, it might eventually be desirable to give an additional monograph, or
an Appendix to that work. The materials which have latterly been placed at the disposal
of the writer are so considerable that he has been induced to endeavour to fulfil the
anticipatory announcement made in 1850, and also to correct some errors, both textual
and typographical, which occur in the former Monograph. In the execution of his task
the writer begs thankfully to acknowledge the assistance he has received in the loan of
specimens from gentlemen whose names will be found mentioned in connexion with each
of the species illustrated, nor can he omit gratefully to mention the great advantages he
has derived from the constant opportunities that have been afforded to him of comparing
the Oolitic fossils of the southern counties with those of Yorkshire, contained in the very
extensive and choice collection of Mr. Leckenby, of this place.

SCARBOROUGH; September 6, 1861.

SUPPLEMENT

A MONOGRAPH

OF THE

MOLLUSCA FROM THE GREAT OOLITE,

CEPHALOPODA.

AMMONITES BULLATUS, D'Orbiy. Tab. XXXI, fig. 1.

AMMONITES BULLATUS, D'Orb. Pal. Fr. Ter. Jurass., p. 412, pi. 142, figs. 1 and 2.

Kiidernatsch. Abband. K. K. Geol. Reich., 1 band., taf. iii,
figs. i_4_n.

TLATYSTOMUS, Querist.? Cephal., t. 15, fig. 3.
BULLATUS, Oppel. Juraform., p. 549.

Quenstedt. ? Der Jura., t. 64, fig. 13, p. 4/9.

Testa bullatd, irreyulari ; anfractibiis subinvolutis, latis, ultimo angustato, transvcrsim
late costafo ; costis incequalibus ; apertitrd constrictu, semilunari. (D'Orbigny.)

Shell inflated, globose, variable in form throughout all the stages of its growth, orna-
mented with large, transverse, slightly elevated ribs, which pass from the umbilicus over
the back to the other side, not straight, but curved forwards ; these are separated by other
shorter ribs, which alternate with the larger series of ribs in the adult state, but iti the
young state there are two and sometimes three short ribs between each of the longer
ones. The volutions of the spire are irregular and embracing, forming a contracted um-
bilicus in the young state ; subsequently the volutions are less contracted, which renders
the shell unsymmetrical or deformed. The back is rounded, the mouth much contracted
and prolonged in the middle part. The septa are very much complicated.

In England this Ammonite is very rare. The aged example figured is seven inches in

4 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

diameter, the aperture having a height and breadth of two inches ; its more advanced
growth will account for the difference of figure when compared with those of D'Orbigny,
Quenstedt, and of Kudernatsch ; but in truth, the variability of figure extends not less
to individuals than to the stages of growth, for in no instance does there appear to be a
very near agreement of figure.

Geological Position and Localities. The sole specimen in my collection is from the
Great Oolite, near Tiltups Inn, two miles south of Nailsworth ; another specimen,
apparently from the same locality, is in the collection of my friend, Dr. Wright, of Chelten-
ham. The foreign localities are St. Maixent, Deux-Sevres ; Masigny, Vendee; Nantua,
Ain ; Vezelay, Yonne ; Wohnkammer, Swinitza.

AMMONITES DISCUS, Sow. Tab. XLI, fig. 8, 8 a.

NAUTILUS DISCUS, Sou-. Min. Con., 1813, i, tab. 12.

AMMONITES DISCUS, Sow. Ibid., 1815, Suppl. Ind. to rol. i, p. fl.

— Morris. Catal., 1854, p. 291.

— Oppel. Juraformation, p. 472.

Testa discoidea, angusto umbilicato, dorse ant/usto acute carinatis, latcri/nis exfcrne,
valde comprcssis, Icevigatis ; apertura sayittcpformi. j'Etate juniori lateribus costis dis-
tantibus flexuosis.

Shell discoidal, with a narrow and deep umbilical cavity, the back acutely keeled; the
sides of the volutions near to the back are much flattened and smooth ; the aperture is
sagittate, the margin of the umbilicus is rounded. In the young state, when the diameter
does not exceed three inches, the sides are ornamented with regular distant, depressed,
flexuose costa3.

The lobes are comparatively simple, with few ramifications, and have but little depth ;
the saddles are in a corresponding manner but little produced ; they therefore differ
altogether from the septa of A. discus, D'Orbigny, and from the A. sub-discus, of the same
author; they are, however, more complicated than is seen in A. discu*, Quenst.
(' CEPHALOPODEN,' tab. viii, fig. 13); A. Stau/ensis, Oppell, from the inferior Oolite of
Boll, Balinger, &c. They also differ from the description given by Roemer ('Nord.
Ool.,' p. 190) of an Ammonite attributed by him to A. discus, Sow., from the lower Coral
Rag of Heersum.

The general figure is less discoidal than A. Waterliousei, Mor. and Lye. (A. discus,
D'Orb.) ; it differs also from that species by the absence of the flattening upon the inner
portion of the sides of the volutions. From A. sub-discus, D'Orb., the general figure
differs in the more acute back and in the smaller umbilicus.

The specimen figured in the ' Mineral Conchology,' is an adult shell, and smooth ; the fine
specimen selected for our illustration exhibits the septa, and also some traces of the
falciform costse proper to the young shell. I am obliged to Mr. Woodward, of the British

GASTEROPODA. 5

Museum, for information respecting it, and also for a careful drawing which exhibits its
palseontological features ; the specimen was obtained in the Bradford Clay of the Tetbury
Road Railway Station, near Cirencester, by Professor Coleman, of the Royal Agricultural
College.

Geological Positions and Localities. It has occurred at several localities in the Corn-
brash, as at Wollaston, Chippenham, Trowbridge, and in Bedfordshire, but it is every-
where rare ; to these positions must be added the single specimen above alluded to from
the Bradford Clay, and another, in the British Museum, from the slate of Stonesfield.

GASTEROPODA.

BRACHYTREHA VARICOSA, Lye. Tab. XLIV, fig. 27.

Testa parva ovata, gibbosa, spira anfractibus 5 subplanis, costis transversalibus ct longi-
tudinalibus inaqualilus cruciatis ; yranulalis, granulis magnis, depressis, ultimo anfractu
varicibus irreyularibus duobus ; apcrtura sinuosa, coliirnella arcuata, canali brcviusculo.

Shell small, ovate, gibbose; spire elevated, obtuse, consisting of five, flattened volutions,
with well-marked sutural depressions ; encircling costse five, of which the first and last
are large, forming elevated bands, the three intermediate costse being smaller, irregular,
and unequal ; they are decussated by very irregular, granulated, straight costae, which
occasionally form large varices, of which the last volution has two ; these -impart a distorted
aspect to the lower part of the shell ; the aperture is rather narrow and sinuated, the
columella much curved, the canal short, the notch narrow and deep; the outer lip is
thickened, but imperfect.

A short, ovate shell, with strongly marked and very irregular ornamentation ; the
varices are prominent only upon the two latter volutions ; the straight 'costse are very
irregular, sometimes crowded, but occasionally very distantly arranged ; the basal canal is
unusually short, and curved forwards ; the lips are without denticulations.

Geological Position and Locality. The Great Oolite of Minchinhampton Common ; very
rare, two specimens.

*

BRACHYTREMA BUCCINOIDEA, Lye. Tab. XLIV, fig. 17.

Testa turrictilata, ovali vcntricosa, anfractibus 5 — 4 convexis, suturis valdc imprcssis,
lonr/itiidinalitcr costatis, costis 14 — 16 rectis, transversimjinissitne lineatis, anfractu ultimo
magno, rotunda, basi attenuate, canali brevi, obliquo ; apcrtura superne ct infernc constricto.

Shell turreted, ovately ventricose, volutions 5 — 4, convex, the sutures deeply impressed,
longitudinally costated ; the costee, from 14 to 16 in a volution, are perpendicular, and not
very strongly defined ; they are decussated by fine, encircling lines ; the last volution is

6 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

large, rounded, attenuated at the base ; the canal is short and oblique ; the aperture is
much contracted at the two extremities.

Geological Position and Locality. The Great Oolite of Minchinhampton, collected by
E. Witchell, Esq., of Stroud.

PURPUROIDEA INSIGNIS, Li/c. Tab. XXXI, fig. 2, 2 «.

PURPUEOIDEA INSIGNIS, Lye. Cotteswold Hills Handbook, &c., pi. 7, fig. 8, a, b.

Testa turbinata, ovata, injlata, spira cxserta, anfractibus 5 subangulatis, tuber cults
depressis (9 in anibitit), anfractii ultimo magno inflato, plerumqiie sine tuberculis ; ajwturd
magnd ovata, canali leviter excavato

Shell turbinated, ovate, inflated ; spire half the length of the aperture ; volutions (5)
slightly angulated and flattened upon their upper surfaces, with nine small, depressed
tubercles upon each volution ; the last volution large, ventricose, rounded, the latter half
of the circumference being destitute of tubercles, and having only oblique folds of growth ;
aperture ovate, columella with an umbilical groove; the basal notch is only slightly
defined, the junction of the columellar and outer lips forming a gentle curvature. The
shorter, angular spire, depressed tubercles, and ventricose figure of the last volution, serve
to distinguish it from P. nodttlata, the species to which it is most nearly allied. The
expanded base, wide, shallow, or obsolete notch, and rounded columella, so constant in all
the species of Purpuroidea, appear to me to justify a generic separation from the recent
Purpura, to which they have been reunited by some French paleontologists of eminence.
The genus Purpurina of D'Orbigny, exemplified by his type P. Scllona, is separated
from Purpuroidea both by the figure of the aperture and by his description, in which the
contracted basal canal is insisted upon ; other so-called examples of Purpurina, in the
' Paleontologie Frangaise,' as Ornata, Bianor, Bixa, and Batltis, have, together with a
thin shell, a lengthened, subulate figure and an entire aperture ; these should be placed with
the Littorinida?, and should range by the side of Amberleya, figured and described in the
first part of this monograph. I am inclined to claim for Amberleya a more important
position than that of a sub-genus.

The Great Oolite species of Purpuroidea have, however, been merged by Professor
Morris (' Catalogue') and by Dr. Oppel (' Juraformation') with Purpurina.

Geological Position and Locality. The Great Oolite of Minchinhampton Common,
associated with other species of the same genus.

CERITHIUM BATHONICUM, Lye. Tab. XLIV, fig. 19.

Testa parva subconica, apice obtuso, anfractibus lutis, paucis, plants ; costis (7) rectis
magnis, oblusis, striisque cingcndis ; apertura parva, cauda brevi.

Shell small, somewhat conical ; apex obtuse ; volutions wide, few, flattened ; costae (7)

GASTEROPODA. 7

straight, large, obtuse, encircled with regular striations ; sutures of the volutions distinctly
marked.

The costse form straight, rounded elevations, which pass the whole length of the spire,
and are only slightly interrupted by the sutures, the height of each volution being equal
to about two thirds of its opposite measurement. It appears to be rare.

Length three lines, breadth half the length.

Geological Position and Locality. The upper beds of the Great Oolite near Bath,
associated with numerous other minute testacea, collected by Charles Moore, Esq.

CERITIIIUM BULIMOIDES, Desl. Tab. XLIV, fig. 3.

CEKITHIUM BULIMOIDES, Deslongchamps. Mem. Soc. Linn, de Normand., 1848,

vol. viii, pi. 11, fig. 40.
D'Orb. Prodr., i, p. 303.

Testa minima, elongaio-turrita, acuta, anfractibus rotundatis, tramvcrsim striatis, longi-
tuditialiter costatin, costis rectis, basi obliqua, transverse striata, apertura subrotunda,
colmnella marginata, canali nullo. (Deslongchamps.)

Shell minute, elongated, turreted, acute ; volutions (8) slightly convex, wide, trans-
versely striated and longitudinally costated ; costse about 8 in a volution, perpendicular
and obtuse ; the sutures are deeply impressed, the aperture is oblique and rounded ;
there is no basal canal.

The costae, which are large and elevated, are slightly knotted where they are crossed
by three encircling lines in each volution ; our specimen is imperfect at the base.

Geological Position and Localities. The Great Oolite of Minchinhampton, collected
by E. Witchell, Esq. France, Luc.

CERITIIIUM MULTIFORJIK, Piette. Tab. XLIV, fig. 20.

CEHITHIUM MULTIFOMME, Piette. Bull. Soc. Geol. Fr., 2 ser., t. 14, pi. 5, p. 553.

Testa parva clongato conica, anfractibus (9 — 10) angustis, convexis, siduris valde im-
prcssis, costis subobliquis (10 ad 12 in ambitu), magnis, lincis cingcndis (5) enqKalibu-'i ;
anfractu ultimo ad basin lincato, canda brevi.

Shell small, elongated, conical; volutions (9—10) narrow, convex, the sutures deeply
impressed; costa; large, from 10 to 12 in a volution, longitudinal, but slightly oblique,
and knotted by five rows of regular encircling lines, the last volution has encircling lines
at the base ; the canal is short.

The tumid, narrow volutions, large costae, and deep sutures, afford strong distinctive cha-
racters, the height of each volution being only slightly greater than a third of its opposite
measurement. The specimens figured by M. Piette vary much in the elevation of the spire,
and consequently in the breadth of the volutions ; the number of costse likewise differ.

8 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Geological Position and Locality. The Great Oolite of Kirklington, Oxon, collected
by J. F. Whiteaves, Esq. Eparcy, France.

GERITHIUM ? STRANGULATUM, Arcldac. Tab. XLIV, fig. 2.

A shorter and less cylindrical variety of this species was figured in the first part of the
' Great Oolite* Monograph, plate ix, fig. 18. The present specimen, which agrees more
nearly with the example figured by D'Archiac, has seven longitudinal costae, which are
conspicuous even to the base ; the contracted, pupaeform aperture, with its prominent lips, is
alike in both varieties.

CeritJtium stranyulatum, C. Bulimoides, C. spicitlum, and C. cxiyua, belong to a small
group of minute, subcylindrical shells, with prominent, longitudinal costse, and small,
thickened, orbicular apertures, which have been referred to Cerithium and to Rissoa ;
perhaps eventually it may be deemed proper to separate them under a new generic
appellation.

Geological Position and Locality. The Great Oolite of Minchinhampton Common ;
rare.

CKRITHIUM UNDULATUM (var.), Dcsl., sp. Tab. XLIV, fig. 6.

MKLAXIA UNDULATA, Deslongchamps. Mem. Soc. Linn, de Normaucl., 18-12, vol. viii,
pi. 11, fig. 58, var. a.

Testa turrita ; anfractibus planis, transversim striatis, ad suturas crenidatis, longitudi-
naliter costatis, in ultimo an/radii costis subincurvis, basi obliqua, striata ; apertura
elliptica, obliqua, columella maryinata ; labro sinistro fissuram umbilicatem obtit/cnte.

Var. a, testa breviori, costis et striis crassioribtts, rariorisque. (Deslongchamps.)

Shell minute, turreted ; volutions flattened, transversely striated, crenulated near to
the sutures, and longitudinally costated ; aperture elliptical, oblique.

Our example constitutes a small and short variety, with narrow volutions (about 8) ; the
costa? are large, straight, and from 7 to 8 in a volution ; they are most conspicuous near
to their upper extremities, which project, forming a kind of coronary border immediately
beneath the suture. Another minute specimen, apparently belonging to the same variety,
has the first three volutions almost plain, and the costa? upon the succeeding volutions are
but little prominent.

The typical form of the species figured by M. Deslongchamps has the costa3 much
more numerous and less prominent.

Geological Position and Locality. The Great Oolite of Minchinhampton, collected by
E. AVitchell, Esq.

GASTEROPODA.

RISSOA? EXIGUA, Lyc. Tab. XLIV, fig. 11.

Testa parva, ovato-conica, spira anfractibus (6) plano-convexis, angustis, suturis valde
impressis, costis longitudinalibus rectis, angustis, 8 — 9 in ambitu ; apertura, parva, sub-
orbiculari, labro externo simplici.

Shell small, ovately conical; spire consisting of six flattened or slightly convex, narrow-
volutions, the sutures being strongly marked ; longitudinal costae elevated, narrow, per-
pendicular, 8 to 9 in a volution ; aperture small, suborbicular, outer lip simple.

A minute lenticular shell, with about eight and a half costal spaces to a volution, the
height of each volution being equal to the half of its transverse diameter ; the apex is
slightly obtuse, and the last volution is somewhat contracted.

Geological Position and Locality. The Great Oolite of Bussage, collected by Mr.
Witchell.

CERITHIUM? SPICDLDM, Lyc. Tab. XLIV, fig. 1.

Testa ovato-elongata, minuta, anfractibus (6) latis subplanis, transversim striatis etlon-
gitudinaliter costatis ; costis rectis (Qin ambitu}, anfractu ultimo cylindrico, apertura parva,
ovata, canali nullo.

Shell minute, ovately elongated subcylindrical ; volutions (6) wide, rather flattened,
transversely striated, and longitudinally costated ; costae straight, six in a volution j the last
volution is nearly cylindrical ; the aperture is small, ovate ; there is no canal.

The costae, which have little prominence, appear to stretch continuously ; the length of
the shell only slightly interrupted by the sutures, which are not strongly marked ; the aper-
ture is pupaeform ; the general figure approximates to C. strangulatum, but more lengthened,
and with higher volutions.
, Geological Position and Locality. The Great Oolite of Minchinhampton.

CERITHIUM ? COMPOSITUM, Lyc. Tab. XLIV, fig. 9.

Testa parva, elongato-conica, anfractibus (6) angustis subplanis, transverse striatis et
costatis ; scilicet anfractu ultimo et penultimo costis crebris longitudinalibus rectis, circa
18 in ambitu; apertura parva, obliqua, ovata, depressa.

Shell minute, conical, elongated ; volutions (6) narrow, flattened, transversely striated,
and longitudinally costated ; but the costae are limited to the two or three latter volutions,
they are closely arranged, little elevated, and about eighteen in a volution ; the aperture is
depressed, oblique, and ovate.

2

10 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Geological Position and Locality, The Great Oolite of Minchinhampton, collected by
Mr. Witchell.

CERITHIUM? WITCHELLI, Lye. Tab. XLIV, fig. 7.

Testa minuta subcylindrica, elongata, anfractibus (5 — 6) subconvexis altis, suturis valde
impressis, costis (circa 15) depresses subrectis, auperne distinctis, in/erne evanescentibus
apcrtura ovata, labro externo simplici.

Shell minute, subcylindrical, lengthened ; volutions (5 — 6) high, rather convex, the
sutures depressed and strongly defined ; costae (about 15 to a volution) depressed, distinct
at the upper and vanishing towards the lower part of each volution ; the aperture is of
moderate size, ovate, the lips rather thickened.

The breadth of each volution is about one third more than its height ; the costse are
only faintly marked ; there are no traces of encircling striations or tubercles.

Geological Position and Locality. The Great Oolite of Minchinhampton, communi-
cated by E. Witchell, Esq.

CERITHIUM ? PCLCHRUM, Lye. Tab. XLIV, fig. 4.

Testa parva, crassa, turrito-subulata, anfractibus (8) convexis, suturis valde impressis,
costis transversis, obliquis, magnis (circa 12 in ambitu), lineis longitudinalibus decussatis,
apertura parva ovata, canali nullo.

Shell small, thick, elongately turreted ; volutions 8, convex, the sutures deeply im-
pressed ; transverse costae about 12 to each volution, oblique, large, decussated, and
rendered nodulous by six narrow encircling lines ; aperture ovate, rather contracted ; no
canal.

Allied to Cerilhium costellatum, Desh., from which it differs in having fewer volutions,
and in possessing encircling lines. C. bulimoides, Desh., with a similar general figure, has
the costae smaller, fewer, and perpendicular.

Geological Position and Locality. The Great Oolite of Minchinhampton Common,
collected by Mr. Witchell.

NERIN^A GRANULATA, Phil., sp. Tab. XXXI, figs. 12, 12 a.

TEREBRA GRANCLATA, Phil. Geol. York., i, pi. 7, fig. 16, p. 173.
CERITHIUM GRANULATUM, Mor. Cat. Brit. FOBS., 1854, p. 240.

Testa subulato-turrita, anfractibus numerosis angmtalis, planis, sed inferne subconcavis,

GASTEROPODA. 11

lineis subnodulosis irregularibus, inaqualibm (9-10) cingendis ; apertura obliqua, columella
uno plicato.

Shell elongated, turreted ; volutions numerous (about twenty), narrow, flattened, but
slightly contracted towards the base of each volution, and encircled with numerous (nine
or ten) irregular, unequal, slightly nodulous lines ; the aperture is small, subquadrate, and
oblique, the columellar lip has a single strong plication.

The volutions are narrow, so that their height is little more than the half of their
opposite diameters ; the upper border of each is rendered prominent by the slight contrac-
tion towards the base of each volution ; the single strong fold upon the pillar lip, and a
trace of another mesial fold upon the outer lip, is all that can be ascertained from the
single specimen at our disposal, which is also the type figured by Professor Phillips.
Sixteen volutions are preserved, but probably four more would be required to render the
spire perfect. Nerinaafasciata, Voltz, approaches this species nearly, both in the general
figure and in the ornamentation; judging, however, from specimens obtained in the Coral Rag
of Yorkshire, the latter has the encircling lines more regularly disposed, and more constantly
and regularly nodulous ; the spiral angle also appears to be somewhat greater : it is there-
fore preferable to regard them as distinct species. The length of the imperfect specimen
above referred to is an inch and a half, to which should be added two lines to perfect the
spire ; the transverse diameter of the last volution is three lines.

Geological Position and Locality. The sole example in the Scarborough Museum was
obtained in the Cornbrash of that locality.

CERITELLA MINUTISSIMA, Lye. Tab. XLV, fig. 5.

Testa minufa, elongata, spira anfradibus (4) elcvatis, subplanis ; aperura ovato-dongalu ;
columella contorta.

Shell minute, elongated ; spire with the volutions elevated, smooth, and flattened ; the
last volution is large, moderately convex, attenuated towards the base ; the aperture is of
moderate dimensions, ovately elongated ; the columella is contorted at the base, as is usual
in the genus.

The length of the aperture slightly exceeds one third that of the entire shell. It is
allied to some of the varieties of Ceritella parvula (Actseonina), but is more subulate ; it
also approaches to Tubifer Gerandoseits, Piette, but is less attenuated than the latter
shell.

Geological Position and Locality. Obtained, both by Mr. Witchell and myself, in the
Great Oolite of Mirichinhampton.

12 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

CERITELLA LYCETTEA, Buv., sp., Lye. and Mor., sp.

CERITELLA RISSOIUES, Mor. and Lye. Gr. Ool. Monog., i, tab. 9, p. 7, 1850, non
Pleurotoma rissoides, Buv. M^ra. Soc. Verd., t. ii, pi. 6,
fig. 9.

ORTHOSTOMA LYCETTEA, Buv. Paleont. de la Mense Atlas, p. 32, 1852.

TUBIFEK PIICATUS, Piette. Bull, de la Soc. Geol. de France, 2 se'r., t. xiii, pi. 13,
p. 587, figs. 7—8, 1857.

I avail myself of the opportunity of giving another figure of this pretty species of
Ceritella, as the magnified figure in Plate IX does not sufficiently exhibit the neatness and
angularity of the volutions of the spire. M. E. Piette, in a memoir entitled "Descrip-
tion des Ceritheum enfouis dans les depots bathoniens de 1'Aisne et des Ardennes," pub-
lished in the work above quoted, rejects the claim of Ceritella to be regarded as a new genus ;
but figures the present and also another Minchinhampton species of Ceritella as examples of
his proposed neio genus Tubifer, under the names of Tubifer plicatus and Tubifer Acteonifor-
mis. It is a satisfaction to discover this singular and unwitting testimony to the correctness of
our appreciation of this generic form.

In the Atlas to the ' Palaeontology of the Mense,' page 32, M. Buvignier shows that we
were mistaken in supposing that our little Ceritella is the Pleurotoma rissoides of that author's
memoir above quoted, and which he subsequently assigned to his proposed new genus
Orthostoma; in this instance, also, our genus Ceritella has the priority.

CERITELLA MORRISEA, Buv., sp. PI. XLIV, fig. 22.

CERITELLA LONGISCATA. Gr. Ool. Monog., i, tab. 9, fig. 14, p. 40, non Pleurotoma

longiscata, Buvig., Mem. Soc. Phil. Verdun, pi. 6, fig. 8.
OHTHOSTOMA MOREISEA, Buvig. Paleont. de la Mense Atlas, p. 32.

In this, as in the last species, the indifferent figures in the earlier memoir of M.
Buvignier led to the error of assigning our Great Oolite shell to his Pleurotoma longiscata ;
the specific name proposed by that gentleman in his ' Palaeontology of the Me use ' is here
adopted.

CERITELLA FUSIFORMIS, Lye. Tab. XLV, fig. 4.

Testa parva elongata, fusiformi, lave ; anfractibus 5, lads, subplanis, anfractu
ultimo magno, subcylindrico, apertura elongata, angusta, antice et posticc valde contracto.

Shell small, elongated, fusiform, smooth ; spire moderately elevated ; volutions 5, wide
and nearly flat, the last volution large and cylindrical ; the aperture is elongated, narrow,
and much contracted at both its extremities, its length slightly exceeding that of the
spire.

GASTEROPODA. 13

More fusiform than other known English examples of the genus.
Geological Position and Locality. The Great Oolite of Minchinhampton, collected by
Mr. Witchell.

NATICA HULLIANA, Lye, Tab. XLI, fig. 2.

Testa ovata, subglobosa lavi ; anfractibus 6 valde converts, suturis prof uncle impressix,
spira elevato, acuto ; apertura oblique ovali, antice rotundata postice angulata ; columella
callosa, umbilico nullo.

Shell ovate, subglobose, smooth ; volutions (6) very convex, the sutures deeply impressed;
the spire is elevated, acute, the last volution being very large ; the aperture is ovate,
oblique, the anterior side rounded, the posterior side acute, the length exceeding a moiety of
that of the entire shell ; the columella is rounded, thickened, and there is no umbilicus.

Allied to N. intermedia, Tab. VI, fig. 1, but with a more elevated acute spire, more
deeply depressed sutures, and a more globose ultimate volution ; specimens vary somewhat
in the figure of the last volution, but the acute, elevated, deeply sutured spire will always
serve to distinguish it.

Geological Positions and Localities. I have obtained it in the Great Oolite of
Mincbinhampton, and in the Inferior Oolite of the same locality ; Mr. Whiteaves has also
kindly forwarded to me a specimen from the Great Oolite of Kirklington, Oxon; the latter,
which is a young form, has the last volution slightly more globose than in the other
examples.

EULIMA? L^EVIGATA, Lye. Tab. XXXI, fig. 3.

Testa parva Icevigata, subulata, acula, atifraclibus (circa 10) planatis, aiiguslis, ilttttng
inipressis ; apertura suborbicidari odliquo, umbilico nullo.

Shell small, smooth, elongated, apex acute ; volutions (about ten) narrow, their sides
flattened, the sutures distinct but not constricted ; the aperture is obliquely orbicular ; there
is no umbilicus.

The height of each volution slightly exceeds the half of the opposite diameter ; length,
nine lines ; diameter of the last volution, three lines.

Compared with Eidima ? communis, the spire is more acute, the volutions more flattened,
and the sutures are less deeply impressed.

Geological Position and Locality. It occurs rarely in the Cornbrash of Scarborough ;
the example figured is from the collection of J. Leckenby, Esq.

14 SUPPLEMENT TO GREAT OOLITE MOLLUSC A.

CHEMNITZIA VITTATA, Phil., sp. Tab. XXXI, fig. 10.

MELANIA VITTATA, Phil. Geol. York., p. 116, pi. 7, fig. 15;
CHEMNITZIA VITTATA, D'Orb. Prodr., xi, et No. 29, p. 208.

Mor. Cat., 2nd edit., p. 242.
— Oppel. Juraformation, p. 479.

Testa crassa, turrila, elongata, apice acuto, anfractibus (circa 10) latis, in media sul-
depressis, ad suturas elatis, carinis duobus instructis, suturis vaMe depressis ; aperfura,
ovafa basi ant/ustata.

Shell thick, smooth, turreted, elongated, apex acute; volutions (about 10) wide, rather
depressed in their middle parts, elevated both above and beneath near to the sutures,
forming two narrow, equal, cord-like carinse ; the sutures are deeply impressed ; the aper-
ture is ovate, rather small and contracted towards the base, where the extremity of the
columella is conspicuous ; the last volution is rendered somewhat angulated by the promi-
nence of both the encircling carinaa ; the surface is shining, with large plications of growth ;
a magnifier also discloses delicate, nearly regular, distantly arranged, encircling, granu
lated lines (about 20 to a volution), or when the surface has been slightly abraded, they
appear as punctated striations.

Length, 4| inches; transverse diameter of the last volution, 1 inch ; the height of each
volution is equal to 3-5ths of its transverse diameter.

The general figure is that of a lengthened cone, and the outline does not exhibit that
step-like figure seen in some other allied species, as in Chemnitzia turris (Desl.), C. coarc-
taia (Desl.), and C. condensata (Desl.). The two narrow and equally elevated cord-like
cinctures which bound each volution, together with the somewhat angular figure of the last
volution, separates it from the foregoing and all other known examples of the genus ;
perhaps the encircling granulated lines may also constitute a good distinctive character
but it can only be discovered in very well preserved specimens. A Chemnitzia, in the
Inferior Oolite of the Cotteswolds and of the south-western counties, which does not
appear to have been figured or described, approaches near to C. vittata, and has sometimes
been regarded as identical with it ; there can, however, be no difficulty in separating
specimens of the two forms, when they are well preserved. The Inferior Oolite shell is
somewhat less conical, or more subulate ; the sides of the volutions are more flattened ; the
upper cincture is rounded and distinct, but comparatively small ; the lower cincture is
angulated, and not cord-like; the last volution is destitute of the prominent lower cincture,
which imparts an angularity to that part in the Cornbrash shell ; the general figure of that
volution is more lengthened and pyriform, so that the base of the aperture is wider and
more produced. The Inferior Oolite shell also does not exhibit any trace of the encircling
granulated lines ; but possibly the test has not been preserved with sufficient delicacy to

GASTEROPODA. 15

exhibit this feature, even if it originally existed ; the plications of growth are also very
large, so that in the latter volutions they render the carinae distinctly nodulous ; in
C. vitfafa the carinse are but slightly modified by this cause.

D'Orbigny, ' Prodrome,' has suggested that Nerincea suprajurensis, D'Archiac, may
be C. vittata ; but, judging from the figure of D'Archiac, N. suprajurensis is more slender,
with the volutions much more numerous and more narrow, the sutures are also desti-
tute of that deeply indented figure which is so conspicuous in our Cornbrash shell.
The general resemblance which C. vittata bears to some examples of the genus Nerinaea
has led me to make a longitudinal section of it, and thus to ascertain with certainty that
it cannot be assigned to that genus.

Geological Position and Locality. The Cornbrash of Scarborough and Gristhorp ; it is
not rare, but is very difficult to disengage from the hard limestone.

KILVERTIA, Gen. Nov.

The views expressed on Cerithium strangulatum, p. 8, suggesting the propriety of
erecting a new genus for the reception of that and other allied forms, have subsequently
been strengthened by the examination of well-preserved specimens from the Forest
Marble of Somerset and Wilts, in the collection of W. Walton, Esq., of Bath. I have
now, therefore, no hesitation in proposing for these the new generic appellation Kilvertia,
which will be found described in the Addenda.

KILVERTIA CONSTRICTA, Lye. Tab. XLIV, fig. 8.

Testa parva turrita, elongata, anfractibus (8) superne planalis, infernc ventricosis, suturi*
dene distinctis, lineis transversalibus et longitudinalibus, delicatissimis, cancellatis ; apertiu-u
suborbiculari deprcssa, incrassato.

The height of each volution is about equal to half its opposite measurement, the first
encircling line beneath the suture is rather more prominent than the others; altogether
there are six ; their size and distances correspond nearly with the lines by which they art'
decussated ; the aperture is imperfect at the outer lip, there is no umbilical chink.

Geological Position and Locality. A minute univalve, obtained by crushing shelly
portions of the Great Oolite of Minchinhampton Common ; Mr. Witchell has also kindly
forwarded a specimen obtained by him at the same locality, and in the same manner.

16 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Genus — FIBULA, Piette, 1857.

Description des Cerithmm enfonis dans les depots bathoniens de 1'Aine et des Ardennes, par M. Ed.
Piette, 'Bull, de la Soc. Ge'ol. de France," 20 Avril, 1857.

M. Piette has founded his proposed genus upon a small group of lengthened spiral
univalves which possess characters intermediate and approximating them to Turritella and
to Cerithium. A rounded, straight columella, with a rudimentary umbilical groove near
the base, is combined with an arcuated outer lip slightly notched posteriorly at the suture ;
the base of the aperture forms a slight canal at its junction with the anterior extremity of
the columella, or in other instances there is no canal, the base being rounded and entire,
depending upon the exact period of growth at which the animal perished ; the surface of
the volutions is plain, or slightly ornamented with oblique costae. The author has figured
and described several species, and has characterised his genus in the following terms : — " Le
principal charactere du ce genre est d'avoir une columella droite. Le bord libre est arque,
legerement echancre a sa partie posterieure, pres de la suture. L'ombilic n'est souvent
que rudimentaire, a peine indique, et affectant seulement la columelle externe. D'autres-
fois, il penetre tout le spire. Un caractere tres curieux que j'ai remarque sur plusieurs
especes de ce genre, mais que je n'ai pu encore constater sur toutes, c'est que la columelle
se termine parfois interieurement par un canal rudimentaire ; que le mollusque forme ce
canal et le rebouche tour a tour, pour le former ensuite de nouveau en grandissant.
. . . . Ainsi il arrive souvent que parmi plusieurs Fibula d'une meme espece, les
unes semblent se rapprocher des Cerithium, les autres des Turritettes. Cela depend du
moment ou elles ont peri."

In admitting the generic value of Fibula, it becomes necessary to arrange with it the
following Jurassic Testacea : — Chemnitzia phasianoides (Mor. and Lye.). Cerithium Eoissii
(Mor. and Lye.), Turritella Roissii (D'Arch.), and Cerithium mturale (Buvignier). The
Great Oolite of Oxfordshire and of Minchinhampton has supplied the two following
additional species.

FIBULA VARIATA, Lye. Tab. XXXI, figs. 4, 4 a.

Testa turriculata, subventricosa ; spira elonyata, acuta, leeve, anfractibus (11 — 12) con-
vexiusculis, angustis, suturis valde impressis ; ultimo anfractu symmetrico-curvato ; columella
interdum ad basin subcanaliculato, aut integro, labro sinistro arcuato.

Shell turriculated, somewhat inflated ; spire lengthened, acute, smooth, consisting of
11 or 12 narrow, somewhat convex volutions, with deeply impressed sutures; the last
volution is conformable with the others, and is symmetrically curved towards its anterior

GASTEROPODA. 17

extremity ; the aperture is oblique, contracted at the base, sometimes slightly channelled,
in other instances entire and rounded ; the outer lip is much curved and thin. Young
specimens are less subulate, but the apex is delicately pointed, the volutions are more flat-
tened and narrow, the sutures being less strongly marked ; the latter two or three volu-
tions in adult specimens are more inflated, and they acquire at the base a rudimentary
umbilical groove.

It is nearly allied to Fibula nudiformis, Piette ('Bull, de la Soc. Geol. Fr.,' 1857,
pi. C, figs. 4, 5), from the Great Oolite of Rumigny, Eparcy, Poix, But, &c. ; but, judging
from the figures of M. Piette, his species has a shorter spire, with less strongly impressed
sutures, and the last two volutions are more lengthened and cylindrical. Fibula =
Clii'mnitzia phasianoides, which has the spine similarly subulate, has the volutions more
flattened, and the sutures much less impressed ; other recognised species are more
lengthened, with flattened volutions.

Geological Position and Localities. Fibula variata has occurred rarely in the Great
Oolite of Minchinhampton, and more commonly in the same formation at Kirklington,
Oxon., from which place Mr. Whiteaves has kindly forwarded specimens. Examples are
deposited in the British Museum, the Woodwardian Museum, Cambridge, in the collection
of Mr. Whiteaves, of Oxford, and in that of the author at Scarborough.

FIBULA EDLIMOIDES, Whiteaves, sp. Tab. XXXI, fig. 5.
CUEMXITZIA EULIMOIDES, Whiteaves. MSS., 1859.

Testa turriculata, elongata, spira apice acuto, anfractibus (circa 12) angmtis, convexis
superne vitta cingcnda, suturis valde constrictis, ultimo anfractu rolundo ; aperturd obliqud,
basi angusto subsinuato, columella itmbilico rudimento ; labro externo arcuato ; anfractibus
costis obliquis obscuris irregularibm.

Shell turreted, elongated, acute ; spire with about 12 volutions, narrow, convex towards
their lower parts, and encircled with a narrow band at their upper borders ; the sutures
are deeply impressed ; the last volution moderately large and rounded ; the aperture is
lengthened, oblique, narrow, and sinuated at the base ; there is also a rudimentary um-
bilical groove ; the outer lip is much arched ; the surface has irregular, oblique, obscure
costse, which resemble lines of growth in the latter volutions.

Compared with Fibula variata, this species is more subulate, with a shorter last volu-
tion ; the encircling band upon the upper border of each volution, the oblique costae, and
the convexity of the lower part of each volution, are also distinguishing features. Fibula
undulosa, Piette, is more nearly allied to it, but the volutions are less narrow and more
flattened or destitute of the swelling of the lower portions of the volutions which is a
conspicuous feature in F. culimoides. The height of each volution is equal to half of its
opposite diameter.

3

18 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Geological Position and Locality. The Great Oolite of Stonesfield, collected by Mr.
Whiteaves.

RISSOINA WITCHELLI, Lye. Tab. XL1V, fig. 12.

Testa elongato-turrita, anfractibus 6, latis, convexis, aut media angulatis, longitudinaliter
costellatis, costellis circa 26 — 28, rectis, simplicibus, crebris ; apertura ovato-obliqua, labro
extus incrassato.

Shell elongately turreted ; volutions 6, wide, convex, angulated at their middle part,
and encircled with a slender band at the mesial angle ; the longitudinal little ribs are very
closely arranged ; they are smooth, narrow, perpendicular, and are united to the mesial
band ; from 26 to 28 in a volution ; the last volution is conformable with the others, both
in figure and ornamentation ; the aperture is of moderate size, it is oblique, ovate, but
rather pointed at the two extremities ; the columella is curved in its middle ; the outer lip
is thickened.

The angulated figure approximates to Rissoina duplicata, Sow., sp., ' Gr. Ool. Mon./
i, p. 52) ; but the last volution is somewhat less expanded, the costse upon the spire are
less conspicuous, and nearly three times as numerous. Mr. Witchell, who discovered the
species, has kindly communicated several specimens which agree with each other in all
essential particulars.

Geological Position and Locality. The Great Oolite of Minchinhampton Common,
associated with other minute testacea.

RISSOINA MILLERI, Lye. Tab. XL1V, fig. 10.

Tesia turrita subcylindrica, anfractibus (6) subconvexis, angustis, longitudinalitcr costel-
latis; costellis 17 — 18, rectis simplicibus; apertura ovato-semilunari, ad basim rffttsa ;
labro extus valde incrassato.

Shell turreted, subcylindrical ; volutions (6) convex in their middle part, narrow, but
with the sutures only slightly impressed ; longitudinally costellated; costellas 17 — 18, per-
pendicular, not very prominent, and plain ; aperture ovately semilunar, oblique, expanded
at the base, the outer lip having a considerable thickening.

Allied to Rissoina acuta, Sow., but having the volutions more narrow and less con-
vex, the sutures being less deeply impressed ; the little ribs are much more numerous ;
the aperture is also larger and more effuse at the base.

Geological Position and Locality. One of a series of minute univalves obtained by
Mr. Whiteaves in the Great Oolite of Minehinhampton Common. The name is an
acknowledgment of the discrimination of the author of ' The Natural History of the Crin-
uoidea,' who appears to have been the first person to discover the fossil riches of this locality,

GASTEROPODA. 19

and whose strongly expressed opinion was originally the means of directing the attention
of the present writer to it.

AMBERLEYA NODOSA, Tab. XLI, fig. 3; et Part I, PL V, fig. 19, 1850.

This elegant shell was represented in so defective a manner at Plate V, fig. 19, as to
render it desirable to give the present illustration, in which the aperture faces the spectator
more directly. The examination of additional specimens has tended to confirm the views
expressed in my manuscript of 1850, viz., that Amberleya should rank as a distinct genus
of the Littorinid(S, separated from Littorina by the thin test, lengthened, almost turricu-
lated, spire, and scarcely less so by the ornamentation of the volutions. Other examples
of Amberleya will be found in A. Jurassi, Lye. (the next species here described), Turbo
capitanem, Munst., Turbo ornatus, Sow., and some other allied Inferior Oolite species
which have been figured by D'Orbigny as examples of Purpwrina, but which are well
distinguished from the type form of that genus (see the observations on Purpuroidea
insignis). The generic appellation Amberleya was derived from Amberley Heath, which
is a second name for Minchinhampton Common.1

AMBERLEYA JURASSI, Lye. Part 1, Tab. IX, figs. 33, 33 a.

Testa turbinato-conicd, acutd, lineatd, anfractibus (6) latis, tricarinatis, carina mediana,
magna, subacuta, anfractu ultimo carinis 8, elevatis, subacutis, striis obliquis serratis, aper-
tura magna, ovata basi subangulato, columetta recta.

Shell turbinated or conical ; spire elevated, acute ; volutions (6) high, with three
elevated, subacute carinae, of which the median carina is the most prominent. The last
volution is large, with eight elevated carinse, their edges being serrated by oblique, longi-
tudinal striations ; the aperture is large, ovate, somewhat angulated at the basal junction
with the columella, which is straight.

Distinguished from Turbo capitaneus, Goldf., both by the characters of the general

1 Subsequently to the completion of this Supplement, I have been favoured by M. Eugene E.
Deslongchamps with a copy of his memoir, extracted from the fifth volume of the ' Bulletin of the Linnean
Society of Normandy,' 1860, entitled " Observations concernant quelques Gasteropodes, Fossiles, des
Terrains Jurassiques places par Vauteur de la ' Paleonlologie Frayaise' duns les genres Purpurina. Trochun
et Turbo. Note sur le genre Eucyclus." The latter proposed new genus is identical with our Amberleya,
quoted in the memoir as Abberleya. The author has in this little work given an excellent critical analysis of
the group of which he has proposed to constitute Eucyclus ; these are Purpurina Patroclus, D'Orb.,
P. Philiasus, D'Orb., P. ornata, D'Orb., P. bathis, D'Orb., Turbo Itys, D'Orb., T. niceus, D'Orb., T.
Julia, D'Orb., T. capitaneus, Munst., T. castor, Eoem., T. princeps, Roem. He has also figured and de-
scribed the following new species — Eucyclus obeliscus and E. papyraceus, from the Upper Lias ; E. pinauis
and E. goniatus, from the Inferior Oolite ; the latter shell, in its general figure and plan of ornamentation
has a considerable resemblance to Amberleya nodosa. Eucyclus is therefore a synonym of Amberleya.

20 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

figure, by the greater number of carinse, and by the absence of tubercles upon them.
Turbo castor, D'Orbigny, resembles it in the characters of the carinae, but they are less
numerous and less elevated ; the spire is also much less produced.

Height 15 lines, transverse diameter of the last volution 11 lines.

Geological Position and Locality. The Great Oolite of Minchinhampton Common, in
which it occurs rarely in the coarse volite or planking.

AMBERLEYA ARMIGERA, Lye. Tab. XXXI, fig. 6.

Testa conica spira elata, apice acuta, anfractibus (5) convexis, subanffulatis, costis
tuberculosis cingendis ; costis duobus superioribus minoribits, inferioribus majoribus ; anfractu
ultimo basi carinis serratis (5) cingendis ; umbilico nullo.

Shell conical ; spire elevated, pointed ; volutions (5) convex, somewhat angulated, with
four encircling costse or carinse, which are densely and delicately tuberculated, and
decussated by fine striations, the two lower costa3 being much larger than the upper, so
that the lowest costa overhangs the upper part of the next volution ; the base has five
encircling, serrated costae ; there is no umbilicus.

Height 10 lines, length of the last volution 8 lines.

The encircling carinse occupy nearly the entire height of each volution, leaving only
narrow, deep, interstitial spaces ; the lowest of the carinae is the largest. The general
figure approaches to Turbo capitaneus, Goldf., but the latter has the encircling carina3 much
more elevated, narrow, more widely separated, and less numerous. Turbo Phillipsi, Mor.
and Lye., has a much shorter spire, with the volutions less ventricose or angulated ; other
species are more remotely allied.

Geological Position and Locality. — The Cornbrash of Scarborough, in which it is rare ;
from the cabinet of John Leckenby, Esq.

NERITA INVOLUTA, Lye. Tab. XXXI, fig. 15.

Testa oblique ovata, l&vigata, spira parva, depressa, sub-celata, anfractu ultimo per
inflato ; qpertura ampla, labro inferno convexo.

Shell oblique, ovate, smooth ; spire (apparently consisting of two volutions) small,
depressed, nearly concealed by the envelopment of the last volution, which is much inflated
at the aperture ; inner lip convex, smooth.

A plain species, distinguished by the great length and volume of the last volution ; the
apex of the spire is imperfect, but though quite depressed, probably it is not altogether
concealed ; the general figure is allied to Neritina Staffcnsis, Forbes, but the latter is
more lengthened and more minute.

Geological Position and Locality. Collected by Mr. Whiteaves in the Great Oolite of
Kirklington, Oxon.

GASTEROPODA. 21

NERITOPSIS ARCHIACI, D'Arch., sp. Tab. XXXI, fig. 7, 7 a.

TDRBO CANALICULATUS, VArchiac. Mem. Soc. Geol. Fr., vol. v, pi. 29, fig. 6.
— ARCIIIACI, TfOrbigny. Prodr., i, p. 300.

Testa ovato-depressa, spira elata, anfractibus tribus vel quarternis, angustis, inflatis,
suturis profunde canaliculatis, anfractu ultimo costis transversis obscuris, inaequalibus,
irregularibus, striisque crcbris decussalis ; striis tenuibus, regularibus, undatis ; apertura
ampla, suborbiculari.

Shell ovate, depressed ; spire elevated, consisting of three or four volutions, which are
narrow, inflated, their sutures deeply channeled ; the last volution has some obscurely
marked, irregular, and unequal transverse costa decussated by encircling striations ; the
striations are regular, very closely arranged, faintly impressed, with small, wave-like
undulations ; the aperture is large and rounded.

More depressed than N. sulcosa and N. striata, but with larger volutions, the sutures
being also more deeply channeled ; the ornamentation of the surface is so faintly impressed
that it is scarcely perceptible without the aid of a magnifier.

Geological Positions and Localities. A rare species, from the Cornbrash of Scar-
borough, in the collection of Mr. Leckenby. Eparcy, France.

TROCHUS GDISEI, Lye. Tab. XLV, fig. 14.

Testa alta conica, apice acuto, anfractibus (6) latis, leviter concavis, anfractu ultimo
subanffulato, basi convexo, concentrice striato ; anfractibus, costis obscuris, obliquis, ad basin
bi-cinctis ; apertura dcprcssa.

Shell elevated, conical; volutions (6) wide, apex acute, slightly concave in their middle
portions ; the last volution angulated ; the base convex, with fine, encircling striations ;
the sides of the volutions have delicate, obscure, oblique costse, which are interrupted
towards the base of each volution by two narrow, encircling bands ; the sutures are
delicate and faintly marked ; the aperture is depressed.

The ornamentation of this little Trochus is regular and but faintly sculptured ; the
encircling bands are rendered slightly nodular by the decussating costse.

The name in compliment to W. V. Guise, Esq., President of the Cotteswold Naturalists
Club.

Geological Position and Locality. The Great Oolite of Minchinhampton, collected by
E. Witchell, Esq.

22 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

MONODONTA EXIGUA, Lye. Tab. XLIV, fig. 29.

Testa parva ovata, spira data, obtusa, anfractibus tribus, suhplanis, anfractu ultimo
rotunda ; striis tenuibus cingendis, costisque obliquis depressis, crebris, decussates ; apertura
ovata, columella ad basin incrassato, subumbilicato.

Shell small, ovate; spire elevated, obtuse; volutions three, very slightly convex, the
sutures distinctly marked; the last volution rounded with densely arranged, delicate,
encircling striations, which are decussated upon the upper and middle portions of the
volution by numerous depressed, oblique costae, which are rendered somewhat granular by
the striations ; the aperture is ovate, the columella is thickened at its base, and there is a
slight umbilical depression ; the base of the last volution is destitute of costae.

Geological Position and Locality. The Great Oolite of Minchinhampton Common,
collected by Mr. Witchell.

MONODONTA LTCETTI, Wlnteaves, MSS. Tab. XXXI, figs. 14, 14 a.

Testa subdepressa, spira brevl, exserta ; anfractu ultimo permagno lateribus planatis,
costisque magnis, crenulatis, cingendis, basi constricta sulcb magno.

Shell depressed ; spire short and slightly mammillated, the last volution very large,
angulated at its upper margin, flattened upon its sides, and slightly convex towards the
base, which has a large, encircling furrow ; the aperture is moderately large, wide above,
contracted towards the base ; the columella is rounded and very tumid.

The whole shell is encircled with rows of rope-like crenulated costae, the upper border
and flattened sides being formed by three costae larger than the others ; beneath these are
five costse diminishing symmetrically to the basal furrrow ; the upper surface, which is
flattened, has three encircling costae, within which rises a small, mammillated apex.

Lateral diameter one fourth greater than the height.

The large, rounded costae, flattened sides, and depressed figure, readily distinguish
it from allied species.

Geological Position and Locality. In soft, pale, gray, marly limestone (Bradford
Clay?), Islip, Oxon., collected by J. F. Whiteaves, Esq.

MONODONTA SPARSISTRIATA, Lye. Tab. XLV, fig. 9.

Testa parva turbinata, depressa, spira anfractibus 4 ; covexiusculis, striis 6, cingendis ;
apertura ovata, basi subplano, l&vigato, umbihco nullo.

Shell small, turbinated, depressed ; spire moderately elevated, consisting of four rather

GASTEROPODA. 23

convex volutions, which are encircled with six regular striations ; the aperture is ovate, the
base somewhat flattened and smooth ; there is no umbilical depression.

A small shell, with the last volution expanded and depressed ; the striations are rendered
slightly scabrous by very delicate, obtuse, decussating ornamentation, partially preserved,
and which is only visible under a considerable magnifying power.

Geological Position and Locality. The Great Oolite of Minchinhampton Common,
collected by Mr. Witchell.

MONODONTA COMPOS JTA, Lt/c. Tab. XLV, fig. 6.

Testa parva subdepressa, spira anfractibus 3 — 4 angustis, angulatis, superne concavis ;
lineis angustis, regularibw subdistantibus cingendis, anfractu ultimo permagno, superne
costulis dcpressis longitudinalibus lineis decmsatis; aperturd magnd ovatd, columella
solida, dentata.

Shell small, rather depressed; spire with the volutions (3 — 4), angulated in their
middle part, narrow, delicate, and rather distantly arranged, the last volution is very large ;
the surface above the mesial keel is concave, and has closely arranged, depressed, longitu-
dinal, little elevations or ribs, which are rendered nodulous in their upper parts by the
encircling lines ; the aperture is moderately large ; the columella has a conspicuous
thickening at its base ; there is also a slight umbilical depression.

Geological Position and Locality. The Great Oolite of Minchinhampton Common,
collected by Mr. Witchell.

SOLARIUM BATHONICUM, Lye. Tab. XLV, figs. 27, 27 a, 27 b, 27 c.

Testa parva depresaa, superne planata, inferne concavo, concentrice striato ; anfractibus
(3) anyustis fabuJatis, externe subcarinatis nodulisque paucis, obscuris, coronatis ; lateribus
subconvexis striatis.

Shell small, depressed, flattened above, concave beneath and concentrically striated ;
volutions (3) narrow, tabulated, externally slightly carinated, and with a few obscure
coronary tubercles; the upper and lateral surfaces have encircling striations, the sides
being slightly convex.

The specimen examined has a diameter of only two lines, the height being equal to
about one third of the breadth.

Geological Position and Locality. The upper beds of the Great Oolite in the vicinity
of Bath, collected by Charles Moore, Esq.

24 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

PLEUROTOMARIA GRANULATA, Sow., sp. Tab. XXXI, fig. 8, 8 a.

TROCHUS GRANULATUS, Sow. Min. Con., t. 220, fig. 2.

PLEUROTOMAKIA GRANBLATA, Deslong. M6m. Soc. Linn., yiii, pi. 16, figs. 6 — 8.

D'Orb. Prodrome, p. 267.

Morris. Cat. Brit. FOBS., 1854, p. 271.

Quenstedt. Der Jura, p. 414, tab. 57, figs. 5 — 7.

Testa trochiformi subturrita, apice acufa, anfractibus convexiusculis, in media angulaiis,
subgradatis, supernc planiusculis, in/erne convexiusculis, transverse et longitudinaliter
sfriatis ; sinu anyusto, fascia sinus prominentc> transverse tenuissime sfriato, in media
anfractuum sita ; ultimo anfractu ad basin suhangulato, basi subconvexa, concentrice striata ;
umbilico minima out subnullo ; apertura subquadrata labro sinistro crassiori reflecto.

Shell trochiform, subturreted; apex acute ; volutions rather convex, angulated in their
middle portions, or somewhat step-like, the upper half of each volution being flattened, the
lower half rather convex ; the surface is longitudinally and transversely striated, the decus-
sations of the striae forming granules or tubercles, of which there are usually five rows
above and four beneath the mesial angle, the uppermost row having the tubercles more
prominent and separated than the others ; the sinus is narrow, and of moderate depth ;
the fascia of the sinus is prominent, with fine, transverse striations, and placed in the
middle of the volution ; the last volution has the base somewhat angulated ; the base is
convex, and concentrically striated ; the umbilicus is very small or almost none ; the
aperture is subquadrate, the left lip being thickened and reflected.

A beautiful species, not very regular in the disposition of the longitudinal and transverse
striations, but for the most part those beneath the mesial fascia are more strongly marked
than above.

The height of the entire shell and diameter of the last volution are equal in the
specimen figured; others have the height somewhat greater; 16 lines is a medium size.

Geological Positions and Localities. The Inferior Oolite of the south-west of England
and the Cornbrash of the coast of Yorkshire. Our specimen is from Gristhorpe, in the
collection of Mr. Leckenby. It is moderately abundant.

CYLINDRITKS EXIGUA, Lye. Tab. XLIV, fig. 14.

Testa parva, subcylindricd, spira elata conica, apice obtitso, anfractibus 5, latis, paulu-
lum convcxis, spira vero lateribus subconcavis ; anfractu ultimo margine rotundato, aper-
tura angimtissimo.

Shell minute, subcylindrical ; spire elevated, conical, its sides being, however, slightly
concave, and its apex obtuse ; the volutions are five in number, moderately wide and

GASTEROPODA. 25

slightly convex ; the last volution is lengthened, its upper margin is rounded ; the aperture
is very narrow.

More lengthened and attenuated, the spire more elevated, and its apex more obtuse,
than in C. acutns, to which species it appears to be most nearly allied.

Geological Position and Locality. The Great Oolite of Minchinhampton, collected by
E. Witchell, Esq.

CTLINDRITES TURRICULATUS. Tab. XLIV, figs. 26, 26 a.

CYLINDRITES TURRICCLATUS, Lycett. Proc. Geol. Soc., 1853, p. 342, vol. ix, pi. 14,

fig. 8.

Testa elongatd, subylindricd ; spird magnd, acutd ; anfractibus (8) convexis ; suturis
profunde imprcssis ; anfratu ultimo ovato ; apcrtura angustata.

Shell elongated, ovately cylindrical ; spire lengthened, its apex acute ; volutions (8 in
the adult state) convex, their sutures deeply impressed, the last volution ovately cylindrical ;
aperture narrow.

The general figure somewhat resembles C. altus, but the volutions are more numerous,
and are not flattened, as in that shell ; the subovate figure and elevated spire readily distin-
guishes it from other contemporaneous species. The length of the aperture is equal to
three fifths of the entire shell.

Geological Position and Localities. Formerly collected at Ponton, Lincolnshire, by
Professor Morris ; recently it has been obtained in the Great Oolite of Minchinhampton
by E. Witchell, Esq.

ACTEON BATHONICTJM, Lye. Tab. XLIV, fig. 16.

Testa parva ovata, spira elevata, anfractibus (4) subplanis, ad suturam angulatis, supra
angulam .yiratis, tabulatis, ultimo anfractu striis regularibus tenuibus ; apertura ovali,
postice angustata.

Shell small, ovate, spire elevated, volutions (4) rather flattened upon the sides and ele-
vated, their superior borders forming a sharply defined angle ; above the angle is a flattened
sutural area, the last volution has regular, delicate, encircling striations ; the aperture is
moderately large, ovate ; the posterior extremity narrow ; its length is more than half the
height of the shell.

A minute but well-marked species, with a spire larger, more lengthened, more angulated
and more pyramidal than Auricula Sedyvici, Phil. ; it is more nearly allied to Tornatella
Aviothensis, Buv., 'Pal, Mense,' pi. xxiii, figs. 32, 33 ; and to Tornatella pulla, Kock and
Dunk., ' Ool.,' pi. xi, fig. 11; but these have the spire more lengthened and less
flattened.

Geological Position and Locality. One of a series of minute and, for the most part,

4

20 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

dwarfed testacea, collected by Mr. Moore from the upper portion of the Great Oolite in
the vicinity of Bath.

ACTEON PHASIANOIDES, Lye. Tab. XLIY, fig. 28.

Testa parva ovato-elongata, subletve, spira alta, turrieulata afractibus 5, superne con-
vexis, in/erne planatis, anfractu ultimo magno, ovato, bast temrrime striato, apertura
ettiptia, eolumclla recta, uniplicatd.

Shell small, ovately elongated, nearly smooth ; spire elevated, turreted ; volutions 5,
convex above, the sides flattened, and the sutures strongly defined ; the last volution
slightly exceeds half the entire length of the shell ; it is ovate, its base having some delicate,
regular spiral striations ; the aperture is. elliptical, the columella straight, having a single
plication.

Possibly the entire surface may have had striations still more delicate than those at the
base, but no traces of them remain ; the spire is larger, and the volutions are more inflated,
than is usually seen in this genus.

Geological Position and Locality. The Great Oolite of Minchinhampton, collected by
E. Witchell, Esq.

•j

AOTEONINA BREVIS. Tab. XLI, fig. 6.

Under the title of Cylindrites brevis, an immature and imperfect example was figured
in the first part of the 'Great Oolite,' Monograph. Tab. VIII, figs. 13, 13, a; the fine
example now figured was collected by Mr. Whiteaves in the Great Oolite of Kirklington,
Oxon., and exhibits in the more advanced stage of growth a change in the last volution,
whose upper margin rises higher than those of the preceding volutions, thus rendering the
vertex slightly concave, a change with which recent conchology presents many analogous
instances. The figure of the columella leaves no doubt that it is an Acteonina.

ACTEONINA KIRKLINGTONENSIS, Lye. Tab. XLI, fig. 5.

Testa ovato-cylindriea, donyata, Itsviffata, spira obtusa, pcrspicua, anfractibus (4)
depressiz, columella ad basin cortorta, apertura inferne elongata, ovata.

Shell ovately cylindrical, elongated, smooth ; spire obtuse, depressed, the upper margins
of the volutions exposed and rounded ; columella contorted at its base, forming with inner
lip an umbilical depression ; aperture narrow above, pyriform, lengthened, and rather
pointed at its base.

A lengthened cylindrical Acteonina, with an exposed, obtuse spire, which does not rise
higher than the upper border of the last volution ; a small specimen is, in proportion,

GASTEROPODA. 27

somewhat shorter. It is nearly allied to Sulla ? primava, Deslongchamps, 'Mem. Soc.
Linn, de Normand.' t. 7., pi. x, figs. 23, 24 ; the latter is a larger shell, with the spire less
exposed, and the aperture at the base much less lengthened and less pointed ; it is there-
fore probably distinct. The elongation of the anterior part of the aperture appears also to
separate it from Acteonina convoluta,Ijyc., ' Cotteswold Hills,' p. 125, the left-hand figure,
pi. iv. As three specimens of each form of different states of growth have been examined,
we may rely upon the persistence of this distinctive feature.

Length 11 lines, opposite diameter 6 lines.

Geological Position and Locality. The Great Oolite of Kirklington, Oxon., collected by
Mr. Whiteaves, who has obtained several specimens.

ACTEONINA LUIDII, Luid., sp. Tab. XXXI, fig. 16. ; Tab. XLI, fig. 18, a, 6, c.

COCHLITES LCID. Lithoph. Brit. Ichnogr., 1699, 417.
ACTEONINA LCIDII, Mor. Cat. Brit. Foss., 1854, p. 234.

Testa subcylindrica, antics mediocriter attenuate, postice truncate, anfractu ultimo
superne angulato, lateribus planatis, spira dcpressa, anfractibus (4 — 5) angustis, apice
exserto.

Shell short, subcylindrical, moderately attenuated anteriorly, truncated abruptly poste-
riorly ; volutions (4 — 5) depressed, narrow, their upper margins exposed upon the flattened
posterior surface ; the apex is slightly elevated and obtuse ; the last volution has its posterior
margin angulated and its sides flattened. Casts exhibit the upper margin of the last
volution somewhat rounded, and also the edges of the other volutions.

Height one third greater than the transverse diameter.

Geological Position and Localities. The Forest Marble of Kidlington, Oxon., collected
by Mr. Whiteaves, and of Cirencester, Gloucestershire, collected by myself, at both of
which localities it is rare.

ACTEONINA CANALICULATA, Lye. Tab. XXXI, figs. 9, 9 a, 9 b.

Testa subcylindrica l&vigata vel ovata, spira exserta, obtusa, anfractibus (7) angustin,
subplanis, sitperne convexis, et canaliculatis, ultimo anfractu subcylindrico, basi . . . . ?

Shell subcylindrical, smooth, or ovate ; spire elevated, obtuse, consisting of 7 narrow volu-
tions, which have their sides flattened, their upper borders being rounded and deeply
channeled ; the last volution is nearly cylindrical, the aperture is not exposed, and the base
is imperfect.

The characters of the spire, with its numerous narrow-channeled volutions, without
angularity, appears to be sufficient to distinguish the species.

Geological Position and Locality. The Great Oolite of Kirklington, Oxon., obtained
by Mr. Whiteaves.

28 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

ACTEONINA SCARBURGENSIS, LyC. Tab. XXXI, figS. 13, 13 «.

Testa ovata ventricosa lavigata, spira brevi obtusa, anfractibus (4) convcxis, anfractu
ultimo ad suturam subcanaliculato ; apertura anffiistata, columella ad basin maryinata.

Shell ovately ventricose, smooth ; spire short, obtuse, consisting of four narrow, convex
volutions ; the last volution has the sides slightly convex, its upper margin rounded and
slightly channeled at the suture ; the aperture is narrow, somewhat expanded at the base,
which is marginated at its junction with the columella.

A handsome ventricose shell, shorter and more tumid than A. convoluta, Lye., which
appears to approximate more nearly to it than other recognised species.

Length 14 lines, diameter of the last volution 10 lines, length of the aperture 11 lines.
The specimen figured is from the fine collection of Mr. Leckenby ; the test, which is thin, is
partially preserved ; it has a corneous aspect. A single specimen.

Geological Position and Locality. The Cornbrash of Scarborough.

ACTEONINA SCALARIS, Lye. Tab. XLIV, fig. 18.

Testa parva, subcylindracea, spira brevi, acuta, anfractibus 4, lateribtis anymtis platiutis,
marginibus acutis, superne tabulatis ; aperturd elongatd, basi elliptico curvato.

Shell small, subcylindrical ; spire short, but elevated and acute, consisting of four
narrow volutions, which are flattened upon their sides, their upper borders are acute, their
upper areas are flattened ; the aperture is moderately large and lengthened, its base is
elliptically curved.

The length is 3 lines, the opposite diameter but little exceeds 1 line.

The upper angle of each volution is acute, and even slightly projects outwards, a
character which is not seen in any other known species with an elevated spire. Possibly
this is the young condition of a much larger species.

Geological Position and Locality. The Great Oolite of Kirklington, Oxon., collected
by Mr. Whiteaves.

DENTALIUM KNTALOIDES, Desl Tab. XXXI, figs. 11, 11 a, 11 b.

DENTALIUM , Phillips. Geol. York., i, pi. 4, fig. 37.

— GLABELLUM, Bean. Cornbrash Fossils, Mag. Nat. Hist., 1839, without

figure or description.

ENTALOIDES, Deslongchamps. 1842. Mem. Soc. Linn., vii, p. 128, tab. vii,
figs. 30—38.

— D'Orb. Prodrome, i, p. 2/2, No. 205.
PARKIN SONI, Quenstedt, Handbook, t. 35, fig. 19.

GASTEROPODA. 29

DENTALIUM PARKINSONI, Quenst. Der Jura, p. 484, t. 65, figs. 5, 6.
ENTALOIDES, Oppel. Die Juraformation, 1856-8, p. 390.
ANNULATUM, Bean, Leckenby. Journ. Geol. Soc., 1858, vol. iv.

Testa crassa, tereti, subarcuata, scepius nitida, slriis tenuissimis densissimis paululim
obliquis ornata. (Deslongchamps.)

Shell thick, tubular, round, smooth, shining, slightly curved ; encircled with striations,
which are somewhat oblique and strongly impressed towards the posterior or smaller
extremity, anteriorly they are more faintly and densely arranged and ultimately disappear,
the surface having some irregular annular folds of growth. Length of an imperfect Corn-
brash specimen 24 lines, the larger diameter 2~ lines. The Calcareous Grit examples have
larger dimensions, they are of more advanced growth, and have the greater portion of their
cylinder devoid of striations.

The Cornbrash imperfect specimens are less slender and more straight than the figures
of I). Parkinsoni given by Professor Quenstedt, and more nearly accord with those of
D. entaloidcs, Deslongchamps ; but the specimens figured by Quenstedt differ also from
each other in their attenuation and curvature. Dentalium cinctum, Goldfuss, has encircling
striations, without obliquity ; D. undulatum of the same author has the figure some-
what compressed ; D. tenue, Goldf., is more slender and more nearly cylindrical.

Geological Position and Locality. Denlalium entaloides appears to have a considerable
geological range; the Cornbrash of Scarborough has produced a few specimens; Mr.
Leckenby has also obtained it in the Kelloway Rock and the Calcareous grit of the same
locality. D. entaloides was obtained by M. Deslongchamps in the Inferior Oolite of
Moutiers and Bayeaux ; by Dr. Oppel in the beds with Ammonites Parkinsoni at Mont
d'Or, near Lyons; in Svvabia it occurs at the upper boundary of the Lower Oolite (Braun
Jura e. Quenst.) at Ehningen and Balingen.

TROCHUS STRIGOSTJS, Lye. Tab. XLV, fig. 12.

Testa alta, conica, transverse costellata, costellis granulosis asqualibus ; anfractibus (5)
subplanis, quadricostatis et vitta striata antcriora ; ultimo anfractu obtuse carinato ; basi
concava ; columella obliqua ; apertura sub-triangulari.

Shell elevated, conical, transversely costellated ; costellae, four to a volution, granulated
and equal ; the anterior border of each volution has also a depressed, striated band ; the
volutions, about five in number, are flattened, and the last volution is rounded ; the base
has a few striations ; the columella is oblique, and the aperture somewhat triangular.

The ornamentation is strongly marked and regular ; the height and breadth are nearly
equal ; the sole specimen is rather imperfect at the apex.

Geological Position and Locality. The Cornbrash of Gristhorp Bay, near Scar-
borough, in the collection of Mr. Leckenby.

30 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

BIVALVIA.
GRYPH.EA MINUTA, Sow. Tab. XL, fig. 30.

GKYPHJEA MINUTA, Sowerby. Min. Con., tab. 547, fig. 4.
— Morris. Catal. Brit. FOBS., p. 186.

Testa parva, valva major a suborbiculata, umboni incurvo, later e untied sulcd brevi
instructo. Valva altera ignota.

Shell small ; the larger valve subglobose, suborbicular ; the beak produced, incurved,
and nearly straight, only slightly roughened by the area of attachment ; the anterior side
with a short sulcation, but no distinct lateral lobe. The smaller valve is unknown.

A minute Grypha?a, of which several specimens have been obtained by Mr. Witchell
in the Minchinhampton Great Oolite ; it has no well-defined distinctive features, and
would scarcely have been deemed worthy of notice had it not been figured by Mr. Sowerby
from Ancliff.

PLACUNOPSIS SEMISTRIATUS, Bean, sp. Tab. XXXIII, figs. 9, 9 a.

ANOMIA SEMISTRIATA, Bean. Mag. Nat. Hist., 1839, p. 61, fig. 21.

Testa, valva majora convexa, subobliqua, ovato rotundata, apice submarginali, acutd,
lamellis conccntricis, irreyularibus, superne leevigata, in/erne lineis radianlibus subaegualibus
nodulosis ornata. Valva affixa ignota.

Shell with the larger valve ovate, slightly oblique, convex; the apex pointed, and
placed near to the margin ; the surface has numerous irregular, concentric lamellae ; the
lower portion has numerous radiating lines, which are nearly equal, granulated, and
undulated. The attached valve has not been obtained.

The test appears to be less delicate than is found in some other examples of the genus,
and is usually affixed to another shell, more especially to Terebraiula lagenalis, so that it
is scarcely possible to obtain a specimen whose figure has not been affected by some
extraneous body. The general aspect has much resemblance to Placunopsis Jurensis
(' Gr. Ool. Monog. Biv.,' tab. i, fig. 13), but the latter has the ornamentation of the
surface much more strongly defined, with larger and more densely arranged radiating lines.
In P. semistriatus these can only be discerned with a magnifier.

Geological Position and Locality. The Cornbrash of the Yorkshire Coast, at Gris-
thorpe and Scarborough, where it is moderately rare. The upper portion of the
Inferior Oolite in the Cotteswold Hills has a species probably identical with this Pla-
cunopsis, and possessing a similar kind of ornamentation.

BIVALVIA. 31

PECTEN KIGIDUS, Sow. Tab. XL, fig. 16.

PECTEN BIGIDCS, Sow. Min. Con., t. 205, fig. 8.
Morris. Catal., 1854, p. 177-
D'Orb. Prodr. Et., xi, p. 314.
Oppel. Juraformation, p. 492.

Testa ovato-orbiculari, sub-aquivalvi, plano-convexa, reticulata, coslis depressis, crebis,
sub-reffularibus, divergentibus, lamellis concentricis angustis, hinc inde decussatis ; auri-
culis incequalibus, transverse lamellosis, lamellis elevatts, crebris.

Shell ovately orbicular, equivalve or subequivalve, moderately convex ; costae diverging,
depressed, slightly unequal, sometimes undulating and closely arranged, crossed by narrow,
irregular, concentric lamellae, which are sometimes elevated upon the ribs, and in other
instances form only narrow lines across the interstitial spaces, giving to them a punctated
aspect ; auricles large, unequal, with numerous transverse, narrow, elevated lamellae.

Geological Positions and Localities. It is not uncommon in the upper portion of the
Great Oolite, in the Forest Marble, and in the Cornbrash of many localities, as at Castle
Combe ; Stanton, near Chippenham ; Kidlington, Oxon. ; Rushden, Northamptonshire ;
Luc, France.

PECTEN GRIESBACHI, Lye. Tab. XXXIII, figs. 6, 6 a.

Testa, valva sinistra crassa subaquilaterali acuta, compressd, auriculis magnis sub-
(Equalibus, radiatim costata et concentrice striatd, costis (circa 26) superne angustis sub-
eequalibtis transverse striatis, inferne obsoletis ; striis concentricis, regularibus tenuissimis ;
auriculis transverse plicatis. Valva altera compressa interne l&vigata.

Shell with the left valve thick, subequilateral, compressed, acute ; auricles large, nearly
equal, and transversely plicated; the surface is ornamented with about twenty-six very
delicate, radiating costae, which are striated, narrow, nearly equal, and regular ; they are
distinct towards the apex, but are only faintly traced towards the middle and lower part
of the valve ; the concentric striations are very fine and regular over the whole surface ;
a few faintly marked plications of growth 'are visible towards the lower border. The
external surface of the right valve has not been exposed ; its convexity is about equal to
that of the other, its inner surface being smooth, without traces of the exterior orna-
mentation.

Geological Position and Locality. The Great Oolite of Wollaston, Northampton-
shire, in the cabinet of the Rev. A. W. Griesbach.

32 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

PECTEN IN^EQUICOSTATUS, Phil. Tab. XXXIII, figs. 1, 1 a.

PECTEN IN^EQUICOSTATUS, Phil. Geol. York., i, pi. 4, fig. 10.
I? Orb. Prodrome, p. 3/3.

— OCTOCOSTATUS, Roemer. Ool., p. 69, pi. 3, fig. 18.

— INJEQUJCOSTATUS, Mw. Cat. Brit. Foss., 1854, p. 176.

Op-pel. Juraformation, p. 607.

Testa ovato-acuta, convexa, longitudinaliter , 8 costata, concentrice lineata, costis con-
vexis latis sulcis conformibus in dorso Idnc inde dentatis, duobus mediis latioribus, lineis
exilibus confer tis sublamellosis auriculis sub&qualibus longitudinaliter lineatis. (Roemer pro
valva desstra.} Valva sinislra costis (8) angustis, elevatis rotundis asymmetricis, subnodosis,
interstiis latis irregulariter concentrice striatis.

A convex, subaequivalve, acute-pointed Pecten, with large, nearly equal auricles ; the
surfaces of both the valves having irregular, concentric striations and several large folds of
growth. The right valve has broad, slightly elevated costse (8), which are unequal and
slightly defined towards the posterior side, separated by narrow and but little depressed
sulcations, which are distinct upon the inner surface of the valve ; the left valve has eight
narrow, elevated, but rounded costse, of which those upon the sides are small and
unsym metrical ; the intervening spaces are broad upon the middle of the valve, and very
narrow laterally ; the auricles are obliquely lineated.

Geological Positions and Localities. Rarely in the Cornbrash and Kelloway Rock of
Scarborough, more commonly in the Coralline Oolite of Malton, but it is seldom well
preserved at either of these geological positions ; Roemer makes a similar statement
respecting its occurrence at Lindner Berges.

PECTEN ARTICCLATCS, Schloth. Tab. XXXIII, fig. 12.

PECTEN AKTICULATCS, Schloth. Petref., pp. 227, 228.

Gold/. Petref., p. 47, tab. 90, fig. 10.
Roemer. Verst, p. 68.

Testa ovato-acuta convexa, costis angustis acittis, subaqualilus cingulatis acuminatis, sul-
cis duplo latioribus concavis subtillissime transversim striatis, auriculis in&qualibus lamelloso-
lineatis costulisque virgatis. (Goldfuss.)

Shell ovately pointed, convex ; radiating costse elevated, narrow, acute, more or less
unequal, with acute transverse lamellae ; interstitial sulcations wider than the costse,
concave, with delicate transverse striations ; auricles unequal, with 'radiating ribs crossed by
lineal lamella?. The more numerous ribs (about twenty-four), their irregularity and in-
equality, will distinguish it from P. vimineus, Sowerby, a species which abounds in the
Inferior Oolite.

Geological Positions and Localities. Pecten articulatus occurs in the Cornbrash of
the Yorkshire coast, and more frequently in the Calcareous Grit and Coralline Oolite of the
same county.

BIVALVIA. 33

PECTEN RUSHDENENSIS, Lye. Tab. XXXTIT, figs. 4, 4 a, 4 b, 4 c.

Testa aquivalvi, suborbiculari, acuta, auriculis incequalibus (auricula antica majord),
valvis plano-convexis rugis concentricis elevatis, crebris, inferne squamatis, squamis brevilms,
reffularibus delicatissime instructis.

Shell equivalve, suborbicular, acute, moderately convex ; auricles unequal (the anterior
one being the larger) ; the valves have a few plications of growth, and very densely arranged,
elevated, concentric rugas, which are slightly wrinkled towards the apices, but towards the
middle of the valves become short, regular, scabrous elevations, disposed checker-wise with
those above and beneath, so that when viewed obliquely the ornamentation resembles
that of an engine-turned watch ; this is more especially the case with the surface of the
right valve, which has the concentric rugae more delicate and closely arranged, and also
the scabrous elevations ; in other respects the valves are alike in the design of their
ornamentation.

A beautiful suborbicular species ; the minute scabrous elevations arrest the finger when
it is passed upwards over the surface. It is very rare.

Geological Position and Locality. The Cornbrash of Rushden, Northamptonshire, in
the collection of the Rev. A. W. Grieshach.

PECTEN WOLLASTONENSIS, Lye. Tab. XXXIII, figs. 2, 2 a, 2 b, 2 c.

Testa ovato-orbiculari compressa, ceqvivahi, aurieulis inaqualibus transverse plicatis et
radiatim costatis ; valva dextra concentrice striata et radiatim costata ; striis tenuissimix,
inferne lamelloso-rugosis ; costis in&qualibus nodosis ; numerosiu, inferne evanescentibus ;
valva sinistra striis subtittissimis concentricis reffularibus.

Shell ovately orbicular, slightly convex, equivalve, with unequal auricles, the anterior
one being the larger ; they have numerous transverse plications and two or three radiating
costae ; the surface of the right valve has concentric striations and radiating costa? ; the
striations are very fine and irregular ; the middle and lower portion of the valve is occupied
by irregular, scabrous, concentric plications ; the radiating costse are very numerous,
irregular, and knotted ; they gradually disappear towards the middle of the valve. The
left valve has very delicate, regular, concentric, densely arranged striations.

This rare Pecten differs from Pecten Di/onisius, Buv., chiefly in being equivalve, and in
the dissimilarity of the ornamentation in the opposite valves.

Geological Position and Locality. The Great Oolite of Wollaston, Northamptonshire,
in the cabinet of the Rev. A. W. Griesbach.

34 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

PECTKN MICHELENSIS, Buviynier. Tab. XXXIII, fig. 3.

PECTEN CANCELLATUS, Bean, on Cornbrash Fossils, Mag. Nat. Hist., 1839 (no figure

or description).
— MICHF.LENSJS, Buvignier. Pal6ont. de la Meuse, Atlas, p. 24, pi. 32, fig. 7.

Testa orbiculari, depressa maxima, concentrice ruffosa et obsolete lineis subpunctatis
irregulariter radiata, ad umbones costulis convexis, distantibus, regularibus radiantibus et
concentricis decussata ; umbonibus acutis ; auriculis in&qualibus, transverse costellatis.
(Buvignier. )

Shell orbicular, depressed, large, rugose in the adult state, with slightly defined, irregular,
radiating lines and large, irregular, concentric lamellae ; the umbones are acute, the auricles
are unequal, the posterior auricle with large, rugose, transverse striations ; the surface near
to the umbo has regular, radiating costae, slightly knotted where they are decussated by the
concentric costae, which are nearly regular, and somewhat less closely arranged than those
which radiate.

The foregoing description applies to the right valve ; the change which the surface
undergoes in acquiring its adult condition is very striking, and is slightly indicated by the
few last lamellae upon the specimen figured ; a very fine example in the Scarborough
Museum, from the Coralline Oolite of Malton, shows that it ultimately acquired the aspect
of Hinnites, thus losing all regularity in its ornamentation, and having very large, irregular,
squamose lamellae ; the left valve has not been obtained.

Pecten retiferus ( ' Gr. Ool. Monogr. Biv.,' p. 9, tab. i, fig. 15) approaches to it in the
kind of ornamentation, but has the radiating costae larger and more distant, as are also the
concentric lamella? ; the umbones are less acute, and the auricles, which have a different
figure, are more nearly equal. Under the name of Pecten cancettatus, it was inserted by
Mr. Bean in his list of Cornbrash fossils, but without either figure or description. The
splendid work of M. Buvignier on the ' Palaeontology of the Meuse' exemplifies an aged
specimen, together with the progressive changes which the ornamentation of the surface
underwent.

Geological Positions and Localities. The specimen figured is from the Cornbrash of
Scarborough ; it occurs also in the Coralline Oolite of Malton ; M. Buvignier has recorded
it in the same formation at St. Mihiel and at Donaument.

PECTEN ANISOPLEURUS, Buv. Tab. XXXIII, figs. 5, 5 a.

PECTEN ANISOPLEUKUS, Buvignier. Paleont. de la Meuse, Atlas, p. 23, pi. 19, figs.
31—35.

Tusta subrotunda, depressa, inaquivalvi ; valva sinistra subplana, quinquecostata, lamellis
concentricis, Jibrosis, interdum interrupts, subtextis, ornata ; costis distantibus, convexis,

BIVALVIA. 35

squamatis, intervallis, triplolatioribus ; costis extremis minoribus ; auriculis subeequalibus,
transverse lamellosis. Valva dextra convexiori quinquesulcata, concentrice tenuiter lamellosa ;
sulcis concavis, costis altera valva respondentibus ; costis latioribus convexis, subdivisis.
(Buvignier.)

Shell suborbicular, inequivalve, depressed. The left valve nearly flat, with fine radiating
ribs, separated by very wide intervals ; the costse have large, squamous plications, rather
irregular, and nearly disappearing as they approach the apex, the costse near to the margins
being the smaller ; the intervals between the costae have five regular, concentric, squarnous
plications ; the auricles are nearly equal, they are transversely lamellated. The right
valve is convex, with five radiating sulcations, corresponding to the five costae of the other
valve ; the whole surface of the valve is covered with delicate, regular, concentric, closely
arranged lamellae. The interior of the valves present an appearance corresponding with
the ornamentation of the exterior.

Height rather greater than the breadth, and thrice the diameter through both the valves.

Geological Position and Locality. The Cornbrash of Scarborough and of Northampton-
shire ; the collections of Mr. Leckenby and of the Rev. A. W. Griesbach contain fine
specimens. M. Buvignier quotes the species from the lower ferruginous beds of the Oxford
Clay, Ardennes and Meuse.

HINNITES GRADUS, Bean, sp. Tab. XXXIII, figs. 10, 10 a.
PBCTEN GRADUS, Bean. Mag. Nat. Hist., 1839.

Testa valva sinistra, ovato orbicuJari convexo-plana, radiatim nndulato costata et con-
centrice lineata ; umboni acuto submediano, auricula antico magno, oblique radiatim lineatis ;
auricula postica subnullo ; costulis radiantibus numerosis, costa una majora et minora al-
ternatim instructis, semel varicibus duobus radiantibm magnis. Lineis decussantibus densis
regularibus ; valva qffixa ignota.

Shell with the left valve ovately orbicular, somewhat convex, the surface irregular, with
unequal, undulating, radiating costae and concentric lines; umbo acute, mesial straight, the
anterior auricle large, with oblique radiating lines, the posterior auricle scarcely produced ;
the surface of the valve has very numerous, unequal, radiating, rounded costae, in two series,
a larger and a smaller costae being arranged alternately ; there are also two elevated,
irregular, large, radiating varices upon the middle of the valve, as in Hinnites abjectus.
The cost33 are about equal in width to the intercostal spaces ; the entire surface of the
shell has densely arranged, very regular, concentric lines, which are scarcely visible without
the aid of a magnifier. The other valve is unknown.

Nearly allied, both in figure and aspect, to Hinnites abjectus, from which it is dis-
tinguished by the regularity and smoothness of the costae and by the regular, concentric
lines crossing both the costae and the intercostal spaces; the latter are equal in width to the

36 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

costae, whereas H. abjectus cannot be said to have any intercostal spaces, every part of the
surface being occupied by unequal, crowded, nodose costse ; the two large, radiating, nodose,
elevated varices are alike in both species.

The specimen figured is the original example, which belonged to Mr. Bean ; it has lost
a portion of the surface near to the lower border, and also a portion of the apex, nor will
it appear remarkable that only a single specimen of a shell so thin and fragile should have
been disengaged from a rock so intractable as the Cornbrash of Yorkshire.

Geological Position and Locality. The Cornbrash of Scarborough, in the collection of
Mr. Leckenby.

AVICULA CLATHRATA, Lye. Tab. XL, figs. 7, 7 a, 7 b.

Testa parva suborbiculari, convexo-plana, valva sinistra auriculis subaqualibtts magnis ;
superficie costis radiantibus (circa 24) acutis, regularibus et nodosis, lineis concentricis dis-
tantibus decussatis ; valva altera subplana, leeviffata, inornata.

Shell small, suborbicular ; the left valve with a low convexity, with large and nearly
equal auricles ; the surface of the valve has about twenty -four regular, acute, and slightly
knotted radiating costse, which are decussated by a few distantly arranged, concentric,
elevated lines; the costae radiate equally over the auricles and the middle of the shell.
The right valve is more flattened, it is smooth and destitute of ornamentation. Diameter,
about three lines.

Geological Position and Locality. The Great Oolite of Minchinhampton ; a single
specimen.

AVICULA SUBCOSTATA, Roemer, sp. Tab. XL, fig. 24.

MONOTIS SUBCOSTATA, Boemer. Nord. Ool., p. 75, t. 4, p. 7.

Testa orbiculari subobliqua, convexa, longitudinaliter costulata, subtillissime concentrice
striata, costulis (10 — 14) remotis superne evanescentibus, incequalibus, auricula leevi,
umbonibw minimis antrorsum incurvis. Valva sinistra. (Roemer.)

Shell orbicular, rather oblique, convex, longitudinally costulated, and with very
delicate concentric striations; costellae (10 — 14) acute, distinct, rather unequal, and dis-
appearing towards the umbo ; auricles plain ; umbo small, curved forwards. The right
valve is not known.

A small shell ; much less convex, less oblique, with a shorter hinge-line and more
delicate ribs than A. costata, Sow.

Geological Position and Locality. The Great Oolite of Minchinhampton Common, at
which place it is very rare.

BIVALVU. 37

GERVILLIA TORTUOSA, Sow., sp. var. Tab. XL, fig. 25.

GASTROCHJENA TORTUOSA, Sow. Min. Con., t. 526, fig. 1.

Phil. Geol. York., t. 1 1, fig. 36.

GERVILLIA TOKTUOSA, Mor. Catal. Brit. FOBS., 1854, p. 168.
Oppel. Juraformation, p. 418.

Testa elongata, antice tortuosa, postice recto, attenuate, umboni perobliquo, subter-
minali ; linea cardinis obliquissimo ; margine antico undulato, plicis concentricis Iteviter
instructis. Valva dextra subconcava, tortuosa ; fades interna ignota.

Shell elongated, convex, and contorted anteriorly, straight and attenuated posteriorly ;
umbo very oblique, with a small anterior auricle; hinge-border very oblique, anterior
border undulated ; the surface of the valve has five irregular, concentric plications upon
its anterior side. The right valve is twisted conformably with the left valve ; it is some-
what concave. The cardinal ligamentary pits have not been exposed in the present variety.
Compared with the Inferior Oolite forms of Gervillia tortuosa, this variety is more
narrow and less contorted, having the posterior extremity nearly straight ; the umbo is
also more acute, and the surface is destitute of the large, rugose, concentric plications
which are conspicuous upon well-preserved examples of the typical form. So much
variability, however, is seen in the contorted species of Gervillia that I prefer to regard
the present as pertaining to G. tortuosa, but constituting a well-marked variety.

Geological Position and Locality. It occurs rarely in the Cornbrash of Scarborough ;
from the collection of Mr. Leckenby.

GERVILLIA ISLIPENSIS, Lye. Tab. XL, fig. 35.

Testa, valva sinistra crassa, obliqua, convexa, linea cardinis elongata, auricula postica
permagna,falciformi, dorso angulo obtuso obliquo instructo ; plicis incrementi paucis. Valva
altera etfoveolis interni ignotis.

Shell with the left valve thick, inflated, very oblique, with a lengthened hinge-line and
falciform posterior auricle ; the anterior border is slightly excavated, and there is an
obtuse, oblique angle, which extends from the umbo to the posterior extremity of the
valve, which is curved backwards ; the folds of growth are few and prominent ; the
surface is destitute of ornament. The other valve is not known, nor has the hinge been
exposed.

The general figure much resembles that of G. crassicosta, Mor. and Lye., but it is
more inflated ; it has a greater posterior curvature, and is destitute of the oblique costae.
The length of our largest example is 2 inches, that of the hinge-line 1^ inch.

Geological Position and Locality. The Cornbrash of Islip, Oxon., also the Great
Oolite of Stonesfield ; collected by Mr. Whiteaves.

SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

PEIINA FOLIACEA, Lye. Tab. XXXVII, figs. 3, 3 a.

Testa amp/a subaquivalvi, subplana, umbonibus prominulis acutis ; latere antico
excavato, margins posteriors et inferiori ettiptico curvato ; lateribus rugis concentricis
paucis irregularibus. Foveolis interni ignotis.

A large, subgequi valve, depressed shell, with prominent, pointed umbones, excavated
and thickened anterior border, the hinge-line short, the posterior and inferior borders
elliptically rounded, the general figure being mytelliform, the left valve being somewhat
more convex than the other ; the test is thin, with delicate margins.

Dimensions. Length, 4| inches ; opposite diameter, 2^ inches ; the hinge-area has
not been exposed.

Geological Position and Locality. The Great Oolite of Minchinhampton Common ;
a single fine specimen of each valve is in the collection of the author, who is not cognizant
of any other examples.

INOCERAMUS QUADRATUS, Sow., sp. Tab. XXXVIII, figs. 1, 1 a, 1 b.

PERNA QUADRATA, Sow. Min. Con., t. 492, non Phil, non Goldf.
— Lycett. Ann. and Mag. Nat. Hist., 1855.

Testa tenue subquadrata, transversa, ineequivalvi, valde inasquilatera, valva sinisfra
antice oblique inflato, postice compresso ; umboni magno, subiiwoluto, antrorsum instructo ;
linea cardinali subhorizontali elongato ; latere anteriore truncato, infra umbonem concavo,
basi subrecto, superficie rugis concentricis paucis irreyularibus. Valva dextra planata
umboni parvo antico. Foveolis interni parvis numerosis.

Shell thin, subquadrate, transverse, inequivalve. The left valve inflated anteriorly,
with a large, subinvolute, projecting beak, and a steep, truncated and excavated slope
beneath it ; the posterior side is very thin, compressed, and expanded ; the hinge-line is
lengthened and nearly horizontal ; the base is lengthened and nearly straight. The right
valve is flattened; the umbo is small, pointed, and anterior. The internal hinge-pits are
placed upon a narrow, lengthened plate ; they are small and numerous. The surfaces of
the valves are smooth, with a few irregular, concentric plications.

The diagnosis in the ' Mineral Conchology ' is as follows : — " Quadrilateral, one side
shorter than the other three ; valves gibbose, unequal, the shorter side very concave,
bounded by two obtuse carinse."

The figure in the ' Mineral Conchology ' has the right or smaller valve facing the
spectator ; the contour of the larger or convex valve is not seen ; even the outline is not
perfect, as there seems to be a portion of the lower (right) border wanting, and thus
forming an angle at its anterior extremity, which would be rourded in the perfect shell ;
but the whole is stated by the author to be little better than a cast. With such an

BIVALVIA. 39

illustration it is not surprising to find that in the plates to the ' Geology of Yorkshire,'
and in the ' Petrefacta ' of Goldfuss, two very different species of Perna (flattened,
equivalve, and rugose) were figured for the Perna quadrata of Sowerby.

The convexity of the left valve, little remarkable in young specimens, becomes very
considerable with advance of growth ; the test upon the anterior side is moderately thick,
but the posterior side is delicate and is rarely preserved entire. Upon the smaller of the
specimens figured the portion denuded of the test exhibits obscure, concentric, and
radiating striations in the convex valve ; the same feature is also visible upon the surface
of the cast of the smaller valve figured by Mr. Sowerby ; it must therefore have existed
upon the inner surface of the very thin, nacreous layer of the test, which has not been
preserved; the exterior surface of the test is quite destitute of ornamentation.

Dimensions. Length of our largest specimen, in the direction of the hinge-line,
5 j inches ; height, 3J inches ; convexity of the larger valve, 2j inches.

Geological Positions and Localities. Mr. Sowerby 's specimen was obtained in the
Cornbrash at Bulwick, Northamptonshire, and, as far as can be ascertained, no second
example has been obtained from that locality. In the Inferior Oolite of the vicinity of
Nailsworth the present author has procured specimens at several quarries, in a single
bed ; its position being the highest bed of the white building-freestone, and immediately
underlying the bed of hard, cream-coloured limestone with Nerinaeas, which appears to be
special to the Nailsworth valley. Perna quadrata does not appear to be very uncommon;
but owing to the thinness of the fibrous test, it can only be disengaged from the Oolite by
a tedious and difficult process ; more frequently, however, the shell is found to have been
crushed or imperfectly preserved at its posterior side.

LIMA PECTINTFORMIS, Scttlotlt. Tab. XXXVI, fig. 1. Part II, Tab. VI, fig. 9. '

In figuring a larger and more characteristic example of this shell some additional
remarks may be allowed. It is widely diffused, abundant and of large dimensions in the
upper portion of the Inferior Oolite, rare and delicate in the Great Oolite, rare in the
Cornbrash, in the Kelloway Rock and Oxford Clay ; it reappears in considerable numbers
in the Coralline Oolite, assuming all its pristine varieties of form ; these are sufficiently
remarkable. In its young condition it was gregarious, and probably was attached by one
of the valves to the ground; such, at least, seems an easy explanation of the fact that the
upper surface of a slab of stone covered with the species usually discloses only the inner
surfaces of single valves, the other valves having probably been removed by marine action
in their dead state ; but although young and thin, the specimens in this condition often
attained to the full dimensions of the species, the radiating flutings of the external surface
being almost equally strongly marked upon the inner surfaces, in which state, also, the
muscular scar is not distinguishable, and when the valves are closed the umbones touch
each other. In old specimens, owing to a continual deposition of shell upon the inner

40 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

surface, more especially towards the urnbones, the triangular sub-umbonal area is large
and oblique, so that the umbones then are widely divergent ; the internal radiating flutings
have gradually disappeared, or are only visible at the lower border of the valves ; the mus-
cular scar is conspicuous ; ultimately, each valve acquired at its utnbonal extremity a
thickness of two inches and a half, the cavity of the interior became much smaller, the
outer surface ceased to be extended at its borders during this internal accretion of shell ;
we may also infer, from its solid, ponderous mass, and from the frequency with which it
became perforated by the Lithophagidas, that, unlike the common Limaa and Pectens, its
habits were sedentary ; doubtless these perforations may have been made in dead shells,
but they are not to be discovered in any other of the Jurassic Lima?.

The test consists of two very distinct layers ; the outer layer is always thin and semi-
transparent, the inner layer is white, opaque, laminated, and received continual additions
to its thickness ; in brief, the structure and mode of growth agrees with that of the genus
Spondylus as fully as does the external aspect of the imbricated rugae and the tubular,
spine-like processes ; it is, in truth, an equivalve Spondylm, destitute of binge-teeth. The
variations of figure are also considerable ; sometimes sub-orbicular, with no more obliquity
than a Pecten or Spondylus, with the sides nearly equal, the radiating costse undulating
and irregular, as in Hinnites ; in other instances it is oblique, with a steep anterior slope ;
add to this latter figure a greater lengthening of the valves, a compression of the posterior
side, and the aspect becomes strictly that of Lima, as in L. squainmicosta, Buv., which
appears to be only the young condition of this variety.

Few shells differ more in the convexity of the valves ; occasionally an example will be
found so much inflated that its figure can only have resulted from having been moulded
upon and remained closely adherent to a convex surface, to which the missing valve
probably remained attached.

The shell is not irisequivalve, although such an appearance is often imparted to it
from a depression, or an irregularity in the convexity of one of the valves ; as, however,
the borders of the valves are found to fit perfectly, this distortion cannot be owing to the
effects of fossilization.

Even from the earlier days of paleontology this shell has been a source of
doubt and perplexity. Schlotheim referred it to Ostracites, as also did Ziethen.
Mr. Sowerby, in the ' Mineral Conchology,' placed it with Lima, but expressed doubts as
to the genus; more recently, Professor Quenstedt, in his 'Jura,' after alluding to the
features which distinguish it from the ordinary Limse, divides it into two varieties, one
having a thick and the other a thin shell; he concludes by assigning it to the genus
Ostrea, but without offering any proofs that it would be correctly placed with the latter
genus. The change from the thin to the thick shell has already been explained, and the
structure of the test is distinct from that of Ostrea.

Lima pectiniformis may be placed at the head of a group of Jurassic Lima? which are
nearly allied, both in their external characters, shell structure, and mode of growth ; these

BIVALVIA. 41

are the following : L. Elea, D'Orb., from the Supraliasic Sands ; L. Electra, D'Orb.,
from the Supraliasic Sands and the Inferior Oolite; L. Hector, D'Orb., Inferior Oolite;
L. Luciensis, D'Orb., Great Oolite; L. rudis, Sow., Coralline Oolite; L. rotundata,
Buv., Coralline Oolite; L. angusta, Buv., Coralline Oolite.

LIMA PUNCTATILLA, Lye. Tab. XL, fig. 32.

LIMA PUNCTATILLA, Lye. Ann. and Mag. Nat. Hist., 1853, p. 420.

Testa parva, injlata, ovato-oblonga, auriculls parvis subcequalibus, lateribus leviter
excavatis ; cos f is radian tidus (circa 24) elevatis, granulatis, inters f Us angustis, striis con-
cent rich crebris decussatls.

Shell small, inflated, ovately oblong ; auricles small and nearly equal, the sides of the
valves steep and slightly excavated ; radiating (costse about 24), elevated, granulated ; large
upon the centre of the valves, and degenerating upon the sides into lines, decussated by
closely arranged concentric striations.

The general figure resembles Lima gibbosa, but more convex, and with radiating lines
or delicate costse upon the sides, which increase in size symmetrically towards the middle
of the valve, each rib being ornamented with a minute line of granules. The specimen
figured is of less dimensions than others, but it has only occurred very rarely.

Geological Position and Locality. The Great Oolite of Minchinhampton ; the Inferior
Oolite of Leckhampton Hill, in the shelly freestone.

LIMA HELVETICA, Oppel Tab. XXXIII, figs. 8, 8 a.

LIMA GIBBOSA, Goldfuss. Pet., t. 102, fig. 10, p. 86, non Sow.
- HELVETICA, Oppel. Juraformation, p. 489.

Lima testa fornicata ovata subobliqua antice declivi, costis (25 — 27) subacutis adpressis
et linea laterali notatis, sulcis conformibus, lunala Icevi convexa. (Goldfuss.)

Shell ovately oblong, convex, slightly oblique ; anterior slope lengthened, steep ; pos-
terior slope more gradual and flattened ; umbones acute, straight ; anterior and posterior
auricles equal and but little produced, forming a short horizontal hinge-line ; radiating
costse upon the middle portion of the valves narrow, sub-acute, 25 — 27 in number at the
lower border, 14 — 15 near to the umbo, the additional costse near to the lower border
consisting of smaller intervening costse or lines, unequal in size, and rather irregularly
arranged ; the larger costse towards the sides of the valves appear as if compressed upon
the shell. The anterior sides of the valves are nearly smooth, but each side has a few
very delicate radiating lines ; the entire surface of the valves has very delicate, closely
arranged, concentric, irregular striations, which impress the costse, and are very con-
spicuous upon the wide, flattened intercostal spaces; the valves are close fitting and thin.

6

42 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Geological Position and Localities. It occurs rarely in the Cornbrash of Scarborough.
Dr. Oppel records it in the same geological position at Marquise, near Boulogne ; also at
Egg, near Aarau, Switzerland. Goldfuss records it at the latter locality, and at Basel.

LIMA RIGIDULA, Phil., sp. Tab. XXXIII, figs. 7, 7 a.

PLAGIOSTOMA RIGIDULUM, Phil. Geol. York., i. t. 7, fig. 13.

Testa elongata, convexa, per-obliqua, umbonibus obliquis, acutis, auriculis parvis sub-
cequalibus ; latere antico elevato, excavato, postico elliptico curvato; valvis costulis radi-
antibus angustis, rotundatis, regularibm, sed undulatis et granulatis ; ititerstiis duplo
latioribus subtillissime transverse striatis, striisque regularibus instructis.

Shell elongated, convex, very oblique ; umbones small, pointed anterior ; auricles
small, nearly equal ; anterior side very convex, with a steep, excavated border ; posterior
side curved elliptically ; the entire surface has delicate but rounded, elevated, and finely
knotted radiating costae, gently waved and separated by interstitial spaces twice the
breadth of the costae ; the spaces have very fine, regular, and closely arranged transverse
striations; the plications of growth are few, but become prominent near to the lower
border.

One of the most elongated and oblique of the Jurassic Limae. The general figure and
ornamentation would much resemble Lima ovalis, Sow., if the convexity of the anterior
side were not much greater, and the costse more elevated, in the Cornbrash shell ; the
striations are so densely arranged that the spaces do not present a punctated aspect, as is
usually seen when the striations are more distant, and larger.

Dimensions. Length, 20 lines; breadth, 12 lines; diameter through both the valves,
10 lines.

Geological Position and Locality. The Cornbrash -of Scarborough, in which it is
abundant.

MODIOLA GIBBOSA, Sow. Tab. XXXIII, figs. 11, 11 a.

MODIOLA GIBBOSA, Sow. Min. Con., t. 211, fig. 2.

RENIFORMIS, Sow. Ib. fig. 3. ?

D'Orb. Prodr., i, p. 282.
— GIBBOSA, Mor. Cat id., 1854, p. 210.

Testa elongato-ovato, convexa subreniformi umbonibus curvatis acutis sulco obliquo
antico ; latere antico in/erne sinuato, latere postico elliptico curvato ; lateribus plicis mag nits
concentricis distantibus.

Shell ovately elongated, very convex ; umbones pointed, curved forwards j an oblique
sulcation proceeds downwards and forwards to the lower part of the anterior border, which

BIVALVIA. 43

is sinuated ; the anterior side has a large, rounded, but compressed lobe ; the posterior
border is very convex, and is curved elliptically ; the surfaces of the valves have a few
large, irregular and distant plications.

The length is twice the breadth, and two fifths greater than the convexity of the united
valves.

The very inflated figure, the curvature of the valves, and the distinct anterior broad
sulcation, distinguishes it from other Jurassic species ; some specimens, smaller and appa-
rently younger, cannot perhaps be distinguished from Modiola reniforniis, Sow., for the
species varies in the length, curvature, and convexity.

Geological Positions and Localities. This species is figured upon the authority of
specimens in the Museum of Practical Geology, which are stated to have been collected in
the Cornbrash of Melbury Osmond. It is common in the Inferior Oolite of the soxithern
counties.

CUCULL^A CORALLINA. Tab. XXXIX, fig. 3.

CUCULL^A OBLONGA, Phil. Geol. York., i, t. 3, fig. 34, non Sow.

— CORALLTNA, Damon. Geol. Weymouth, Suppl., pi. 4, fig. 8.

Testa inflata, subrhomboidali, subatquilaterali, umbonibus magnis mediants acutis,
incurvis, latere postico abbreviato abrttpte truncato, area cardinis brevi, superficie lineis
longitudinalibus crebris, irregularibus aliis radiantibus subobsoletis decussata.

Shell much inflated, subrhomboidal, nearly equilateral; umbones large, mesial,
incurved, elevated, slightly oblique, and nearly in contact.

The anterior side is produced and rounded, the posterior side is very short, abruptly
truncated, slightly excavated, and separated from the other portion of the surface by a
strongly defined subacute angle ; the hinge area is short and not wide ; the surface has
densely arranged, irregular, longitudinal lines, decussated by others radiating, but much
less clearly defined.

Dimensions. — Height, three fourths of the length .

A very short, tumid, abruptly truncated Cucullsea, possessing these characters in a greater
degree, and less oblique than any of the shorter examples of C. oUonga, Sow. ; the latter
shell has also several large, widely separated, radiating lines upon the anterior side, of which
our species is destitute. It appears to be identical with Cuculltea ohlonga, Phil., from the Coral
Rag, at least with the more short examples of that species, for the Coral Rag shell presents
great variability in its general figure, more especially in that of the posterior side, and it is
easy to obtain specimens which insensibly connect the shorter with the more lengthened
and oblique forms ; it rarely happens that the surface ornamentation can be discovered,
but the portions of the surface obtained agree with that of the Cornbrash shell.

Geological Positions and Localities. Cucullaa corallina occurs rarely in the Cornbrash
of the Yorkshire coast, but is abundant in the Coral Rag of Pickering and of
Oxfordshire.

44 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

CUCULL^A CLATHRATA, Leclc. Tab. XXXIX, figs. 4, 4 a.

CLATHRATA, Leckenby. Journ. Geol. Soc., 1858, vol. xv, pi. 3, fig. 4.

Testa subrhomboidali injlata, umbonibus antemedianis magnis, valde separates, area
amp/a, excavata, lanceolata, basi subrecto ; valvis ruyis lont/itudinalibus, irregularibus,
lineisque radiantibus, crebris tenuibus, dorso angulo obtuso et obliquo.

Shell subrhomboidal, inflated ; umbones large, placed anterior to the middle of the
valves, separated by a large lanceolate area ; there is an oblique obtuse angle upon the
posterior side, separating a concave posterior space from the middle portion of the valves ;
the surface has large, longitudinal, irregular, rugose plications crossed by closely arranged,
delicate, radiating lines; the lower border is nearly straight, and slightly sinuated.

The shorter posterior side and larger umbones distinguish it from Area lata, Dunker,
to which in other respects it has a considerable resemblance.

Dimensions. — Length, 26 lines; height, 14 lines; diameter through both the valves,
16 lines ; space separating the points of the umbones, 3 lines.

Geological Position and Locality. The Cornbrash of Scarborough, also in the
Kelloway Rock of the same locality. In the collection of Mr. Leckenby.

NUCULA MENKEI, Roem. Tab. XXXIX, fig. 2.

NOCULA MENKEI, Roemer. Nordd. Ool., t. 6, fig. 10, p. 98.

Testa ovata, media ventricosa concentrice striata, antice brevissima acuta oblique
truncata, cordato-subexcavata, posterius producta rotundata, basi subarcuata, umbonibus
crassis incurvis, aream lanceolatam hand efformantibus. (Roemer.)

Shell ovate, anterior side very short, somewhat excavated, and pointed at its lower
extremity ; posterior border lengthened, curved, sloping obliquely downwards, its lower
extremity rounded, base slightly curved elliptically, umbones large, incurved, area very
slightly defined ; the middle portion of the valves is moderately convex, with a few distant
plications of growth, and delicate concentric striations obscurely defined.

Nucula variabilis, Sow., approximates to this species, but is without the anterior
excavation, and has a more lengthened posterior side. Nucula nuclens, Desl., is shorter
and more globose.

Geological Positions and Localities. Roemer records Nucula Menkei in the Portland
Limestone of Wendhausen. Mr. Whiteaves has collected it in the Great Oolite of Kirk-
lington, and in the Corabrash of Islip, Oxon.

BIVALVIA. 45

Genus — ISOARCA, Munster.

Shell equivalve, ventricose ; umbones large, anterior or antero-mesial, sometimes more
or less spiral, ligament external ; hinge-border lengthened, curved, with two series of small
transverse teeth, which decrease in size towards the centre ; pallial impression simple.

ISOARCA SCARBURGENSIS, Lye. Tab. XXXIX, figs. 5, 5 a.

Testa tenui, ovato-oblonga, tumida, umbonibus magnis subanticis, prominentibus, latere
antico brevi, curvato, postico elongato, oblique declivi, sulcis duobus evanescentibus ; margine
inferiore subrecto ; valvis striis concentricis irregularibus, in/erne semel granulis irregularibus
instructis,

Shell thin, ovately oblong, somewhat inflated ; umbones large, prominent, placed
anterior to the middle of the valves, directed obliquely forwards ; anterior side short and
curved elliptically, posterior side lengthened, the margin sloping obliquely downwards with
two slightly impressed oblique furrows, which are distinct towards the umbo ; the lower
border is lengthened and nearly straight ; the surface has fine irregular, concentric striations,
and the sides have towards their lower border irregular, rounded granules, rather distantly
arranged.

Dimensions. — Length, 24 lines; height, 1 6 lines ; diameter through the valves, 12 lines.

A fine and rare example of a genus which seldom occurs in the Jurassic rocks of this
country. It is much less inflated, and the umbones are more prominent than in Isocardia
transversa, Munst., less oblong, and with the anterior side more produced than in
Isoarca Lochensis, Quenst., and Isoarca eminens, Quenst. Other Jurassic species more
remotely allied and approaching the orbicular figure are Isoarca subspirata, Munst.,
Isoarca texata, Munst., Isoarca decussata, Munst., and Isoarca cordiformis, Querist. The
general figure resembles Cypricardia, but when the hinge cannot be exposed, the genus
may be distinguished by the granulations upon the surface, and by the tenuity of the test.

Geological Position and Locality. The Cornbrash of Scarborough, in the collection of
Mr. Leckenby.

LEDA ANGLICA, If Orb. Tab. XXXIX, fig. 7.

NUCULA LACHRYMA (obtuse variety) Phil. Geol. York., i, pi. 9, fig. 25.
LEDA ANGLICA, If Orb. Prodr., p. 275.

Testa Icevigata parva, inflata, subtrigona, umbonibus inediaiiis obtusis i/icurvis depressis,
latere antico curvato, oblique-declivi, latere postico abrupte declivi, acute cttri/iata, carina.
obliqua promimula ; valvis striis longitudinalibus obscuris et plicis increment i pauci* i

46 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Shell small, inflated, short, subtrigonal ; umbones depressed, mesial, obtuse and incurved;
the anterior border is rounded, sloping downwards and uniting with elliptical curvature of
the lower border; the posterior side slopes abruptly downwards, it has an oblique posterior
carina, which becomes conspicuous and raised towards its lower extremity ; it separates a
posterior, depressed, lanceolate area from the sides of the shell. The surface has obscure
longitudinal striations, and several folds of growth.

The inflated figure, short posterior side and projecting oblique posterior carina, dis-
tinguish it from Leda lachryma, Sow., and also from other species of the Lower Oolites.

Geological Positions and Localities. The Cornbrash of Scarborough, in which it occurs
rarely. Professor Phillips records it in the lower stage of the Inferior Oolite (Dogger),
and in the gray limestone or upper stage of the same formation upon the coast of Yorkshire.

TRIGONIA ELONGATA, Sow. Tab. XXXIX, figs. 6, 6 a.

TRIGONIA ELONGATA, Sorv. Min. Con., t. 431.

D'Orb. Prodr., vol. i, p. 338.

Morris. Catal., 1854, p. 228.

Oppel. Juraformation, p. 525.

Damon. Geol. Weymouth, Suppl., pi. 2, figs. 1, 2.

Testa subtrigona, alta, convexa, antici brcvissima truncata, costis, magma, subhorizon-
talibus, leviter undulatis ; umbonibus prominentibus acutis incurvis ; area cardmali fata,
ornatissima, distincte tripartita, carinis prominentibus, denticulatis.

Shell subtrigonal, very convex and lengthened ; anterior side short, its border abruptly
truncated with numerous large, nearly horizontal and slightly undulated costas ; the
umbones are elevated and much incurved ; the posterior area (which nearly equals in size
the other portion of the surface) is very wide, and is separated into three distinct parts by
as many prominent denticulated carinse ; the marginal carina is very large and nearly
straight ; the mesial and inner carinse though smaller are likewise conspicuous in both the
valves ; the space between the mesial and inner carina is much depressed and its orna-
mentation is very delicate ; the superior or post ligamental space is short and wide, it has a
few elevated perpendicular plications. The convexity of the united valves is somewhat
greater than the breadth of the shell, and equal to two thirds of the length of the marginal
carina.

The general figure and other characters are so strongly defined that it will not readily
be mistaken for any other example of the group of the Costata ; the figure of the Cornbrash
specimens agrees with those from the Oxford Clay, but the sculpture upon the area is less
strongly marked in specimens from the latter formation, which are also usually smaller.
Compared with other examples of the same group of species, T. clongata is remarkable
for the short, widely-separated horizontal costse, for the great size and straightness of the

BIVALVIA. 47

marginal carina, for the prominence of the sculpture upon the tripartite area, and more
especially for the shortness and great breadth of the superior or post-ligaruental space,
which, when the valves are united, becomes cordate rather than lanceolate. D'Orbigny
(Prodrome) believes it to be identical with T. cardissa, Agassiz, it is, however, only necessary
to compare the marginal carina in the two forms to perceive their distinctness.

Geological Positiotis and Localities. It is abundant in the Oxford Clay of the southern
counties, more especially at Radipole near Weymouth, and in the Cornbrash of the coast
of Yorkshire, at Gristhorp, and at Scarborough. The foreign localities cited are France,
Dives, Villers (Calvados), Clucy, Mont Orient, near to Salins (Jura), Montsec, near to St.
Mihiel (Meuse), Marault, near to Chaumont (H. Marne), Beaumont, Pizieux, Chauffour
(Sarthe).

TRIGONIA TUBERCULOSA, Lye. Tab. XL, fig. 6.

TRIGONIA TUBERCULOSA, Lycett. Ann. and Mag. Nat. Hist., 1850, p. 12, t. 11, fig. 9.
Morris. Cat. Brit. FOBS., 1854, p. 229.

Testa ovato-trigona, subdepressa, umbonibus parvis, recurvatis, margins anteriore et
inferior e rotunda, margine postico excavato, area augustata, transverse plicata, plicis magnis
acutis ; carina marginali delicati nodulois ; carina interna varicibus magnis regularibus
ornata ; area lanceolata varicibus paucis obliquis ; valvis lateribus costis numerosis concen-
tricis et dense tuberculosis, tuberculis crebris elevatis, compressis.

Shell ovately trigonal, depressed ; umbones small, mesial and recurved, anterior and
lower borders rounded, superior border rather excavated ; area narrow, with two oblique
carinae, and with transverse acute plications, every second plication forming a varix upon
the inner carina ; the marginal cariua is delicately tuberculated ; the post ligamental
lanceolate space is small, with several oblique varices ; the sides of the valves have very
numerous, closely arranged, concentric tuberculated, costa ; the tubercles are much elevated,
and compressed laterally, imparting to them a club-shaped figure, the lower extremity of
each extending to the succeeding costa.

A pretty little species, remarkable for the delicacy and salient features of its orna-
mentation. The characters of the tubercles upon the sides of the valves closely resemble
those in Trigonia elathrata Ag., but in other particulars the two species are widely
separated ; the close contiguity of the extremities of the tubercles between row and row
gives to them, when viewed from the posterior side, the appearance of forming a series of
vertical costa? ; the tubercles are, however, very well separated in the rows, and towards
the lower border they project considerably from the sides of the valves ; eighteen rows of
cost* may be counted in a specimen whose length is only nine lines.

Geological Positions and Localities. The specimen figured is from the cabinet of
the Rev. A. W. Griesbach, and was obtained by him from the Cornbrash of Rushden ; it

48 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

is silicified, and is a beautiful object for the delicacy of its ornamentation ; the original
specimen figured by me in the ' Annals and Magazine of Natural History,' was obtained
by the Rev. P. B. Brodie in the shelly freestone of the Inferior Oolite at Leckhampton
Hill ; at each locality it ranks as one of the more rare productions.

TRIGONIA CLTTHIA, D'Orbigny. Tab. XXXVII, fig. 2 ; Tab. XL, figs. 5, 5 a.
TRIGONIA CLTTHIA, TfOrbigny. Prodr. de Paleont., i, p. 309.

" Coquille singuliere par ses cotes concentriques formant de deux en deux un angle svr
la region anale, independamment de la area costulee en travers." (D'Orbigny.)

Testa subtrigona, convexa, transversim costata, costis numerosis, crebris, curvfifi-s,
postice alternatim angidatis, carina marginali leevigato, elevato, area planatd transversim
costata, costis magnis, depressis.

Shell subtrigonal, convex, transversely costated ; costae numerous, small, closely
arranged, curved, convex upon their lower and concave upon their upper sides ; the first
few costae are united to the marginal carina, the succeeding costze are bent suddenly
upwards at their posterior extremities, forming a series of angles, one of which proceeds
from every second costa j the marginal and inner carinse are smooth and elevated ; the
area is moderately wide, flattened, traversed transversely by a few large depressed and
waved costae, which are interupted by an oblique mesial furrow.

The general figure is nearly triangular ; the umbones are mesial, much elevated and
pointed ; the anterior border is nearly straight, sloping obliquely downwards, but slightly
sinuated immediately beneath the umbones ; the posterior border is short and oblique.

Dimensions. — The height and the lateral diameter are nearly equal ; the diameter
through both the valves is one fifth less.

The costae upon the sides of the valves are so closely arranged that about twenty
occur in a specimen seven lines in height.

Geological Positions and Localities. The Great Oolite of Minchinhampton and Bisley
Commons, also in the upper zone of the same formation near to Bath. Luc (Calvados).

TRIGONIA SCARBURGENSIS, Lye. Tab. XXXVII, fig. 1.

Testa ovato-trigona subdepressa, elongata, umbonibus recurvatis, margine antico rotunda,
postico excavato, producto ; area angusta, elongata, carinis tribus delicatissimis ornato ;
valvis costis tuberculatis, magnis per series levifer arcuatis, antice parvis, irregular ibus,
postice magnis curvatis.

Shell ovately trigonal, rather depressed, elongated ; umbones recurved ; anterior side
rounded and produced ; posterior slope somewhat concave, lengthened ; the area is narrow,
flattened, with irregular transverse striations, and ornamented with three very delicate

BIVALVIA. 49

knotted carinse, the lanceolate, post-ligamental space is much lengthened, smooth, and
excavated. The costated portion of the shell has the rows at first regular and concentric,
with regular, distinct tubercles ; subsequently the costas become more ridge-like and the
tubercles less separated ; anteriorly they are small, and the rows are broken and confused ;
posteriorly they are large and more regular, curving upwards slightly, but their extremities
are well separated from the marginal carina.

This is the shell attributed by Messrs. Young and Bird to T. clavettata, and subsequently
also by Professor Phillips, Professor Williamson, and Mr. Bean, in their lists of Cornbrash
fossils.

Trigonia signata, Ag., figured in the second part of the Great Oolite Monograph
under the name of Trigonia decorata, is also an elongated shell, but is destitute of the
recurvature of the umbones and of the produced anterior side j the rows of costse likewise
differ ; the posterior portions are not larger than the anterior, and there is wanting that
arrest in the continuity of the rows always conspicuous in the Cornbrash shell, and which
imparts to the anterior portion of the latter form a broken, irregular character.
Trigonia clavettata, Lhwyd, Parkinson, and Sowerby, so abundant in the Lower Cal-
careous Grit of England, France, and Switzerland, has a much shorter and more convex
figure, the umbones are not recurved, features which will suffice to distinguish them
irrespective of the ornamentation of the surface. T. perlata, Ag., and T. Sronnii, Ag.,
from the same beds, appear to be only varieties of T. clavellata. Trigonia Scarburgensis
is also allied to that beautiful and well-known Oxford Clay representative of the Clavellata
so long procured at Weymouth, and of which a good figure is given in Mr. Damon's
' Geology of Weymouth,' Suppl., pi. ii, fig. 3 ; the latter, in addition to the unusual
elongation of its posterior side, has a wide diagonal space, destitute of ornament, separating
the posterior extremities of the costa3 from the marginal carina.

Geological Position and Locality. Trigonia Scarburgensis is moderately common in
the Cornbrash of the Yorkshire coast ; it may also occur in the same rock of the southern
counties, but the condition of the specimens is such that it has not been ascertained with
any confidence.

TRIGONIA CASSIOPE, D'Orb. Tab. XXXVII, fig. 10.

TRIGONIA CASSIOPE, If Orb. Prodrome de Paleont., 1, p. 308.

Testa ovato-triffona, transverse elongata, subdepressa, costis transversis, subhorizontalibus,
numerosis, laevigatis, aracilibus curvatis, antice rotundata, postice producta ; area tricari-
nata, carina marginali et interna crenulata, carina mediana parva ; carinarum intervallo
costellis longitudinalibus aranosis, confer/is, ornatis ; area postica lanceolata, delicate
reticulata.

Shell ovately trigonal, transversely elongated, somewhat depressed; transverse cost*

7

50 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

numerous, smooth, slender, nearly horizontal, and gracefully curved ; the anterior border
is rounded ; the area is lengthened, narrow, and slightly excavated, having three carinae,
of which the marginal and inner carinae are conspicuous, curved, and crenulated ; the
median carina is small ; the spaces between the carinae have longitudinal, delicate, closely
arranged, granulated little costas; the post-ligamental lanceolate space has a very
delicately reticulated surface.

A transversely lengthened, large, and gracefully curved form, much less convex than
T. costata, with more depressed umbones, and having the anterior side greatly more
rounded and produced. The costated portion of the shell is very large ; the costse are
numerous, not much elevated ; their direction is nearly horizontal, excepting near to the
apex, where they have an elegant sigmoidal curvature. The length upon the marginal
carinae is one fourth greater than the opposite measurement ; the diameter through both
the valves is somewhat less than half the height. The area is very narrow and length-
ened, the ornamentation of its surface is minute and delicately sculptured, the general
figure is depressed, which, together with the small prominence of the umbones, the
excavated posterior side, and the large, rounded anterior side, will, in the aggregate, serve
to distinguish it from other allied forms.

Geological Position and Localities. It is moderately abundant in the Cornbrash of
the coast of Yorkshire. The foreign localities quoted by D'Orbigny are Luc (Calvados),
Vezelay (Yonne), Grange- Henry, near Nantua.

TRIGONIA COMPTA, Lye. Tab. XL, fig. 1.

Testa ovato-triffona, subdeprcssa, umbonibus ob/usis, depress, latere anlico bred,
rotunda, poslico producto ; area planata, carinis fribus delicutissimis et striis transversis
tcnuissimis instruciis, costis (circa 12) postice noddosis, inter mptis, anticc rugis obliquis
instructis.

Shell ovately trigonal, rather depressed ; umbones obtuse, depressed, not recurved ;
anterior side short, rounded, posterior side more produced, its border straight, sloping
obliquely downwards ; area flattened, with three very delicate, tuberculated carinae, and
fine transverse striations, lanceolate; post-ligamental space narrow, lengthened, and smooth.
The other portion of the surface has about twelve rows of costae, which become large, hori-
zontal, nodulose, interrupted varices posteriorly, and form small, oblique, rather imperfectly
tuberculated, but continuous costae anteriorly, so that all the costae reach the anterior
border in an oblique rather than in a concentric direction.

The diagnostic characters are not very strongly marked, but in the aggregate arc
sufficiently distinctive. The delicately ornamented area separates it from T. Morcfonis,
Mor. and Lye., and the posterior, interrupted varices from T. impressa, Sow. From T.
Goldfumi, Ag., it is distinguished by the smaller oblique costae, more especially of their

BIVALVIA. 51

posterior extremities, where they do not form large, continuous varices, bent upwards at
a considerable angle, as in the latter species. T. costatula, Lye., is more convex, the
costae are more regular, smooth and concentric, the area also is much larger, which imparts
a subquadrate figure to the outline; other species are more remotely allied.

Geoloffical Position and Locality. The slate of Collyweston, Northamptonshire, in
which the specimens are usually compressed.

TRIGONIA CLYTHIA, D'Orb. Suppl., p. 48, Tab. XXXVII, fig. 2 ; Tab. XL, fig. 5.

Some fine specimens received subsequently to the printing of page 48 have enabled
the artist to illustrate the more adult aspect of this species. Tab. XL, fig. 5 a exhibits
the nodulous character of the posterior extremities of the costa3, their anterior portions
remaining regular and concentric ; fig. 5 is an aged specimen, exhibiting further changes.
In common with many other of the Jurassic Trigonise in the ultimate stage of growth, the
smooth costae are no longer regular or concentric ; they become less distinctly marked,
broken, undulating or wrinkled, constituting the approach to the period when all orna-
mentation ceases.

TRIGONIA TRIPARTITA, Forbes. Tab. XL, fig. 4.

TRIGONIA TRIPARTITA, Forbes. Journ. Geol. Soc., vii, tab. 5, fig. 11.
Morris. Catal., 1854, p. 229.

Testa ovato-triffona, subdepressa, umbonibus obtusis sed recurvatis, lalere antico rotunda,
postico subconcavo oblique dcclivi, antice costis laevigatis parvis obliquis crebris, postice
aliis (7 — 8) obliquis magnis dcpressis, nodulatis ; area subconcava, sulco mediano obliquo,
costis transversalibus penes apicem instructis.

Shell ovately trigonal, rather depressed ; umbones obtuse, but recurved ; anterior margin
rounded ; posterior margin somewhat concave, sloping obliquely downwards ; the anterior
side has numerous (about thirty) delicate, oblique, smooth costse, which are interrupted
posteally by others which cross them nearly at right angles ; the latter costae (about seven
or eight) are large, nodulous and depressed, the two latter only reach the lower border;
the marginal carina is but little conspicuous; the area is somewhat concave, it is transversed
by a mesial furrow, and has a few transverse costae near to the apex. Our specimen is
slightly imperfect at the apex and at the inferior border.

Geological Positions and Localities. A single example from the Cornbrash of Chippen-
ham, in the collection of W. Walton, Esq. This pretty species was also obtained by the
late Professor E. Forbes in a stratum of yellowish, crumbly limestone and shale, beneath
the Oxford Clay at Lock Staffin, in the Isle of Skye, associated with fresh-water and marine

52 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

testacea, which are believed to represent estuary conditions, a geological horizon which
possibly is not very dissimilar to that of our specimen.

TRIGONIA ARATA, Lye. Tab. XL, fig. 2.

Testa ovato-triffona, subdepressa, umbonibus antemedianis, obtusis depressis, latere
antico brevi, rotunda, postico oblique declivi, area planata, oblique irregulariter, striatis,
carina marginali subnullo, lateribus costis antice obliquis, postice anffulatis, depressis, sim-
plicibus. Testa cetate juniori costis concentricis simplicibus.

Shell ovately trigonal, somewhat depressed ; umbones anterior to the middle of the
valves, obtuse and depressed ; anterior side short, rounded ; posterior side sloping obliquely
down ; area flattened, with transverse, irregular striations ; marginal carinse not conspicuous,
and obsolete posteriorly ; the sides of the valves with numerous closely arranged, oblique,
plain costae, which are bent upwards posteriorly at an obtuse angle, and meet the area at
a right angle.

The costae are rounded and rather depressed ; they become more distantly arranged
posteriorly, but only slightly increase in size. The young shell has the costae regular
and concentric ; the marginal carina is small, but forms a distinct elevation ; a specimen
more aged than the one selected for our figure has the posterior portions of the costae
slightly nodulous ; anteriorly they become waved and irregular.

Geological Positions and Localities. A rare species ; Mr. Walton's specimens are
from the Forest Marble of Farleigh, near Bath ; it has also occurred in the same position
near to Cirencester.

TRIGONIA BATHONICA, Lye. Tab. XL, fig. 3.

Testa subtriyona, depressa, umbonibus altis mediants, latere antico et postico subrecto,
oblique declivi, lateribus costis elevatis, angustis, crebris, subundulatis, et spinulosis,
oblique instructis ; area parva planata oblique striata, carina marginali minimo, subnullo.

Shell subtrigonal, short, depressed ; umbones elevated, mesial, and not recurved ; anterior
and posterior borders nearly straight, sloping obliquely downwards, the surface with
numerous (about twenty-four) narrow, elevated, spinose, and somewhat undulated oblique
costae, which are directed from the marginal carina anteally downwards, and all reach the
lower margin ; the area is narrow and obliquely striated ; the marginal carina is very small,
and rather indistinct.

The narrow, ridge-like costae have numerous minute, obtuse spines, which impart
roughness to the surface ; they are distinct, rather irregular, and therefore very different
from the serrated, elevated, regular costae of T. striata, Miller, and its allied species ; the

BIVALVIA. 53

general aspect resembles T, duplicata, Sow., but it has no bifurcating costae near to the
lower border, and is also destitute of concentric costae near to the apex. The sole specimen
at our disposal is imperfect at the posterior extremity ; it has twenty costae, and would
require about four others to complete its surface. Possibly Trigonia Cybele, D'Orb.,
from the Great Oolite of Luc, may not differ from this species, but the seven words allotted
to it in the ' Prodrome' of that author are insufficient to characterise it.

The figure is nearly that of an equilateral triangle, each of the sides having a length
of about an inch.

Geological Position and Locality. In rubbly, hard, ferruginous Oolite (Great Oolite)
from the Box Tunnel ; communicated by W. Walton, Esq.

CARDIUM LINGCLATUM, Lye. Tab. XXXIII, figs. 2, 2 a; Tab. XXXV, figs. 11, 11 a.

Testa ovato-oblonga, mediocriler convexa, umbonibus prominentibus, mediants, subacutis,
valvis maryinibus ellipticis curvatis, rugis concentricis irregular ibus, striisque tenuibus,
delicate impressis ; postice striis obliquis regularibus decussatis.

Shell ovately oblong, moderately convex ; umbones prominent, mesial, and subacute ;
the anterior, posterior, and inferior margins of the valves are elliptically curved ; the
surface has numerous irregular, concentric rugae, and delicate, regular striations ; the
posterior side has some regular, oblique striations, which decussate those which are con-
centric. The height and the transverse diameter are equal.

Allied to Cardium coynatum, Phil, but the latter has much greater convexity, it has
larger and less pointed umbones, its surface is also destitute of the concentric rugae and
striations.

Geological Position and Locality. The Great Oolite of Kirklington, Oxon., collected
by J. F. Whiteaves, Esq.

CARDIUM INCERTUM, Phil. Tab. XXXV, figs. 14, 14 a.

CARDTOM INCERTUM, Phil. Geol. York., i, pi. 11, fig. 5.
UNICARDIUM INCERTOM, D'Orb. Prodrome, i, p. 279, No. 323.
CARDIUM INCERTUM, Morris. Catal., 1854, p. 192.

Testa suborbiculari convexa, Icevi, umbonibus submedianis elevatis subacutis incurvis,
margine antico concavo, lunula subnuHa ; latere postico planato angulo obliquoformante,
maryine postico subrecto in/erne angulato ; lateribus plicis concentricis paucis, irmju/uribus

et tenuibus.

Shell suborbicular, moderately convex, smooth ; umbones mesial or slightly antero-mesial,
elevated, acute, and incurved ; anterior border concave and rounded ; lunule scarcely

54 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

defined ; posterior side forming a flattened area, well separated from the other portion of
the surface by a clearly defined, oblique, and acute angle ; the posterior border, at first
curved, slopes suddenly downwards, nearly in a straight direction, forming an angle at its
junction with the lower border ; the surface has a few faintly marked, irregular, concentric-
plications.

Dimensions. — Length, 13 lines ; height, 1 1£ lines ; diameter through both of the valves,
8 lines. The hinge has not been examined.

Geological Positions and Localities. The fine specimen figured was collected by J. F.
Whiteaves, Esq., in the Great Oolite of Kirklington, Oxon. It occurs rarely in the Inferior
Oolite of Blue Wick ; it was also collected in the roe stone of the Inferior Oolite at Leek-
hampton Hill by the Rev. P. B. Brodie.

CARDIUM COGNATUM, Phil. Tab. XXXVI, figs. 3, 3 a.

CARDIUM COGNATUM, Phil. Geol. York., i, t. 9, fig. 1-4.

— COGNATUM, Mow*. Catal., 1854, p. 192.
UNICARDIUM COGNATUM, D'Orb. Prodr., Et. x, No. 324.
Oppel. Juraformation, p. 410.
CARDIUM Leckenby. Journ. Geol. Soc., xv, pi. 3, fig. 8.

Testa ovato-orbiculari, convexa, mnbonibus magnis, medianis, subrectis, margine
antico et postico, elliptico curvato, lunula nulla ; valvis striis concentricis, crebris, instructis;
postice striis radiantibus obliquis decussatis.

Shell ovately orbicular, convex ; umbones large, prominent, mesial, straight, or directed
slightly forwards ; the anterior and posterior margins of the valves are curved elliptically ;
there is no lunule ; the whole surface has very densely arranged, delicate, concentric
striations; the posterior side is not compressed, but has some oblique, faintly marked
striations, which produce a roughened surface where they decussate the concentric
striations.

The specific characters are not strongly defined, and reside more in the general figure
than in the ornamentation of the surface ; the Cornbrash specimens have a thin, shining
test, and the striations can scarcely be distinguished without the aid of a magnifier ; the
posterior side is scarcely so much produced as the other, and the greatest convexity of
the valves is placed a little posterior to the mesial line; the Kelloway Rock examples
are smaller.

Cardium cognatum is nearly allied to an inferior Oolite species, casts of which are
very common in the Cotteswold Hills ; the latter fossils are more ovate, the muscular
scars more strongly impressed ; the test is much more thick ; the striations, both
concentric and oblique, are more strongly defined, especially the oblique striations

BIVALVIA. 55

upon the posterior side, which deeply indent the shell, and are therefore always
conspicuous. The Cardium cognatum of Goldfuss is a very different shell, having a
posterior angle and oblique umbones. D'Orbigny (' Prodrome') has arranged our species
.with his genus Unicardiuni, in which he has been followed by Dr. Oppel (' Juraforinatiou') ;
but, having examined the muscular impressions and also those of the hinge, I can affirm
that Professor Phillips correctly discriminated the genus.

Geological Positions and Localities. The specimens figured are from the Cornbrash
of Scarborough ; it occurs also in the Kelloway Rock of the same neighbourhood and in
Wiltshire.

CARDIUM. WITCHELLI, Lye. Tab. XL, fig. 36.

Testa parva ovato-trigona, convexa, umbonibas magnis prominentibus mediums, sub-
acutis, latere posterior e angulo obliquo et area postica planata, in medio sulco obliquo in-
structo ; dorso striis tenuissimis concentricis regularibi/s.

Shell small, ovately trigonal, convex ; umbones mesial, prominent, and somewhat
pointed ; the anterior and lower margins are rounded ; the posterior margin is somewhat
angulated at its lower extremity ; the posterior side has a conspicuous, oblique angle,
separating a flattened, smooth, posterior area, which is traversed by a mesial, oblique furrow ;
the other portion of the surface has very fine, regular, concentric striations. The height
and length are equal ; the diameter through both the valves is somewhat less.

The abruptness of the posterior angle, the flattened, smooth area, with its mesial
groove, appear to separate it from other allied Jurassic species. Possibly it may be a
dwarfed representative of a much larger form.

Geological Position and Locality. The Great Oolite of Bussage, near Bisley Common ;
the process of crushing shelly portions of the white Oolite has yielded this little species
to Mr. Witchell.

CYPIUCARDIA CAUDATA, Lye. Tab. XXXVI, figs. 8, 8 a.

Testa transversa, subtriyona, obliqua, subdepressa, uiiiboiiibux mayn't*, elevatis, sub-
involutis, incurvis, latere postico oblique declivi, obtusangulo iiistrucfo ; lunula depressa ;
valvis striis lo/igitudinalibus tenuissimis, intequalibus, latere antico semcl striis radiantibus
tenuissimis decussatis. Nucleo striis obscuris radiaiitibus et concentricis.

Shell transverse, subtrigonal, oblique, rather depressed ; umbones large, elevated, and
subinvolute ; the posterior side slopes obliquely downwards, and has a slightly defined,
obtuse angle ; the anterior side is moderately produced ; the lunule is strongly defined ;

56 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

the lower portion of the anterior border is elliptically curved ; the base is nearly straight ;
the inner borders of the valves are crenulated ; the surface has closely arranged, delicate,
unequal, longitudinal striations, which are decussated upon the anterior side by others
which radiate from the umbones, and when the outer layer of the test has been removed
a series of strongly marked, radiating striations are exposed over the whole of the
valve ; both kinds of striations are also impressed more or less distinctly upon the
nucleus.

This delicately ornamented Cypricardia might at the first glance be mistaken for a
depressed variety of Cypricardia cordiformis, Desh., a shell which in the young condition
possesses great differences of figure ; it will be found, however, that Cypricardia caudata is
more depressed, more trigonal, the anterior side more lengthened, and the posterior angle
much less defined, so that the portion of the surface posterior to it is even somewhat
convex ; but in Cypricardia cordiformis it is flattened or often slightly concave in some
instances ; the entire absence of ornamentation, both upon the test and the nucleus, is
another distinctive feature. The fine specimen figured has the area delicately preserved,
and exhibits the ligament ; the test is of moderate thickness, and the inner borders of
the valves are crenulated ; an exposed portion of the nucleus has striations corresponding
to those upon the inner layer of the test.

Geological Position and Locality. The Cornbrash of Northamptonshire j also in the
Forest Marble of Wiltshire, obtained by W. Walton, Esq.

ISOCARDIA MINIMA, Sow. Tab. XXXVI, figs. 1, 1 a.

ISOCAEDIA MINIMA, Sow. Min. Con., t. 295, fig. 1.

— Phillips. Geol. York., i, t. 7, fig. 6.

— Morris. Catal., 1854, p. 204.

— ? Quenstedt. Der Jura, p. 443, pi. 60, fig. 17.
Non ISOCARDIA MINIMA, Gold/. Pet., p. 211, t. 140, fig. 18.

Testa crassa, lavigata, tumida, umbonibus parvis submcdianis incurvis, margine dorsali
oblique-curvato, lunula cxcavata ; lateribus striis concentricis crebris tequalibus, tenuissimis
instructis.

Shell thick, smooth, convex ; umbones small, somewhat oblique, and placed a little
anterior to the middle of the valves ; dorsal border curved obliquely ; lunule excavated ;
the surface of the valves with very delicate, closely arranged, concentric striations.

A smooth, short, rounded, and moderately convex shell, with rather small umbones,
quite different from the casts figured by Goldfuss and attributed by him to this species,
but which probably belong to the genus Cardium.

The single figure given by Quenstedt is much more inflated, with larger umbones,

BIVALVIA. 57

and is probably also distinct ; it is from a lower geological position, associated with
Trigonia signata, Ag., and other Inferior Oolite fossils of that stage.

Another shell erroneously attributed to our species is I. minima, Damon (' Geol.
Weymouth,' SuppL, pi. iv, fig. 7), from the Coral Rag of Weymouth ; it is much more
oblique, with produced umbones.

The figures given in the ' Mineral Conchology' and in the ' Geology of Yorkshire' may
each be objected to for the great prominence of the umbones and the large excavation of
the lunule. The Yorkshire examples, which are very well preserved, differ somewhat from
each other in the degree of their obliquity ; some have a slightly defined, oblique, posterior
angle. The height and length are usually equal, the diameter through the valves being
one fourth less.

Geological Position and Locality. The Cornbrash of the Yorkshire coast, in which
it is not uncommon.

ISOCARDIA TENERA. Tab. XXXVIII, figs. 5, 5 a, 5 b.

ISOCARDIA TENEUA. Gr. Ool. Monog., t. 7, fig. 1, part 2, p. 66.
Ibid., t. 38, fig. 5, Supplement.

As the figures given in the former portion of this Monograph represent a specimen
deprived of the test, a fine example in a perfect condition is now given, together with a
magnified figure of the ornamentation of the surface. The Cornbrash and the Lower
Calcareous Grit of Yorkshire yield specimens with the test very beautifully preserved,
brown and shining. One from the former rock has been selected ; the valves have delicate,
regular, concentric striations ; and when a portion of the external lamina of the test has
decomposed, the striations are decussated by others radiating from the umbones, as is also
seen in Isocardia nitida; these radiating striations belong only to the inner layer of the
test.

ISOCARDIA NITIDA, Phil. Tab. XXXVIII, figs. 6, 6 «, G b.

ISOCARUIA NITIDA, Phil. Geol. York., i, pi. 9, fig. 10.

TIUANGULARIS, Bean. Mag. Nat. Hist., 1839, p. 60, fig. 20..
NITIDA et I. TRIANGULARIS, Morrii. Catal., 1854, p. 204.

Testa crassa, nitida, injlata, ovato-trigona, umbonibus mediants, altis, acuminatis, sub-
involutis, laicre postico angulo obliquo acuto et area postico subconcavo; basi postice sinuato ;
valvis striis rcyularibim, longitudinalibus, crcbris ; nucleo lefvi.

Shell thick, shining, moderately inflated, ovately trigonal ; umbones mesial, elevated,
acuminated, subinvolute ; the posterior side with an oblique, acute angle, which separates

58 . SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

a slightly concave, posterior area ; the base is sinuated posteriorly ; the sides of the valves
have closely arranged, regular, delicate, longitudinal striations. The nucleus is smooth.

The anterior side is more produced and less inflated than Isocardia tenera, Sow.,
from which, also, it differs in having an acute posterior angle. When the external shining
surface has been abraded, it becomes the Isocardia triangularis of Bean, with radiating
striations, which indent the longitudinal ridges, a feature of which there are analogous
examples in some species of Ceromya, Pecten, &c. The inner border of the valves
is crenulated, and the ultimate stage of growth is distinguished by a deeply grooved,
longitudinal fold.

Length, 14 lines ; height, 11 lines ; diameter through the valves, 10 lines.

Geological Position and Locality. The Cornbrash of Scarborough, in which it is not
uncommon.

LUCINA STKIATULA, Buv. (var.). Tab. XXXVIII, fig. 7.

LUCINA STRIATULA, Buvignier. Paleont. de la Meuse, Atlas, p. 12, pi. 12, figs. 6, 7, 8.

Testa orbiculari, depressa, striis concenlricis, tenuibus, interdum majoribus et striis
radiantibus obsoletis decussata ; cardine subbidentato ; impressione musculari anteriore
lont/a, anyusta, posteriore obovata ; impressione palleali rugosa, substriata, sulco obliquo
incurvo notata. (Buvignier.)

Shell suborbicular, depressed, inequilateral; anterior margin horizontal and nearly
straight ; outline of the borders of the valves rather irregular ; the surface with very deli-
cate, densely arranged, and a few distant, large, concentric striations, decussated by nume-
rous faintly marked, longitudinal lines ; anterior muscular impression lengthened, narrow,
the posterior one obovate ; the pallial impression rugose, with an obliquely curved sulcus.
Height and transverse diameter equal.

The original of our figure is less transverse than that of M. Buvignier, but in other
particulars strictly agrees with it ; it is much less convex then L, rofundata, Roem., and
the surface ornamentation is quite distinct, but the outline of the two species is very
similar.

Geological Positions and Localities. Collected in the Great Oolite of Kirklington,
Oxon., by Mr. Whiteaves. M. Buvignier records it from the Upper Coral Rag of the
Meuse. Casts which are not uncommon in the Coral Rag of the southern counties of
England appear to belong to the same species.

BIVALVIA. 59

LUCINA ? BURTONENSIS, Lye. Tab. XL, figs. 20, 20 a, 20 b.

Testa suborbiculata, depressa, umbonibus subangulatis antrorsum curvatis, latere postico
area dcpressiuscula, superjicie striis tenuibus concenfricis crebris notatis.

Shell suborbicular, depressed ; umbones antero-mesial, angulated at their extremities, and
curved forwards ; the posterior side has a depressed, oblique area, without any angle ; the
surface has very delicate, closely arranged, regular, concentric striations ; the hinge-border
is short, and slightly curved.

As the hinge has not been exposed, some doubt may exist whether it is really a
Lucina ; the umbones are more produced than is commonly seen in that genus.

Geological Position and Locality. The Forest Marble of Burton Bradstock, Dorset, in
the collection of W. Walton, Esq.

LUCINA BEANII, Bean, sp. Tab. XXXVIII, fig. 3.

ASTARTE ROTUNDATA, Bean. Mag. Nat. Hist. 1839, non Roemer.

Testa tumida ovato-obliqua, umbonibus antemedianis, m.agnis, incurvis, margine cardinali
oblique-dcclivi, curvato, margine antico brevi, arcuato curvato ; valvis striis irregularibus,
plicisque semel instructis.

Shell somewhat inflated, oblique, ovate ; umbones prominent, obtuse, incurved, placed
anterior to the middle of the valves j hinge-margin lengthened, curved, sloping obliquely
downwards ; anterior margin short, rounded ; lunule very slightly excavated ; the surface of
the valves has irregular, concentric striations, and also a few large plications of growth.
The interior has not been exposed, but neither the hinge-margin nor the anterior border
possesses the usual characters of Astarte, the lunule being nearly, obsolete. It is shorter
and more convex than Lucina crassa, nor does it nearly resemble any other contempo-
raneous species.

Height and lateral diameter nearly equal ; diameter through both the valves, one
third less.

Geological Position and Locality. The Cornbrash of Scarborough, in the collection of
Mr. Leckenby.

CORBIS NEPTTJNI, Lye. Tab. XXXV, fig. 19.

Testa transverse ovali subatquilatera, concentrice costata, margine cardinali curvato,
oblique declivi, lunula magna excavata, umbonibus mediants subdepressis, antrorsum curvatis ;
costis concentricis regularibus angustis, striisque interstitiis instructis.

Transversely oval, convex, nearly equilateral ; umbones rather depressed, curved for-

60 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

wards; lunule large, excavated; hinge-border curved and sloping downwards; the extremities
are rounded and the base curves elliptically ; the concentric costas are regular, narrow, ele-
vated, the interstitial spaces having delicate longitudinal striations. The convexity is mo-
derate beneath the umbones, the extremities of the shell being rather compressed ; the
general figure approaches to C. Ley-merit, Buv., but that species has the posterior side
shorter and less rounded. The present shell is more lengthened than is usual with the
Jurassic species, and the concentric costse are less conspicuous.

Length, 19 lines; height, 12 lines ; diameter through the valves, 9 lines.

Geological Position and Locality. The upper portion of the Great Oolite, near
Minchinharnpton, in pale, buff-coloured Oolite ; few specimens have been obtained, and
these, for the most part, are only casts.

CORBIS ELLIPTICA, Whiteavcs, MSS. Tab. XXXV, fig. 1.

Testa ovato-elonffata, depressa, umbonibus parvis medianis, margine antico subhorizon-
tali, postico oblique declivi ; basi elliptico curvato ; superf.de rugis longitudinalibus regu-
laribus, magnis, elevatis, crebris.

Shell ovately elongated, rather depressed ; umbones small, but little elevated, mesial ;
anterior margin nearly horizontal ; posterior margin sloping obliquely downwards ; the two
extremities of the shell are rounded, and the base is curved elliptically ; the surface is orna-
mented with large, elevated, longitudinal, regular, and 'closely arranged rugae.

Length, 7 5 lines ; height, half the length.

A small, depressed, and unusually lengthened Corbis, which will not readily be mis-
taken for any other known Jurassic species.

Geological Position and Locality. The Forest Marble of Kidlington, Oxon., collected
by Mr. Whiteaves.

CORBIS ROTUNDA, Walton, MSS. Tab. XL, fig. 17.

Testa crassa, ovato rotundata, umbonibus magnis medianis antrorsinn curvatis, laieribus
sub-cequalibus postice subcomjtressa, superficie rugis concentricis magnis, crebris, sub-
cequalibi<s ; atate adulto rugis obsoletis ; cardo denle antico laterali magno.

Shell thick, ovately orbicular, subglobose ; umbones large, mesial, curved forwards ; the
sides nearly equal, but the posterior side is slightly compressed and shortened ; the surface
with large, closely arranged, concentric, but somewhat unequal rugae, which degenerate in
the adult state and nearly disappear.

It has sometimes been mistaken for Spliaera Madridi, but it is more orbicular, and the

BIVALVIA. 61

umbones are larger ; the concentric rngse will also at once distinguish it, as the young shell
of S. Madridi is smooth.

Geological Positions and Localities. The Great Oolite of Hampton cliffs ; the Corn-
brash of Laycock. In the collection of W. Walton, Esq.

OPIS LECKENBYI, Wright. Tab. XXXVII, figs. 9, 9 a.

OFIS LECKENBYI, Wright, in Proc. Geol. Soc., vol. xvi,.part 1, 1860.

Testa crassa, trigona, obliqua, fornicata, inesquilafera, cordiformi, transverse regulariter
costafa, postice acute carinata, umbonibus magnis elevatis, anticis, involutes, la/ere antico
brevissimo, postico subrecto oblique declim ; lunula magna profunda, marginibus obtusis,
striatis ; costis transvcrsis, regularibus, angustis, subacutis ; valvis striis longitudinalibus et
decussantibus subtillissiinis instructis.

Shell thick, trigonal, oblique, very convex, and inequilateral, cordiform, with transverse,
regular costa? ; a large, flattened, posterior area is separated from the other portion of the
shell by an elevated, acute carina, anterior and parallel to which is a slight depression ; the
umbones are large, elevated, much inclined forwards, and involute ; the anterior side is
very short, having a large and deep lunule, whose margin is rounded and striated ; the
costse upon the sides of the valves are regular, narrow, subacute, and not much elevated ;
the wide, posterior area has large, oblique striations ; the costated portion is covered with
extremely fine perpendicular and decussating striations, which are only distinguishable
under a magnifier.

Height, 15 lines ; length, 15 lines ; diameter through both the valves, 13 lines.

A large and elegant species, distinguished from Opts lunulatus, Sow., by the more con-
vex figure, the rounded margins of the lunule, and by the more acute and more densely
arranged costae ; the posterior carina and bordering sulcation are also very prominent
features ; the costse under a magnifier exhibit a beautifully decussated surface.

Geological Position and Locality. The Cornbrash of Scarborough ; a single specimen
in the collection of Mr. Leckenby.

OPIS PULCHELLA, V Orb. Part II, Tab. VI, fig. 3, p. SO.

OPIS PULCHELLA, D'Orligny. Prodrome, i, p. 30".

LUNULATUS, var. Great Ool. MOD., Pal. Soc., part 2, pi. 6, fig. 6, p. SO.

Espece voisine de I'O. lunulata, maisbienplus court e et moins oblique, presque carree
ornee de cotes concentriques." (D'Orbigny.)

The experience derived from a multitude of examples leaves no room to doubt that the

62 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Minchinhampton Opis allied to 0. hnulatus is distinct from the typical Inferior Oolite
shell, and that D'Orbigny has correctly indicated its distinctive characters in the brief
sentence above quoted ; our figures in Part II, Tab. VI, faithfully represent the Great Oolite
species.

OPIS LUCIENSIS, D'Orb. Tab. XL, figs. 19, 19 a.

OPIS LUCIENSIS, D'Orbigny. Prodrome, i, p. 307, No. 106.

Testa subtriffona, postice acute carinata, umbonibus prominentibus acutis, lunula per-
magna, profunda, lasvigata, in/erne rostrata, area posteriora sulco obttquo instructo ;
superficie striis tenuibus concentricis, interdum obsoletis.

Shell subtrigonal, short, posteriorly acutely carinated, with a conspicuous, oblique sulcus
upon the post-carinal area ; the umbones are elevated, acute, moderately incurved ; the
lunule is very large and deeply excavated, occupying the entire anterior side ; the surface
is smooth, with an acute, plain margin, its lower extremity forming a rostrated projection ;
the posterior surface of the valves has very delicate, concentric striations, which are only
partially visible.

It is allied to 0. pulchella, but is shorter, less convex, the umbones are more prominent
and less incurved, the lunule is very much larger, the posterior keel more acute, the
surface more smooth.

Geological Position and Locality. The Great Oolite of the Box Tunnel, near Bath, in
the collection of W. Walton, Esq.

COHBULA ATTENUATA, Lye. Tab. XXXVII, figs. G, 6 a.

Testa convexa, parva, subaquilatera, transversa, longitudinaliter, subtiHissime striata ;
latere posteriore attenuato, rostrato, producto ; angulo obliquo instructo ; basi leviter
curvato, postice subsinuato.

Shell small, convex, nearly equilateral, transverse, longitudinally very finely striated ;
anterior and posterior borders sloping obliquely downwards ; the posterior side is attenu-
ated ; it has an oblique angle, which separates a narrow posterior space ; its lower extremity
is rostrated i the anterior lower extremity is elliptically curved; the lower border is
lengthened, slightly curved, and posteriorly somewhat sinuated ; the umbones are small and
somewhat pointed. The figure is more elongated and has less convexity than the other
Great Oolite species of the genus ; the striations upon the posterior slope are bent
upwards at a right angle to their direction across the valve.

Height, equal to two thirds of the length, and a third greater than the diameter through
both the valves.

BIVALVIA. 63

Geological Positions and Localities. This well-marked little Corbula has been kindly
forwarded by J. F. Whiteaves, Esq., from the Great Oolite of Kirklington, Oxon.; also by
W. Walton, Esq., from the Forest Marble of Laycock, Wilts.

CORBULA INVOLUTA, Munst. Tab. XXXVII, figs. 4, 4 a.

CORBULA. INVOLUTA, Gold/. Pet., t. 151, fig. 14.
CYPKINA D'Orb. Prodrome, i, p. 2/8, No. 309.

Testa crassa, parva, perinflata ; concentrice subtillissime striata ; umbonibus magnis
obtitsis, submedianis ; latere antico rotunda, postico rostrato, obtuse carinato et attenuate.

Shell small, thick, greatly inflated, with very delicate, concentric striations ; umbones
large, obtuse, submesial ; anterior side short, rounded, posterior side attenuated, rostrated,
its margin concave, and forming at its lower extremity an acute angle ; the posterior slope
has delicate, transverse striations; it is somewhat flattened, very narrow, and is only
obscurely separated from the dorsal portion of the shell by an obtuse angle ; the lower
border is nearly straight.

Length, one third greater than the height and the diameter through both the valves.

The foregoing description will serve to distinguish it from a small, thick, but less in-
flated species, abundant in the Great Oolite of Minchinhampton, and which was formerly
regarded by me as C. involuta of Munster, and figured under that title in Part II, Tab. VI,
of the ' Great Oolite Monograph/ and described in Part II, p. 97 ; it had previously
been figured and described by Professor Buckman, in Sir R. Murchison's ' Geology of
Cheltenham,' 2nd ed., p. 97, pi. 3, fig. 4, under the title of Corbula striata ; but as that
name had already been appropriated by Lamarck for an Eocene Corbula, it becomes
necessary to change it to C. Buckmatii, under which name it is refigured, Tab. XXXVII,
fig. 8, thrice magnified.

Geological Position and Locality. The Great Oolite of Kirklington, Oxon. ; collected
by J. F. Whiteaves, Esq.

CORBULA ISLIPENSIS, Lye. Tab. XXXVII, fig. 7.

Testa parva, infiata, umbonibus medianis, magnis, crectis, latere anteriore rotunda,
posteriors brevi, abrupte truncato, angulo obliquo instritcto ; valvis longitudinaliter striatis,
striis magnis regularibus, lineis angustis separatis ; lunula excavata ; basi subrecto.

Shell small, inflated, but subquadrate or cuculaeform ; umbones large, mesial, erect ;
anterior side rounded, its lunule excavated; posterior side short, abruptly truncated, with
an oblique and subacute angle separating a posterior smooth and slightly concave
area ; the lower border is nearly straight ; the dorsal surface has large, regular,

64 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

longitudinal striations, separated by elevated, narrow lines, which disappear at the posterior
angle.

The height, length, and diameter through the united valves are nearly equal; the test
is thick.

The shortness of the posterior side, its angle, and the greater prominence of the
umbones, will distinguish it from C. striata, Buck. (C. Buckmanii, nobis, PI. XXXVII,
fig. 8). Corbula involuta, Munster, has the posterior side more lengthened and
rostrated, and is almost destitute of the posterior angle ; the striations upon the surface
are much more delicate and faintly traced, they are oblique rather than concentric or
longitudinal. Corbula cuculceformis, Kock and Dunker, is also allied to it, but with the
figure less inflated and with more pointed umbones ; it is therefore, probably, distinct.
Possibly C. amata, D'Orb., may be identical with our species, but unfortunately the few
words of description in the ' Prodrome ' of that author are insufficient to characterise it ; the
same remark will also apply to his C. Aglaya and C. Alimcna.

Geological Position and Locality. The Bradfordian beds of Islip, Oxon. ; collected by
J. F. Whiteaves, Esq.

CORBULA HULLIANA, Mor. Tab. XXXVII, fig. 5.

COKBULA HULLIANA, Morris. Hull. Mem. Geol. Surv., Cheltenham, 1857, pi. 1, fig. 6.

Testa crassiuscu/a, inflata, ovato-trigona, subecquivahi, subaiquilaterali, antice producta,
rotunda, postice attenuata, sulco obliquo et carina marginali obtuse; umbonibtis magnis
subacutis incurvis ; basi subarcuato out subrecto ; latcribus costis obliquis angustis, elevatis,
regularilus poslice undulatis ; striis radiantibus decussatis.

Shell of moderate thickness, much inflated, ovately trigonal, subaequivalve, subsequi-
lateral; umbones large, incurved, and pointed ; anterior side produced and rounded, posterior
side more attenuated, with an oblique groove and subniarginal, obtuse, rugose keel, the
base arcuated, or in other specimens nearly straight and slightly irregular ; the surface of
the valves with prominent, oblique, regular, narrow costse, which are slightly undulated
posteriorly ; occasionally the left valve exhibits towards the middle of its lower portion a
few perpendicular striations, which decussate the costa3 and render the lower margin
dentated.

The largest of the British Oolitic Corbulae, with the hinge -characters strongly marked;
the valves are less thick than usually obtains in the genus ; it is also apparently equivalve ;
a well-preserved specimen of the left valve is destitute of the perpendicular striations.

Geological Position and Localities. The specimen figured in the ' Memoirs of the
Geological Survey of Great Britain' was obtained in the Forest Marble near to Northleach ;
it occurs in the same position at Hinton, atFarleigh, and at Kidlington, Oxon., specimens

BIVALVIA. 65

have been forwarded to me by Mr. Walton and by Mr. J. F. Whiteaves ; at the Oxford-
shire locality, the specimens are small and usually compressed.

CORBDLA AGATHA, D'Orb. Tab. XL, figs. 28, 28 a.

CORBULA AGATHA, D'Orb. Prodrome, i, p. 307, No. 100.

Testa parva, subglobosa, lavigala, nitida, mnbonibus magnis, obtiisis, mediants, erectis,
latere anteriore rotundo ; lunula inagna, concava, cordata ; latere posteriore brevi, sub-
carinata, truncata.

Shell small, globular, smooth, shining ; umbones large, obtuse, mesial, erect ; anterior
side rounded, lunule large, cordiform, concave ; posterior side very short, with a faintly
marked oblique carina, and a truncated posterior border ; the surface has a few delicate,
irregular folds of growth ; it appears to be equivalve.

The diameter through both the valves is equal to the height, and somewhat less than
the length.

Corbula Deshaysea, Buv., is also a smooth species, but less short, the posterior border
being also slightly sinuated. Corbula Macneittii, Mor., another smooth shell, is much
more oblique, and more produced posteriorly. Corbula obscura, Sow., appears to be less
convex, and to have the posterior side more produced.

Geological Position and Locality. The Forest Marble of Cirencester and of
Wiltshire.

Genus — SOWERBYA, D'Orb., 1850.

ISODONTA, Buv. Bull. Soc. Ge'ol. de Fr., s6r. 2, t. 8, p. 353, 1851.

Shell equivalve, subequilateral, the valves close fitting ; hinge in the right valve, with
two oblique, diverging, symmetrical cardinal teeth separated by a mesial trigonal pit, and
two lamellar lateral teeth separated from the hinge-border by longitudinal grooves. The
left valve with a projecting conical tooth between two oblique pits ; lateral teeth two,
longitudinal, lamellar, projecting and united to the superior border. Ligament external.
Muscular impressions small, rounded, deeply marked ; palleal impression emarginated
posteriorly.

M. D'Orbigny in his 'Prodrome de Paleontologie/ vol. i, 13 Et., p. 362, characterised
his genus Sowerbya as follows : — " Sowerbya, D'Orb., 1847. — Coquille voisine des Mactra
par son sinus, mais avec des dents laterales enormes, et une fossette interne ligamentaire
simplement creusee."

9

66 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

It appears from the above quotation that M. D'Orbigny was acquainted only with
the hinge of the right valve of his Sowerbya crassa, upon which species the genus was
founded, and that he mistook the mesial dental pit for a fosse destined to receive an
internal ligament. In 1851, M. Buvignier having worked out the details of the generic
characters from specimens obtained in the upper ferruginous Oolite of the Oxfordian
strata of Ones (Mense), and Launoy (Ardennes), gave them to the public in the ' Bulletin
of the Geological Society of France,' ser. 2, t. 8, p. 353, under the new generic
designation of Isodonta. It is to the researches of M. Buvignier, therefore, that we are
indebted for a full and accurate description of Soioerbya. The same author states that
M. Terquem has discovered one nearly allied to the typical form in the Bradfordian beds
of the Mozelle.

The Jurassic rocks of England contain upwards of five species of Sowerbya : — 1,
S. triangularis, from the Oxfordian and Lower Oolites of Yorkshire ; 2, 8. Woodwardi,
from the Great Oolite of the Minchinhampton district ; 3, a small abruptly truncated
species from the Coral Rag of Yorkshire and Oxfordshire ; 4, a small subaequivalve shell,
with a posterior strongly marked oblique angle from the Coral Rag of Bullingdon ; 5, an
internal cast of a large species determined by Mr. Woodward, and figured by Mr. Damon
in his ' Geology of Weymouth,' from the Portland Oolite, under the name of S. Dukei.

SOWERBYA TRIANGULARIS, Phil., sp. Tab. XXXV, figs. 3, 3 a, 3 b.

CUCULL/EA TRIANOULARIS, Phil. Geol. York., i, pi. 3, fig. 30.
ARCA TRIANGULABIS, D'Orb. Prodr., i, p. 369.
CUCULLJBA TRIANGULARIS, Mor. C.itdl., 1854, p. 197.

Testa transverse, ollonga, injlata, sulaquilatera, postice oblique carinata, wmbonibus
parvis poster •o-medianis, margine inferiore angulo formante ; superficie plicis lonffitudi-
nalibus paucis magnis et striis longitudinalibus subtillissimis ornata.

Shell transverse, oblong, inflated, slightly inaequilateral ; the posterior side the shorter,
with a posterior oblique angle, separating a posterior slightly excavated surface which
terminates downwards in a conspicuous angle ; the anterior side is produced and curved
elliptically ; the umbones are placed a little posterior to the middle of the valves ; they are
small and contiguous. The surface has one or two large folds of growth, and is orna-
mented with longitudinal, regular, closely arranged striations, which disappear upon the
posterior excavated slope.

The height is about equal to the diameter through both the valves, and to three fifths
of the length.

The species exhibits much variability in the general figure, in the degree of convexity,
in the prominence of the posterior angle, and in the length ; differences which are not
limited to a single formation or locality, as it occurs in the Yorkshire Oolites in the

B1VALVIA. 67

Dogger, the Gray Limestone, the Cornbrash, the Kelloway Rock, and the Coral Rag ;
numerous specimens are also in the Tessonian collection from Normandy, now in the
British Museum. Some of these examples are almost destitute of the posterior angle, and
approach so nearly in the general figure to Sowerbya crassa, D'Orb. = Tsodonta Des-
Itaysea, Buv., that they might fairly have been assigned to that species, if we had not the
assurance of M. Buvignier that his specimens from two localities are in a good state of
preservation, and that they are destitute of ornamentation — a feature which is always dis-
coverable in good examples of S. triangularis, whether British or Foreign.

Mr. Whiteaves has figured a small species of Sowerbya, ' Ann. and Mag., Nat. Hist.,'
August, 1861, under the name of 8. triangularis, Phil. Having had the advantage of
comparing the original specimen, through the kindness of Mr. Whiteaves, with various
Yorkshire specimens of 8. triangularis, I feel unable to coincide in the opinion that it is
identical with the species of Professor Phillips ; the new Oxfordshire form is much
smaller, less inflated, destitute of ornamentation ; and the posterior side is so short that
' truncata would be an appropriate name : it is from the Coral Rag of Oxfordshire. I
have also found it in the Calcareous Grit at Scarborough Castle.

The second small species figured by Mr. Whiteaves upon the same plate under the
name of S. Deshaysea, Buv.? also appears to be distinct from each of the foregoing
examples ; the general figure is more compressed, the anterior slope is excavated,
which renders its lower extremity pointed ; the whole aspect somewhat resembles a
Nucula.

Our specimen figured is from the Cornbrash of Scarborough.

SOWERBYA WOODWARDI, Lye. PI. XL, figs. 27, 27 a, 27 b, 27 c.

Testa ovato-trigona suldcpressuj sub<zquilalera, latere posteriore breviori, planata,
laevigata angulo obliquo diviso, dorso et latere antico striis longitudinalibus regularibus
crebris, delicate instructis.

Shell ovately trigonal, rather depressed, subequilateral, the posterior side being the
shorter ; the umbones are not very prominent nor large; the anterior and posterior borders
slope obliquely downwards ; the extremities of the valves are rounded ; the surface has
delicate, closely arranged regular longitudinal or concentric striations, which are separated
from the smooth and flattened posterior side by a distinct angle.

It is much smaller, more depressed, more lengthened, and the umbones are much less
elevated than in 8. triangularis. Our right hand figure is imperfect at the posterior
extremity, and the posterior oblique angle is not clearly shown ; the left hand figure
has the anterior extremity too obtusely rounded, the specimen wanting a little of its
border.

Geological Position and Locality. The Great Oolite of Bussage, near to Bisley

68 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Common, collected by E. Witchell, Esq. A specimen has also been brought under my
notice by S. P. Woodward, Esq., but its locality is uncertain.

TANCREDIA GIBBOSA, Lye. Tab. XXXV, fig. 7. Tab. XXXVI, fig. 1 1.

TANCREDA GIBBOSA, Lye. Cott. Hills Handb., p. 121, pi. 7, fig. 4.

Testa subtrigona, tumidula, umbonibus mcdianis acutis, latere antico attenuate, postice
tumido subangulate ; dorso l&vigato, plicis increments, paucis irregularibus.

Shell subtrigonal, tumid; umbones elevated, pointed, and placed a little anterior to the
middle of the valves ; the anterior side is rather attenuated and pointed at the lower
extremity ; the posterior side slopes obliquely downwards, it is somewhat tumid, and has an
oblique angle slightly defined ; the surface is smooth, but with a few plications of growth
towards the lower border.

Height, 10 lines; length, 13 lines; diameter through both the valves, 6 lines.

It is distinguished from other Great Oolite species by the combination of a trigonal
outline with a tumid figure.

Geological Position and Locality. It occurs rarely in the Great Oolite shelly
weatherstones of Minchinhampton Common, and the Forest Marble of Farleigh,
Somerset.

TANCREDIA MACTR^OIDES, Whiteaves, MSS. Tab. XXXV, fig. 4.

Testa ovato trigona, convexa, umbonibus submedianis elcvatis, incurvis ; margine antico
breviore, leeviter excavato, margine postico oblique declivi, angulo oblique leeviter instructe,
basi elliptico curvato.

Shell ovately trigonal, convex, with a few concentric plications ; umbones antero-
mesial, elevated, and incurved; anterior border the shorter, slightly concave; the extremity
pointed ; posterior hinge-border sloping obliquely ; there is also a posterior oblique angle
faintly marked.

lancredia gibbosa, Lye., approximates to this species, but is more convex, with a more
elevated and rounded posterior slope. T. axiniformis, Phil., from the Inferior Oolite of
Yorkshire, is more flattened, with more pointed umbones and acute posterior angle.
Height two thirds of the length.

Geological Position and Locality. The Great Oolite of Stonesfield, Oxon., where it
appears to be rare ; collected by J. F. Whiteaves, Esq.

TANCREDIA SIMILIS, Whiteaves, MSS. Tab. XXXV, fig. 9.

Testa ovato clongata, umbonibus antcmedianis, latere antico attenuate, breviore ; postico
convexo, angulo obtuso obliquo j basi ettiptica curvata.

BIVALVIA. 69

Shell ovately elongated; umbones placed anterior to the middle of the valves, rather
depressed and obtuse ; anterior side the shorter, its upper margin slightly excavated, its
lower extremity pointed ; posterior side larger, more convex, with an oblique obtuse angle ;
the hinge-border is moderately lengthened and horizontal ; the surface is smooth, the lower
border is elliptically curved.

T. extensa, Lye., ' Gr. Ool. Mon.,' p. 93, approximates to the present form, but has a
much larger anterior side, with the umbones more elevated and mesial.

The height slightly exceeds half the length.

Geological Position and Locality. The Great Oolite of Kirklington, Oxon., collected
by Mr. Whiteaves.

CORBICELLA SUB^QUILATERA, Lye. Tab. XXXV, fig. 12.

COBBJCELLA suB^EQUiLATERA, Lycett. Cotteswold Hills Handbook, p. 126.

Testa ovato-obliqua laviffata, umbonibus parvis, antero-medianis, lunula angusta, sulco
ligamenti angmto, margine superiore oblique curvato.

Shell oblique, ovate, smooth ; umbones not prominent, placed a little anterior to the
middle of the valves ; anterior border slightly depressed, lunule narrow ; superior border
curved obliquely ; ligamental sulcus narrow and lengthened ; surface of the valves smooth,
the lines of growth being only faintly impressed. The height is equal to two thirds of
the length ; the diameter through both the valves is equal to about half the height.

This shell presents an example of a remarkable series of Jurassic bivalves, whose cha-
racteristic features are intermediate between Corbis and Tancredia, and which may usually
be discriminated without reference to the hinge ; compared with Corbis, the more depressed
form, the smallness of the anterior side, and the surface destitute of ornament, will always
distinguish it ; from Tancredia by the more ovate form, and by the absence of the posterior
oblique angle. The hinge is figured upon PI. XII, fig. 15, of the ' Great Oolite Monograph ;'
but the artist has scarcely extended the hinge-lamina sufficiently to exhibit the depressed
posterior lateral lamellar process ; the absence of the anterior lateral tooth, and the figure
of the cardinal dentition, is also distinct from Corbis, and is more nearly allied to Tancredia,
from which it differs chiefly in possessing a lengthened hinge-lamina and depressed
remote posterior lateral tooth; these distinctive features are remarkably persistent in
every example of Corbicella, and tends greatly to strengthen its claims to a generic
distinction.

Under the name of Corbis lucida our species was included in Mr. Bean's list of
Cornbrash Fossils, published in the 'Magazine of Nat. Hist.,' 1839, but was not accom-
panied by any figure or description.

Geological Positions and Localities. The specimen figured is a fine example from the

70 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Corubrash of Scarborough, in which rock it is rare. The lower grit of the upper portion
of the Inferior Oolite at Rodborough Hill, near Stroud, has produced a considerable
number of specimens, for the most part smaller, and sometimes more nearly equilateral ; it
also occurs in the same position at Leckhampton Hill ; at each of these Inferior Oolite
localities it is associated with a larger, more lengthened, aud more depressed species.
(C. complanata, Lye.). Corbis depressa, Desh., from the Oxfordian strata of Viel,
St. Remy, approaches nearly to it in the general outline, but is more depressed and some-
what less ovate.

CORBICELLA suBANGULATA, Lye. Tab. XL, fig. 9.

Testa ovata sub-compressa, transversa, umbonibus antemedianis , mcdiocri magnitudine,
margine cardinali oblique declivi, later e postico angulo oblique instructo, maryine antico
subconcavo, sitperficie plicis incrementi maynis irregularibus.

Shell ovate, somewhat depressed, transverse ; umbones of moderate size, placed anterior
to the middle of the valves ; hinge-border of moderate length, sloping obliquely down-
wards ; the posterior side has an oblique angle ; the anterior border is slightly concave ;
the surface has numerous plications of growth, which become large and irregular towards
the lower border.

Allied to C. complanata, Lye., from which it is distinguished by the strongly marked
posterior angle, and by the larger umbones ; our specimen is imperfect, at the posterior
extremity.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection
of W. Walton, Esq.

CYPRINA ISLIPENSIS, Lye. Tab. XXXV, fig. 13.

Testa ova/o- transversa, convexa, Iffvi, obliqua, umbonibus antemedianis magnis,
incurvis, lunula magna, excavata, area parva lanceolata ; latere postico compresso, angulo
olliquo formante ; basi elliptica curvata; striis concentricis tenuibus, irregularibus,
subobsoletis.

Shell ovately transverse, convex, smooth, oblique ; umbones large, incurved, placed
anterior to the middle of the valves ; area small, lanceolate ; posterior side compressed and
slightly concave, forming an oblique and well-defined angle with the other portion of the
surface ; lower border curved elliptically, forming an angle at its junction with the posterior
border. Nearly allied to Cyprina Loweana, Mor. and Lye., from which it is distinguished
by the larger umbones ; larger lunule, by the posterior flattened or concave area, and by
the well-defined oblique and acute angle, which renders the posterior extremity some-
what rostrated.

BIVALVIA. 71

Geological Positions and Localities. The specimen figured was obtained by
Mr. Whiteaves in the Great Oolite of Kirklington, Oxon. ; it has also occurred rarely in the
same formation at Minchinhampton Common, and in the Cornbrash of Islip, Oxon.

CYPRINA BELLA, Lye. Tab. XL, figs. 15, 15 a.

Testa ovato-orbiculari Icevigata, subdepressa, umbonibus mediocris, antero-medianis ,
margine cardinali recto, subhorizontali, postice subangulata, lunula angusta vix depressa ;
superficic angulo postico obliquo instructo ; striis incrementi crebris, irregularibus.

Shell transverse, ovately orbicular, smooth, rather depressed ; umbones of moderate
size, but little elevated, placed a little anterior to the middle of the valves and curved
forwards ; hinge margin straight, nearly horizontal, and slightly angulated posteriorly ; the
lunule is narrow, and but slightly impressed ; the exterior surface has an oblique angle,
posterior to which the surface is flattened ; the striations of growth, and delicate, numerous,
and irregular.

The depressed form, posterior subhorizontal straight hinge border, and oblique
posterior angle, are the features that will serve to distinguish it from allied contemporaneous
forms. The numerous specimens placed at my disposal include examples from two to
nine lines in length, which measurements usually exceed the height by one fifth.

Geological Position and Localities. The Forest Marble of Laycock and Pound Pill.
In the collection of W. Walton, Esq.

CYPRINA DAVIDSONI, Lye. Tab. XXXVI, figs. 6, C a.

Testa ovato-orbiculari crassa, convexa, obliqua, umbonibus obtusis submedianis antrorsum
inflectis, marginilus arcuatis curvatis, latere postico area subplanata, angula obtitso obliquo
interdum instructo, aut nullo ; lunula vix excavata, inconspicita, superficie striis concent-rids
irrcffularibus.

Shell ovately orbicular, thick, convex, oblique, but varying much in the length and
obliquity ; umbones obtuse, submesial, directed forwards ; margins of the valves curved
elliptically and close fitting, lunule not conspicuous and scarcely excavated ; the posterior
side has a narrow, oblique, flattened space, sometimes separated from the other portion of
the surface by an obtuse angle ; in other instances there is no distinct angle ; the surface
has numerous irregular concentric and faintly marked plications.

Dimensions of a large specimen of medium figure; length, 17 lines ; height, 15 lines ;
diameter through the valves, 11 lines.

It is liable to be mistaken for Cyprina Lowcana, compared with which our shell is

72 SUPPLEMENT TO GREAT OOLITE MOLLUSC A.

shorter, more convex, the test thicker, the umbones larger, less oblique, and more obtuse ;
the posterior flattened area is also a distinguishing feature when it is present.

Geological Position and Localities. The Forest Marble of Laycock and Farleigh, in
the collection of W. Walton, Esq., of Bath.

ASTARTE UNGULATA, Phil., sp. Tab. XXXV, fig. 20.

ASTAKTE LURIDA, Phil. Geol. York., i, pi. 5, fig. 2, p. 137, non A. lurida, Sow.

— Williamson. Trans. Geol. Soc., 2d ser., vol. vi, p. 149.

— Bean, on Cornbrash Fossils, Mag. Nat. Hist., 1839.

— Leckenby, on Kelloway Rock Fossils, Journ. Geol. Soc., 1858.

Testa suborbiculari aut subquadrangulari, depressa, ineequilatera, ad periphtzriam con-
centrice costellata, costellis elevatis, subangularibus, concentrice subtittissime striatis;
costellis in/erne evanescentibus ; margine cardincdi curvato, lunula subnulla.

Shell suborbicular or somewhat subquadrangular, depressed, inequilateral ; umbones
small and only slightly produced ; posterior and inferior margins rounded, lunule,
obsolete ; the surface near to the umbo with elevated acute concentric rugae, which are
impressed with very delicate concentric striations ; the rugaB disappear towards the middle
of the valve, the lower portion having only some plications of growth.

The character of the surface has a considerable resemblance to Astarte Wiltoni, f Gr.
Ool. Monogr.,' Tab. IX, f. 16 ; but the latter has the umbo much more produced, it has a
distinctly excavated lunule and is more convex ; other depressed species are sufficiently
separated by their ornamentation.

Astarte lurida, Sow., which occurs in Gloucestershire at Nailsworth in gray shale
near to the upper boundary of the Upper Lias, and in the lower portion of the overlying
Supraliassic Sands associated with Ammonites variabilis, is a very different shell, whose
figure is ovately trigonal and moderately convex, with prominent apex, well-marked lunule
and depressed concentric ruga? ; it does not therefore present a near approximation to our
species.

Astarte unguluta has the height and lateral diameter equal ; the valves are moderately
thick ; the size varies from 4 to 1 0 lines across. It is rare.

Geological Positions and Localities. Professor Phillips figured the interior of a valve
from the Oxford Clay of Scarborough. Mr. Leckenby has recorded it in the Kelloway
Rock of the same locality ; our figure is taken from a Cornbrash specimen of the same
coast now in the collection of Mr. Leckenby, and formerly in that of Mr. Bean, who
identified the species with that originally figured in the ' Geology of Yorkshire.'

BIVALVIA. 73

ASTARTE ORBICULARIS, Sow. Tab. XL, fig. 33.

ASTARTE ORBICULARIS, Sow. Min. Con., v, p. 65, tab. 444.
Morris. Catal., p. 187.
D'Orb. Prod, de Paleont., i, p. 308.

Testa parva miborbiculari, convexa, umbonibiis medianis elevatis, lunula mat/na, valvis
costulis concentricis numerosis, depressis, interstiis latioribus, subcequalilus.

Shell small, nearly orbicular, convex ; utnbones mesial and produced ; lunule distinctly
marked, rounded, the surface with numerous (about twenty) depressed, narrow, con-
centric little ribs, separated by somewhat wider and nearly equal spaces, upon the posterior
side the ribs are slightly undulated.

The little ribs are strongly marked upon the sides, but much less so upon the middle
of the valve, and are scarcely to be distinguished upon the umbones ; they are so delicate
that the surface appears plain without the aid of a magnifier; this latter feature will
serve to distinguish it from other small species, as A. minima, Phil., A. pisiformis, Sow.,
A. Parkinsoni, Quenst. Of other small examples of the genus, A. pisum, Kock and
Dunker, and A. Pontonis, Lye., are much less orbicular, and have more prominent costae ;
A. mediolfevis, Buv., has the ornamentation of a similar character, but the figure is ovately
trigonal, and therefore sufficiently distinct.

Geological Positions and Localities. The upper beds of the Great Oolite near Bath,
where it appears to be not uncommon ; also upon the same horizon at Ancliff, Wilts.
Luc (Calvados).

ASTARTE POLITULA, Sean. Tab. XXXV, fig. 16.

ASTARTE POUTULA, Bean. Mag. Nat. Hist., 1839.

%

Testa suborbiculari, convexo-plana, umbonibus antemedianis parvis, acutis, incurvis,
maryine cardinali curoato, fossa ligamenti, anyuxto, elonyato, maryine antico subrecto
lunula lanccolata, Icviter excavate ; valvis striis rcyularibits tenuissimis concenfricis, inferior?
irrcgdariter plicatis.

Shell suborbicular, rather depressed ; umbones anterior to the middle of the valves,
small, acute, incurved ; hinge-border slightly curved ; ligamental groove narrow and
lengthened ; anterior border nearly straight ; lunule lanceolate and slightly excavated, its
margins subacute ; the surface of the valves with very fine, regular, concentric situations ;
the lower portion of the surface is destitute of striations, but has several irregular, con-
centric plications.

The convexity is moderate about the middle of the valves, but the test has not much

10

74 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

thickness towards the borders, the outline has a considerable resemblance to Liicina
crassa but the latter is much thicker towards the borders of the valves, and has a different
kind of surface. The hinge has not been exposed.

Geological Position and Locality. The Cornbrash of Scarborough ; in the collection
of Mr. Leckenby.

ASTARTE LECKENBYI, Wright. Tab. XLII, fig. 3.

Testa crassa, transversa, ovata, subdepressa, wmbonibus parvis, prominutis antero-
medianis ; latere antico brevi, margine rotundo, lunula subnulla ; latcre posfico producto,
margine superiori subrecto, elongato, oblique declivi ; basi arcuato curvato ; super/lew
rugis crebris concentricis et striis subtilibus ornatis.

Shell thick, transverse, ovate, rather depressed ; umbones small, prominent, placed at
the commencement of the anterior third of the shell ; anterior side short, its margin
rounded with scarcely any lunule ; posterior side produced and compressed, its superior
margin nearly straight, lengthened, sloping obliquely; the base is elliptically curved; the
surface has prominent, concentric, closely arranged, rounded rugae near to the umbones,
which afterwards degenerate into depressed, irregular plications ; there are also fine, con-
centric striations.

A large species, remarkable for the depression of the valves and for the great
length and straightness of the superior border, whose measurement is equal to the
height or to two thirds of the entire length of the shell ; the rugae are so closely
arranged near to the apex that upwards of thirty may be counted upon one fourth the
height of the shell.

From Astarte elegans, Sow., it is distinguished by the more lengthened, depressed
figure, and by the absence of a smooth, excavated lunule ; it is much less orbicular and
convex than A. detrita, Goldf. ; the depressed figure, lengthened, straight, upper margin,
and large rugae, will serve to distinguish it /rom other large ovate species of the lower
Oolites. Specimens in Mr. Leckenby's collection exceed three inches in length. It is
not rare, but, in common with other large shells of the Cornbrash, it has usually undergone
compression.

Geological Position and Locality. The Cornbrash of Scarborough, in hard, gray
limestone.

ASTARTE ROBUSTA, Lye. Tab. XXXV, figs. 6, 6 a.

Testa parva suborbicuJari, perinjlata, umbonibus magnis mediants incurvis, margine
poster lore et inferior e rotundo, lunula magna concava marginibus rotundis ; valvis costis

BIVALVIA. 75

concentricis, regularibun, angustis, elevatis (16 — 18) striisque subtillissimis, concentricis,
impressis.

Shell small, suborbicular, much inflated ; umbones large, mesial, incurved ; posterior and
lower margins rounded ; lunule very large, concave, its margins rounded ; the surfaces of
the valves have narrow, concentric, regular, elevated costae, 16 — 18 in number, which are
impressed by very delicate concentric striations ; the intercostal spaces are upwards of three
or four times the breadth of the costa.

Height, lateral diameter, and diameter through both the valves, each about 4 lines.

About thrice the size of a minute Cotteswold Inferior Oolite species which possesses
a similar figure, but whose costae are irregular. Astarte Sulla, Goldf., is also globose, but
has only half the number of costae. A. Integra, Goldf., has less convexity and is more
oblique ; other small species, figured by Roemer, Buvignier, and by Quenstedt, have less
convexity and more obliquity.

Geological Position and Locality. One of the more rare testacea of the Scarborough
Cornbrash; in the collection of Mr. Leckenby.

ASTARTE POXTOMS, Lye. Tab. XL, fig. 31.

Testa parva, conveza, ovato-orbiculari, umbonibus submedianis, acuminatis, antrorsum
curvatis, margine cardinali elongato, subrccto, oblique declivi, lunula magna, costata ; valvis
costis concentricis numerosis (20) elevatis, rotundis, interstiis angustis ; latere superiore,
area, elongata, planata et Icevigata.

Shell small, convex, ovately orbicular ; umbones elevated, pointed, nearly mesial, and
curved forwards ; hinge-border lengthened, nearly straight, sloping obliquely downwards,
forming a narrow, smooth area, separated from the costated part of the shell by an acute
angle ; the lunule is large, costated, and somewhat excavated ; the surfaces of the valves
have large, numerous (about 20) concentric, elevated, and rounded costse, separated
by more narrow interstitial spaces ; adult shells have a large fold of growth near to the
lower border.

A small, convex, neatly ornamented species, allied to A. minima, Phil., and A. pisum,
Kock and Dunker ; from the former it is distinguished by the more numerous and more
closely arranged costse, by the more pointed and more curved umbones, by the larger
lunule, and by the posterior, straight, smooth, acutely bordered area ; the latter feature will
also separate it from A. pisum and from A. supracorallina, D'Orb.

The height and lateral diameter are about 4 lines.

Geological Position and Localities. It is abundant in the White Oolite (Great
Oolite ?) of Ponton, Lincolnshire.

76 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

ASTARTE BATHONICA, Lye. Tab. XL, figs. 23, 23 a.

Testa ovato-trigona, crassa gibbosa ; umbonibus sub-anticis antrosum curvatis ; lunula
cor data, excavata, marffinibus rotundatis, latere postico obtusangulo formante, superficic costis
regularibus, rotundis, crebris, concentricis, marginibus interne denticulatis.

Shell ovately trigonal, thick, gibbose ; utnbones anterior and curved forwards ; lunule
excavated, cordate, its margins rounded ; the posterior side has an obtuse, oblique angle ; the
surface has closely arranged, rounded, regular, concentric costas ; the margins of the valves
are denticulated internally.

Height, fi lines ; opposite diameter, 5 lines ; diameter through the valves, 4| lines.

A short and very convex, thick, shell, with elevated umbones and slightly truncated
posterior border, which is pointed at its inferior extremity, near to which is a large fold of
growth .

Geological Position and Locality. Hampton, Cliffs near Bath ; collected by W.
Walton, Esq., who states that, having found it at the base of the cliffs, some doubt may
exist as to its real geological position. The mineral character of the specimen is ferru-
ginous and identical with that of the bed of Great Oolite Corals and of other shells which
unquestionably belong to the Great Oolite.

ASTARTE RUSTICA, Walton, MSS. Tab. XXXV, fig. 5 ; Tab. XL, f. figs. 8, 8 a.

Testa parva, crassa, ovato-oblonga, plano-convcxa, umbonibus parvis, antemedianis,
acutis, margine, cardinali brevi, subhorizontali, antice rotundato, basi subarcuafo, marginibus
internis dentatis ; lateribus costis angustis imprimis regularibus, deinde in&qualibus.

Shell small, ovately oblong, moderately convex, with thickened margins, internaly den-
ticulated ; umbones anterior to the middle of the valves, curved forwards, and acute ; hinge-
border short and horizontal, terminating in an obtuse angle. The anterior border is
rounded ; the lunule is only slightly excavated ; the base line is nearly straight ; the sur-
face of the valves has an obscure, posterior, oblique angle ; the costse are narrow, at first
regular, afterwards they become irregular and crowded.

Length, 5 lines ; height, 4 lines ; diameter through the valves, 3 lines.

Much variability exists in the prominence and arrangement of the costse, which are
sometimes very numerous and nearly obsolete, or they are distant and elevated. A little
species, allied to A. Voltzii, Roem., A. recondita,Phi]., and the young of A. rhomboidulis,
Phil. ; neither of these species, however, has the test so thickened towards the margins.

Geological Position and Locality. The Forest Marble of Laycock, Somerset ; in the
cabinet of W. Walton, Esq.

BTVALVIA. 77

ASTARTE FIMBRIATA, IFoIton, MSS. Tab. XL, figs. 34, 34 a.

Testa transversa, ovata, stibdepressa, umbonibus antemedianis parvis, margine cardi-
nali elongato, subrecto, obliquo, ac/efo ; lunula magna elliptica ; lateribus costulis concen-
Irids acutis, elevatis subdistantibus ; eefate progrediente crebrioribus et irregularibiis
instructis.

Shell transverse, ovate, somewhat depressed ; urabones small, depressed, curved forwards;
liinge-margin lengthened, nearly straight, its margin acute and rendered fimbriated by
the acute, projecting extremities of the costae, which are elevated, concentric, distantly
arranged, and regular in" the young shell, but more closely arranged and irregular in
specimens of adult growth ; the Kmule is large, elliptical, its margins acute.

Allied to A. dcpressa, Goldf., compared with which the umbones are less prominent
and more oblique, the hinge-border more lengthened, the costas more elevated and fewer ;
the convexity of the valves is also greater. The test is thinner than is usual with this
genus.

Occasionally a small and ill-preserved specimen has been found in the Great Oolite of
Minchinhampton, and mistaken for A. minima, Phil. ; the costaB in the latter shell are more
obtuse and more closely arranged, the general figure being more orbicular.

Geological Positions and Localities. The Forest Marble of Farleigh and the Great
Oolite of Bussage, near Bisley Common.

ASTARTE? IGNOTA, Lye. Tab. XL, fig. 10.

Testa subovafa, subdcpressa, postice truncata, in/erne etpostice oblique subangulata, um-
bonibus antemedianis acuminatis, lunula parva, supcrficie, plicis incrementi numerosis, deli-
cate instructis.

Shell snbovate, subdepressed posteriorly, with a truncated extremity to the
hinge-border and with an oblique angle proceeding from the umbo to the inferior-
posterior border ; umbones antero-mesial, pointed, and curved forwards ; lunule slightly
impressed ; the surfaces of the valves with delicate, irregular, numerous plications of
growth.

The hinge not having been seen, the genus is rather doubtful ; possibly it may be a
Cypricardia.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection of
W. Walton, Esq.

78 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

ASTARTE HILPERTENSIS, Lt/c. Tab. XXXVI, fig. 10.

Testa crassa, convexa, ovato-trigonata, umbonibus subanticis prominentibus, lunula ovata
profunda, margine cardinali curvato, elongate, oblique declivi, marginibus anterioribus, pos-
terioribus et inferioribus ellipticis curvatis ; superficie plicis incrementi crebris tenuibus.

Shell thick, convex, ovately trigonal ; umbones antero-mesial, elevated, and curved
forwards; lunule smooth, ovate, deep ; hinge-margin lengthened, curved, sloping obliquely
downwards ; the anterior, posterior, and lower borders curved elliptically ; the surface with
delicate, numerous plications of growth.

A large, thick species, somewhat allied to A. subtrigona, Murist., but more convex, less
angulated, and with a larger lunule.

Geological Position and Locality. The Cornbrash of Hilperton, Wilts, in the collection
of W. Walton, Esq.

ASTARTE AYTONKNSIS, Bean MSS. Tab. XL, fig. 13.

Testa ovato-oblonga, valde elongata, compressa, umbonibus depressis antemedianis,
lunula concava, margine cardinali subhorizontali elongata, margine inferiore parallelo ; latc-
ribus ruffis ellipticis, crebris, depressis subregularibus instructis.

Shell ovately oblong, much elongated, compressed; umbones anterior to the middle of
the valves flattened ; lunule concave ; the hinge-margin lengthened and nearly horizontal ;
lower border conformable; the two extremities elliptically rounded ; the surface with closely
arranged, depressed, rounded, elliptical, partially irregular rugae.

The general aspect has some resemblance to the shell figured in Part II, PI. IX, figs.
18, 19, as a variety of Astarte excavata, but still more flattened and more elongated, with
more conspicuous, regular, elliptical ruga3. Additional experience now leads me to rank A.
excavata, var. compressiuscula, as a distinct species, and not as a dwarfed variety of the large
Inferior Oolite shell ; the present form is even more thin and flattened than compressiuscula,
so much so as scarcely to allow any space for the animal.

Length nearly twice the height ; the diameter through the united valves is little more
than equivalent to their apparent thickness.

Geological Positions and Localities. The Great Oolite of Hampton Cliffs and of
Comb Down, near Bath ; collected by W. Walton, Esq. It occurs also in the Calcareous
Grit of Ayton, near Scarborough, quite unaltered in any particular ; the name from the
locality having been adopted by Mr. Bean many years since, and sent to public collections,
has therefore been retained.

TY

BIVALVIA. 79

ASTARTE FLEXICOSTATA, Lye. Tab. XL, fig. 26.

Testa transversa, subtrigona, convexa, umbonibus anticis acutis, elevatis, margins an-
terior e truncata, abrupte declivi inferne angula formante ; lunula magna l&vigata concava,
margine acuto ; margine inferiore subrecto ; margine posteriore imprimis subhorizontali
postice oblique declivi ; supcrjicie striis concentricis regularilus instructis, in media cvanes-
centibus.

Shell transverse, subtrigonal, convex ; urabones anterior, pointed, and conspicuous ;
anterior side truncated, descending abruptly, and forming an angle with the lower border
at its extremity ; the lunule is large, concave, smooth, with an acute margin ; the lower
border is nearly straight ; the posterior margin is nearly horizontal for the half of its length,
then slopes obliquely downwards ; the shell is moderately convex, with an oblique, obtuse
angle, posterior to which the surface is more flattened ; it has regular striations, which
follow the direction of the lines of growth ; they are conspicuous near to the umbones,
but disappear upon the middle portion of the dorsal surface.

Height, 5 lines ; length, 1 lines ; diameter through the united valves, 3| lines.

Geological Position and Locality. Collected by E. Witchell, Esq., in the white stone
(Great Oolite) of Bussage, near to Bisley Common ; a single specimen.

GRESSLYA PEREGRINA, Phil., sp. Tab. XXXVI, figs. 2, 2 a, b.

In addition to the specimen figured in PI. XV, Part II of the ' Great Oolite Monograph,'
it has been deemed advisable to exemplify three other variations of form, by the aid of
which the intermediate connecting links may readily be imagined. This Gresslya is very
abundant in the Cornbrash, both in Wiltshire and Yorkshire, so that ample opportunities
are afforded of studying every variation of form which it presents ; these, as will be seen
from our figures, are so considerable and so common that it seems impossible fairly to
disconnect from them some other examples of Gresslya from the Inferior Oolite, as Unio
aMuctus, Phil., Gresslya latior, Ag., G. conformis, Ag., G. lunulata, Ag., G. erycina, Ag.,
G. conccnlrica, Ag., and perhaps also G. sonata, Ag. In all these the same kind of
surface obtains, and the outer, granulated tegument is precisely identical, belonging to
that section of the genus in which the radiating lines and the granules are of the most
minute size, and very densely arranged. It has been usual to select for G. abducta
Inferior Oolite examples with short forms, elevated umbones, tumid anterior sides, and
compressed posterior sides ; but the shortness of figure is surpassed by some from the
Cornbrash, and the inflation of the anterior side varies in amount with every specimen.
From these, probably, must be separated G. latirostris, Ag., which attains to large

80 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

dimensions, with a lengthened general form, compressed anterior side, and large longitudinal
plications over the whole of the surface ; it appears to be comparatively rare, and belongs
to the upper stage of the Inferior Oolite.

THRACIA AMYGDALOIDEA, Lye. Tab. XLIII, fig. 4.

Testa convexa, elongata, umbonibus dcpressis submedianis, lutcre antico prodticfo, ro-
tundato ; postico subcompresso, attenuate, basi curvato, plicis longitudinalibus panels,
levitcr instructis.

Shell elongated, convex ; umbones postero-mesial, depressed ; anterior side produced,
its margin curved elliptically ; posterior side rather compressed and attenuated, its superior
border slightly excavated ; the base is nearly straight ; the surface has a few faintly
marked, longitudinal plications of growth.

Compared with other examples of the genus, the length and the convexity are con-
siderable ; the umbones are likewise much depressed, obtuse, and but little conspicuous ;
the posterior angle is only distinguishable near to the umbones ; the posterior extremity is
slightly truncated. The height only very slight exceeds half the length.

Geological Position and Locality. Associated with valves of Myacites calceiformis in
flaggy, argillaceous Oolite, upon the western border of Minchinhampton Common, at the
lower boundary line of the Great Oolite ; a single specimen.

MYACITES CALCEIFORMIS, Phil., sp. Part II, Tab. XI, fig. 2 ; et Tab. XLII, figs. 1, 1 a.

As this shell possesses considerable variability of figure, another example is given from
the Cornbrash of the Yorkshire Coast. In the former description (p. 1 14, line 8), these
words should be erased — " in the upper beds of the Inferior Oolite." An examination of
numerous Yorkshire specimens has proved that they were all obtained in the Cornbrash,
including the original specimen figured in the ' Geology of Yorkshire,' which was erroneously
placed with the Inferior Oolite fossils, and figured with them in pi. xi of that work.
The Cornbrash specimens have the test with its granulated tegument well preserved, but
usually the fossil has undergone some compression or distortion. The former figure,
Plate XI, fig. 2, represented a Minchinhampton specimen from the base of the Great
Oolite. An Inferior Oolite shell frequently mistaken for Myacites calceiformis occurs
only in the form of casts ; it is more gibbose, with larger, more elevated umbones, the
posterior side being much shorter and more attenuated. As the casts are common, and
these distinctive characters are persistent, there can be no doubt that it must be dis-
tinguished from the species of Professor Phillips. Authorities generally have followed the
' Geology of Yorkshire,' and placed Myacites calceiformis in the Inferior Oolite, and Dr.

BIVALVIA. 81

Oppel (' Juraformation') has made the Cornbrash shell into a new species, with the name of
Panopea Haueri ; I can, however, with confidence state that there is no evidence that the
fossil in question has ever been obtained in Yorkshire lower than the Cornbrash ; in
Gloucestershire its lowest position is at the base of the Great Oolite.

MYACITES RECURVUM, Phi!., sp. Tab. XXXVI, figs. 4, 4 a.

AMPHIDESMA RECURVUM, Phil. Geol. York., i, pi. 5, fig. 25.
LUTRAKIA SINUOSA, Eoemer. Ool., tab. i9, fig. 24, Nachtr., p. 42.
PLEUROMYA RECUKVA, Ag. Et. Cret. Myes., p. 234 et p. 246, t. 29, fig. 9.
LYONSIA RECURVA, D'Orb.1 Prodr., 12 et., No. 123.
MYACITES RECURVA, Mor. Cat. Brit. Foss., 1854, p. 214.
AMPHIDESMA RECURVUM, Bean. Mag. of Nat. Hist., 1839.
MYACITES RECURVUM, Leckenby. Proc. Geol. Soc., vol. xv.

Testa elongato-trapeziformi plano-convexa concentrice striato-mgosa antice brevissima
oblique trmicata basi perarcuata postering producta dorso antice sinuaHm deprcssa, maryine
cardinali postico sinuato, umbonibus crassis incurvis. (Roemer.)

Shell a lengthened trapeziform, moderately convex, with large, concentric, rugose pli-
cations; anterior side very short, obliquely truncated ; base curved elliptically ; the posterior
side produced, compressed, close-fitting ; the superior margin somewhat sinuated or
concave ; the umbones elevated, pointed, and incurved. Usually the anterior side has a
furrow, which passes from the umbones downwards perpendicularly or slightly directed
forwards to the inferior border, but in some of the more gibbose specimens it cannot be
distinguished. The test is delicate; the ornamentation of the surface has the radiating
lines of granules so dense and minute, that they can only be distinguished by the aid of a
considerable magnifying power. The height is two thirds of the length, the diameter
through the valves being equal to half the length. These dimensions apply to the shorter
Cornbrash examples, but many of the Kelloway Rock specimens are more elongated. To
the latter variety may be attributed the Lutraria sinuosa, Roemer ; it is necessary, however,
to separate altogether the Lutraria recurva, Goldf. ('Petref.,' tab. cliii, fig. 15), which has
the general figure very different. The example of Agassiz is unusually short and gibbose ;
and as he has figured a cast, we are precluded from comparing the ornamentation of the
surface. D'Orbigny ('Prodrome,' i, p. 359) has separated it under the title of Panopea
subrecurva ; but, considering the varieties of figure which this species assumes, probably it
is only a short variety of the species of Professor Phillips.

Myacites recvrvutn possesses so little of the aspect of a Gresslya (Lyonsia, D'Orb.)
that we are led to speculate upon the probability that Lyonsia recurva, D'Orbigny, is a
form erroneously ascribed by that author to the species in question.

Geological Positions and Localities. Mi/acites rccurvum is almost peculiar to the

11

82 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Oxfordian Oolites ; for although it occurs in the Cornbrash of Yorkshire and Wiltshire, it
is rarely found in a lower position than the Kelloway Rock. Roemer records his Lutraria
sinuosa in the Lower Coral Rag of Heersthum ; Agassiz places his Plcuromya recurva in
the Terrain a Chailles of Chamsol, in the department of Doubs.

MYACITES SINISTRA, Agassiz, sp. Tab. XXXV, figs. 17, 17 a.

ARCOMYA SINISTRA, Agassiz. £t. Grit. Myes., p. I/O, tab. 9, figs. 1 — 3, et tab. 9',

figs. 10—13.
PANOP.&A SINISTRA, If Orb. Prodr., i, p. 273.

— Oppel. Juraformation, p. 480.

Testa ovato-elongata antice attenuata, postice convexa producta, margine hiaitfe,
umbonibus subcompressis, depressis, antemedianis, laterc antico obligue-declivi, lunula
concavo, margine superior* subhorizontali margine inferiore subrccto; valms lateribus
plicis irregularibm crebis lonf/itudinalibm, ct sidco supcrficiali antemediano oblique-declivi.
Nucleus glaber.

Shell ovately elongated, with the sides of the valves rather flattened ; anterior side
attenuated, its margin sloping obliquely downwards ; lunule concave ; posterior side more
convex and lengthened, its superior border nearly horizontal ; the posterior extremity is
somewhat rounded, with an aperture moderately large ; the umbones are depressed, and
somewhat compressed laterally ; they are placed a little posterior to the anterior third of
the shell, and there is a slight sulcation, which proceeds from them obliquely forwards and
downwards towards the lower border; the inferior margin is lengthened and nearly
straight ; the surface of the test has numerous irregular and rather delicate longitudinal
plications ; the granules over the greater portion of the valves are so minute and crowded
that they cannot be traced to form connecting lines, but towards the sides they are larger,
more distantly arranged, and distinctly linear ; the test upon the anterior side is of
moderate thickness, posteriorly it is much thinner; the nucleus is smooth, and exhibits
the adductor and pallial scars.

Length, 2 inches ; height, 1 inch ; diameter through both the valves, f inch ; but our
specimen is imperfect, and appears to have lost about 2 lines in length at the posterior
extremity.

The more depressed umbones, the anterior attenuation, and the nearly horizontal
figure of the superior border, will serve to distinguish it from all the varieties of Pleuromya
elongata, Ag., to which it bears some resemblance.

The Arcomya sinistra ofQuenstedt, 'Der Jura,' p. 451, tab. Ixii, fig. 2, from the higher
stage of the Inferior Oolite, occurs also in the same position in the vicinity of Cheltenham ;
it is, however, distinct from Myacites sinistra. Some varieties of Myacites decurtatum
approach to it in the general figure, but are readily distinguishable when the granulated

BIVALVIA. 83

surface can be examined and compared, the minute, crowded pattern upon M. sinistra,
with the widely separated lines of granules upon M. decurtatum.

Geological Positions and Localities. The Cornbrash of Scarborough ; in the col-
lection of Mr. Leckenby. In Switzerland M. Agassiz records it from the same geological
position (calcaire roux-sableux) at Goldenthal, Soleure ; also in the Bernese Jura.

MYACITES MODICA, Bean, sp. Tab. XLIII, figs. 1, 1 a.

MYA MODICA, Bean. Mag. Nat. Hist., 1839.

Testa-ovato elongata suldepressa, umbonibus subdepressis antemedianis, margine antico
producto, rotundo, poslico oblique declivi subrccto, margine inferiore elliptico curvato, area
ligamenti lanceolata lata, sitbdepressa, marginilus acutis, valvis lateribus concentrice delicate
plicatis ; lineis radiantibus granulatis, subtillissimis dense instructis.

Shell ovately elongated, rather depressed ; umbones antero-mesial, rather depressed ;
anterior margin produced, rounded; posterior margin more lengthened, nearly straight,
sloping downwards obliquely, lower border curved elliptically ; the granulated test consists
of extremely delicate, very densely arranged, radiating lines, visible only under a magnifier;
the concentric plications are numerous and faintly traced, so that the surface is smooth ;
the valves are close-fitting, or have no perceptible aperture at either of the extremities.

Length, 2£ inches; height, 1^ inch; diameter through both the valves, i inch.

The general figure and aspect of this species renders it easy to distinguish from other
examples of the genus.

Geological Position and Locality. The Cornbrash of Gristhorpe Clio's, in which it has
occurred very rarely ; Mr. Leckenby 's collection.

ANATINA (CEREOMYA) SILIQUA, Ag. Tab. XXXV, fig. 15.

SANGUINOLAKIA UNDULATA, Phil. Geol. York., i, pi. 5, fig. 1, non Sow.
CERCOMYA SILIQUA, Ag. fit. Crit. Myes., p. 148, tab. 11 a, figs. 9 — 13.

ANTICA, Ag.l Ib., p. 147, tab. 11, figs. 16—18; tab. ll<z,

figs. 14—16.

AXATINA BELLONA, D'Orb. Prod., i, p. 336, 12 et., No. 132.
— UNDATA, Id. Ib., p. 361, 13 et., No. 221.

SANGUINOLARIA CNDULATA, Quenstedt. Der Jura, p. 508, t. 68, fig. 9.
ANATINA UNDULATA, Leckenby. Proc. Geol. Soc., vol. xv, 1858.

Testa transverse elongata inaquilatera wnbonibvs subanticis parvis acutis, postice

84 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

rostrata, attenuata, area Jata, plicis duobus longitudinalibus ; latere antico subcompresso,
elliptico curvato, plicisque regularibus ct longitudinalibus.

Shell transversely elongated, very inequilateral ; unibones placed anterior to the
middle of the valves, small, depressed, and anterior ; posterior side rostrated or attenuated,
and much elongated ; area large and wide, with two longitudinal ridges, in addition to a
distinct marginal ridge which separates the area from the other portion of the shell;
anterior side rather compressed, its border is curved elliptically ; the anterior portion of
the sides of the valves have regular, longitudinal ridges and furrows, which disappear
posterior to the umbones; the oblique sulcation which proceeds downwards from the
umbones in all examples of Cercomya is only faintly impressed.

The specimen figured has the general form of the shell unusually well preserved, but
the test has disappeared ; the very inequilateral figure, with the attenuation and elongation
of the posterior side, will readily distinguish it from Anatina undulata, Sow., as also from
most other examples of the genus.

Height, one third the length ; diameter through both the valves, one fourth the
length.

Geological Positions and Localities. It occurs rarely in the Cornbrash of Scarborough.
Professor Phillips has recorded it in the Oxford Clay, and Mr. Leckenby in the
Kelloway Rock and Calcareous Grit of Yorkshire. M. Quenstedt quotes it from the
Cornbrash of Wurtemburg ; M. Agassiz from the Oxfordian Strata of the Vadois Jura and
the Jura of Soleure.

PHOLADOMTA OVUUJM, Ag. Tab. XXXV, figs. 18, 18 a.

PHOLAUOMYA OVULUM, Ag. fit. Crit. Myes., p. 119, tab. 3, figs. 7— 9 ; tab. 3 I,

figs. 1—6.

— D'Orb. Prodr., 11 &., No. 168, vol. 1.
Morris. Catal. Brit. Foss., 1854, p. 221.
Oppel. Juraforraation, p. 481.

Testa ovato-elongata, antice breviore, rotundata, cordata, posterins producta, attenuata,
margine inferiore arcuato curvato, superiore subhorizontali, concavo, umbonibis crassis
subanticis prominulis ; valvis concentrice plicatis, plicis longitudinalibus numerosis ince-
qualibus mediocriter tenuibus ; costellis radiantibus obliquis aqualibus angustis, in/erne
evancscentibus, apcrtura postico et antico angusto.

Shell ovately elongated; the anterior side short, rounded, cordiform ; the posterior side
produced and attenuated ; the inferior margin is curved elliptically ; the superior margin is
moderately lengthened and concave ; the unibones are elevated and tumid ; the sides of
the valves are convex, with closely arranged but not prominent longitudinal plications ;
the radiating costae are very narrow or linear, disposed obliquely, about twelve in number;

BIVALVIA. 85

iney are slightly impressed by the decussating plications, and disappear before reaching
the lower border ; the apertures, both posterior and antero-inferior, are narrow, and not
much lengthened ; the post-ligamental area is wide, and bounded by a distinct elevation
upon each side.

The test is thin, and is sometimes preserved, the characters of the surface being very
well shown upon the casts ; in many specimens the radiating lines, or little costae, are so
faintly marked that they are only visible near to the umbones. The very delicate,
radiating little ribs and the nearly equally faintly marked longitudinal plications will
usually serve to distinguish it from allied forms of the genus when combined with the
elongated figure. In the Pholodomyse the relative measurements of the parts are little to
be depended upon ; but in the Cornbrash specimen figured, the diameter, the height,
and the length, are as 1 — 1^ — 2. Occasionally the length has a greater proportion.

Geological Positions and Localities. It is somewhat rare in the Cornbrash of the
coast of Yorkshire, but it is common in the Inferior Oolite of the Cotteswold Hills, its
position being the stratum with Conchifera itfimediately underlying the bed with
Gryphaea sublobata.

PHOLADOMYA PHILLIPSII, Phil., sp. Tab. XLII, figs. 2, 2 a.

PHOLAUOMYA MURCIIISONI, Phil. Gcol. York., i. pi. 7, fig. 9, non Sow.
— PHILLIPSII, Morris. Cat. Brit. Foss., p. 221.

Testa ovato-cordata, inflatra, nmbonibus magnis elevatis, antice brevissima tnmcata,
postice producta, valde hiante ; lateribus rugis irreytfaribus numerosis, leviter impressis,
costisque (1 — 8) perpendiculariter, angustis ; costa secunda majora.

Shell ovately cordate, much inflated ; umbones large, anterior, elevated, but obtuse ;
anterior side short and truncated ; posterior side produced, its superior border concave,
with a lengthened, large aperture, which extends upwards even to the ligament ; the sides
of the valves have very numerous, irregular, longitudinal ruga3, which are not very promi-
nent, and only slightly indent the narrow, perpendicular costae, of which there are seven or
eight ; the second costa is much larger than the others, and is more remotely placed,
imparting a degree of angularity to the anterior side of the shell ; the other costaa are
symmetrical, and descend almost perpendicularly to the lower border, leaving a con-
siderable space upon the posterior side of the valves destitute of costaa. The young shell
is much less inflated, and more produced upon the posterior side, the aperture at that part
being, in proportion, more narrow ; the second costa has very little more prominence than
the others, so that the anterior side has less angularity and its border is more rounded
than in the adult form. In old specimens the height, and convexity of the valves are
nearly equal, the length being a little more considerable ; in young shells, not exceeding an
inch and a half in length, the convexity is one third less.

86 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

It has only been after -long consideration, and an ample comparison of specimens of
various dimensions, that 1 have seen fit to adopt the view taken by Professor Morris in his
' Catalogue/ and separate this shell both from Pholadomya dcltoidea and from Pholadomya
Heraulti, of the Inferior Oolite. Compared with the latter form, it will be found that
P. Phillipsii has the anterior side more truncated, and the posterior side gapes with a
larger aperture ; this latter feature is, in fact, distinguishable in shells of all dimensions ;
the longitudinal rugae are more irregular and much less conspicuous, so that they only
slightly indent the costae, these latter being less oblique than in P. Heraulti. The
superior largeness and regularity of the rugae, together with the deep indentations of the
costae, is the feature which, at the first glance, impresses the spectator upon inspecting
P. Heraulti ; the costae are usually somewhat more numerous, there being two anterior
to the large costae and an additional one posterior to it, so that, together with their
greater obliquity, only a small portion of the posterior side of the shell is destitute
of costae.

Compared with P. deltoidca, Sow., the figure of the latter is more inflated, the costae
larger and less indented, it also is without the angularity which is imparted by the second
large costa of P. Phillipsii.

Geological Position and Locality. Pholadomya Phillipsii is abundant in the Cornbrash
of Scarborough, Gristhorpe, &c., and usually has the test preserved.

PHOLADOMYA DELTOIDEA, Soiv. Tab. XLII, figs. 4, 4 a.

CAHDITA DELTOIDEA, Sow. Min. Con., t. 197, fig. 4.

PHOLADOMYA MUKCHISONI, Sow. Ib., t. 545, the shorter figure only.

BUCARDIUM, Ag. £t. Grit. Myes., p. 77, pi. 5, figs. 3 — 7 ; pi. 5 a,

fig. 8.
Chapuis and Dewalque. Fos. Ter. Sec. de Luxembourg,

p. 124, pi. 18, fig. 1.
Damon. Geol. Weymouth, p. 17, fig. 6.

SOLITARIA, Mor. and Lye. Gr. Ool. Moll., part 2, p. 124, tab. xii, fig. 2,
ettab. 11, fig. 1.

This species, so abundant in the Great Oolite, Fuller's Earth, and Cornbrash of the
south of England, varies greatly in its general figure, even in the same bed and locality ;
and as its synonyms may now be considered as clearly ascertained, I have deemed it
desirable to figure a specimen from the Cornbrash of Wiltshire, in which the costae are
irregularly arranged, and the general figure is more lengthened than in the two specimens
formerly figured in the second part of the ' Monograph of the Great Oolite Mollusca,'
under the name of P. solitaria. Of these latter, the index facing Tab. XII, fig. 2, by a
typographical error, was printed P. ollita, a shell which is given at fig. 5 upon the same
plate. Even the two Great Oolite specimens have the anterior side less truncated, the

BIVALVIA. 87

umbones more obtuse, and the general figure less inflated, than obtains in the greater
number of those from the Minchinhampton district ; and, upon the other hand, all of them
are less lengthened upon the posterior side than is seen in the figures given by Agassiz
and by Messrs. Chapuis and Dewalque.

Pholadomya deltoidea is remarkable for the large, prominent, and slightly indented
costae, usually seven in number, of which the two posterior ones are much less conspicuous,
and are usually evanescent towards the lower border.

The frequent truncation of the anterior side in Pholadomya, and the general distortion
of the shell which usually accompanies it, is a source of frequent difficulty in the dis-
crimination of species, and is seen commonly and even usually in P. deltoidea, when
specimens are collected without selection. The shell in its normal position rested upon
the compressed anterior side ; the general distortion of figure consequent upon it com-
menced at a 'very early period in the growth of the mollusc, continued throughout its
existence, and did not prevent it from attaining to the usual dimensions of the species ; it
occurs equally in all the other forms assumed by the genus. Where the flattening of the
anterior side is considerable the umbones become more pointed and prominent, the
radiating elevations or ribs are directed more obliquely backwards ; in other instances they
become more closely arranged, or they are waved and irregular. The distortion is not
limited to specimens connected with any particular kind of lithological condition, as it
occurs in compact, thin-bedded limestones, in thick beds of soft, sandy marl, or in thick-
bedded Oolitic limestone ; it is also common to find both compressed and uncompressed
examples in contiguity.

PHOLADOMYA LYHATA, Sow. Tab. XLIII, figs. 3, 3 a.

CARDITA ? LIRATA, Sow. Min. Con., t. 197, fig. 3.

PllOLAUOMYA LYEATA, Sow. Ibid., p. 220.

— Oppel. Juraformation, p. 482.

Testa obovato-triffona, ventricosa, umbonibus clevatis antero-medianis, latere antico
truncato, postico oblique declivi, costis 9 — 10, tertia majora, carinam efformante, costis
aliis approximatis, plicis inagnis concentricis reyularibus indentatis ; apertura postica
angmta, elongata.

The figure is nearly that of a cone, compressed laterally ; the umbones are elevated,
pointed, and placed a little anterior to the middle of the valves ; the steepness and
straightness of the posterior slope, together with the nearly straight lower border, imparts
a distinctive character to the shell, irrespective [of the large, carinated third costa, which is
so much more conspicuous than the others that it forms a kind of keel or angle upon the
anterior side ; it descends to the lower border without curvature, but is directed slightly

88 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

forwards; the six or seven costse posterior to it are much smaller, they diminish
regularly in prominence, are closely arranged, and are deeply indented by the regular,
large, concentric plications ; the anterior side gapes slightly, and has two inconspicuous,
indented costse ; the posterior aperture is narrow and lengthened.

The sub-conical figure, pointed posterior side, and large, carinated rib, will serve to
distinguish it from P. Heraulti, Ag., to which it is nearly allied ; the more angulated
figure, and more numerous costse, from P. carinata, Ag. Some examples of Pholadomya
from the Inferior Oolite are not distinguishable from P. lyrata ; but between these and
P. Heraulti are others, which apparently serve to connect the two forms, so that it is
difficult to separate them altogether from P. lyrata, although undoubtedly they must be
merged with P. Heraulti ; these connecting links are also quite irrespective of any changes
that may be due to the stage of growth in either of the two species.

Geological Positions and Localities. P. lyrata is common in the 'Cornbrash of
Wiltshire and Dorsetshire. Dr. Oppel records it in the same rock at Marquise, near
Boulogne, and Egg, nearAran. D'Orbigny (' Prodrome/ i, p. 252) quotes it from the
Upper Lias, near Bath, which is an error copied from the 'Mineral Conchology of
Great Britain/

HOMOMYA GIBBOSA, Sow., sp. Part II, Tab. XII. fig. 14 ; Tab. XLIII, figs. 2, 2 a.

»

Described at page 138, Part II, under the name of Myacites giblosus. As this shell
occurs abundantly both in the Cornbrash and the Inferior Oolite of the southern counties
of England, a full-sized average example is here figured ; occasionally, indeed, the species
acquired much larger dimensions, as in the Cornbrash of Wiltshire, but it is then
invariably more or less distorted and imperfect ; it is also more gibbose than the smaller
examples. Since the publication of the former portions of this Monograph more
extended information respecting this and other allied species comprised in the proposed
genus Homomya of Agassiz has led to the conclusion that they cannot be assigned to the
genus Myacites, of which they possess neither the external granulated tegument nor the
peculiar characters of the hinge.

When the surface of Myacites has been denuded of the granulated tegument it is
smooth, with irregular, longitudinal laminae, whereas Pholadomya and Homomya have a
wrinkled or corrugated surface.

The genus Homomya was intended by Agassiz to include shells whose forms
resemble those of the more lengthened Pholadomyas, but which are destitute of radiating
costae, and have usually a thicker test, the hinge being identical with that of Pholadomya,
usually, indeed, more massive ; but although the sides of the valves are destitute of
costse, it occasionally happens that a few delicate, radiating lines, more or less obscurely
marked, are visible upon the uuibones, but vanish before they reach the middle of the

BIVALVIA. 89

valves. Examples of this are supplied by the large Liassic Homomya ventricosa, Ag.,
by Homomya Vezelayi, D'Arch., and by Ilomomya crassiuscula, Mor. and Lye. The
hinge of the latter shell exhibits its perfect identity with that of Pholadomya. It is
therefore evident that Homomya cannot claim a generic separation ; but that, viewed as a
subgenus or section of Pholadomya, the name may conveniently be retained. Myacites
Vezelayi, page 111, and Myacites crassiusculus, page 112, should therefore also be removed
to Homomya.

HOMOMYA CRASSIUSCULA, Mor. and Lye. Tab. XLIII, figs. 5, 5 a.

A small example from the Great (?) Oolite of Lincolnshire was figured, Part II,
Tab. XI, fig. 3. As the species occurs of full dimensions in the Cornbrash of Scarborough,
a specimen, with the test preserved, is here given.

12

ADDENDA.

A PORTION of the text of this Supplement passed through the hands of the printer long
prior to the execution of the plates ; and during this lengthened interval many additional
testacea were placed at the disposal of the author, including a considerable series from the
Forest Marble of the counties of Wilts, Somerset, and Dorset, which had recently been
disengaged from the investing matrix by the exertions of W.Walton, Esq., of Bath,
obtained by that gentleman, and by the late John Kilvert, Esq., of the same place. This
fine collection has yielded many new forms, and also some superior examples of others
that had previously been figured from specimens less suitable for the purpose ; advantage
has been taken of the opportunity thus afforded to give additional illustrations. The
descriptions of the more recently acquired fossils could not, therefore, for the most part, be
placed in their proper order, and necessarily form Addenda to the Supplement.

CEKITHIUM(?) HEMICINCTUM, Lye. Tab. XLI, fig. 17.

Testa parva, elongata, anfractibus (7), valde convexis, postice subplanis, Icevigatis,
antice tricinctis, convexis, anfractw ultimo basi concentrice striato. Apertura et canali
ir/nota.

Shell small, elongated ; volutions (7) very convex, their posterior portions oblique,
flattened and smooth, their anterior portions with three prominent encircling costae, the
sutures are deeply constricted ; the last volution has the base concentrically sulcated ; the
outer lip and the base are imperfect ; the genus, therefore, is somewhat uncertain ; there
are some traces of an umbilical opening at the base of the columella.

Geological Position and Locality, The Forest Marble of Laycock ; in the collection
of W. Walton, Esq.

92 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

CERITHIDM(?) NEGLECTUM, Lye. . Tab. XLIV, fig. 21.

Testa parva, subulaba, anfractibus (circa 7) subplanis, longitudinaliter costatis, costis (5),
magnis, deprcssis, subobliquis, a sinistro ad dextrum versus, apertura parva, canala (?).

Shell small, subulate ; volutions (about seven) flattened, with five longitudinal large,
depressed, and smooth costse, which are directed somewhat obliquely from left to right,
and are slightly interrupted by the sutures ; the aperture is small and depressed, the canal
is imperfect.

The extremities of the costae do not always exactly accord with those of the next
volution, which gives some irregularity to the appearance of the volutions ; no traces of
encircling striations are visible.

The spire is not angulated as in C. pentagonum, the subulate figure and plain surface
distinguishes it from C. sexcostalum.

Geological Position and Locality. The Great Oolite of Bussage ; collected by
E. Witchell, Esq.

CERITHIUM COSTIGERUM, Piefte. Tab. XLI, figs. 11, 11 a, b.

Testa inflata, subcylindrica , anfractibus (7 — 9), costis (12) rectis, angustis, elevatis,
postice acuminatis, lineisque transversalibm, instructis ; apertura parva, canali recto,
elongato.

Shell somewhat inflated and subcylindrical, volutions (7 to 9) with the sides perpen-
dicular, costae (12) perpendicular, narrow, and much elevated, terminating posteriorly each
in a projecting point, anteriorly they bend inwards slightly to the suture, there are also
regular encircling lines ; the base is smooth, the aperture is small, the canal lengthened
and straight.

There is much variability in the elevation of the spire, and, consequently, in the
height of the volutions ; a specimen more than usually lengthened has the costse some-
what oblique.

Geological Positions and Localities. The Forest Marble of Laycock ; in the collection
of W. Walton, Esq. It is recorded by M. Piette in the Great Oolite Limestones of Eparcy
and Rumigny.

CERITHIUM (?) WALTONI, Lye. Tab. XLI, fig. 16.

Testa parva turriculata anfractibus numerosis angustis, inflatis, saturis dene impressis,
costis rectis angustis, elevatis (circa 11) in ambitti lineis regidaribus cingendis ; apertura et
canali iff not a.

ADDENDA. 93

Shell small, turreted, volutions numerous (8 — 9), narrow, inflated, the sutures deeply
impressed; costae (about 11 in the circumference) perpendicular and narrow, crossed by
a few regular encircling lines. The aperture and canal are imperfect.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection
of W. Walton, Esq.

CERITHIUM (?) POCCLUM, Lye. Tab. XLIV, fig. 24.

Testa jyarva, subcylindrica, anfractibus (9) l&vigatis, postice expamis et profunda
canaliculatis, antice contractis ; apertura parva, canali contracto et contorto.

Shell small, subulate, subcylindrical, volutions (about 9) smooth, expanded posteriorly
and deeply channelled, contracted anteriorly, the aperture is small, the canal is produced ,
narrow, and twisted.

The genus is somewhat doubtful, additional specimens may prove it to be a Nerinaa.

Geological Position and Locality. The Great Oolite of Bussage, near Bisley Common ;
collected by E. Witchell, Esq.

CERITHIUM EXSCALPTUM, Lye. Tab. XLIV, fig. 23.

Testa parva, subulo-elongata, anfractibus (10) angustis, sub-planis, transverse tenuissime
striatis, anfractu ulfimo rotundo, canali brevi, sub-recto.

Shell small, subulately turreted, pointed, volutions (10) slightly convex, narrow (two
and a half times as wide as high), with numerous very delicate encircling striations, the
last volution has the base rounded, the canal is short and nearly slight.

Obtained by crushing the white stone for the Great Oolite for minute Gasteropoda.

Geological Position and Locality. The Great Oolite of Bussage; collected by
E. Witchell, Esq.

KILVERTIA, Gen. Nov.

Testa elongata, sub-cylindrica, anfractibus numcrosis, perpendiculariter costatis tubercu-
latis aut spinosis ; anfractu ultimo cylindrico, basi sub-contracto ; apertura Integra, rotun-
data aut ovali, labris protractis, tenuiter incrassatis, non nunquam sub-undulatis, cotumetta
solida.

Shell elongated, sub-cylindrical, sometimes somewhat pupaeform ; volutions numerous,

94 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

perpendicularly costated, tuberculated or spined ; the last volution cylindrical, sometimes
contracted at the base ; aperture entire, orbicular or ovate, the lips elevated, produced
and slightly thickened, sometimes undulated, columella solid.

Allied to Cerithium, Potamides, Turritella, Omphalia, Rissoa, and Aclis ; from the
two former it is separated by the absence of an anterior and posterior canal, the thickened
and produced margins of the aperture distinguish it from Turritella, and from the
Omphalia of Zekeli, from Omphalia more especially by the absence of a sinus or fissure
of the outer lip, from Rissoa by the many-whirled figure and produced lips, from Aclis
by the costated or spined volutions, cylindrical last volution, and produced aperture.

The Great Oolite species obtained in the Minchinhampton district are always small
and sometimes minute, these are Cerithium (?) spiculum, Lye., p. 9; C. (?) strangulatum
D'Arch., p. 8 ; C. (?) pulchrum, Lye., p. 10, of which latter species very fine and large
examples occur also in the Forest Marble clays of Laycock, accompanied by Kilvertia
formosa, Lye. Other examples, known only in foreign localities, are Rissoa (?) elegantula,
Piette, from the Great Oolite of Eparcy ; Cerithium angistoma, C. quinquangulare and
C. fupoides, Hebert and Deslongchamps, from the Kelloway Rock of Montreul-Bellay ;
Scalaria (?) minuta and Cerithium pygmeum, Buvignier, from the Calcaire a Astartes of the
department of the Moselle. In selecting a name for this proposed genus, I have much
pleasure in adopting the suggestion of Mr. Walton, and dedicate it to the memory of the
late John Kilvert, Esq., of Bath, whose researches in the Palaeontology of the Jurassic
rocks of the southern counties resulted in the acquisition of a fine and instructive
collection of the Mollusca.

KILVERTIA PCLCHRA, Lye. Tab. XLIV, fig, 4 ; Tab. XLI, figs. 12, 12 a.
CERITHIUM 1 PULCHRUM, p. 10, of this Supplement.

The fine collection of Forest Marble shells forwarded by the kindness of Mr. Walton,
contains many specimens of this Kilvertia which exhibit much variability in their orna-
mentation, and are upwards of three times the linear dimensions of the Minchinhampton
examples ; the Laycock shells having been obtained by washing layers of clay and shale ;
there is an entire absence of that abrasion of the surface to which oolitic fossils have so
frequently been subjected ; additional figures of this fine species will be found Tab. XLI,
figs. 12, 12 a. The figure of the aperture in shells of the same size also presents some
variability, the typical suborbicular figure becomes sub-quadrate, and in other instances is
somewhat pointed at the two extremities, but in the young condition apparently the
aperture is always orbicular.

ADDENDA. 95

KILVERTIA FORMOSA, Lye. Tab. XLIV, fig. 5.

Testa parva subulo-pup&formi, anfractibus (6 ?) latis, planatis, suturis dene distinctis,
costis longitudinalibm rectis (circa 7 in ambitu) rotundis, depressis, inferne evanescentibus ;
lineis transversis (circa 7) regularibus, elevatis ; apertura parva suborbiculari, labris inte-
gris, simplicibus.

Shell small, elongated, pupaeform or lessening at both the extremities, volutions (6 ?) wide,
flattened or very slightly convex, the sutures well impressed, aperture small, suborbicular ;
the lips continuous without undulation ; longitudinal costse (about 7) straight, rounded,
and but slightly elevated, indistinct upon the latter volutions, knotted where they are
crossed by encircling lines, of which each volution has about seven, regular and conspicuous ;
the costa3 are not continuous, neither do their extremities exactly correspond at the sutures
of the successive volutions, they are more prominent upon the upper half of each volution ;
the apex is imperfect, the first volution having disappeared.

Allied to Kilvertia strangulata=Cerithium strcmgulaium, D'Arch., from which it is
distinguished by the smaller dimensions, the greater elongation of the spire, and by the
costse, which are much smaller, more depressed, and do not form continuous elevations.

Geological Position and Locality. Collected by E. Witchell, Esq., in the white (Great)
Oolite of Bussage, near Bisley Common.

AMBERLEYA CAPITANEA, Goldf., sp. Tab. XLI, fig. 1.

Part I, p. 65, contains a correct description of this species (Turbo capitaneus, Goldf.),
which is not uncommon in the Supra-liassic sands and the Inferior Oolite of the southern
counties ; Mr. Walton has also forwarded two small examples obtained in the Forest
Marble of Laycock, and of Pound Pill. The shell figured Tab. IX, Part I, fig. 33, was
referred doubtfully to this species, of which it was supposed to be a badly preserved
example ; subsequent examinations of other specimens from the same locality have proved
that this view was erroneous, and that it is a distinct species ; a description of this latter
shell will be found in this Supplement (p. 19) under the title of Amberlct/a Jurassi.

AMBERLEYA MONILIFERA, Lye. Tab. XLI, fig. 10.

Testa parva, ovato-elongata, spira alia, acuta, anfractibus (4 — 5) in medio cartnafis,
tabulo-nodifcris, postice et antice concavis, cjusdcm carina parva, nodifera ; anfractu
ultimo basi sulcis quinis, conccntricis, apertura antice subconfracto.

Shell small, ovately elongated, spire elevated, acute, consisting of four or five volu-

96 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

tions, which have a prominent encircling nodiferous carina in their middle portion, their
posterior and anterior surfaces being concave, each having a small noderous carina ; the
last volution has at its base fine encircling sulcations; the aperture has the anterior
extremity rather pointed.

The tubercles upon the mesial carina are large, projecting slightly forwards, very
closely arranged and tubular, about eighteen in a volution, the anterior and posterior
carinaa have similar tubercles, but much smaller. The height of the shell is one third
greater than the opposite measurement.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection of
W. Walton, Esq.

AMBERLEYA TRICINCTA, Lye. Tab. XLI, fig. 14.

Testa ovato-elongata, anfractibus (8 — 9) turbinatis, inferne angulatis, citigillis, tribust
lineis perpendicularibus decussatis, anfractu ultimo, lineis maynis concentricis ; apertura
pyriformi.

Shell ovately elongated, volutions (8 — 9 turbinated, angulated towards their lower
portions, and flattened or slightly convex above the angle, the sutures are strongly marked,
encircling lines three, of which one is above and another beneath the angle ; these are
decussated by other lines perpendicular and smaller, forming tubercles more or less distinct
where they cross the angle, the decussating lines are distantly and sometimes irregularly
arranged ; the last volution has large, regular, concentric elevations ; the aperture is
pyriform.

An elegantly turbinated more or less lengthened shell, with convex volutions and a
delicately ornamented surface ; about a dozen specimens have been compared, which do not
vary much in size ; the length of the aperture is about two fifths of the entire shell. All
the examples are more or less imperfect at the base.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection
of W. Walton, Esq.

NATICA TEXATA, Lye. Tab. XLV, figs. 30, 30 a.

Testa ovata, dcpressiuscula, crassa, spira anfractibus (3) patens, vix elevatis, convexis ;
anfractu ultimo inflato, basi umbilicato, apertura subreniformi, labro inferno crasso ; svperficie
striis vel lineis texatis delicatissimis ornata.

Shell ovate, depressed, thick, spire consisting of three depressed but exposed and
rounded volutions, the last volution much inflated, the base umbilicated, the aperture
somewhat reniform, the inner lip thick and conspicuous ; the surface with very delicate
encircling lines or striations, which are rendered granular by others decussating them.

ADDENDA. 97

Allied to Natica Montr euilensis, Heb. and Desl., from the Kelloway Rock of Montreul-
Bellay, which species, however, is less depressed and the aperture more lengthened.

The ornamentation of the surface in our shell is partially preserved, and can only be
perceived by the aid of magnifying power.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection of
W. Walton, Esq.

NATICA ARATA. Tab. XLV, fig. 2.

Testa parva, crassa, inflata, spira exserta, anfractibus (4) convexis, ultimo, permagno,
transverse striato, suturis valde impressis, apertura ovata, umbilico nullo.

Shell small, thick, inflated, spire produced, volutions (4) convex, the last volution very
large and globose, with delicate encircling striations, the sutures deeply impressed, the
aperture is ovate ; there is no umbilicus.

Geological Position and Locality. The Great Oolite of Bussage ; collected ty E. •
Witchell, Esq.

NATICA (EUSPIRA) ALTA, Lye. Tab. XLV, figs. 22, 22 a.

Testa parva, laevigata, subglobosa, spira elongata, apice acuto, anfractibus (4) con-
vexis, latis, suturis valde impressis, anfructu ultimo permagno, subgloboso, apertura ovata,
obliqua, subumbilicata.

Shell small, smooth, spire elevated, its apex pointed, volutions (4) convex, moderately
wide, the sutures strongly marked, slightly constricted, the last volution very large, sub-
globose, the aperture ovate, oblique, the inner lip prominent, the base with an umbilica?
groove. The height of the aperture is slightly greater than that of the other portion of the
shell. Perhaps this is the young condition of a much larger species.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection
of W. Walton, Esq.

NATICA INSIGNIS, Lye. Tab. XLV, fig. 21.

Testa parva inflata, spira elevata, acuta, anfractibus (7) convexiusculis, angustis,
suturis dene impressis, anfractu ultimo permagno, subgloboso, apertura ovali, umbilico nullo.

Shell small, inflated, spire much elevated, its apex acute, volutions (7) moderately con-
vex, narrow, the latter two volutions increasing rapidly, and becoming much inflated, the
last volution is very large, subglobose, the aperture rather depressed, ovate, with no distinct
umbilicus, or with a slight groove.

13

98 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

The unusual number of the volutions and the sudden inflation of the last volution
renders its discrimination easy.

The height is about equal to the transverse diameter of the last volution.

Geological Position and Locality. Collected by E. Witchell, Esq., in the Great Oolite
of Bussage, near Bisley Common; it has also occurred rarely in the Cornbrash of
Scarborough.

RISSOINA SUBULATA, Lye. Tab. XLI, fig. 9.

Testa elongata, subcylindrica, anfractibws (9) convexis, altis, longitudinaliter oblique
costellatis, costellis, crebris (circa 30 in ambitu), apertura ovato-obliqua, parva.

Shell .elongated, subcylindrical, volutions (9) convex, high, longitudinally obliquely
costellated, costellse closely arranged (about 80) in a volution; aperture ovate, oblique,
small.

A slender, subulate, delicately ornamented shell ; the height of the volutions is equal to
three fourths of their opposite diameter.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection of
W. Walton, Esq.

RISSOINA (?) TUMIDULA, Lye. Tab. XLIV, fig. 13.

Testa ovato-tumidula leevigata, spira elevata, anfractibus (5) convexis, latis, suturis bene
distinctis, apertura ovata, antice angulata, labro externo crasso.

Shell ovate, inflated, smooth; spire short, but elevated; volutions (5) convex, wide,
their sutures deeply impressed ; aperture ovate ; the outer lip thick, forming an angle at
its junction with the base of the columella. There is no distinct notch.

A short, inflated species, resembling in the figure of the aperture R. laevis, Sow., both
seeming to constitute aberrant examples of Rissoina, and approximating to Rissoa.

Geological PosUion and Locality. Collected by E. Witchell, Esq., in the Great
Oolite of Bussage, near to Bisley Common, Gloucestershire.

NERITA CLAVATULA, Lye. Tab. XLV, fig. 3.

Testa hemispherica, spira parva, subdepressa, anfractu ultimo per magno, inflate, tuber-
culis parvis, remotiusculis, per series quinis, regularibus, et lineis radiantibw, tenwibus,
decu#satis ; basi carina una, l&vigata.

Shell hemispherical ; spire small, obtuse, and rather depressed ; the last volution very

ADDENDA. 99

large, inflated, with small depressed tubercles, rather remote, and arranged in fine
encircling rows, the rows of tubercles are connected by delicate radiating lines, one of
which is united to each tubercle ; the base has a single, smooth, encircling keel ; the
aperture and inner lip are similar to those of Nerita minuta.

A pretty little and rare species, with the tubercles rather distantly arranged in each
row, they are somewhat lozenge-shaped or pointed posteriorly, about fourteen occupying
an entire volution.

Geological Position and Locality. The Great Oolite of Bussage, adjoining Bisley
Common, in the bed of white stone ; collected by E. Witchell, Esq.

TROCHUS BURTONENSIS, Lye. Tab. XLV, fig. 16.

Testa conica, laevigata, spira clevata, anfractibus (6), postice planatis antice concavis et
obtuse anyulatis, anfractu ultimo basi leviter convexa, imperforata, apertura subrotunda,
columella basi dente callosa.

Shell conical, smooth ; spire elevated ; volutions (6), their posterior portions flattened,
the anterior portions concave, bounded by an obtuse carina, the last volution has the
base slightly convex, imperforate, but with an umbilical depression ; the aperture is
rounded ; the base of the columella has a thickened dental process. Small specimens
have the spire less elevated, and the bounding carina much less prominent.

Geological Position and Locality. The Forest Marble of Burton Bradstock ; in the
collection of W. Walton, Esq.

TURBO DEPAUPERATUS, Lye. Tab. XLV, fig. 13.

PLEDROTOMAKIA PAGODUS, var. DEPAUPERATA, Gr. Ool. Mon., Pal. Soc., 1850, part 1,
pi. 10, fig. 9, p. 77.

The shell figured in the first part of this Monograph as a doubtful variety of
Pleurotomaria pat/odus, Desl., has, by the aid of other specimens, been clearly shown to be
a different shell, which does not belong to the genus Pleurotomaria. Very few examples
have hitherto been obtained, all of which are more or less imperfect, have suffered com-
pression, or have been indifferently preserved ; however, by comparing one with another,
the distinctive characters have been fully ascertained.

A Forest Marble specimen, slightly compressed, is now figured ; compared with the
original of the former figure the spire is less elevated, the ornamentation of the surface
and of the base are better preserved.

The description formerly given applies to the species of Deslongchamps, the following
to Turbo depauperatus.

Testa turbinata, spira elevata, apice obtuso, anfractibus (5) convexis, imprimis inornatis,

100 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

anfractu ultimo ct penultimo in media anyulato, costis subnodulosis cingendis, angulo tuber-
culis regularibus depressis coronatis ; basi striis concentricis el radiantibus decussatis,
umbilico patens, angulato, concentrice striato ; apertura depressa, sublunulata.

Shell turbinated ; spire elevated, its apex obtuse ; volutions (5), of which the first
three are rounded and without ornamentation, the two latter enlarge rapidly, are angulated
in their middle, and coronated with a row of regular depressed encircling tubercles, above
and beneath the angle are also three or four rows of nodulous encircling costae, of which
those beneath the angle are the most prominent ; the base is slightly convex, concentri-
cally and radiately striated; there is an open umbilicus encircled by an angle, and
concentrically striated ; the aperture is depressed and sublunulate.

The last volution has the surface above the angle much flattened, and rendered rugose
by the nodulous elevations ; the encircling costae are closely arranged, somewhat irregular,
and become smaller towards the base of the last volution. In the specimen figured the
outer lip is imperfect.

Geological Positions and Localities. The Forest Marble of Laycock and Pound Pill ;
in the collection of W. Walton, Esq.

TURBO BURTONENSIS, Lye. Tab. XLV, fig. 15.

Testa turbinata, spira elevata, anfractibus (4) convexis, cingillis tuberculosis tribus
magnis instructis ; ultimo anfractu basi cingillis (3 aut 4) ; apertura ovata, umbilico nullo.

Shell turbinated ; spire elevated ; volutions (4) convex, each encircled by three rows
of closely arranged large tubercles ; the last volution has at the base three or four con-
centric rows of smaller tubercles ; the aperture is ovate ; there is no umbilicus.

The upper part of each volution is somewhat flattened, upon which is one row of
tubercles, the other two rows are more closely arranged j the tubercles are large and
obtusely rounded. The basal transverse diameter is one fourth greater than the height.
It is allied to Turbo muricatus, Sow., but with a shorter spire, more constricted sutures,
and the tubercles much larger.

Geological Position and Locality. The Forest Marble of Burton Bradstock ; in the
collection of W. Walton, Esq.

TURBO SUBTEXATUS, Lye. Tab. XLI, figs. 15, 15 a.

Testa parva, in/la/a, spira elevata, anfractibus valde convexis, postice subhorizontalibus,
antice convexis, suturis profunde impressis, anfractu ultimo permagno, apertura ovali,
umbilico nullo ; superficie lineis concentricis et longitudinalibus tenuisssimis, aut punctis vix
notatis.

ADDENDA. 101

Shell small, inflated ; spire elevated ; volutions (4) very convex, their posterior portions
nearly horizontal, their anterior portions convex, with the sutures deeply impressed ; the.
last volution very large and ovate ; the aperture oval, no umbilical depression ; the surface,
with lines encircling and perpendicular, very densely and irregularly arranged, having
sometimes an imperfectly punctated aspect.

It is allied to Turbo gibbosus, D'Orb., but the latter is shorter and more inflated.

Geological Position and Locality. The Forest Marble of Farleigh ; in the collection
of W. Walton, Esq.

MONODONTA COMMA, Lye. Tab. XLV, figs. 24, 24 a.

Testa ovato-discoidea, anfractibus (4), clevatis, subplanis, suturis distinctis, anfractu
ultimo magno, apertura elliptica, umbilico parvo, dente basili mac/no obtuso ; superficie striis
concentricis tenuissimis, regularibus.

Shell ovate, discoidal ; spire elevated ; volutions (4) rather flattened, apex obtuse ; the
sutures distinct ; the last volution large, rather depressed, aperture elliptical ; umbilicus
small ; basal tooth large, obtuse ; the surface has very delicate, closely arranged, regular
encircling striations.

The general figure nearly approaches to Monodonta (Crossostoma) heliciforme, but the
latter shell is without ornamentation, and has a smaller and more depressed basal tooth
and sulcus.

Geological Position and Locality. The Forest Marble of Farleigh ; in the collection
of W. Walton, Esq.

MONODONTA WALTONI, Lye. Tab. XLV, figs. 31, 31 a, b.

Testa crassa, ovoidea, tenuissime concentrice striata, spira brevi depressa, suturis
distinctis, anfractibus (5) angustis, subconvexis, anfractu ultimo permagno ; basi obliquo
subumbilicato, dente et sulco magno obtuso ; apertura ovata.

Shell thick, ovoidal, delicately concentrically striated ; spire short, depressed ; volu-
tions (5) narrow, slightly convex, their sutures distinct, the last volution very large, base
oblique, and slightly umbilicated ; the basal tooth and sulcus prominent; aperture ovate,
outer lip thick.

A pretty little delicately ornamented species, of twelve examples the smallest is
scarcely larger than the head of a pin, and has a distinct umbilicus ; the largest has a
diameter of four lines.

Geological Position and Locality. The Forest Marble of Farleigh ; in the cabinet of
W. Walton, Esq.

102 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

MOUODONTA ARATA, Lye. Tab. XLV, fig. 19.

Testa trochiformi, spira elevata, anfractibus (6) latis, concavis, postice et antice carina,
striata, obtusa, suturis valde impressis, anfractibus semel concentrice tenuissime lineatis et
decussatim oblique striatis ; basi lineis concentricis majoribus et minoribus alternatis ;
sulco columellari magno et dente obtuso.

Shell trochiform ; spire elevated ; volutions (6) wide, concave, having a striated obtuse
keel upon their posterior and anterior borders ; there are also very delicate encircling
lines, which are indented by oblique decussating striations ; the base is concentrically
lineated, the lines being alternately large and small ; there is also a conspicuous colu-
mellar groove and obtuse tooth ; the aperture is nearly circular.

Height and basal diameter nearly equal.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection
of W. Walton, Esq.

MONODONTA TEGULATA, Lye. Tab. XLV, figs. 17, 18.

Testa sub-trochiformi, spira elata, anfractibus (4), latis, in media angulatis, carinis,
tribus cingendis, superne oblique planatis, inferne concavis, anfractibus semel concentrice
lineatis, lineis granosis, striis tenuissimis decussatis ; basi concentrice lineatis, sulco magno
vmbilicali et sulco et dente obtuso instructo.

Shell sub-trochiform ; spire elevated, consisting of four wide and carinated volutions,
angulated in their middle portions by a prominent encircling keel, a keel being also
placed at the anterior and posterior border of each volution ; between the carinse are
numerous regular encircling lines, rendered granulated by decussating very fine oblique
striations ; the base is concentrically lineated, and has a large umbilical groove bounded
by a prominent keel ; the columellar sulcus and tooth are also conspicuous ; the aperture
is subcircular, its outer border impressed by the carinse.

The diameter at the base is one third greater than the height. A pretty species, with
strongly sculptured ornamentation. The volutions are obliquely flattened above and con-
cave beneath the median carina.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection
of W. Walton, Esq.

ADDENDA. 103

Genus — ONUSTUS, Humphrey.

Shell conical, with several volutions, which are flattened or are rendered somewhat
concave by an expansion of their lower borders, which overhang and conceal the suture ;
the lower border of the last volution is produced horizontally to support a membranous
expansion ; the surface has striations, or radiately undulating lines, which are somewhat
irregular. The base is concave towards the outer border, and convex towards the centre ;
the umbilical orifice is sometimes large, but in other instances small, and becomes nearly
concealed by advance of growth ; the aperture is depressed and ovate. Some Tertiary and
Recent species have the spire encrusted with fragments of shells or stones, which obscure
the ornamentation.

Xenophora, Fischer, and Phorus, Montfort, are synonyms of this genus.

ONUSTUS BURTONENSIS, Lye. Tab. XLV, figs. 7, 7 a, b.

Testa subconica, spira elevata, obtusa, anfractibm (4-5), angustis subconcavis, longi-
tudinaliter costatis, costis (circa 24 — 26) inferne alternatim in spinis producta ; basi sub-
concavo, concentrice et radiatim striafo, umbilico amplo.

Shell subconical, wider than high ; spire moderately elevated obtuse ; volutions four
or five, narrow, slightly concave, with about twenty-four to twenty-six longitudinal rounded
and elevated costse ; the base of every alternate costa forms, with the lower expanded mar-
gin of each volution, a projecting process, which renders the lower margins of the volu-
tions undulated; the base is expanded, slightly concave, concentrically and radiately
striated ; the umbilicus is large.

A pretty species, possessing the generic features strongly defined, more especially the
expansions at the lower border of each volution, which impart a pagoda-like aspect to the
spire. Only two other British Jurassic species are known, viz , Trochus pyramidatus, Phil.,
= Trochus lamellosus D'Orb., a more depressed species, which occurs in the Supra-Liassic
sands, and in the Inferior Oolite of Gloucestershire and of Yorkshire ; the other is the
Trochus ornalissimus, D'Orb., with a very elevated spire, and inordinately expanded at
the lower border ; it occurs in the Inferior Oolite of the Cotteswolds, and in the White
Oolite of Ponton, Lincolnshire. Our species is most nearly allied to Trochus ornatissimus,
but with a shorter spire, fewer volutions, and with prominent overwrapping expansions at
the lower border of each volution. Other foreign Jurassic species are Trochus heliacus,
D'Orb., T. Tytirus, D'Orb., Solarium callaudianum, D'Orb., Onustus exul, Eug. Desl.,
and Onustus liasinus, E. Desl. None of these species exhibit those agglutinations of
shells and stones which are so characteristic of the Tertiary and Recent examples of
Onustus.

104 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Geological Position and Locality. The Forest Marble of Burton Bradstock ; in the
collection of W. Walton, Esq.

PHASIANELLA VARIATA, Lye. Tab. XLV, figs. 28, 28 a, b.

Testa ovato-elongata, spira acuta, an/ractibus (6-7), xubconvexis, latiusculis, suturis valde
impressis, ultimo anfractu amplo, apertura obliqua, ovato-elongata.

Shell variable in figure, ovately elongated ; spire lengthened, with the apex acute ; volu-
tions six to seven, wide, more or less convex ; the sutures strongly impressed ; the last volu-
tions conformable, the aperture oblique, ovate, narrow, but always less than half the height
of the shell.

The variability in the convexity of the volutions and their height is considerable. The
general aspect resembles P. elegans, Mor. and Lye., in which the spire is always less
pointed and less slender, the last volution being also longer.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection of
W. Walton, Esq.

SOLARIUM TURBINIFORMIS, Lye. Tab. XLV, figs. 23, 23 a, b.

Testa turbinata, spira dextra, elevata, obtusa, anfractibus (4), tuberculis numerosis, coro-
natis ; basi convexa, umbilico magno, margine, nodis (circa 9) cingendo, superficie lineii
transversalibus et longitudinalibus decussatis ; apertura suborbiculari,

Shell turbinated, spire dextral, elevated, volutions four, their borders coronated with a
circle of tubercles, about eighteen in a volution ; the base is convex, with a large and
deep umbilical cavity, bordered by large nodose elevations, about nine in the volution ; the
aperture is suborbicular ; the entire surface has encircling lines, with more narrow inter-
stitial spaces decussated and rendered granular by densely arranged transverse striations.

Allied to Straparottus altus, D'Orb. ; the latter species, however, has the last volution
more elevated and the sides much more flattened, which impart a subquadrate figure to
the aperture ; the nodose elevations encircling the umbilicus are also fewer and larger.

Geological Position and Locality. The Great Oolite of Hampton Cliffs ; in the collec-
tion of W. Walton, Esq.

SOLARIUM WALTONI, Lye. Tab. XLV, figs. 26, 26 a, b, c.

Testa disco-idea, latere superiori et inferiori concavo, dorso angusto, convexo, tuberculis
per series duobus instructis ; latere superiori anfractibus subconcavis, varicibus obscuris

ADDENDA. 105

transversalibus instructs ; latere inferiore anfractibus planatis ; lineis transversalibus et
longitudinalibus cancellatis ; apertura siibquadrata.

Shell discoidal, the superior and inferior sides concave, the back narrow, rounded,
encircled upon its upper part by two rows of tubercles, of which there are about nineteen in
a volution ; the upper surface has the volutions slightly concave, and traversed transversely
by obscure varices, proceeding from the tubercles ; the lower side is but little more con-
cave than the other ; the volutions are flattened. The entire surface of the shell has deli-
cate transverse and encircling lines, forming a regularly reticulated surface ; the aperture
is subquadrate.

A beautiful and remarkably discoidal species.

Geological Position and Locality. The Great Oolite of Hampton Cliffs ; in the collec-
tion of W. Walton, Esq.

PLEUROTOMARIA BATHONICA, Lye. Tab. XLV, fig. 10.

Testa trochiformi, conoidea, spira apice obtuso, anfractibus convexis lineis transversis et
perpendicularibus, sub-eequalibus, cancellatis; ultimo anfractu supcrne tuberculato-nodosis ;
sinu maffno, fascia sinus, plana, transversim lineata, in baso anfractuum sita ; ultimo an-
fractu basi piano, concentrice lincalo ; umbilico subnullo, apertura siibquadrata.

Shell trochiform, conoidal ; spire obtuse; volutions convex, with cancellated transverse
and perpendicular lines ; the last volution with a row upon the upper part of nodose
tubercles ; the sinus is large, the fascia of the sinus is flattened and transversely lineated ;
the base is flattened, and concentrically lineated ; the aperture is subquadrate ; there is no
umbilicus.

The encircling lines, of which there are three or four above the fascia of the sinus, are
more prominent than the perpendicular lines. The height is one third less than the basal
diameter.

Geological Position and Locality. The Forest Marble of the Box Tunnel, near Bath ;
in the collection of W. Walton, Esq.

PLEUROTOMARIA BURTONENSIS, Lye. Tab. XLV, fig. 8.

Testa trochiformi, conoidea, anfractibus (5 — 6), superne itijlatis, nodoso-unaulatis, inferne
subplanis ; superficie lineis transversalibit* ct perpendicularibus, (eqi/alibust dense cancellatis,
anfractu ultimo basi concentrice et radiatim lincatis, subconvexo, umbilico subnullo; xi/iti
mayno, in medio anfractuum situ ; fascia sinus delicate cancellatis.

Shell trochiform, conoidal ; volutions (5 — 6), very convex in their upper parts, and
nodosely undulated; their lower portions rather flattened; the surface, with encircling and

14

106 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

perpendicular equal lines, forming a delicately cancellated surface ; the last volution has
the base wide, somewhat convex, with regular concentric and radiating lines, the latter
being the less conspicuous ; there is scarcely any umbilical depression ; the sinus is large,
placed in the middle of the volutions ; the fascia of the sinus is delicately cancellated ; the
nodose elevations upon the upper half of each volution are regular, numerous, and not
very strongly defined in the greater number of the specimens.

The height is equal to two thirds of the basal diameter. Of the seven specimens
examined, the largest has a basal diameter of about an inch.

Geological Position and Locality. The Forest Marble of Burton Bradstock; in the
collection of W. Walton, Esq.

PLEUROTOMARIA RECONDITA, Lye. Tab. XLV, fig. 7.

Testa trochiformi, discoidea, anfractibus (4) subplanis, infcrne obtuse carinatis ; fascia
sinus lata, transverse delicate striata, in medio anfractum situ ; anfractibus cingiUis anyustis
(3 — 4) supra et infra sinus instructo, striis obliquis tcnuissimis, impressis ; carina mar-
ginali Icevi ; basi lato, concavo, umbilicato, delicate concentrice striato.

Shell trochiform, discoidal ; volutions (4) flattened, but rendered concave in the lower
portions by a prominent, obtuse, smooth, marginal carina; the fascia of the sinus is
mesial, wide, with very delicate transverse striations ; above aud beneath the sinus are
three or four narrow encircling little costae, which are impressed by delicate oblique stria-
tions ; the base is wide, concave, with a distinct umbilicus, with fine concentric striations ;
the outer lip and sinus have not been obtained perfect.

The height is equal to about three fifths of the basal diameter.

A small species, remarkable for the great breadth of the mesial band, and the pro-
minence of the infero-marginal smooth carina.

Geological Position and Locality. The Great Oolite of Bussage, near Bisley Common,
and of Minchinhampton Common ; it is rare.

ACTEONINA LCIDII, p. 27. Tab. XXXI, fig. 16, and Tab. XLI, fig. 18.

A fine series of examples kindly communicated by Mr. Walton, and collected by him
in the Forest Marble of Laycock, has enabled the artist to illustrate the more striking
varieties of figure. The differences in the elevation of the spire are so considerable that
any measurement of the spiral angle is useless ; the sides of the volutions are always
flattened, with a mesial angle ; in short spired examples the space anterior to the angle is
nearly concealed, and the space posterior to it is nearly horizontal.

Another remarkable instance of variability in the elevation of the spire in the same

ADDENDA. 107

genus is seen in A. olivaformis, Tab. XLI, figs. 4, 4 a, which may be compared with that
given in Tab. VIII, fig. 14, part 1.

ACTEONINA SUESSEA, Lye. Tab. XLV, fig. 29.

Testa ovato-elongata, spira elevata, apice acuminata anfractibus (7) angustis, subangu-
latis, superne concavis anfractu ultimo basi attenuate ; apertura obliqua subreniformi, labro
inferno incrassato.

Shell ovately elongated ; spire elevated ; apex pointed ; volutions (7) narrow, convex,
subangulated, their upper surfaces concave, their upper borders strongly impressed with
a slightly tumid band ; the last volution attenuated towards the base ; the aperture
oblique, and somewhat reniform ; the inner lip conspicuous and thickened ; the lines of
growth are very conspicuous upon the spire.

Geological Position and Localities. The Forest Marble at Farleigh, Laycock, and
Pound Pill ; in the collection of W. Walton, Esq.

ACTEONINA FASCIATA, Lye. Tab. XLIV, fig. 15.

Testa jjarva, ovato-elongata aut sub-cylindrica, spira magna elevata, anfractibus (7)
'ingustis, superne convexis, inferne planatis, ultimo anfractu, valde clonffato, apertura basi
°lliptico curvato, postice angusto ; superficie lineis plicisque perpendicularibus crebris et
irreyularibm notatis.

Shell small, ovately elongated or subcylindrical, the two extremities being somewhat
pointed ; spire large, lengthened, consisting of seven narrow volutions, which have their
upper portions inflated and their sides flattened ; the last volution is much elongated and
sub-cylindrical ; the aperture has its anterior extremity curved elliptically, its posterior
position narrow and lengthened ; the surface of the shell, with perpendicular, crowded,
irregular plications and lines.

The test is delicate, and all the specimens are more or less broken. Length of the
largest specimen, 6 lines ; breadth, 2j lines ; length of the aperture, 4 lines.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection of
W. Walton, Esq.

ACTEONINA WILTONENSIS, Lye. Tab. XLV, fig. 25.

Testa parva, sub-fusiformi, ovato-elongata, spira data, anfractibus (5 — 6) sub -convexis,
anfractu ultimo ovato, apertura elliptica, basi angmto ; superficie lineis pcrpendicularibm,
fcntiissimis, crebris notatis.

108 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Shell small, sub-fusiform or ovately elongated, spire elevated, volutions 5 or G, rather
convex ; the last volution ovate ; aperture elliptical, its base narrow ; the surface, with very
delicate, closely arranged, perpendicular lines, which render the surface slightly rough.

As the outer lip is much broken in both the specimens examined, the figure of the
anterior extremity of the aperture is rather doubtful, and the general figure of the shell is
more fusiform than is usual in this genus ; the columella is rounded, and quite destitute
of any plication.

Geological Position and Locality. The Forest Marble of Laycock ; in the collection of
W. Walton, Esq.

OSTREA WILTONENSIS, Lye. Tab. XXXIV, figs. ], 1 a.

Testa, valva libera planata, crassa, solida, ovato-triangufari, brevi, apiceerecto, obtuso ;
sulco cardinis lato, superficial. Valva ajjixa iynota.

Shell with the free valve flattened, but solid and thick ; its borders are raised inter-
nally, rendering the inner surface somewhat concave ; the figure is ovately triangular, but
short, with the apex erect and obtuse ; the hinge sulcus is wide and superficial. The
affixed valve is unknown.

Several large specimens of this ponderous but flattened oyster have been obtained by
Mr. Walton, including the monstrosity, Tab. XXXIV, fig. 1 a. The height is greater than
the opposite measurement ; it has some resemblance to 0. dclfoidea, but less flattened, not
transverse, and with the umbones not oblique ; and as the specimens are constant in their
general characters, there can be no doubt of its distinctness from that species.
Geological Position and Locality, — The Forest Marble of Pound Pill.

OSTREA (EXOGYRA) LINGULATA, Walton MSS. Tab. XXXII, figs. 2, 2 a, 2 b.

Testa valva inferiore sublavi, cxcavata, clonyata, postice carinata, maryine anteriore
subrecto, cardine brevi, anirorsuni curvato. Valva libera planata, elonyata, linyucKformi,
umloni comprcsso, arcuato ; facie inter no sulco lonyitudinali oblique instructo.

Shell, with the affixed valve excavated, elongated, smooth, with a posterior external,
longitudinal angle ; hinge margin short, and curved forwards ; anterior border straight,
posterior border curved elliptically. Free valve flattened, smooth, lengthened, and tongue-
shaped, tapering towards both the extremities ; the umbo is depressed, and much curved ;
the inner surface with a lengthened posterior sulcation. The length is usually about twice
the opposite diameter.

A species allied to Exogyra carinata. Roerner Nordd, Ool., p. 66, pi. 3, fig. 15.
This latter, however, appears to have the affixed valve more flattened and lunulate.

ADDENDA.. 109

Geological Positions and Localities. This oyster appears to be abundant in the Upper
Bathonian Clays of Wiltshire. Mr. Walton has collected it in the Forest Marble of Pound
Pill, Farleigh, and Hinton, also in the Cornbrash of Hilperton.

Genus — Harpax — Parkinson, 1811. Deslongcharaps, 1858.

Shell irregular, inequivalve, attached by the umbo of the larger or right valve ; surface
radiately ribbed or smooth, usually with concentric, irregular, lamellose plications, imbricated
or tuberculated ; borders of the valves close fitting and irregular.

Hinge in the attached valve consisting of a large, flattened, triangular plate, traversed
by a central perpendicular or oblique furrow to receive the ligament, with somewhat
elevated borders, exterior to which are slightly marked diverging sulcations to receive the
elevated borders of the ligamental groove in the other valve ; the outer borders of the
plate form lengthened and elevated dental processes.

Hinge in the left or free valve with a triangular plate traversed mesially by the liga-
mental groove, the borders to which are elevated and but slightly diverging ; exterior to
these are strongly impressed grooves to receive the dental processes of the other valve ;
the dental processes forming the diverging borders of the plate are but little produced.

The hinge plate in each valve has transverse striations of growth.

The adductor scar is round, placed posterior to the middle of the valve, and strongly
marked ; the pallial sinus is simple.

The genus Harpax having originally been imperfectly described by Parkinson, and
founded upon a single small species, remained but little noticed and accepted by few
authors until the year 1858, when it was re-established and amply illustrated in a copious
work* on the ' Fossil Plicatulas and allied Genera,' by that eminent and veteran palaeon-
tologist M. Eudes, E. Deslongchamps, who to the long list of memoirs in which he has so
ably developed and illustrated the Jurassic fossils of Normandy, has added the present,
which probably surpasses all the former in the critical acumen and lengthened researches
which it has necessitated. Of the fifteen species of Harpax known to M. Deslongchamps
all are Liassic, with one exception (//. ncaplia), from the ferruginous (Inferior?) Oolite of
Longwy ; the following fine species is therefore the first example of the genus in the
oolites of this country.

* Essai sur lea Plicatules fossiles et quelque autre genres voisins ou ddmembres de ces coquilles,
par M. J. A. Eudes Deslongcharaps. Extract du Xle volume des ' Memoires de la Societe Linnecnue de
Normandie,' Caen, 1858.

110 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

HARPAX WALTONI, Lye. Tab. XXXII, figs. 1, 1 a, 1 b.

Testa (valva dextra) magna, crassa, ovata, convexa, sub-auriculata, late adJierente,
radiatim costatis, lamellis incrementi crebris, crassis nodiferis et imbricatis, facie interno,
tabula cardinali magno dentibus et foveis longissimis insigni. Valva sinistra depressa,
crassa, lamellis ut in valva altera, tabula cardinali dentibus prominentibus, longissimis,
obliquis, sulcis conformibus.

Shell of large dimensions, the right valve with a very large surface of attachment, sub-
auriculated, thick, ovate, convex, the surface radiately costated, with thickened, crowded,
imbricated and elevated lamellae of growth ; the triangular hinge plate is very large,
oblique, transversely striated ; the diverging outer grooves which receive the dental pro-
cesses of the other valve are large, deeply impressed, and exhibit in their course three
deeper portions or pits adapted to the successive positions occupied by the anterior, pro-
jecting or bossed extremities of the dental processes in the free valve ; the adductor scar is
very large and posterior.

The left or free valve is thick, but less convex than the other ; the hinge area occupies
upwards of two fifths of the length of the valve ; the ligamental groove is narrow and
deeply marked, but the other furrows are superficial ; the outer diverging dental pro-
cesses are lengthened and conspicuous, terminating anteriorly in projecting bosses ; the
adductor scar is prominent and sub-central. In the specimen figured with the valves in
contact, the right valve has adhered to a smaller specimen of the same species, whose
exposed inner surface exhibits the usual characters of the left valve.

Our species is allied to Harpax calvus and H. scnescens, Desl., from the Middle Lias
of Calvados, but has more prominent rugose lamellae, and a larger hinge area in both the
valves. In the left valve the anterior termination of the dental processes in bosses with
corresponding pits in the furrows of the other valve, has no counterpart in the figures or
descriptions of M. Deslongchamps, but as they do not appear to be equally persistent in
all specimens their importance can only be small.

Geological Positions and Localities. The Forest Marble of Farleigh Wick, Somerset ;
collected by W. Walton, Esq., whose labours have been rewarded by the acquisition of
several good specimens. The interiors of the valves of this species have also been observed
in the Great Oolite of Minchinhampton ; in these instances, however, their external
surfaces could not be disengaged.

GERVXLLIA WALTONI, Lye. Tab. XXXII, figs. 4, 4 a, b.

Testa frfigili, ovato-oblonga, valva sinistra antice convexa, postice explanata in alam
brevcm producia, umboni prominente, apicc acuto, subterminali, ala antica brevi, margins

ADDENDA. 1 1 1

cardinali obliquo, area cardinis longitudinaliter strialis, sulcis transversis magnis (4),
dentibus obliquis internis paucis inconspicuis ; mperfaie plicis incrementi delicate instructis.
Valva altera mediocri convexa.

Shell fragile, ovately oblong; left valve anteriorly very convex, moderately thick,
and steep; posterior side expanded, attenuated, and produced into a short wing; urnbo
prominent, acute, subterminal, the anterior wing being short ; the hinge margin is
oblique, of moderate length ; the hinge area has two or three prominent longitudinal
striations ; the cardinal transverse sulci, four in number, are large and irregular ; the
internal oblique teeth are few and inconspicuous ; the surface with numerous delicate plica-
tions of growth. The other valve is of nearly equal convexity and more strongly plicated.

A well marked convex species, with the hinge border moderately oblique, and the
whole of the posterior side expanded and delicate.

Geological Position and Locality. The Forest Marble of Earleigh and Pound Pill ; in
the collection of W. Walton, Esq.

GERVILLIA ORNATA, Lye. Tab. XXXVI, fig. 7.

Testa parva, ovato obliqua ; valva sinistra convexa, umboni prominente, ala antica
producta ; postica obliqua, brevissima ; superficie striis tenuissimis concentricis, regularibus,
lineisque radiantibus decussatis, Valva altera ignota.

Shell small, ovately oblique ; the left valve inflated, the umbo prominent and situated
nearly in the middle of the hinge line, which slopes from it obliquely in upon each side ;
the anterior wing is produced and rounded, the posterior wing is very short ; the surface
of the valve has very delicate, regular, concentric striations, which are decussated by
elevated lines which diverge from the umbo. The other valve is unknown.

A short, oblique, and very convex Gervillia ; the radiating lines upon the middle of
the valve are slightly undulating and conspicuous, but gradually disappear towards the
sides. The general figure is allied to G. ovata, Sow., but the latter is less convex, and its
surface is destitute of ornamentation.

Length, 5 lines ; breadth, 3 lines. Prom the position of the shell in our figure the
short posterior wing is not seen, and the convexity is scarcely sufficiently conspicuous.

Geological Position and Locality. The Great Oolite of Bussage, adjoining Bisley
Common ; collected by E. Witchell, Esq.

GERVILLIA BICOSTATA, Lye. Tab. XL, fig. 21.

Testa per-obliqua, convexa, ala antica brevi, altera longiora, emarginata, dorso, costis
obliquis elevatis (2) distantibus, plicis incrementi magnis decussatis. Valva dextra
iynota.

112 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

Shell small, very oblique, convex ; the anterior wing short, thick, and gibbose ;
posterior wing more lengthened, emarginated posteriorly ; the middle of the valve with
two elevated, oblique, longitudinal, distantly arranged costas, which are crossed by large
irregular folds of growth ; the right valve has not been obtained.

Our sole specimen has the posterior extremity imperfect.

Geological Position and Locality. The Great Oolite of Bussage, near Bisley
Common ; collected by E. Witchell, Esq.

PERN A MYTILOJDES, Lam. Tab. XXXII, fig. 3.

PEKNA MYTILOIDES, Lanark. An. sans Vert., 6 Bd., p. 142.
Zieten. Pet., p. 71, pi. 54, fig. 2.
Gold/. Pet., p. 104, t 107, fig. 12.
D'-Orb. Prodrome de Pajeont., 1, p. 31 1, No. 21 1.
Morris. Catal., 1854, p. 1/9.
— — Oppel. Jura formation, p. 607, No. 79.

Quenstedt. Der Jura, p. 383, tab. 52, fig. 8.
Damon. Geol. Weymouth, Suppl., pi. 2, fig. 5.

Testa ovala-sigmoidea, convexo-plana in aJam brcvem producta, umbonibus acuiis
prominentibm, margine cardinali obliquo, foveolis (8-12) plano-concavis.

Shell thick, ovately sigmoidal, with a moderate convexity, slightly produced pos-
teriorly into a short imperfect wing ; the hinge margin is wide, oblique with transverse
pits from eight to twelve in number, and only slightly impressed ; the anterior border of
the valves is much thickened and excavated.

Geological Positions and Localities. The Forest Marble of Farleigh ; in the cabinet
of W. Walton, Esq. Unfortunately none of the Forest Marble specimens are altogether
perfect. The Geological range of this Perna must be very considerable, if there is no
mistake in the identification of the species. Professor Quenstedt records it in the
Inferior Oolite of Wurtemburg; Goldfuss, in the Oxford Clay and Upper Oolite of
Baireuth and Wurtemburg; D'Orbigny quotes it from Villiers, Trouville, Lyon,
Chaumont, Pizieux, Marolles (Sarthe), and other localities in the same department,
all in his ' Etage Callovien.'

Mr. Damon has figured it from the Oxford Clay of Weymouth ; and it has been
recorded in the Kimmeridge Clay of the latter place ; and the Portland Oolite of Swindon,
by Professor Morris.

PERNA OBLIQUA, Walton MSS. Tab. XXXIV, fig. 22 a.

subaquivalvi convexo-plana, crassa, umbonibus acutis, prominentibus, maryui<>
antcriorc redo, mnryine cardinali recto, oblique dcclivi, vahis lamellis irregularibm

ADDENDA. 113

conccntricis instructis. Area cardinis angusta, elonyata, foveolis (8) latis, subcon-
cavis.

Shell subequilateral, moderately convex, slightly arched longitudinally in the left
valve ; test thick, umbones acute and prominent ; anterior border straight ; hinge-border
moderately lengthened, straight, sloping obliquely downwards. Hinge-area narrow,
elongated, pits (8) wide, and only slightly concave; lamellae of growth large and
irregular.

Length, about twice as great as the transverse measurement ; diameter through the
valves, one third of the length.

Geological Position and Locality. The Forest Marble of Gastard ; in the cabinet of
W. Walton, Esq.

PECTEN SUBSPINOSUS, Sckloth. Tab. XL, fig. 14.

PECTEN SUBSPINOSOS, Schloth. Petref., p 223.

Goldfuss. Petref., t. 90, fig. 4.

Quenst. Der Jura, p. 500, pi. 67, figa. 3, 4 ; and pi. 92, figs.
5, 6.

Testa ovato-orbiculari fornicata aquivalvi, co-stis (12) aqualibus elatis subacutis in dor so
spinosis, sulcis conformibus transversim lineatis, auriculis inaqualibua costatis lincisque
dccussantibus striatis. (Goldfuss.)

Shell ovately orbicular, equivalve; costae (12) large, elevated, subacutc, each having
upon its ridge a few short spines ; the interstitial sulcations are narrow, with delicate,
transverse lines ; the auricles are unequal, the anterior auricle of the right valve being the
larger ; they have radiating and decussating lines. The valves have but little convexity ;
the radiating costse form one third of a circle.

Height, 7 lines ; transverse diameter, 9 lines.

Geological Positions and Localities. The Forest Marble of Locus and Earleigh,
Somerset ; in the collection of W. Walton, Esq. The foreign localities cited by Professor
Quenstedt are Bopfingen and Waldenburg, in the Parkinson! Oolite and the Bradford
Clay ; also Nattheim, in the Coralline Oolite.

MACRODON HIRSONENSIS, var. RUGOSA. Tab. XXXVI, fig. 9.

The Forest Marble of Wilts and Somerset has this species in the form of a variety
which is distinguished from the shell of the Inferior and Great Oolite by the following
features: — It has greater convexity, a wider hinge-area; the posterior side is more de-
pressed, and is not uncommonly traversed by two or three radiating furrows, and is in
some instances separated from the other portion of the surface by a distinct keel. The

15

114 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

folds of growth upon the sides of the valves are also remarkably, conspicuous, rendering
the surface rugose, and the basal sinuation is very strongly defined ; in some of the more
aberrant forms the posterior side is so much shortened that the umbones are nearly
mesial ; they are then much elevated, and an oblique keel descends to the infero-posterior
extremity. Our illustration faithfully represents this variety, numerous specimens of
which have been placed at our disposal by the kindness of Mr. Walton.

CARDIUM GLOBOSUM, Sean. Tab. XXXVIII, figs. 2, 2 a, 2 b.

CARDIUM GLOBOSUM, Bean, in Mag. of Nat. Hist., 1839, p. 60, fig. 18.

Testa suborbiculari, cequilatera, convexa, marginibus ellipticis curvalis ; superjicie striis
concentricis, tenuissimis, crebris instructis.

Shell suborbicular, equilateral, convex ; the umbones moderately produced, acuminated,
and incurved ; the margins of the valves are elliptically curved ; the surface has very deli-
cate, regular, closely arranged, concentric striations.

The length and breadth are equal ; the diameter through the valves is two fifths less.
Our illustration is taken from the original specimen figured by Mr. Bean ; its outline
should be somewhat more orbicular. The striated surface readily distinguishes it from
Cardium cognatum, Phil., which in other respects it resembles.

Geological Position and Locality. The Cornbrash of Scarborough ; in the collection
of Mr. Leckenby.

LITHODOMUS POKTERI, Lye Tab. XL, fig. 29.

Testa parva ovato-oblonga, convexa, angusta, umbonibus obliquis, subterminalibm ;
margine anteriore recto, posteriore ettiptico curvato, costis longitudinalibus numerosis,
tenuibus lineis concentricis decussatis.

Shell small, ovately oblong, narrow, convex ; umbones oblique, subterminal ; anterior
border straight, its sides steep ; posterior margin curved elliptically ; longitudinal costae
numerous, delicate, closely arranged, sometimes bifurcating towards the lower border, and
decussated by closely arranged, concentric lines.

The ornamentation is most prominent towards the middle of the valves, and is very
faintly traced upon the anterior side. It is allied to Lithodomus parasiticus, Desl., Mor.,
and Lye. (' Gr. Ool. Mon./ "Biv.," p. 41, Tab. IV, fig. 19), but has greater convexity,
and is more narrow and cylindrical ; the numerous costa3 and decussating lines are also
distinctive features.

Geological Position and Locality. Collected by W. Walton, Esq., in the Great Oolite
of Hampton Cliffs, near Bath.

Dedicated to Henry Porter, Esq., M.D., who has investigated the geology in the
neighbourhood of Peterborough.

NOTES AND CORRECTIONS.

Fossils fyured in the former parts of this Monograph from the Coast of Yorkshire, and

attributed to the Great Oolite.

IT may now be stated, as the general conviction of Palaeontologists who have critically studied the
subject, that the Testacea of all the marine beds intercalated with the important but local plant-bearing
shales and sandstones of the Yorkshire coast, intermediate the Cornbrash and the Dogger, constitute an
Inferior Oolite fauna, but that the mineral character of these deposits and their sequence are peculiar to the
locality ; it is found also, as might be expected in deposits so isolated in their general conditions, that the
fauna of these several marine beds, although undoubtedly pertaining to the Inferior Oolite, cannot be
arranged with precision upon any corresponding horizons of the same formation, either in Britain or upon
the Continent. But in discarding the correlative value of the minor subdivisions, it appears that they may
be assigned approximately to those groups of beds which constitute the upper portion of the Inferior
Oolite, and which have been divided by Quenstedt, Oppel, and others, into two distinct stages, the lower of
which is characterised by the presence of Ammonites Humphriesianus, the upper by Ammonites Parkinsoni.
Upon the coast of Yorkshire these Ammonites, however, have occurred in the same bed, and the number of
marine floors is so few that they cannot be considered as representing the two superior stages in the
entity of their mass and of their fauna ; their deficiencies are more especially remarkable in the rarity of
the Brachiopoda and of the Ammonites.

These conclusions have been arrived at by an investigation of a series of details so extensive and
decisive in their results as to admit of no uncertainty upon the subject. That the marine beds in question
should have been assigned to the Great Oolite upwards of thirty years since by the author of the ' Geology
of Yorkshire ' will not excite surprise in any one who is able to recall to memory the rudimentary condition
of Palaeontology at that period, and the absolute ignorance which then prevailed of the Testacea of the
Great Oolite ; that the Paloeontology of the Jurassic portion of the work in question constituted a great
advance upon the previous work of Messrs. Young and Bird was at once recognised, and the author candidly
stated that he assigned these marine intercalated beds to the Great Oolite solely from their position — higher
than certain beds of undoubted Inferior Oolite, and lower than the Cornbrash. The progress of knowledge
tending to arrange them with the Inferior Oolite, was gradual. Following the work of Professor Phillips, in
1839 appeared the two well-known memoirs of Professor Williamson on the distribution of organic remains
in the Oolitic rocks of Yorkshire, in which the subordinate beds of the Lower Oolites and their organic

116 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

contents are detailed with all the care and precision that might be expected from a person who had been
long resident in the locality. Within the few years following appeared the elaborate works of Goldfuss,
Ziethen, Roemer, Bunker, Agassiz, Deshayes, Sir R. Murchison's second edition of the ' Geology of Chel-
tenham,' the ' Catalogue" of Professor Morris, the memoir of D'Archiac on the Aisne, several memoirs by M.
Eudes Deslongchamps on the fossils of the Oolites of Normandy, a portion of the ' Pale'ontologie Fran9aise '
of D'Orbigny, Quenstedt's ' Wurtemburg,' and the ' Lethea ' of Bronn. These works, together with others
which bear less directly upon the subject of the Lower Oolites, tended very materially to extend and correct
the knowledge of their fossils. During the same period also the fossils of the Great Oolite in Gloucester-
shire had become extensively dispersed, and were compared with those from the Yorkshire coast, collected
and distributed with great perseverance by Mr. Bean during a lengthened period. The first published
results of influences so potential appeared in 1850, when M. d'Orbigny, in his ' Prodrome de Pale'ontologie,'
placed many of the so-called Great Oolite Yorkshire fossils in his Etage Bajocien, or Inferior Oolite. In
the same year appeared the first part of the monograph on the Great Oolite Mollusca, in the introductory
remarks to which the authors pointed out the affinity of the Yorkshire so-called Great Oolite fauna to that
of the Inferior Oolite, and, as a measure of precaution, were careful to keep the doubtful Yorkshire fossils
distinct, both in plates and descriptions, from the Great Oolite fossils of the south of England. The various
works and lesser memoirs upon the Lower Jurassic rocks published between 1850 and the preoent time
would of themselves constitute a considerable list. Without enumerating them, it will be sufficient to
mention that, in 1856-8, Dr. Albert Oppel, in his remarkable work, ' Juraformation,' placed the Yorkshire
Phytiferous beds with the Inferior Oolite, and considered that they did not even represent the highest stage
of that formation. In 1857 the present writer expressed, in a little work, 'The Cotteswold Hills,' convic-
tions of similar import. In 1859 Dr. Wright enforced similar views, accompanied by extensive details and
lists of Inferior Oolite fossils, in a contribution to the 'Journal of the Geological Society.' The previous
Great Oolite Monograph contains four plates of these Yorkshire intercalated marine Testacea ; some of
which, however, pass upwards into the Great Oolite of the Cotteswolds and into the Cornbrash, as will be
ascertained from the descriptions. In excluding them from the present Supplementary Monograph, the
writer begs to state that he consented to their admission into the former work with great reluctance, in
deference to the opinion then prevalent that they pertained to the Great Oolite, but with a strong impression
(formed in 1839, upon perusing the memoir of Professor Williamson) that they constituted an Inferior
Oolite fauna.

The Palaeontologists of France, in their expositions of the Great Oolite fossils of that country, have,
within the last few years, fully proved, by the general identity and association of species, that the fauna of
the Minchinhampton beds is not exceptional or local merely, as some have supposed, but represents a very
ample and characteristic series of Mollusca, a large number of which are also found in other and distant
localities at the same geological horizon. Other not less interesting and important facts, confirmatory of
this view, have recently been afforded by researches in English strata of the same epoch. The Oxfordshire
railway sections of the Great Oolite and Forest Marble have yielded to Mr. Whiteaves a varied series of
Testacea, a list of which he has kindly communicated to me, together with many of the fossils, including
those which are not known in the Minchinhampton beds; the result is, that of 122 Great Oolite and 48
Forest Marble shells, in all 140 species, obtained by that gentleman in the Oxfordshire beds, upwards of
1 14 are also common to the Minchinhampton beds. An extensive series of Forest Marble shells from
the clay beds of Wiltshire, Somersetshire, and Dorsetshire, liberally placed at my disposal by Mr. Walton,
has produced a larger number of novel forms, as might have been expected from the very different litho-
logical conditions of the deposit ; nevertheless there is still a majority of Minchinhampton shells, and the
entire assemblage is even more remotely allied to the Yorkshire fauna than is that of Minchinhampton.
The general discordance, therefore, of the Yorkshire and southern faunas of the supposed Great Oolite
within so small an area as England would lead us to infer their separation chronologically, even if we were
unable to assign the northern series to that of an older and well-known era.

NOTES AND CORRECTIONS. 117

The following is a list of Yorkshire Testacea figured in the former Monograph which are not known to
occur in any stratum more recent than the gray limestone of Scarborough, and should therefore, in accord-
ance with the foregoing views, be excluded from the fauna of the Great Oolite :

PART I.

AMMONITES BRAIKENRIDGII. Tab. XIV, fig. 1.

BLAGDENI. Tab. XIV, figs. 3 a, b.

BELEMNITES GIGANTECS. Tab. XIV, figs. 4, 4 a.

SERPCLA PLICATILIS. Tab. XIV, figs. 5, 5 a, b.

SULCATA. Tab. XIV, fig. 6.
CEKITHICM BEAKII. Tab. XV, fig. 5.
CHEMNITZIA (?) VETUSTA. Tab. XV, fig. 7.

SCAEBUEGENSIS. Tab. XV, fig. 8.
AcTjEon SEDGVICI. Tab. XV, figs. 9, 9 a.
PULLUS. Tab. XV, fig. 11.

ACTEONINA GLABRA. Tab. XV, fig. 10.

TUMIUCLA. Tab. XV, fig. 14.
PHASIAVELLA LATIUSCULA. Tab. XV, fig. 16.
NATICA ADDUCTA. Tab. XV, figs. 17, 17 a.

— (EUSPIRA) CINCTA. Tab. XV, fig. 20.
TROCHUS LECKENBYI. Tab. XV, figs. 21, 21 a.

PART II.
MTTILUS (MODIOLA) LECKENBYI. Tab. XIV, fig. 9.

CuCDLLjEA CANCELLATA. Tab. XIV, fig. 12.

UNICARDIUM GIBBOSUM. Tab. XIV, fig. U.
TRIGONIA SIGNATA- — DECOKATA. Tab. XV, fig. 1.
ASTARTE ELEGANS, Phil, (non Sow.). Tab. XIV, fig. 1-1.

ISOCAKDIA CORDATA. Tab. XV, fig. 5.

MYACITES BEANII. Tab. XV, figs. 11 a, b.

SCAHBCRGENSIS. Tab. XV, fig. 13.
;EQUATUS. Tab. XII, fig. 15.

Cornbrash of the Coast of Yorkshire : its MoUuaca.

The Mollusca of the Yorkshire Cornbrash offer, in their association, some marked contrasts with those of
the southern counties and of the Continent upon the same geological horizon. In the southern localities
the marine floors, crowded almost exclusively with Brachiopoda, is the predominating feature that arrests
the attention ; in the northern the Conchifera constitute the great majority ; the Brachiopoda, few indivi-
dually, are reduced almost to the two species Terebratithi lagenalis and T. obovata, the latter being
represented by forms dwarfed to about a third of the linear dimensions which the species attains in
Wiltshire. The condition of the Testacea also offers some interesting contrasts. In Wiltshire the
Conchifera are usually in the condition of casts, of which a large proportion are compressed and distorted ;
in Yorkshire the hard, dark-coloured limestone has preserved the more delicate external characters in a very

118 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

perfect manner, including the thin tests of Pholadomya, Myacites, Gresslya, Goniomya, and Cercomya,
together with the outer, granulated tegument of the four latter genera ; and when the matrix is less hard,
even their internal hinge characters may be disclosed. The Gasteropoda are few, both as to species and
individuals ; the Cephalopoda are, with the exception of a small Belemnite, limited to Ammonites macro-
cephalus, which affords great variety in the details of its figure and ornamentation, but which never attains
to the large dimensions of Wiltshire specimens.

Its Molluscs, viewed comprehensively, may be regarded as n transitive series, a chain of life serving to
connect the fauna of the Inferior Oolite with that of the Oxfordian rocks, comprising a considerable
proportion of the former, perhaps an equal number of special forms, a much smaller number of species
which pass upwards into the Oxfordian beds, and a still lessening proportion of forms which are recognised
in the Great Oolite or Forest Marble, but these latter consist almost entirely of shells which pass upwards
from the Inferior Oolite.

Minute Testacea of the Great Oolite and Forest Marble.

Only a portion of these have been selected for illustration, others, inconveniently minute, having been
rejected upon that account. That some of these minute forms attain to much larger dimensions under
different conditions may be inferred from the fact that many minute Gasteropoda and Conchifera associated
with them are only dwarfed forms of well-known Great Oolite species, which in other beds are of the
dimensions figured in the former parts of this Monograph.

Forest Marble Testacea.

The following note, kindly communicated by Mr. Walton, describes the localities of the Forest Marble
cited in this Monograph :

" The principal localities from which these fossils have been obtained are Farleigh, Hungerford, in
Somersetshire ; Pound Pill, near Corsham, and Laycock, in Wiltshire ; and Burton Bradstock, about five
miles from Bridport. The lithological character of the Forest Marble is very various, demonstrating the
littoral character of the deposit, which is shown also by the trails of animals and the numerous remains of
what can hardly be anything but Fucoids. The best locality at Farleigh is a superficial cutting opposite
Wick Farmhouse, made in forming the new Warminster Road, and the bed is a crumbly, shelly marl, and
the fossils, when first found, apparently mere lumps of clay. In the small quarries near Hinton Charter-
house, Cumberwell, and Philips Norton, the rock is a hard, calcareo-arenaceous stone, and at Pound Pill
it is as hard and more intractable than Carboniferous limestone. At the railroad-cutting near Laycock it
is a cream-coloured clay, containing shells better preserved than usual, and from this nearly all the small
shells have been procured. In many places the Forest Marble is a mere mass of broken shells, and
frequently formed almost exclusively of crushed Rhynchonellae. At Burton Bradstock the Forest
Marble clay rests on the lower beds of the Inferior Oolite, and most of the fossils from that locality were
picked up from a bank on the sea-shore. I have never found an Ammonite in the Forest Marble, and only
one very doubtful trace in the Cornbrash."

Testacea from the Clays of the Forest Marble compared with those from the Limestones of the Great
Oolite. — As might be anticipated from the widely differing mineral conditions of the two deposits, they are
tenanted to a great extent by different races of Molluscs. The fossils figured in this Supplement from the
Forest Marble by no means represent the whole of the additional species contained in the clay beds of that
stage, but such only as from their state of preservation are suitable for our plates ; a large proportion have

NOTES AND CORRECTIONS.

119

suffered from vertical compression and consequent distortion, so that in many instances it has only been
possible, even with the choice of numerous specimens, to select one or two as representatives of their
respective species, and some tablets covered with shells have with reluctance been rejected when specific
forms could only have been made up by the aid of doubtful restorations. Our note on the age of the
gray limestone of the Yorkshire coast alludes to the general identity of species which obtains between the
Testacea of the Great Oolite and Forest Marble limestones of Gloucestershire and of Oxfordshire ; they
form, in fact, but one fauna, the most prominent species of which are abundant only over very limited
areas. In the Forest Marble clays we find that the great mass of the organic forms belong to but few
genera ; the deficiencies in this respect are very striking. The large collection of Mr. Walton contains not a
single Ammonite or Belemnite ; of Gasteropoda there is almost an entire absence of Nerinsea, Cylindrites,
Ceritella, and Trocholoma, genera so abundant and varied in the limestones ; these deficiencies are to a
great extent compensated for by an abundance of special forms of Phasianella and of Acteoniua, which is
the more remarkable as the latter genus is everywhere one of the most rare forms of the limestones. The
genus Cerithium is abundant, consisting of forms less dwarfed than is usually seen in the limestones. The
genera Nerita, Trochus, and Monodonta, are well represented, but the two latter genera for the most part
by forms special to the clays. Of the Conchifera the clays produce Tancredia comparatively in small
numbers and apparently of few species, but their condition is usually such as will not admit of a rigid
scrutiny ; a similar paucity applies to the Areas, Trigonias, Limas, and Pectens. Perna, Gervillia,
Pteroperna, and Astarte, are for the most part represented by species special to the clays or rare in the
limestones ; Pholadomya, Homomya, Myacites, and Goniomya, appear to constitute the rarest generic forms
in the deposit ; Cercomya and Thracia, perhaps, are absent altogether. Wanting these, the clay banks
swarmed with a profusion of Nuculse and Cyprinse, usually of forms differing from those of the limestones.
Perhaps about 25 per cent, would be a fair estimate of the testaceous species special to the clays ;
but taking only the more common forms of each deposit, the differences between them are much more
marked and important than would be inferred from such a proportion of species.

The following, probably, have not been obtained in any other deposit than the Forest Marble :

Turbo Burtonensis.
subtexata.
nodifera.

Trochus Burtonensis.
Monodonta comma.
Waltoni.
arata.
tegulata.

Onusbus Burtouensis.
Natica arata.
texata.
alta.

Acteonina Luidii.
Suessea.
fasciata.
Wiltonensis.
Phasianella variata.
Solarium turbiniformis.
Waltoni.

Pleurotoraaria Bathonica.
Ostrea Wiltonensis.
Gervillia Waltoni.
Perna obliqua.
Trigonia arata.
Lucina Burtouensis.
Corbis rotunda.
Corbula Hulliana.
Islipensis.
Agatha.

Corbicella subangulata.
Cyprina bella.

Davidsoni.
Astarte robusta.

rustica.

fimbriata.

ignota.

Hilpertonensis.

Alaria parvula, p. 22. Tab. Ill, fig. 12; and A. cirrus, p. 22. Tab. Ill, fig. 13.

Further observations lead to the conclusion that the former shell is the young condition of the latter,

120 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

and that the differences in the last volution are owing only to the stage of growth to which the specimens
have respectively attained.

Index to Tab. XII, Part II, add fig8. 13, 13 a, Hinge of Corbicella.

Page 95, fifth line from the bottom, add, and Tab. XII, figs. 13, 13 a.

Index to Tab. XIII, fig. 16, for p. 139, read p. 140.

Myoconcha Action, p. 77, Part II, for Tab. Ill read Tab. IV.

Tab. XIII, fig. 18, Part II, alter dereference to, Pholas costellata, p. 142.

Index to Part II, add, Pholas oolitica, p. 126. Tab. IX, fig. 21.

Alaria trifida, Part I, p. 21, add the following to the description: — The first two or three
volutions are longitudinally costated, the transverse striations extend even upon the caudal and digital
processes.

Pholodomya oblita, Part II, p. 142* ; Tab. XII, fig. 5. It is now ascertained that the specimen figured
was erroneously assigned to the Great Oolite ; its true position is in seams of sandy marl near to the base of
the Inferior Oolite, in which position it occurs at various localities in the vicinity of Stroud and Nailsworth ;
the officers of the Ordnance Geological Survey have also procured it from a similar position in Somer-
setshire. It sometimes attains very large dimensions, as is exemplified by a remarkable specimen in the
Bristol Museum, which has been mistaken, as in other instances, for the aged condition of Pholadomya
fidicula, Sow. The delicate, radiating lines are scarcely distinguishable upon the aged and inflated
examples of P. oblita, but are always acute and conspicuous upon P.fidicula.

Trigonia decor ata, Lye., Part II, p. 133, Tab. XV, fig. 1, alter the title to Trigonia signata, Ag., a
fine species, abundant in the Upper Trigonia Grit of the Inferior Oolite in the Cotteswolds, and more
rarely in the gray limestone of the coast of Yorkshire ; it occurs in a similar geological position at various
Continental localities. Professor Quenstedt has figured it from Wurtemberg under the name of Trigonia
clavellata. It has never been found to pass upwards into the Great Oolite.

Patella paradoxa, Part I, p. 90, Tab. XII, fig. 2. This rare species is the Patella lata, Sow., 'Min.
Con.,' t. 48-1, fig. 1, p. 133. ,The compressed and imperfect specimen figured in the latter work will
account for our having failed at an earlier period to identify it with the very few examples which have been
obtained at Minchinhampton.

Tancredia curtansata, Part II, p. 93, Tab. XIII, figs. 7, 7 a, 1 b, alter the title to Tancredia sub-
curtansata ; it is much less inflated, the umbones are more elevated and pointed, the posterior side is more
produced, and it is destitute of the large longitudinal plications which distinguish the species of the Coral
Rag ; the latter is also a much larger shell, only two specimens of which have come to my knowledge, the
type specimen in the York Museum, the other in the fine collection of Mr. Leckenby at Scarborough.
Tancredia Lycetti, Oppel, from the Inferior Oolite of Wurtemberg and of Gloucestershire, is also nearly
allied to the Coral Rag shell, and appears to be equally rare.

Tancredia axiniformis, p. 93, Tab. XIII, fig. 6, and Tab. XII, fig. 7, alter the title to Tancredia
exlensa, Lye. In this instance the name proposed in my first notice of the Genus Tancredia, ' Ann. and
Mag. Nat. Hist.,' Dec., 1850, must be retained, as an examination of many Yorkshire specimens of
T. axiniformis leaves no doubt that it is a distinct species, which occurs in the Inferior Oolite, both in that
county and in Gloucestershire ; compared with the Great Oolite T. extensa, it is shorter, more flattened,
approaching more nearly to the outline of T. brevis, but with much less convexity.

Tab. XV, Part II, figs. 2, 2 a, alter the title to Ceromya Bajociana, D'Orb. ; the figure represents the
usual size attained by this Ceromya in the Inferior Oolite of the Yorkshire coast ; in the Cotteswolds the
same formation produces it of far larger dimensions, and justifies the terms in which it is described by
D'Orbigny in his ' Prodrome,' p. 274, as follows : — " Magnifique espece courte, renfle'e a crochets tres-

NOTES AND CORRECTIONS. 121

contourneX ornee de stries concentriques d'accroisement, comme rostree a la region anale." It is the
Isocardia concentrica of Phillips, 'Geol. York.,' i, pi. xi, fig. 40, but not of Sowerby. The Yorkshire
examples may, therefore, be considered as dwarfed forms of this really magnificent shell, the southern
examples of which have the distinguishing features of the species much more strongly marked ; the umbones,
more especially, are larger and more elevated, the posterior extremity being also more rostrated. It
is worthy of remark that this degenerated form is the only one of the genus that has been obtained from
the whole of the Jurassic rocks of Yorkshire.

Anatina undulata and Anatina plicatella, Tab. II, Part II, transpose figs. 6 and 4 upon the tab. ;
the references to them at p. 118, and also upon the page facing the tab., will then be correct.

Pholadomya ovulum, Part II, Tab. XIII, fig. 12, alter the title to Pholadomya ovalis, Sow. ; also at
p. 122.

Turbo capitaneus, Goldf., Part I, p. 65, erase the words " Tab. IX, fig. 33," and alter to " Supplement,
Tab. XLI, fig. 1." The index to Tab. IX, fig. 33, should be altered to Amberleya Jurassl, Supplement,
p. 19.

Stomatia? Buvignieri, Part I, p. 85, alter the generic title to Nerita. Another figure is given,
Supplement, Tab. XLI, fig. 7.

Part II, Tab. VI, fig. 15, p. 67. I agree with Dr. Oppel (' Juraformation,' p. 487) in the propriety
of separating this Lucina from L. Bellona ; its title should, therefore, be Lucina Lycetti, as suggested by
Dr. Oppel.

Cerithium Roissii, Part I, p. 32, alter the generic title to Fibula. See p. 10 of this Supplement.

Myacites cratsiusculus, Part I, p. 112, alter the generic title to Homomya. See p. 89 of this Supple-
ment.

Myacites Fezelayi, Part I, p. Ill, alter the generic title to Homomya. See p. 88 of this Supplement.
Myacites gibbosus, Part I, p. 138, alter the generic title to Homomya. See p. 88 of this Supplement.

Corbula involuta, Part I, p. 97, alter the title to Corbula Buckmani. See p. 63 of .this Supplement.
Corbula Buckmani will be found refigured, Tab. XXXIV, figs. 6, 6 a.

Part II, p. 123, erase the first reference to Pholadomya Seemanni, Tab. II, fig. 1, which is P.
solitaria.

Part II, p. 28, Tab. IV, fig. 12. This little shell, erroneously ascribed to the Modiola pulcherrima of
Roemer, has been rectified by Professor Morris, ' Catal.,' p. 210, under the appellation of M. Lycetti.
Compared with the allied species of the Hilsthone, it is smaller, more inflated, the radiating lines are more
narrow or more distantly arranged, the test is very thin, and the specimens are usually imperfect.

Mytilus (Modiola) lumidus, Part II, p. 37, Tab. IV, fig. 5. It is stated that the rude figure of a
Modiola, Young and Bird, 'Geol. York. Coast,' pi. vii, fig. 10, is intended to represent this shell, and
that Professor Phillips inserted it in his list of Yorkshire fossils, 'Geol. York.,' i, p. 171, in the following
terms: — "Modiola ungulata, Coralline Great and Inferior Oolite." It is not uncommon in the upper stage
of the Inferior Oolite in the Cotteswold Hills.

Purpuroidea Moreausea, Part I, p. 27, Tab. IV, figs. 1 — 4, alter the title to P. Morrisea. The
publication of the splendid work of M. Buvignier on the Palaeontology of the Meuse has shown that we
were mistaken in assigning our Minchinhampton species to that figured in a very indifferent manner in
the little memoir by M. Buvignier in 1843. The new specific name selected for our shell by the latter
author should therefore be adopted.

Part I, Tab. II, figs. 3, 3 a, p. 12. The Ammonite obtained at the base of the Great Oolite, and
referred doubtfully to A. macrocephalus, is now ascertained to be A. viator, D'Orb., ' Pal. Fr. Terr. Jurass.,'

16

122 SUPPLEMENT TO GREAT OOLITE MOLLUSCA.

tab. 172, of which numerous specimens are now in the British Museum, obtained from a similar geological
position in Somersetshire ; in some of these the last volution quite conceals all the others, leaving only a
small umbilical orifice ; the absence of costse upon the inner portion of the last volution distinguishes it
from A. macrocephalus. Dr. Oppel (' Juraformation,' p. 478) proposes for it the new title of A. Morrisii,
which, in accordance with the above views, must remain as a synonym of A. viator.

Aeteonina? parvula, Part I, p. 104, alter the generic title to Ceritella.

Part II, Tab. 5, figs. 18 a, 19 a. Both these figures represent the young condition of Trigonia
Goldfussii.

Trochus pileolus, Part I, p. 66, Tab. 10, fig. 5. Additional specimens have proved that the smooth-
ness of the surface is accidental ; traces of encircling striations are sometimes visible ; the shell then
becomes identical with Turbo obtusus, Sow., of which Trochus Bixa, D'Orb., is also a synonym.

Nerita hemispherica, Eoem., Tab XI, figs. 14, 16; Nerita minuta, Sow., Tab. XI, fig. 19. A com-
parison of very ample materials, including all the connecting forms, leaves no choice but to regard N-
hemispherica as the adult shell of 2V. minuta. The preservation of the epidermal pattern of coloration has
materially tended to this result; the older shells, as in fig. 14, with their strong, rugose plications, thickened
columellar lip, and entire absence of the epidermal coat, appear at first sight sufficiently distinct, but from
these we pass to specimens of less advanced growth, as in fig. 16, without plications, but still possessing
the callosity upon the inner lip ; some in this state, however, retain portions of the external tegument, in
which may be traced remains of the two broad bands of white between the three of dark-coloured pigment,
the latter consisting of transverse, wrinkled lines. From these to the smallest forms the transition is easy ;
the latter are most commonly more ovate, but this is by no means an invariable feature, nor are the adult
shells very constant in the degree in which the spire is produced. The minute forms, which usually retain
the epidermal coat, are smooth and shining ; with advance of growth the shell exhibits continual and
considerable increase of thickness. The two extremes of aspect are fairly represented in figs. 14 and 19.
Nerita minuta is so inappropriate a name for the adult shell, that it seems desirable to adopt Nerita
hemispherica, although the former has priority.

Fusus ? subnodulosus, Part I, Tab. V, fig. 9, p. 23, alter the generic title to Brachytrema.

Phasianella conica, Part I, Tab. XI, fig. 30, p. 74 ; Phasianella acutiuscula, Tab. XI, fig. 28, and
Tab. IX, fig. 2. An examination of numerous additional specimens has led to the conclusion that these
forms should be regarded as only varieties of one species . for although some examples are even more
lengthened than the figures of P. acutiuscula, others connect the typical specimens of each variety in a
very perfect manner.

Genus Brachytrema, Part I, p. 24. Further information has shown that the generic description before
given should be slightly modified ; the outer lip was stated to be thin, which is correct as far as regards the
greater number of specimens ; but some species, as B. varicosa and B. pygmea, acquired at certain arrests
of growth thickened outer lips or varices, as in Triton ; from the latter genus they are distinguished by the
shorter trochiform spire and absence of denticulations upon the borders of the aperture.

Turbo? pygmeus, Tab. IX, Part I, figs. 29, 29 a, alter the title to Brachytrema pygmea. The doubt
as to the genus expressed in Part I, p. 65, has been justified in an example with the aperture perfect, figured
by M. Piette, 'Bull, de la Soc. Geol. de France,' 2 ser., pi. xv, fig. 21, under the name of Brachytrema
brevis ; the base is strongly striated, and the aperture much contracted.

Alaria lievigata, p. 17, Tab. Ill, figs. 3, 3 a ; Tab. XLI, fig. 13, alter the title to Alaria Myurus,
Desl., sp. It was stated at p. 17 " that in everything excepting its smooth surface this shell agrees with the
Roitellaria Myurus of Deslongchamps." A specimen recently obtained exhibits some encircling striations
upon the upper portions of the two larger volutions ; the sole distinction, therefore, that separated it from

NOTES AND CORRECTIONS. 123

the species of Deslongchamps is thus removed. The specimen figured Tab. XLI, fig. 13, exhibits the first
spine, which is monodactyle ; a second and much larger spine, also monodactyle ; the third and ultimate
spine being didactyle.

Acteonina ?, Part I, Tab. VIII, fig. 12*, is the young shell of A. olivceformis, p. 103.

Lima Luciencis, D'Orb., 'Gr. Ool. Mon.,' Part II, p. 28, Tab. Ill, fig. 4. This shell is a synonym of
Lima rudis, Sow. The number of costse vary from eight to eleven ; the specimen figured in the ' Mineral
Conchology,' tab. 214, has only seven costae, and the figure is unusually gibbose. Its geological range is
considerable ; it occurs sparingly in the Great Oolite of the Minchinhampton district and in the Cornbrash
of the coast of Yorkshire, but in the Coral Rag of Malton it is moderately abundant.

Sub-genus Crossostoma, Part I, p. 72. Of the three Oolitic species assigned to this proposed sub-genus
of Delphinula, the only one which exhibits the distinctive characters is C. Pratii; the other two forms,
discoideum and heliciforme, were formerly supposed to represent in their apertures the immature condition
of that sub-genus. Subsequent observations of numerous specimens has compelled me to abandon that view,
and to regard discoideum and heliciforme as adult shells, or discoidal forms of smooth Monodonta. Other
examples of Monodonta allied to the Great Oolite forms, but less depressed, have been figured by Messrs.
Hebert and Deslongchamps, in their ' Memoir on the Kelloway Rock Fossils of Montreuil-Bellay,' under
the names of Monodonta ovulata and papillata.

Cerithium quadricinctum, Goldf., and C. limceforme, Roetn. These two forms must be united into one
species ; individuals with large nodules and with only three distinct rows have been assigned to C. limce-
forme, but, even with these, indications of a fourth row are occasionally to be discovered, and the promi-
nence of the nodules, and their number in each volution, are very variable. C. quadricinctum has a
considerable geological range, and it occurs also in the Coral Rag of Germany.

Patella suprajurensis, Part I, p. 92, Tab. XII, figs. 9, 9 a. I can now only regard this form as a variety
of P. Aubentonensis, in which the lamellse of growth are strongly marked and the cancellated lines have
disappeared. It is also not uncommon to meet with smooth examples of the latter species.

Pholadomya solitaria, Part II, p. 124, Tab. XI, fig. 1, et Tab. XII, fig. 2 ; erroneously printed P. oblita
upon the reference facing the latter table. Pholadomya oblita is Tab. XII, fig. 5, p. 142*. The variations
of figure and of ornamentation, either separately or combined, are so considerable in the cordiform examples
of Pholadomya, that a large number are indispensable to enable us to legislate upon them with any
confidence ; probably P. solitaria is only a variety of P. deltoidea, Sow.

[Note. — The Author desires to tender his best thanks to Mr. West for the very careful drawings in the
plates that illustrate this Monograph ; and more especially for the fidelity and attention to
the more minute details exhibited in the magnified figures of the smaller Gasteropoda,
from the Great Oolite and Forest Marble.]

INDEX

TO

SPECIES RETAINED IN THIS SUPPLEMENT.

PAGE

ACTEON Bathonicum 25

— phasianoides ... ... 26

ACTEONINA brevis 26

canaliculata ... ... 27

fasciata 107

Kirklingtonensis ... 26

Luidii 27, 106

scalaris... ... ... 28

Scarburgensis ... ... 28

Suessea ... ... 107

Wiltonensis ... ... 107

AMBERLEYA armigera ... ... 20

capitanea ... ... 95

Jurassi ... ... 19

monilifera ... ... 95

tricincta ... ... 96

AMMONITES bullatus 3

discus ... ... ... 4

BBACHYTKEMA buccinoidea ... 5

varicosa ... ... 5

CERITELLA fusiformis ... ... 12

Lycettea ... ... 12

Morrisea ... ... 12

minutissima ... ... 11

CERITUIUM Bathonicum ... ... 6

bulimoides ... ... 7

compositum

costigerum ... ... 93

hemicinctum ... ... 91

— multiforme ... 7

TABLE

XLIV, fig. 16.
XLIV, fig. 28.
XLI, fig. 6.
XXXI, figs. 9, 9 a.
XLIV, fig. 15.
XLI, fig. 5.

XXXI, fig. 16 ; XLI, fig. 18.
XLIV, fig. 18.
XXXI, figs. 13, 13 a.
XLV, fig. 29.
XLV, fig. 25.
XXXI, fig. 6.
XLI, fig. 1.
IX, figs. 33, 33 a.
XLI, fig. 10.
XLI, fig. 14.
XXXI, fig. 1.
XLI, figs. 8, 8 a.
XLIV, fig. 17.
XLIV, fig. 27.
XLV, fig. 4.
XLIV, fig. 25.
XLIV, fig. 22.
XLV, fig. 5.
XLIV, fig. 19.
XLIV, fig. 3.
XLIV, fig. 9-
XLI, figs. 11, llo, 6.
XLI, fig. 17.
XLIV, fig. 20.

126

INDEX.

CERITHICM exscalptum

neglectum

poculum

undulatum

Witchelli

Waltoni
CYLINDRITES exigua

turriculatus ...
CHEMNITZIA constricta

— vittata
DENTALIUM entaloides
EULIMA? laevigata ...
FIBULA eulimoides ...

— variata
KILVEBTIA composita

— formosa

— pulchra

— spicula ...

— strangulatum . . .
MONODONTA arata ...

comma
composita
exigua
Lycetti

— • sparsistriata . . .
tegulata
Waltoni
NATICA alta

— arata

— 1 1 ul liana

— insignia

— texata
NEBIN^EA granulata
NERITA clavatula

— involuta
NEKITOPSIS Archiaci
ONUSTUS Burtonensis
PHASIANELLA variata
PLEUROTOMAKJA Bathonica

Burtonensis
granulata . . .
recondita . . .

PCEPUROIDEA insignia

RISSOA ? exigua

RISSOINA Milleri

— subulata ...

— tumidula . .

PAGE

93
92
93
8
10
92
24
25
15
14
28
13
17
16
9

95

10, 94
9
8

102

101

23

22

22

22

102

101

97

97

13

97

96

10

98

20

21

103

104

105

105

24

106

6

9

18
98
98

TABLE

XLIV, fig. 23.

XLIV, fig. 21.

XLI, fig. 24.

XLIV, fig. 6.

XLIV, fig. 7.

XLI, fig. 16.

XLIV, fig. 14.

XLIV, figs. 26, 26 a.

XLIV, fig. 8.

XXXI, fig. 10.

XXXI, figs. 11, 11 a, \\b.

XXXI, fig. 3.

XXXI, fig. 5.

XXXI, figs. 4, 4 a.

XLIV, fig. 9.

XLIV, fig. 5.

XLI, figs. 12, 12 a ; XLIV, fig. 4.

XLIV, fig. 1.

XLIV, fig. 2.

XLV, fig. 19.

XLV, figs. 24, 24 a.

XLV, fig. 6.

XLIV, fig. 29.

XXXI, figs. 14, 14 a.

XLV, fig. 9.

XLV, figs. 17, 18.

XLV, figs. 3 1,3 la, b.

XLV, figs. 22, 22 a.

XLV, fig. 2.

XLI, figs. 2, 2 a.

XLV, fig. 21.

XLV, figs. 30, 30 a.

XXXI, figs. 12, 12 a.

XLV, fig. 3.

XXXI, fig. 15.

XXXI, figs. 7, 7 a.

XLV, figs. 7, 7 a, b.

XLV, figs. 28, 28 a, b.

XLV, fig. 10.

XLV, figs. 8, 8 a, b.

XXXI, figs. 8, 8 a.

XLV, fig. 7.

XXXI, figs. 2, 2 a.

XLIV, fig. 11.

XLIV, fig. 10.

XLI, fig. 9.

XLIV, fig. 13.

INDEX.

127

RISSOIXA Witcbelli ...
SOLARIUM Bathonicum
Waltoni
turbiniformis
TROCHUS Burtonensis
Guisei
strigosus ...
TURBO Burtonensis ...

depauperatus
— subtexata
EULIMA? leevigata ...

PAGE

18

23
104
104

99

21

29
100

99
100

13

TABLE
XLIV, fig. 12.

XLV, fig. 27.

XLV, figs. 26, 26 a, b, c.

XLV, figs. 23, 23 a, b.

XLV, fig. 16.

XLV, fig. 14.

XLV, fig. 12.

XLV, fig. 15.

XLV, fig. 13.

XLI, figs. 15, 15 a.

XXXI, fig. 3.

BIVALVIA.

ANATINA siliqua

ARCA (cucullrea) clathrata ...

— corallina
ASTARTE Aytonensis

— Bathouica
flexicostata

— fimbriata ...

— Hilpertonensis

— ignota

— Leckenbyi

— orbicularis
politula . . .

— Pontonis ...
robusta ...
rustica

— ungulata ...
AVICULA clathrata ...

— subcostata
CARDIUM cognatum

incertum...

globosum...

lingulatum

Witchelli
CORBIS elliptica
Neptuni
— rotunda
CORBULA Agatha ...

attenuata ...

Hulliana ...

— Isltpensis . . .

83
44
43
78
76
79
77
78
77
74
73
73
75
74
76
72
36
36
54
53
114
53
55
60
59
60
65
62
64
63

XXXV, fig. 15.
XXXIX, figs. 4, 4 a.
XXXIX, fig. 3.
XL, fig. 13.

XL, figs. 23, 23 a.

XL, fig. 26.

XL, figs. 34, 34 a.

XXXVI, fig. 10.
XL, fig. 10.
XLH, fig. 3.
XL, fig. 33.
XXXV, fig. 16.
XL, fig. 31.
XXXV, fig. 6, 6 a.

XXXV, fig. 5 ; XL, figs. 8, 8 a.

XXXV, fig. 20.
XL, figs. 7, 7 a, I.
XL, fig. 24.

XXXVI, figs. 3, 3 a, 2 b.
XXXV, figs. 14, 14 a.
XXXVIII, figs. 2, 2 a, b.
XXXIII, figs. 2, 2 a ; XXXV, fi
XL, fig. 36.

XXXV, fig. 1.
XXXV, fig. 19.
XL, fig. 17.
XL, fig. 28.

XXXVII, figs. 6, 6 a.
XXXVII, fig. 5.
XXXVII, fig. 7.

11, lln.

128

INDEX.

PAGE

CORBULA involuta ... ... ... 63

CORBICELLA subangulata 70

subsequilatera... ... 69

CYPRICARDIA caudata 55

CYPEINA bella 71

Davidson!.. . ... ... 71

— Islipensis ... ... ... 70

GERVILLIA bicostata Ill

— Islipensis ... ... 37

— ornata ... ... ... Ill

— tortuosa (var.) ... ... 37

— Waltoni 110

GRESSLYA peregrina 79

GRYPHJSA minuta ... ... ... 30

HARPAX Waltoni ... ... 101

HINNITES gradus , 35

HOMOMYA gibbosa ... ... ... 88

crassiuscula ... ... 89

INOCERAMUS quadratus 38

ISOCAHDIA tenera ... ... 57

— minima... ... ... 56

— nitida ... ... ... 57

ISOARCA Scarburgensis ... ... 45

LED A Anglica ... ... ... 45

LIMA Helvetica ... ... 41

— pectiniformis . . . ... ... 39

— punctatilla 41

— rigidula ... ... ... 42

LITHODOMUS Porteri ... ... 114

LUCINA Beanii 59

— Burtonensis? ... ... 59

— striatula ... ... ... 58

Macrodon Hirsonensis, var. rugosa 113

Modiola gibbosa .. 42

Myacites calceiformis ... ... 80

— modica ... ... ... 83

— recurvura ... ... ... 81

— sinistra ... ... ... 82

NUCULA Meukei ... ... 44

OPIS Leckenbyi ... ... ... 61

— Luciensis ... ... ... 62

— pulchella ... ... ... 61

OSTREA Wiltonensis ... ... ] 08

(Exogyra) lingulata ... 108

PECTEN anisopleurus ... ... 32

— articulatus ... ... ... 34

— Griesbachi ... 37

TABLE

XXXVII, figs. 4, 4 a.
XL, fig. 9.

XXXV, fig. 12.

XXXVI, figs. 8, 8 a.
XL, figs. 15, 15 a.
XXXVI, figs. 6, 6 a.

XXXV, fig. 13.
XL, fig. 21.

XXXVI, fig. 7.
XL, fig. 29.
XL, fig. 25.
XXXII, figs. 4, 4 a, b.
XXXVI, figs. 2, 2 a, 2 b.
XL, fig. 12.

XXXII, figs. 1, 1 a, b.

XXXIII, figs. 10, 10 a.

XLIII, figs. 2, 2 a; Part II, XII, fig. 14.
XLIII, figs. 5, 5 a.

XXXVIII, figs. 1, 1 a, 1 4.
XXXVIII, figs. 5, 5 a, b.
XXXVI, figs. 1, 1 a.

XXXVIII, figs. 6, 6 a, 6 b, 6 c.

XXXIX, figs. 5, 5 a.
XXXIX, fig. 7.
XXXIII, figs. 8, 8 a.
XXXVI, fig. 1.

XL, fig. 32.
XXXIII, figs. 7, 7 a.
XL, fig. 9.
XXXVIII, fig. 3.
XL, figs. 20, 20 a, b.

XXXVIII, fig. 7.
XXXVI, fig. 9.

XXXIII, figs. 11, 11«.
XLII, figs. 1, 1 a.
XLIII, figs. 1, 1 a.

XXXVI, figs. 4, 4 a.
XXXV, figs. 17, 17 a.

XXXIX, fig. 2.

XXXVII, figs. 9, 9 a.
XL, figs. 19, 19 a.
Part II, VI, fig. 3.

XXXIV, figs. I, I a.

XXXII, figs. 2, 2 a, b.

XXXIII, figs. 5, 5 a.
XXXIII, fig. 12.
XXXIII, figs. 6, 6 a.

INDEX.

129

PECTEX iufequicostatus

— Michelensis

— rigidus
Rushdonensis
subspinosus
Wollastonensis

PERXA foliacea

— mytiloides ...
obliqua

PHOLADOMYA deltoidea
lyrata
ovulum
Phillips!

PLACUNOPSIS semistriatus
SOWERBYA triangularis
Woodwardi
TANCREDIA gibbosa

mactraeoides
similis ...

THRACIA amygdaloidea
TRIGOMA arata

Batbonica
Cassiope

— clythia

— compta

— elongata
Scarburgensis

— tri partita

— tuberculosa

PAGE
32
34
31
33

113
33
38

112

112
86
87
84
86
30
66
67
68
68
68
80
52
52
49

48,51
50
48
48
51
47

TABLE

XXXIII, figs. I, I a.

XXXIII, fig. 3.

XL, fig. 16.

XXXIII, figs. 4, 4 «, l>, c.

XL, fig. 14.

XXXIII, figs. 2, 2 a, b, c.
XXXVII, figs. 3, 3 a.

XXXII, fig. 3.

XXXIV, figs. 22, Tin.
XLIT, figs. 4, 4 a.
XLIII, figs. 3, 3 a.

XXXV, figs. 18, 18 a.
XLII, figs. 2, 2 a.

XXXIII, figs. 9, 9 a.
XXXV, figs. 3, 3 a, 6.
XL, figs. 27, 27 a, f>, c.
XXXV, fig. 7 ; XXXVI, fig. 11.
XXXV, fig. 4.

XXXV, fig. 9.

XLIII, fig. 4.

XL, fig. 2.

XL, fig. 3.

XXXVII, fig. 10.

XXXVII, fig. 2 ; XL, figs. 5, 5 a.

XL, fig. 1.

XXXIX, figs. 6, 6 a.

XXXVII, fig. 1.

XL, fig. 4.

XL, fig. 6.

LONDON : POINTED BY J. E. ADLAKD, BAKTUOLOMBW CLO8E, S.C.

TAB. XXXI.

FIG.

1. Ammonites Bullatus, D'Orb. Reduced one half. Great Oolite (page 3).

2. 2 a. Purpuroidea insignis, Lye. An aged shell, in which the tubercles have

disappeared upon the anterior portion of the
last volution. Great Oolite (page 6).

3. Eulima? laevigata, Lye. Cornbrash (page 13).

4. Fibula variata, Lye. Specimen with the anterior extremity of the aperture

approaching to Cerithium.

4 a. „ „ With the anterior part of the aperture approaching to

Turritella. From the Great Oolite of Kirklington,
Oxon. (page 16).

5. „ eulimoides, Whiteaves. From the Great Oolite of Stonesfield (page 17).

6. Amberleya armigera, Lye. Cornbrash (page 20).

7. Neritopsis Archiaci, D ' Archiac, sp. Cornbrash (page 21).

7 a. „ „ A portion of the surface magnified (page

21).

8. Pleurotomaria granulata, Sow., sp. Cornbrash (page 24).

8 a. „ „ A portion of the surface magnified, in-

cluding the fascia of the sinus.

9. Acteonina canaliculata, Lye. Great Oolite of Kirklington, Oxon. (page 27).

9 a. „ „ The spire enlarged.

10. Chemnitzia vittata, Phil., sp. Cornbrash (page 14).

11. Dentalium entaloides, Desl. Cornbrash (page 28).

1 1 a. „ „ A portion of the posterior part of the shell

enlarged, to exhibit the oblique striations.

\\a. „ „ Enlarged view of the anterior portion of the shell,

in which the striations have disappeared.

12. Nerina3a granulata, Phil., sp. Cornbrash (page 10).

12. „ „ A portion of the spire enlarged.

13. 13 a. Acteonina Scarburgensis. Cornbrash (page 28).

14. Monodonta Lycetti, Wldteaves. Bradfordian beds of Islip, Oxon. (page 22).

15. Nerita involuta, Lye. Great Oolite, Kirklington (page 20).

16. Acteonina Luidii, Luid., sp. Forest Marble, Kidlington, Oxon. A small speci-

men, with short spire (page 27). See also
Tab. LX1, figs. 18 a, b, c.

PI. XXXL

10

TAB. XXXII.

FIG.
1.

Harpax Waltoni, Lye. The attached valve. Forest Marble (page 110).

» » Interior of the left valve.

» Interior of the right valve.

Ostrea (Exogyra) lingulata, Walton, MSS. Forest Marble (page 108).
" » Interior of the convex valve.

" » " Interior of the flat valve.

Perna mytiloides, Lam. Forest Marble (page 112).

4, 4 a, 4 6. Gervillia Waltoni, Lye. Forest Marble (page 110).

'•• •' lull :iH n;.i

w w*

TAB. XXXIII.

FIG.

1. Pecten inaequicostatus, Phil. Left valve. Cornbrash (page 32).

1 a. „ „ Right valve.

2. Pecten Wollastonensis, Lye. Great Oolite (page 33). Right valve.

2 b. „ „ Magnified surface of the right valve.
2 a. „ „ Left valve.

2 c. „ „ Magnified surface of the left valve.

3. „ Michelensis, Suv. Cornbrash (page 34).

4. „ Rushdenensis, Lye. Cornbrash (page 33).

4 a. „ „ Magnified portion of the right valve.

45. „ „ Left valve.

4 c. „ „ Magnified portion of the left valve.

5. „ anisopleurus, Suv. Right valve. Cornbrash (page 34).

5 a. „ „ Left valve.

6. „ Griesbachi, Lye. Left valve. Great Oolite (page 37).

6 a. „ „ Portion of the surface magnified.

7. Lima rigidula, Phil., sp. Cornbrash (page 42).

7 a. „ „ Portion of the surface magnified.

8. „ Helvetica, Oppel. Cornbrash (page 41).

8 a. „ „ Portion of the surface magnified.

9. Placunopsis semistriatus, Sean, sp. Cornbrash (page 30).

9 a. „ „ Portion magnified.

10. Hinnites gradus, Sean, sp. Cornbrash (page 35).
10 a. „ „ Portion magnified.

11. 11 a. Modiola gibbosa, Sow. Cornbrash (page 42).

12. Pecten articulatus, Schloth. Cornbrash (page 34).

PLXXXJII.

;

TAB. XXXIV.

FIG.

1 . Ostrea Wiltonensis, Lye. Forest Marble.

1 a- " » A monstrosity of the same species.

2, 2 a. Perna obliqua, Walton, MSS. Forest Marble.

Ostrea costata, Sow. Great Oolite. Also Part II, Tab. I, fig. 5, page 3.

Pi. XXXIV

Mill .,,|,,.,l

TAB. XXXV.

FIG.

1. Corbis elliptica, Whiteaves, MSS. Forest Marble. Slightly enlarged (page 60).

2. 2 a. Cardium subtrigonum, Mor. and Lye. Great Oolite. See also Part II, Tab. VII,

fig. 3, page 64.

3. Sowerbya triangularis, Phil., sp. Cornbrash (page 66).

3 a. „ „ Portion of the surface magnified.

3 b. „ „ Hinge of the right valve magnified.

4. Tancredia mactrseoides, Whiteaves, MSS. Great Oolite (page 68).

5. Astarte rustica, Walton, MSS. Great Oolite and Forest Marble (page 76).

Also Tab. XL, fig. 8.

6. „ robusta, Lye. Cornbrash (page 74).

6 a. „ „ A portion of the surface magnified, exhibiting the inter-

stitial striations.

7. Tancredia gibbosa, Lye. Great Oolite (page 68).

8. Naeara Ibbetsoni, Mor. Slightly enlarged. Great Oolite. See also Part II,

Tab. XII, fig. 9.
8 a. „ „ A portion of the surface magnified.

9. Tancredia siniilis, Wliiteaves, MSS. Great Oolite (page 68).

10. Isocardia? nitida, Phil. Cornbrash. See also Tab. XXXVIII, figs. 6, 6 a.
10 a. „ „ A portion of the surface magnified,

11. 11 a. Cardium lingulatum, Lye. An oblique specimen. Also Tab. XL, fig. 22,

page 53.

12. Corbicella subaequilatera, Lye. Cornbrash (page 69).

13. Cyprina Islipensis, Lye. Great Oolite. Our figure is scarcely sufficiently

lengthened and inequilateral (page 70).

14. 14 a. Cardium incertum, Phil. Great Oolite (page 53).

15. Anatina (Cercomya) siliqua, Ag. Cornbrash (page 83).

16. Astarte politula, Bean. Cornbrash (page 73).

17. 17 a. Myacites sinistra, Ag., sp. Cornbrash. A breadth of two lines would require to

be added to the posterior side to render the
outline perfect (page 82).
173. „ „ A portion of the surface magnified.

18. 18 a. Pholadomya ovulum, Ag. Cornbrash (page 84).

19. Corbis Neptuni, Lye. Great Oolite (page 59).

20. Astarte ungulata, A. lurida, Phil., non Sow. Cornbrash (page 72).

PL.XXXV.

i>. 3*

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TAB. XXXVI.

FIG.

1. la. Isocardia minima, Phil. Cornbrash. Specimen with the posterior angle

more strongly defined than usual (page 56).

2. 2 a, 2 b. Gresslya peregrina, Phil, sp. Cornbrash. Three varieties. See also Part II,

Tab. XV, fig. 8, page 79.

3. Cardium cognatum, Phil. Cornbrash (page 54).

4. Myacites recurvum, Phil., sp. Cornbrash (page 81).

5. Ceromya concentrica, Sow., sp. Great Oolite. See also Part II, Tab. X, fig. 3.
0, 6 a. Cyprina Davidson!, Lye. Forest Marble (page 71).

7. Gervillia ornata, Lye. Great Oolite. Enlarged (page 111).

Cypricardia caTidata, Lye. Great Oolite and Forest Marble (page 55).
^ "• „ „ A portion of the surface magnified.

9. Macrodon Hirsonensis, Arch., var. rugosa. Forest Marble (page 113).

10. Astarte Hilpertonensis, Lye. Forest Marble (page 78).

11. Tancredia gibbosa, Lye. Forest Marble. See also Tab. XXXV, fig. 7.

PLXXXV7

'.

TAB. XXXVII.

Fio.

1. Trigonia Scarburgensis, Lye. Cornbrash (page 48).

2. „ Clythin, BOrb. Great Oolite (page 48). See also Tab. XL, fig. 5.

3. 3«. Perna foliacea, Lye. Great Oolite (page 38).

4. 4 a. Corbula involuta, Munst. Enlarged. Great Oolite (page 63).

5. „ Hulliana, Mor. Enlarged. Forest Marble (page 64).

6. 6 «. „ attenuata, Lye. Enlarged. Great Oolite (page 62).

7. „ Islipensis, Lye. Enlarged. Great Oolite (page 63).

8. „ Buckmani, Buck., sp. Great Oolite. Also Part II, Tab. IX, fig. 6,

page 97.

9. 9 a. Opis Leckenbyi, Wright. Cornbrash (page 61).
10. Trigonia Cassiope, If Orb. Cornbrash (page 49).

PLXXXVIJ

WW.-.<: ..MI.

TAB. XXXVIII.

FJG.

1. Inoceramus quadratus, Sow., sp. An aged example (page 38).

1 a- » » A smaller specimen, partially denuded of the

test, and exhibiting concentric and radiat-
ing striations upon the surface of the cast.

1 &' » „ Interior of the right or flat valve.

2. 2 b. Cardinal globosum, Bean. Cornbrash. The original specimen figured bv Mr.

Bean (page 114).

2 a. „ „ Portion of the surface magnified.

3. Lucina • Beanii, Scan., sp. Cornbrash (page 59).

4. „ despecta, Phil. Cornbrash (Part II, p. 69).

4 a. „ „ Portion of the surface magnified.

5. 5 a. Isocardia tenera, Sow. Cornbrash. Part II, p. 57.

6. 6 a. „ nitida, Phil Cornbrash (page 57). Also Tab. XXXV, fig. 10.
6 b. „ „ Portion of the surface magnified.

7. Lucina striatula, Btiv. Cornbrash (page 58).

PL xxxvni.

. Aesl hill

W WcsLunp

TAB. XXXIX.

FIG.

1. Lima pectiniformis, Schloth. A large specimen, with tubular spines (page 39).

2. Nucula Menkei, Rocm. Great Oolite (page 44). See also Tab. XL, fig. 12.

3. Cucullaja corallina, Lye. Cornbrash (page 43).

4. 4 a. „ clathrata, Leek. Cornbrasb (page 44).

5. Isoarca Scarburgensis, Lye. Cornbrash (page 45).

5 a t> Portion of the surface magnified.

6. 6 a. Trigonia elongata, Sow. Cornbrash (page 46).

7. Leda Anglica, If Orb. Cornbrash (page 45).

PI. XXXIX.

WWest,im{..

TAB. XL.

FIG.

1. Trigonia compta, Lye. Collyweston Slate (page 50).

2. „ arata, Lye. Forest Marble (page 52).

3. ,, Bathonica, Lye. Great Oolite (page 52.)

4. „ tripartita, Forbes. Cornbrash (page 51.)

5. „ Clythia, D'Orb. Great Oolite. A specimen of advanced growth.
5 a. „ „ An adult specimen (pages 48 and 51).

6. ,, tuberculosa, Lye. Great Oolite. Magnified (page 47).

7. Avicula clathrata, Lye. The smaller valve, magnified. Great Oolite.
7 a. „ „ The larger valve, magnified (page 36).

7 b. „ „ Portion of the surface magnified.

8. 8 a. Astarte rustica, Walton, MSS. Great Oolite and Forest Marble (page 76).

9. Corbicella subangulata, Lye. Forest Marble (page 70).

10. Astarte ignota, Lye. Forest Marble (page 77).

11. Pecten personatus, Gold/., var. Great Oolite. Magnified. Part II, page 11.
11 a. „ ,, Another variety, magnified.

12. Nucula Menkei, Roem., var. Also Tab. XXXIX, fig. 2, page 44.

13. Astarte Aytonensis, Bean. Great Oolite (page 78).

14. Pecten subspinosus, Schloth. Forest Marble (page 113).

15. Cyprina bella, Walton, MSS. Forest Marble (page 71).
15 a. » » -A. shorter specimen.

16. Pecten rigidus, Sow. Great Oolite (page 31).

17. Corbis rotunda, Lye. Forest Marble (page 60).

18. 18 a. Cardium Buckmani. Young specimen. Forest Marble. Part II, page 64.
185. „ ,, The striated surface magnified.

19. 19 a. Opis Luciensis, If Orb. Great Oolite (page 62).

20. 20 a. Lucina? Burtonensis, Lye. Forest Marble (page 59).

21. Gervillia bicostata, Lye. Great Oolite.

22. Cardium lingulatum, Lye. Also Tab. XXXV, fig. 1 1, page 53.

23. 23 a. Astarte Bathonica, Lye. Great Oolite (page 76).

24. Avicula subcostata, Roem. Great Oolite (pages 36, 1 1 1).

25. Gervillia tortuosa, Sow., var. Cornbrash (page 37).

26. Astarte flexicostata, Lye. Great Oolite (page 79).

27. 27 a. Sowerbya Woodwardi, Lye. Left valve. Great Oolite (page 67).
27 b, 27 c. „ „ Right valve.

28. 28 a. Corbula Agatha, D'Orb. Forest Marble. Magnified (page 65).

29. Lithodomus Porteri, Lye. Forest Marble. Magnified (page 114).

30. Gryphsea minuta, Sow. Great Oolite. Magnified (page 30).

31. Astarte Pontonis, Lye. Great Oolite. Magnified (page 75).

32. Lima punctatilla, Lye. Great Oolite. Magnified (page 41).

33. Astarte orbicularis, Sow. Great Oolite. Magnified (page 73).

34. 34 a. „ fimbriata, Walton, MSS. Forest Marble (page 77).

35. Gervillia Islipensis, Lye. Great Oolite (page 37).

•66. Cardium Witchelli, Lye. Great Oolite. Magnified (page 55).

PL XL.

fax, W«st ||th. ad t\.V

W. West imp.

TAB. XLI.

FIG.

1. Amberleya capitanea, Gold/., sp. Forest Marble (page 95).

2. 2 a. Natica Hulliana, Lye. Great Oolite (page 13).

3. Amberleya nodosa. See also Part I, Tab. V, fig. 19.

4. Acteonina olivaeformis. Great Oolite and Forest Marble. See also Part I,

Tab. VIII, fig. 14, and fig. 12*.

4 a. „ „ A specimen of more advanced growth, with the spire

more produced.

5. „ Kirklingtonensis, Lye. Great Oolite (page 26).

6. „ brevis, Lye. See also Cylindritis? brevis, Part I, Tab. VIII,

fig. 13, page 26.

7. 7 a. Nerita Buvignieri. Examples of two stages of growth. See also Stomatia

Buviynieri, Part I, Tab. IX, fig. 32. The specimens
now figured are from the Forest Marble of Lay cock.

8. 8 a. Ammonites discus, Sow. Forest Marble. Slightly reduced (page 4).

9. Rissoina subulata, Lye. Great Oolite. Enlarged (page 98).

10. Amberleya monilifera, Lye. Forest Marble. Enlarged (page 95).

11. Cerithium costigerum, Piette. Variety with flattened volutions and oblique

costse (page 92).

11 a. „ „ A portion of the surface enlarged.

\\b. „ „ Specimen with shorter, more inflated volutions,

and perpendicular costae.
lie. „ „ A portion of the surface enlarged.

12. Kilvertia pulchra, Lye. Great Oolite and Forest Marble. For the form of the

aperture see Tab. XLIV, fig. 4, pages 10 and 94.

12. „ „ A portion of the surface enlarged.

13. Alaria myurus, Desl. See also Maria Icevigata, Part I, Tab. Ill, fig. 3.

14. Amberleya tricincta, Lye. Forest Marble (page 96).

15. Turbo subtexatus, Lye. Forest Marble.

16. Cerithium ? Waltoni, Lye. Forest Marble (page 92).

17. ,, hemicinctum, Lye. Forest Marble. Enlarged (page 91).

18. 18 a. Acteonina Luidii, Mor. An adult specimen, with the spire moderately elevated.

Forest Marble. See also Tab. XXXI, fig. 16,

page 27.

IS 6. „ „ A specimen with the spire elevated.

18 c. „ ,, Specimen with the spire elevated and the last whorl

unusually lengthened.

//a.

s

/v

GeoWeahth

WW.st.imp.

TAB. XLII.

FIG.

1, la. Myacites calceiforrais, Phil., sp. Cornbrash. Specimen with the test preserved

(page 80).

2, -2 u. Pholadomya Phillipsi, Mor. Cornbrash (page 85).

3, Astarte Leckenbyi, Wrigld. Cornbrash (page 74).

4, 4 a. Pholadomya deltoidea, Smo. Forest Marble (page 86).

h JOJL

GeoW.

TAB. XLIII.

FIG.

1, 1 a. Myacites modica, Bean, sp. Cornbrash (page 83).

2, 2 a. Homomya gibbosa, Sow., sp. (Page 88.)

3, 3 a. Pholadomya lyrata, Sow. Cornbrash (page 87).

4, Thracia amygdaloidea, Lye. Great Oolite (page 80).

5, 5 a. Horoomya crassiuscula. An adult specimen, with the test preserved. Part II,

page 112; Supplement, page 89.

5a

!• A..; i,t,

W.Wost imp.

TAB. XLIV.1

FIG.

1. Kilvertia spicula, Lye. Great Oolite. Enlarged (page 9).

2. „ strangulata, If Arcli. Great Oolite. For another variety see Part I,

Tab. IX, fig. 18.

3. Cerithium bulimoides, Desl. Great Oolite. Enlarged (page 7).

4. Kilvertia pulchra. Great .Oolite. Enlarged. See also Tab. XLI, fig. 12,

page 10.

5. „ formosa, Lye. Great Oolite. Enlarged (page 95).

6. Cerithium undulatum, Desl. Great Oolite. Enlarged (page 8).

7. „ Witchelli, Lye. Great Oolite. Enlarged (page 10).

8. Chemnitzia constricta, Lye. Great Oolite. Enlarged. Printed Kilvertia by

mistake at page 15,

9. Cerithium compositum, Lye. Great Oolite. Enlarged (page 9).

10. Rissoina Milleri, Lye. Great Oolite. Enlarged (page 18).

11. Rissoa? exigua, Lye. Great Oolite. Enlarged (page 9).

12. Rissoina Witchelli. Great Oolite. Enlarged (page 18).

13. Rissoina? tumidula, Lye. Great Oolite. Enlarged (page 98).

14. Cylindrites exigua, Lye. Great Oolite. Enlarged (page 24).

15. Acteonina fasciata, Lye. Forest Marble. Enlarged (page 107).

16. Acteon Bathonicum, Lye. Great Oolite. Enlarged (page 25).

17. Brachytrema buccinoidea, Lye. Great Oolite. Enlarged (page 5).

18. Acteonina scalaris, Lye. A small specimen from the Great Oolite (page 28).

19. Cerithium? Bathonicum, Lye. Great Oolite. Enlarged (page 6).

20. „ multiforme, Pieffe. Great Oolite. Enlarged (page 7).

21. „ ? neglectum, Lye. Great Oolite. Enlarged (page 92).

22. Ceritella Morrisea, Orthostoma, BHV. See also Part I, Tab. IX, fig. 14.

23. Cerithium exscalptum, Lye. Great Oolite. Enlarged (page 93).

24. „ poculum, Lye. Great Oolite. Enlarged (page 93).

25. Ceritella Lycettea, Orthostoma, Buv. See also Part I, Tab. IX, fig. 7.

26. 26 a. Cylindrites turriculatus, Lye. Great Oolite. Enlarged (fig. 25).

27. Brachytrema varicosa, Lye. Great Oolite. Enlarged (page 5).
Acteon phasianoides, Lye. Great Oolite. Enlarged (page 26).

29. Monodonta exigua, Lye. Great Oolite. Enlarged (page 22).

1 All the fossils upon this Tab., excepting No. 15, were obtained by crushing shelly portions of the
Great Oulite.

PLXIJ\

ti

a

19

W

25

27

Geo Wosblith adnai.

TAB. XLV.

FIG.

1. Monodonta Lyellii, If Arch., sp. Young shell. For the adult condition see Part I, Tab. XI,

fig. 4.

2. Natica arata, Lye. Great Oolite. Enlarged (page 97).

3. Nerita clavatula, Lye. Great Oolite. Enlarged (page 98).

4. Ceritella fusiformis, Lye. Great Oolite. Enlarged (page 12).

5. „ minutissima, Lye. Great Oolite. Enlarged (page 11).

6. Monodonta composita, Lye. Great Oolite. Enlarged (page 23).

7. Pleurotomaria recondita, Lye. Great Oolite. Enlarged (page 106).

8. „ Burtonensis, Lye. Forest Marble (page 105).
8 a. „ „ The base.

8 b. „ „ Portion of the surface magnified.

9. Monodonta sparsistriata, Lye. Great Oolite. Magnified (page 22).

10. Pleurotomaria Bathonica, Lye. Great Oolite. Magnified (page 105).

11. 11 a. Onustus Burtonensis, Lye. Forest Marble. Slightly enlarged (page 103).

12. Trochus strigosus, Lye. Cornbrash (page 29).

13. Turbo depauperatus, Lye. Forest Marble. See also Pleurotomaria pagodus, Part I, Tab. X,

fig. 9.

14. Trochus Guisei, Lye. Great Oolite. Magnified (page 21).

15. Turbo Burtouensis, Lye. Forest Marble (page 100).
10. Trochus Burtonensis, Lye. Forest Marble (page 99).

17. Monodonta tegulata, Lye. Forest Marble, Specimen with fine striatious (page 102).

18. „ „ Forest Marble. Enlarged.

19. „ arata, Lye. Forest Marble. Enlarged (page 102).

20. „ „ Variety with the encircling lines more distantly arranged.

21. Natica insignis, Lye. Great Oolite. Enlarged (page 97).

22. „ (Euspira) alta, Lye. Forest Marble (page 97).

23. Solarium turbiniformis, Lye. Forest Marble (page 104).

23 a. „ „ A portion of the surface enlarged.

23 b. ,, „ The lower surface.

24. 24 a. Monodonta comma, Lye. Forest Marble (page 101).

24 b. ,, ,, A portion of the surface enlarged.

25. Acteonina Wiltonensis, Lye. Forest Marble (page 107).

26. 26 a. Solarium Waltoni, Lye. Forest Marble. Upper surface and profile (page 104).

26 b, c. „ „ Forest Marble. Lower surface.

27. 27 a. Solarium Bathonicum, Lye. Great Oolite. The upper surface and profile (page 23).

27 b, 27 c. „ „ The lower surface of a smaller specimen.
2/ d. „ „ A portion of the upper surface magnified.

28. 28 a, 28*. Phasianella variata, Lye. Page 104.

29. Acteonina Suessea, Lye. Forest Marble (page 107).

30. 30 a. Natica texata, Lye. Forest Marble (page 96).

31. 31 a. Mouodonta Waltoni, Lye. Forest Marble. Enlarged (page 101).

31 J. „ A portion of the striated surface magnified.

Pl.XLV.

n

il

16

22 **

16

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14 DAY USE

RETURN TO DESK FROM WHICH BORROWED

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