LIBRARY UNIVERSITY OF j CALIFORNIA J EARTH SCIENCES LIBRARY BERKE LIBR/A UNIVERSI CALIFQI EARTH SCIENC1 LIBRARY EAPTU LIBRA? A MONOGRAPH OF THE CRAG MOLLUSCA, WITH DESCRIPTIONS OF SHELLS FROM THE UPPER TERTIARIES OF THE BRITISH ISLES. BY SEARLES V. WOOD, F.G.S. VOL. I. UNIVALVES. LONDON: PRINTED FOR THE PAL^ONTOGRAPHICAL SOCIETY. 1848. .1. E. AULAK1), PRINTEK, BARTHOLOMKW CI.OSK. EARTH SCIENCES LIBRARY INTRODUCTION. A GEOLOGICAL HISTORY or details of the different Formations, not coming within the object of the Palseontographical Society, it is only necessary here to state that this work may be considered as an illustrated description of my Catalogue of Crag Shells, published in the ' Annals and Magazine of Natural History/ 1840-42, including such Species as have since been discovered, in addition to those already enumerated. It is intended to include as Crag Shells all those species, hitherto considered as coming under this general and well-understood denomination, from the three different Periods, into which that Formation has been divided by geologists, viz., the Coralline Crag, as representing in this country the remains of the Miocene Period ; the Red Crag, those of the Pliocene Period ; and the Mammaliferous Crag, those of the Pleistocene Period. In the latter are included the several species that have been obtained at Bridlington, as that bed is now considered to be a Marine Formation of the Pleistocene Period, and consequently synchronous with the Estuary deposits of Bramerton and Thorpe. The northern beds of the Clyde, &c., may belong to the same Period ; but I am not sufficiently acquainted with those deposits to express an opinion on that point, as I have seen only such shells from them as may be considered identical with existing species. A Catalogue of the Mollusca from the Lacustrine or Fluviatile deposits of Grays,* Clacton,t Stutton,J and Copford,^ will be given as an Appendix to the Second Part of this work, as those beds are * Grays, on the river Thames, twenty-one miles from London, in the county of Essex. f Clacton, in Essex, on the coast, seven miles south-west of Walton Naze. | Stutton, in Suffolk, on the banks of the river Stour, six miles south of Ipswich. § Copford, in Essex, about four miles south-west of Colchester. 87490 vi INTRODUCTION. probably the Freshwater equivalents to the Crag Periods ; the first three mentioned localities belonging, perhaps, to the Red Crag Period, while the Copford deposit may be of a more modern date. As these localities contain Mollusca, of which all the species are identical with existing forms, and which have been already figured and described, it is presumed that a name alone, with reference to the work in which each species is given, will be sufficient for geological purposes. The land and Freshwater shells delineated here, having been found in the Red and Mammaliferous deposits, intermixed with Marine species, may be considered as forming an integral portion of these beds, as their geological age cannot be doubted : they therefore cannot well be omitted, more especially as they exhibit, in most instances, a variation in form, more or less considerable, from their typical characters, thus exciting our interest regarding the climatal and other conditions under which they existed, and which appear to have exerted no little influence upon most of the animals of that Period. In justice to my predecessors in this field of geological and palseontological research, a small space may be allotted for a brief summary of their labours. * An Attempt towards a Natural History of Fossils,' by John Woodward, in 1729, contains the first notice of any organic remains from the Crag Formation. Robert Dale, in his ' History and Antiquities of Harwich,' published in 1730, gives copious descriptions, as well as representations, of several species from the Crag, that were found at that time in the Cliff near Harwich ; the execution of some of these figures is by no means to be despised, and the shells may be readily recognised. This author states that during the time he had observed the Cliff, the wearing away of its materials was so rapid, that after a period of forty years but little of the stratum remained from which he had, in the early part of his life, collected his fossils ; and although portions of the Crag were remaining during the time of his publication, all vestiges of it have long disappeared from that locality. Parkinson, in his ' Organic Remains of a Former World,' 1811, gives a few good figures of Crag shells. In 1816, William Smith, "the Father of Geological Science in England," published a plate of good figures of Crag fossils in his ' Strata Identified by Organized Fossils.' INTRODUCTION. vii Mr. Richard Cowling Taylor published, in the 'Philosophical Magazine,' 1822-24, some observations on the Norfolk Cliffs, as well as a Paper, in the * Geological Transactions,' upon the Tertiary deposits of Norfolk and Suffolk ; some good figures of Crag Corals were also given by him in the 'Magazine of Natural History,' 1830. In 1826, Mr. Robberds published some ' Observations on the Eastern Valleys of Norfolk.' In 1833, 'An Outline of the Geology of Norfolk' was published by Samuel Woodward the elder, in which there are some good figures of Crag fossils, from the beds in the immediate neighbourhood of Norwich, relating only to the Mammaliferous Crag. The geological features of the upper Tertiaries of this country, more especially those portions from which the shells here illustrated have been extracted, have been ably delineated by Mr. Lyell, in his ' Principles' as well as in his 'Elements of Geology;' and also in a special Memoir, published in the 'Magazine of Natural History' for 1839. Mr. Charlesworth also published a series of Papers in the ' Philosophical Magazine' for 1835, in which the Crag Formation was separated into three different Periods, the oldest of which he designated the " Coralline Crag," as expressive of its contents, that Formation being in some places composed entirely of Zoophytic remains. The succeeding Period, or " Red Crag," was so denominated from its peculiar ochreous colour, the beds being strongly stained by large quantities of the hydrous oxide of iron ; but it was considered as geologically distinct, on account of the absence of the great mass of Zoophytes peculiar to the lower beds, as well as of the introduction of a new group of Testacea. A further examination of what had previously been considered as an extension of the Red Crag Formation into Norfolk, induced that author to suspect the Crag of Norfolk to be of posterior age, and, as position in this case was no guide to such determination, he appealed to the certain evidence of zoological distinction, which presented a more recent aspect than either of the preceding ; and as amongst its imbedded fossils are the remains of numerous Mammalia, he gave to this Formation the title of "Mammaliferous Crag." These terms are employed in the present work. In 1836, Mr. John Morris published some observations, in the ' Magazine of Natural viii INTRODUCTION. History/ upon the Freshwater Formation of the upper Tertiaries at Maidstone, in Kent. The Period to which this bed belongs has not yet been satisfactorily determined. In the eighth volume of the 'Magazine of Natural History/ 1839, Mr. W. Bean gave an account of a deposit at Bridlington Quay, whence some of the shells I have figured were obtained. In 1840, Mr. John Brown, of Stan way, communicated a Paper to the ' Magazine of Natural History/ describing a Lacustrine deposit at Clacton, on the coast of Essex, which is probably the Freshwater equivalent to the Red Crag Formation. This gentleman also printed and privately distributed a list of Crag Shells, obtained by him from a place called Beaumont, in Essex. In this list, however, there are not the names of any species but such as have been obtained at Walton-on-the-Naze by myself; and as I have not been able personally to inspect the locality referred to by Mr. Brown, no special reference has been made to it. In December, 1843, Professor Henslow read a Paper before the Geological Society, describing fossils from the Crag at Felixstow, which he considered to be the Croprolitic remains of whales ; and introduced a notice respecting some tympanic bones, which were referred to the genus Balsenodon by Professor Owen. As early as the year 1812, Mr. James Sowerby, senior, commenced the 'Mineral Conchology/ which for a long series of years has been almost the only publication by which British fossil shells of all Periods have been made known to the public in this country ; and this work has been ably continued by his son, Mr. James De Carle Sowerby, to the present time. The first portion of the present work contains descriptions of univalve shells, or the calcareous remains of Gasteropodous Molluscs. The great variety of forms pre- sented by the testaceous coverings of this class of animals, depends upon the height or length of the cone. This ranges through every degree of angularity, from the nearly discoidal form exhibited by some of the Patelliform species, in which the cone is so depressed as to form an angle, from the vertex to the margin, of 1 70 degrees, to that of an elongated tube, extended in some cases so much as to become nearly cylindrical, and twisted into almost every conceivable form of spiral, for the convenience, INTRODUCTION. ix or rather according to the necessities of the animal. Among the spiral shells these varying forms are the result of an obliquity in the mode of growth, caused by a greater development or increase of one side of the opening, whereby an heliciform direction is given to the shell in the process of enlargement. It is, perhaps, needless to say, that the mode of increase or growth of the shell is by the successive deposition of calcareous matter secreted by the mantle, and deposited on the margin of the aperture, and moulded as it were upon the soft body of the animal, by which means the impress of every peculiarity is formed, and permanently fixed in the calcareous covering. It may, however, be observed, that some of the exterior ornaments of these shells are formed by an extension or protrusion of the mantle, whereby a fimbriated, and sometimes a spinose, varix is formed upon the margin of the outer lip, producing many varied and beautiful ornaments upon the spiral shell, which, however, have no corresponding characters upon the soft body of the animal. It is from these appearances alone, that presumed specific distinctions can be determined ; and the characters drawn from them, although they may be considered as somewhat extrinsic to the animal, are the only means afforded to the palaeontologist for the determination of species. From the recent researches of Mr. Bowerbank and Dr. Carpenter, in their Microscopic Examinations into the Structure of Shells, it would appear that there is a more intimate connexion between the animal and its envelope during its lifetime than could be imagined by the supposition of a simple addition of earthy matter deposited upon its cuticle ; and that this strong covering is an organized body, and part and parcel of the animal itself. Important as are those observations and suggestions, which bear considerably on generic groups, and by which, perhaps, even minor distinctions may hereafter be pointed out, the specific determinations referred to in the present monograph have not been submitted to such tests, but are merely drawn from the various external differences existing in the shells, and which variations in structure are generally considered as resulting from some internal economy of the animal. This mode of determination may, perhaps, be correctly applicable only to shells in perfect condition ; whereas, some of those figured in this work have undergone con- siderable alteration, either by the loss of colour and animal matter, or by decom- position of the outer coating, while many of them have sustained mutilation by the mechanical action of the waves. These accumulated difficulties are serious impediments to accurate comparisons ; and the identifications in many cases must be looked upon only as approximations : a correct Marine Fauna of this period will, it is to be feared, be for many years to come a desideratum. x INTRODUCTION. In regard to the admeasurement of shells in the present work, minute fractional descriptions have not been very particularly attended to, but a general approximation only has been given, from a belief that a comparison of the dimensions of the aperture and the axis of a shell is a test of fallacious dependence. In many instances, specimens of the same species have a much greater range in variation than, as a general character, would be exhibited between two proximate species ; the aperture in some individuals being equal to two thirds of the length of axis, while in others of the same species it does not exceed one third. In an elevated or cylindrically formed shell, with numerous volutions, the aperture of a young individual bears a greater proportion to the axis of the shell than it does when the animal is fully grown ; and it is not always possible to ascertain when an individual has reached a state of maturity. The form of the aperture is nearly the same at all ages or states of the individual, but the lengthening or shortening of the convoluted cone, which may be the result of external causes, will materially affect any mathematical proportion that may be assumed as a standard for specific determination ; and the spiral angle, or angle of volution,* upon which some Continental conchologists have placed so great reliance, is a test, in my opinion, equally illusory and deceptive. In Littorina littorea, for example, the variations extend, in what I firmly believe to be individuals of the same species, from a subulate or tapering form of volution, denoting an angle of scarcely twenty degrees, to another form which, by the application of the same rule, would show an angle of ninety degrees ; this may be seen in Plate X, where the figures are by no means exaggerated, but rather fall short of the two extremes. A like want of permanent regularity in proportionate dimensions is equally exhibited in the Acephala or bivalve molluscs; and minute attention to accurate detail or mathematical proportions is rarely to be depended upon, even in that class. In some species, of which the general form may be con- sidered as transverse, the character may be traced through trifling and almost imper- ceptible gradations until it is decidedly elongate, so that mathematical proportions in such cases are of no determinate value. This is more particularly evident in some of the species in the Crag Formations, where, perhaps, a rather more than ordinary degree of variation may be seen ; and such are the extraordinary varieties in many of the species, that no reliance can be placed, for specific determination, upon minute proportionate dimensions, although, as an auxiliary, they may in some cases be usefully referred to. No alteration has been thought necessary in the generally accepted terms of * The angle formed by a line drawn from the vertex on each side of the shell, which varies, of course, upon the greater or less depression of the volution, the sutural angle, also, depending upon the same cause. INTRODUCTION. XI longitudinal and transverse, applying them to what is so in appearance only ; and the term labrum is applied to that portion of the peritreme which corresponds with the right hand of the investigator ; while labium is given to its opposite or columella lip. For the dates of publication of the different genera, I am much indebted to the work of M. A. N. Hermansen, entitled ' Indicis Genera Malacozoorum Primordia,' now in course of publication ; and also to a very valuable Paper on a similar subject, by J. E. Gray, Esq., published in the 'Proceedings of the Zoological Society,' November, 1847. Considerable difficulty has been experienced in selecting an Order of Arrangement for the shells described. An immense mass of information regarding the soft parts of Mollusca has been obtained within the last few years ; and the animal inhabitants of no less than five thousand species are now known, and have been examined ;* yet, notwithstanding this additional information, we are still without a Natural Classification, to which anything like a general concurrence appears to be given ; and it is only necessary to compare such as have been most recently published on the Continent with those of our own naturalists in England, to observe the great dissimilarity between them. It has therefore been thought most advisable to employ the old artificial arrangement, with some slight modifications, uniting in different sections those shells in which the aperture is emarginate, or furnished with a canal for the siphon of the animal, and those in which the mouth is circular, or with a continuous peritreme, and merely placing in advance the Pulmonata, or air-breathing animals, after the manner of Cuvier, conceiving them to be more highly organized than those which breathe simply by means of gills. If at first sight it should be considered improbable that some of the extreme varieties in form belonged to one species, it must be stated that these results have been arrived at, not only by the possession, but by the careful examination of a large series of individuals. Some information has been introduced that may be thought unnecessary ; but I have considered that the newly-established Palseontographical Society will, in all probability, contain among its members students just entering the field of Palseonto- / * Gray, Zoological Proceedings, p. 132, November, 1847. xii INTRODUCTION. logical research, to whom every species of information, although familiar to those long engaged in the study, will be acceptable. It has been, of course, my endeavour to make the work as complete as possible, though it merely professes to be a plain and faithful delineation and history of the " Remains of Mollusca from the Crag." I do not pretend to put it forth as free from errors ; on the contrary, it would be surprising if they were not numerous, more especially when it is recollected that in many instances, in consequence of the insufficient materials, and imperfect and altered condition of the shells, a more than ordinary degree of labour is imposed upon the Palaeontologist. The figures, in every instance, have been engraved from specimens in my own cabinet, and obtained by myself, excepting where otherwise particularly expressed ; and I beg to return my sincere thanks to my friends for their liberal assistance during the progress of the work ; particularly to Miss Alexander, Mr. Lyell, Capt. Alexander, Mr. Gibson, Mr. Charlesworth, Mr. Daniel, Mr. Perry, Mr. Robert Fitch, and Mr. Wigham, who have allowed me the use of their best specimens for the purpose of comparison and for figuring ; and to Mr. Bean and Mr. Leckenby, for the loan of their specimens from the Bridlington beds. I beg also to express my obligations to several friends who have assisted me with their opinions upon conchological subjects, especially to Professor E. Forbes, Mr. Alder, Mr. Hanley, and Mr. W. Thompson. SEARLES V. WOOD. January, 1848. A MONOGRAPH OF THE MOLLUSCA FROM THE CRAG. CLASS— CEPHALOPODA. No remains of any animal belonging to this Class have, that I am aware of, been detected in any of the three Formations into which the Crag is divided. My cabinet contains a few specimens of Belemnites belonging to two different species, found by myself among the gravelly portion of the Red Crag. These, however, as they have been introduced from the older rocks, and have no connexion with the Tertiary Periods, do not require to be here particularised. CLASS— GASTEROPODA. ORD. PULMONATA, Cuv. TERHICOLA, FLEM. HELIX,* Linn. 1758. Generic Character. Shell turbinated, orbicular, subglobose or depressed, light and thin : spire slightly elevated, with several more or less convex volutions, mostly smooth ; last whorl often large and ventricose, with an oblique aperture of a lunate or semi-ovate form, generally broader than long, impressed by the prominent part of the body whorl : peristome confluent with the columella, mostly strengthened internally by a thickened rib, and often having a reflected edge, especially on the left side covering the umbilicus, without an operculum. Animals belonging to this order (Pulmonata), differ from the generality of the Gasteropoda in being capable of respiration direct from the atmosphere, and are fur- * Etym. "EXt£, quod contortum est. 1 2 MOLLUSCA FROM THE CRAG. nished with a simple pulmonary cavity, situated beneath the edge of the mantle, on the right side of the animal ; most of them are covered and protected by a calcareous shell, more or less convolute. Those which are constant inhabitants of the water, come occasionally to the surface for a supply of air, a necessary and vital element, which they cannot sufficiently obtain from the water alone. As the species of this genus are entirely terrestrial, the presence of specimens found associated with marine shells in the Mammaliferous Crag may be due to the transporting power of rains and floods, conveying them into the ancient estuary, and to their buoyancy (more especially if dead shells) permitting them to be carried to greater or less distances, before they become entombed with the marine exuviae. Upwards of a hundred synonyms are given by Hermansen to this genus as originally established, many authors conceiving a very slight alteration of character sufficient to constitute generic distinction. A genus like the present, which, even when shorn of all those marine, fluviatile, and terrestrial forms that were included in it by Linnaeus and other ancient authors, contains in a living state, nearly one thousand species, might, however, be considered as deserving of subdivision, were it only to assist the student in the difficult task of investigation. 1. HELIX HISPIDA. Linn. Tab. I, fig. 3, a — c. HELIX HISPIDA. Lin. Syst. Nat. p. 1244, 1/66. Muller. Verm. 11, p. 73, No. 268, 1/74. Mont. Test. Brit. p. 423, t. 23, fig. 3, 1803. Rossmasler. Iconog. t. 31, fig. 426-427, 1835. Gray. 2d edit, of Turk Man. p. 154, t. 4, fig. 51, 1844. S. Wood. Catalogue 1842. var. concinna. Jeffreys, Synopsis. H. Testa orbiculato-convexd; spird depressd, anfractibus 4 — 5 via; carinatis; aperturd semilunari, labro tenui, sub-refleoaa ; umbilico prof undo. Shell orbiculato-convex, with a somewhat depressed spire ; whorls four or five, slightly carinated ; aperture semilunate, with a moderately sized, and deep umbilicus. Diameter, \ of an inch ; elevation, $ ditto. Locality. Mam. Crag, Bulcham. Recent, Britain. Several specimens have been kindly lent to me for comparison, from these, with a few of my own, I have no hesitation in assigning this to H. hispida. Two varieties are among those belonging to Mr. Lyell, one of which has the name of H. plebeium upon the tablet, which I think, however, is only a variety of H. hispida with a spire rather more de- pressed, and an umbilicus a little larger. I have the same varieties from Stutton and Clacton. This shell appears to present a slightly carinated form in the young state, though not quite so much so in the middle of the volution as in H. rufescens ; this character is less distinct in the older specimens. GASTEROPODA. 3 2. HELIX PULCHELLA. MillL Tab. I, fig. 4, a — c. HELIX PULCHELLA. Mull. Verm. p. 30, No. 232, 1773. — PALUDOSA. Mont. Test. Brit. p. 440, 1803. ZURAMA PULCHELLA. Leach. Moll. p. 108, 1819. LUCENA PULCHELLA. Hartmcm. t. 1, fig. 6, 1821. HELIX COSTATA. Flem. Brit. An. p. 263, 1828. AMPLEXIS PALUDOSIS. Brown. Con. Illust. pi. 41, f. 76, 77, 1827. — CEENELLUS. pi. 41, f. 78, 79. HELIX MINUTUS. Say. Journ. Acad. Nat. Sc. I. 123, 1830. — PULCHELLA. Gray. 2d edit, of Turt. Man. p. 141, pi. 5, fig. 49, 1844. S. Wood. Catalogue 1842. If. Testa minutd, orbiculato-depressd, umbilicatd; anfractibus 4, convexis, suturis depressis ; labri margine crasso, albo, reflexo ; umbilico magno. Shell small, orbiculato-depressed, with about four volutions, finely marked with lines of growth ; suture deep ; aperture subcircular ; peritreme thickened and reflected; a large and open umbilicus, showing the volutions within. Diameter, ^ of an inch ; elevation, half the diameter. Locality. Red Crag, Bawdsey. Recent, Britain. The only specimen of this species in my cabinet was found in loose and disturbed Crag ; it is, however, deeply tinged with the hydrous oxide of iron, having all the appearance of a genuine Crag shell ; and as it is very abundant in the fluviatile deposits of Stutton and Clacton, it was in all probability a living species during the Red Crag period. 3. HELIX ARBUSTORUM (?) Linn. Tab. I, fig. 2. HELIX ARBUSTORUM (?) Linn. Syst. Nat. p. 1245. Draparnaud. Moll. p. 38, t. 5, fig. 18, 1805. Turt. Man. pi. 3, fig. 25, 1819. Rossmasler. Iconog. p. 56, pi. 1, fig. 4, 1835. H. Testa subglobosd, perforatd, lavigata (?); spird obtusd ; anfractibus quinqne, subcari- natis; aperturd oblique semilunari, labri margine refiecco ; umbilico obtecto. Shell subglobose and perforated ; smooth (?), with a short conoidal spire ; volutions five, slightly convex above, and rather compressed beneath, very obtusely carinate ; margin reflected, covering the umbilicus. Diameter, \ of an inch ; elevation, \ ditto. Locality. Mam. Crag, Southwold. Recent, Britain. The specimen figured is from the cabinet of Mr. Lyell, and is the only one I have seen. I have assigned it to the well-known recent species, although it is considerably altered in appearance, and differs from the general form of that shell in being more depressed, and in the obtusely or roundedly carinated form of the volutions. I have, however, some recent specimens as much depressed, and some which, in the young state, show a carinated form of volution. It somewhat resembles H. Turonensis, but that species is generally much larger, and the peristome of our shell is never so much 4 MOLLUSCA FROM THE CRAG. reflected or thickened, more especially at the lower and inner part of the mouth. The perfectly smooth appearance of the specimen is in all probability the result of attrition. A recent specimen from Ayrshire, much depressed in form, has been obligingly sent me by Wm. Thompson, Esq., of Belfast, which very strongly resembles our Crag shell. 4. HELIX RYSA. S. Wood. 1847. Tab. I, fig. 1. If. Testa orbiculato-depressdy perforatd, supra convexd, radiatd, rugosd, sen cor rug aid ; subttts rotundatd, profunde umbilicatd et subtilissime striatd ; anfractibus septem obtuse carinatis, carinis prope suturam distinctis : aperturd subdepressd, late lunari ; peritremate acuto, reflexo. Shell orbiculato-depressed, perforated, convex, rugosely striated, or rather corru gated, on the upper half of the volutions, rounded, and faintly striated on the under surface, with a large and deep umbilicus ; volutions seven, obtusely but distinctly keeled ; keel visible at the suture on the upper side ; aperture broadly lunate, with a sharp and reflected peritreme. Diameter, f of an inch ; elevation, \ ditto. Locality. Red Crag, Walton Naze. The elegant and, as far as I know, unique specimen, from which the figure above referred to was taken, is from the cabinet of G. S. Gibson, Esq., of Saffron Walden, who has kindly intrusted me with this rarity for publication. It was found, he informs me, in the interior of a specimen of Buccinum undatum. By careful examination, as well as by the assistance of my conchological friends, I have been unable to find a species with which this could be identified. In comparing it with H. rufescens, the shell to which it appears to have the greatest affinity, some essential differences exist ; it is rather larger, and has seven volutions, whereas in that species I have never been able to obtain a specimen with more than six ; it is more distinctly and roughly corrugated on the upper surface, and the keel, though obtuse, is visible up the spire ; the lines of growth are not more prominent upon the under surface than those upon H. rufescens., where there is a strong resemblance between the two. In this the aperture is of the same form, though the peritreme is rather more reflected, and a little depressed at the suture. CYCLOSTOMA,* Lam. 1799. CYCLOSTOMA ELEGANS. Drop. Specimens of this well-known species are found in the upper part of the Coralline Crag, as well as of Helix cry stallina, Pupa marginata, and Cyrena trigonula, in association with marine species. The locality from which they were obtained is rather a doubtful one, and from their very recent aspect they must, at least for the present, be considered * Etym. KVK\OS, a circle, and orb pa, a mouth. GASTEROPODA. 5 as not of the age of the Coralline Crag. The material in which they are found may probably be a disturbed deposit of a more recent period. I have also found this species, with its operculum in position, in the superficial earth resting upon the Red Crag, at the depth of six or eight feet from the surface, but have never seen it in a living state in the eastern part of the county of Suffolk. SUCCINEA,,* Drop. 1805. AMPHIBULIMA. Lam. 1805. COCHLOHYDRA. Ferus. 1819. Gen. Char. Shell ovate, rather elongate ; volutions few ; spire short ; texture thin, fragile, subcorneous, semitransparent ; aperture large and entire, longitudinally ovate ; peritreme sharp, and confluent with the columella, inner lip spread over a part of the body whorl. This approaches in general form the genus Limnsea, but may be distinguished by the absence of an oblique fold, which is always more or less distinct upon the columella of the latter. The British species are found about the margins of ponds and ditches, where the surface is moist and damp, and generally upon the stems and leaves of plants. The Succineae are strictly land animals, although capable of remaining a con- siderable time under water. 1 . SUCCINEA PUTRIS (?) Linn. Tab. I, fig. 5. HELIX PTJTRIS. Linn. Syst. Nat. p. 1249, 1766. — SUCCINEA. Mull. Verm. 11, p. 97, No. 296, 1774. — PUTRIS. Mont. Test. Brit. p. 376, t. 16, fig. 4, 1803. SUCCINEA AMPHIBIA. Drop. Moll. p. 58, t. 3, fig. 22, 23, 1805. PUTRIS. Flem. Brit. An. p. 267, 1828. — AMPHIBIA. Rossm. Icon. p. 91, t. 2, fig. 45, 1835. S. Testa elongato-ovatd, tenui, fragili ; anfractibus tribus convexiusculis, supra depressis, suturis profundis ; aperturd ovatd, subverticaU. Shell elongato-ovate, thin and fragile, with about three slightly convex volutions, rather depressed on the upper part; aperture broadly ovate, subvertical; suture moderately deep. Axis, | of an inch. Locality. Mam. Crag, Bramerton. Recent, Britain. This species I presume to be rare ; but one specimen has come into my possession since the publication of my Catalogue, and this appears to be only a little more elongated than the general form of this species, but in that character it is variable, especially among my specimens from the fluviatile deposit at Stutton, where it is abundant. The artist has given rather too great an expansion to the lower part of the aperture; bringing the resemblance too near to the following species. It is, however, a doubtful identification. * Etym. Succineus, of amber. 6 MOLLUSCA FROM THE CRAG. 2. SUCCINEA OBLONGA. Drop. Tab. I, fig. 6. SUCCINEA OBLONGA.. Drop. Moll. p. 59, tab. 3, fig. 24-25, 1805. HELIX ELONGATA. Daudeb. Hist, des Moll. pi. 1 1, fig. 1-3. AMPHIBULINA OBLONGA. Pfeif. p. 68, t. 3, fig. 39, 1821. SUCCINEA OBLONGA. Rossm. Icon. p. 92, t. 2, fig. 47, 1835. Grateloup. Cat. des Moll, de Dax, p. 123, 1838. Nyst Coq. foss. de Belg. p. 466, pi. 39, fig. 11, 1844. S. Wood. Catalogue 1844. 8. Testa elongato-ovatd, tenui ; spird elevatd, acuminatd ; apice obtuso, suturd profundd; anfractibus tridus subobliquis ; aperturd ovatd, spiram vix superante. Shell elongato-ovate, with an elevated and acuminated spire, and an obtuse apex ; volutions three, rather oblique and ventricose, with a deep suture ; aperture ovate, not exceeding the length of the spire. Axis, \ of an inch. Locality. Mam. Crag, Bulcham. Recent, Britain. One specimen of this species, from the cabinet of Captain Alexander, is all that I have seen. It appears to correspond with the recent shell, although the suture is not quite so deep. This species is also found, I believe, abundantly at Maidstone ; some specimens from that locality were given me by Mr. Morris, and I have found the same species, though sparingly, at Clacton, in which specimens the suture is rather deeper than in the Crag shell. AQUATIC, Flem. Lam. 1799- LIMNEUS. Drop. 1805. LYMN^US. Brand. 1815. LYMN^A. Desmarest. LYMNEA. Risso. 1826. LIMNEA. Flem. 1828. LYMNUS. Montf. 1810. LEPTOLIMNEA. Swains. 1840. STAGNICOLA. Leach. 1820. GULNARIA. — 1820. Gen. Char. Shell ovate or oblong, sometimes elongate and acutely turreted, smooth and naked ; spire always apparent, more or less elevated ; semitransparent and of a subcorneous texture ; volutions convex, somewhat depressed, sometimes tumid and rapidly enlarging ; aperture large, open, and ovate, with a flexuous or plicated colu- mella ; peritreme acute. Animals of this genus are inhabitants of fresh water, more especially of that which is still and stagnant, although a few have been occasionally found in marshes where * Etym. Atpvatos, of stagnant water. GASTEROPODA. 7 the water is brackish. The species found in the Crag are, however, such as in the present day are frequenters of ponds and ditches, and were in all probability conveyed to their present locality as dead and empty specimens. Hitherto this genus has not been found in any older formation than the Eocene, during which period it lived and flourished in great profusion. 1. LIMN^A PALUSTRIS (?) Linn. Tab. I, fig. 9, a — d. HELIX PALUSTRIS. Gmel. Syst. p. 3658, 1782. LIMNEUS PALUSTEIS. Drap. Hist. Nat. desMoll. ter. et fluv. p. 52, tab. 2, fig. 40, 1805. HELIX PALUSTRIS. Mont. Test. Brit. p. 373, t. 16, fig. 10, 1803. LYMN^A TENUIS. Woodward. Geol. of Norf. t. 3, fig. 30, 1833. LIMNEUS PALUSTRIS. Gray. 2d edit. Turt. p. 239, fig. 107, 1844. LYMNEUS PALUSTRIS. S. Wood. Catalogue 1842. L. Testa clongato-ovatd, tenui : spird elevatd, apice acuto ; anfractibus 4 — 5 converts, lavigatis ; aperturd ovatd. Shell elongato-ovate, thin, with an elevated spire and acute apex ; whorls about five, convex and smooth, aperture ovate, half the length of shell. Axis, | of an inch. Locality. Mam. Crag, Bramerton and Bulcham. Recent, Britain. Two or three belonging to Mr. Lyell, with one of my own, are all the fossil specimens that I have been able to examine ; they do not satisfactorily agree with the above recent species, although they resemble it more than any other with which I am acquainted, and present a sort of intermediate form between it and L. pereger, having the elevated spire of L. palustris and the convex whorls of L. pereger, or perhaps more like gigantic specimens of L. truncatulus. The left lip, which in the recent shell is a good deal reflected, is broken away in the Crag specimens, showing a small umbilicus. This species I have found at Stutton and Clacton, precisely resembling the recent form. 2. LIMN^A PEREGRA. Mull. Tab. I, fig, 7, a — b. BUCCINUM PEREGRUM. Mull. Verm. p. 130, No. 324, 1774. BULIMUS PEREGER. Sruffuiere. Diet. No. 10, 1789. LIMNEUS PEREGER. Drap. Moll. pi. 2, fig. 34-37, 1805. HELIX PEREGRA. Mont. Test. Brit. 1803. LIMN^EUS VULGARIS. Rossmasler. Icon. p. 97, t. 2, fig. 53-54, 1835. — PEREGER. S. Wood. Catalogue 1842. L. Testa ovato-oblongd, tenui, fragili ; anfractibus quatuor, convexis ; suturis profundis ; spird mediocri, acutd ; labio reflexo, aperturd ovatd. Shell ovato-oblong, thin, and fragile, with four convex volutions and a deep suture ; moderately elevated spire, and acute apex ; aperture elongato-ovate, with a subreflected peritreme ; left lip covering the umbilicus. Axis, \ an inch. Locality. Mam. Crag, Southwrold and Bramerton. Recent, Britain. One specimen of my own, with a few belonging to Mr. Wigham, obligingly sent to MOLLUSCA FROM THE CRAG. me for the purpose of being figured, are sufficiently characteristic to be fairly identified with one of the recent British forms ; and I feel justified in assigning it to L. peregra. This is also found at Stutton and Clacton, but I have only met there with the more ovate and less elongated variety. 3. LIMN^A TRUNCATULA (?) Mull. Tab. I, fig. 8, a — b. BUCCINUM TRUNCATULUM. Mull. Verm. p. 130, No. 325, 1774. HELIX FOSSARIA. Mont. Test. Brit. p. 372, t. 16, fig. 9, 1803. LYMXEUS MINUTUS. Drop. Moll. pi. 3, fig. 5-7, 1805. — FOSSARIUS. Turt. Man. fig. 108. LIMNEA FOSSAUIA. Flem. Brit. An. p. 274, 1828. LIMXEUB MINUTUS. Rossm. Icon. p. 100, t. 2, fig. 57, 1835. L. Testa pnsittd, ovato-conicd, perforatd, tenui,frayili ; anfractibvs quinque conveosis ; suturis profundis ; spird elevatd ; apice acuto ; aperturd ovatd. Shell small, ovato-conical, perforated, thin, and fragile, with about five convex volutions, and a deep suture ; spire elevated ; apex acute ; aperture ovate ; and a slightly reflected pillar lip. Axis, \ of an inch. Locality. Mam. Crag, Bramerton. Recent, Britain. One small specimen, represented at fig. 8 b, sent to me by Mr. Wigham for the purpose of description, appears to belong to this species ; it has the convex volutions, deep suture, and open umbilicus, corresponding with those of the recent shell. Fig. 8 a is the representation of a specimen from the cabinet of Mr. Lyell of a more doubtful character ;* although more elongated than the general form of the recent species, it appears to correspond in other respects, and I feel disposed to assign it to L. truncatulus. This species is found in the truly Lacustrine beds of Stutton and Clacton, corresponding precisely with the recent form. PLANORBIS/I* Mutter, 1781. Gen*. Char. Shell orbiculato-depressed, discoidal ; volutions apparent above and below, convoluted upon a nearly horizontal axis, thin, light, smooth, and somewhat corneous ; aperture simple, lunate, crescent-shaped, or subquadrate ; outer lip thin, sharp ; inner lip slightly spreading over the body whorl. No operculum. The animals belonging to this genus are inhabitants of pure fresh water ; their most favoured places of abode being in waters that are stagnant, although a few are found in gentle streams ; but none are as yet known in those places to which salt or brackish water has access ; the specimens, therefore, found in the Crag must of course have been accidentally introduced, and are few in number. Shells of this genus are formed upon a nearly horizontal plane, and some considerable disagreement * Mr. Lyell's specimen measures f of an inch, t Etym. Planus, fiat, and orbis, a circle. GASTEROPODA. 9 (not yet satisfactorily adjusted) has existed among conchologists as to the correct determination of the upper and under sides of these shells ; some have considered them as dextral, while others maintained them to be sinistral ; in my descriptions they are considered as dextral, although the artist has made them sinistral. 1. PLANORBIS COMPLANATUS. Linn. Tab. I, fig. 10, a — c. HELIX COMPLANATA. Linn. Syst. Nat. p. 1242, 1766. PLANORBIS TJMBILICATUS. Mull. Verm. p. 160, No. 439, 1774. HELIX COMPLANATA. Mont. Test. Brit. p. 450, t. 25, fig. 4, 1803. PLANORBIS COMPLANATUS. Flem. Brit. An. p. 278, 1828. PLANORBIS MARGINATUS. Drop. Moll. p. 45, pi. 2, fig. 11-12, 1805. Gray. 2d edit. Turt. Man. p. 265, fig. 88, 1840. S. Wood. Catalogue 1842. PL Testa discoided, complanatd, Icevigatd: anfractibus superne convexis, inferne complanatis : carina marginali, non prominenti ; spird depressd. Shell discoidal, flattish, smooth, with the spire slightly depressed ; nearly flat beneath, with the margin carinated but not prominent; volutions convex above; aperture lunate ; the upper part of the peritreme projecting beyond the lower. Diameter., § of an inch. Locality. Red Crag, Butley. Mam. Crag, Bulcham. Recent, Britain. My cabinet contains but one specimen of this species, found by myself in undis- turbed Red Crag. It corresponds with the common recent form of this shell, and has a slightly carinated edge on the flat or lower side, while the volutions on the other side are convex, with the spire depressed and concave, and the edge of the outer lip projecting and curved. Two specimens from the Mam. Crag, near Norwich, were sent to me for description by Mr. Wigham ; they do not differ, however, in any respect from my own. 2. PLANORBIS SPIRORBIS. Mull. Tab. I, fig. 11, a — c. PLANORBIS SPIRORBIS. Mull. Verm. 11, p. 161, 1774. HELIX SPIRORBIS. Gmel. Syst. p. 3624, No. 36, 1788. Mont. Test. Brit. p. 455, t. 25, fig. 2, 1803. PLANORBIS VORTEX, var. /3. Drap. Moll. t. 2, fig. 6-7, 1805. PLANORBIS SPIRORBIS. Gray. 2d edit. Turt. Man. p. 268, fig. 98. S. Wood. Catalogue 1842. PL Testa discoidea, utrinque plano-depressd ; anfractibus subcylindraceis, ultimo obsolete angulato. Shell discoidal, thin, fragile, somewhat concave on both sides, with very slightly increasing, sub cylindrical or subquadrate volutions ; outer or lower margin obsoletely angulated. Diameter, \ of an inch. Locality. Mam. Crag, Bulcham. Recent, Britain. 2 10 MOLLUSCA FROM THE CRAG. This is figured and described from a single specimen, belonging to Mr. Lyell. Its outer edge is rounded and not carinated, corresponding in that respect with the recent shell, which is now considered by most conchologists to be distinct from P. vortex, in which one edge is strongly keeled, and the surface thereby made quite flat, with the suture reduced to a fine and narrow line. Both these species are found in the fresh- water deposit, at Clacton, although P. vortex is the most abundant. 3. PLANORBIS CORNEUS. Linn. Tab. I, fig. 12, a — c. HELIX CORNEA. Linn, Syst. Nat. p. 1243, 1766. Mont. Test. Brit. p. 448, 1803. PLANOEBIS COENEUS. Drap. Moll. pi. 1, fig. 42, 44, 1805. Gray. 2d edit. Turton's Man. fig. 95, 1840. G. B. Sowerby. Genera, fig. 1, 18—? — Lam. 2d edit. Hist. Nat. des An. sans Vert. viii. p. 382, 1837. Rossmasler. Icon. t. 2, p. 14, pi. 7, fig. 113, 1838. Dujardin. Mem. Soc. Geol. de France, t. 11, 1837. — S. Wood. Catalogue 1842. PL Testa discoided, tenui,fragili, plano-depressa, altero late et profunde umbilicata ; anfractibm teretibus rapide crescentibus ; aperturd lunato rotunda. Shell discoidal, thin, and fragile, rather flat on one side, with a deep or canaliculated suture ; umbilicus broad and deep ; volutions subcylindrical, rapidly increasing, impressed by the previous whorl. Diameter, f of an inch. Locality. Mam. Crag, Bulcham. Recent, Britain. The figure is from a specimen in the cabinet of Capt. Alexander, and the only one I have seen. It corresponds precisely with specimens of the same size, of the common recent British species, and there is no doubt of its identity. The recent shell, in its young state, is marked with fine spiral striae, and the volutions, in more advanced age, are sometimes angulated. The striae are more especially distinct in the perios- traca, which, when removed, leave the shell nearly smooth. Our specimen has the slightest possible trace of spiral striae. This species has much the character of a sinistral shell, taking that for the under side in which the spire is most depressed and umbilicated ; but the portion of the peritreme is more produced and projecting on that side which, if it were a dextral shell, would be the uppermost. The depression of the vertex appears rather an anomaly in the mode of volution, but it occasionally occurs in species that are convolute upon a horizontal axis, as among some of the Bullte, where the lip is elevated above the spire, giving it there a deep umbilicus. Moreover, I should imagine that the projection of the lower portion of the aperture of the shell would rather impede the action of the foot, and incommode the motions of the animal. I have therefore considered that to be the upper side (fig. 12, b), in which the projecting portion of the peritreme would act rather as a protective covering to the animal. GASTEROPODA. 11 CONOVULUS,* Lam. 1812. MELAMPUS. Montf. 1810. CONOVULA. Ferus. 1819. MARINULA. King, 1831. CONOVULUM. G. B. Sow. jun. 1841. AURICULA. Lam. VOLUTA (spec.) Linn. Gen. Char. Shell oval or elongate, sub cylindrical ; with generally a smooth exterior and short conoidal spire ; aperture rather long and narrow ; peritreme continuous, with two or three folds upon the columella ; outer lip sometimes plain, occasionally denticulated within. This was proposed, in the first instance, by Lamarck, as a division of his extensive genus Auricula, but was afterwards suppressed by himself. Mr. J. E. Gray has recently adopted it in his edition of Turton's ' Manual of Land and Fresh Water Shells,' as a distinction from the Auriculae, which are land shells. The Conovuli live generally in water, and are found sometimes where it is purely fresh ; at others they extend their range into the sea. 1. CONOVULUS PYRAMIDALIS. /. Sow. Tab. I, fig. 13, a — b. AURICULA PYRAMIDALIS. J. Sow. Min. Con. t. 379, 1822. Nyst. Coq. foss. de Belg. p. 473, pi. 39, fig. 12, 1844. CONOVULUS PYRAMIDALIS. S. Wood. Catalogue 1842. C. Testa ovato-ventricosd, striatd, crassd ; spird conoided pyramidali ; apice obtusiusculo ; anfractibus 7 — 8 anyustis, superne convems, subcylindraceis ; aperturd ovato-oblongd auri- formi ; columella biplicatd. Shell ovato-ventricose, striated ? thick and strong, with a conoidal or pyramidal spire, and a slightly obtuse apex; volutions about seven, elongated and subcylindrical, with an ear-shaped aperture, and two folds upon the columella ; inner lip slightly reflected, generally covering the umbilicus. Axis, | of an inch. Locality. Red Crag, Sutton. Mam. Crag, Bramerton and Thorpe, near Aldborough. Found rather sparingly, in the Red Crag, but abundantly in the estuary deposit, at Thorpe, where the specimens are generally more perfect, though seldom so large. It is a thick and strong shell, rather clumsily formed, with a sharp and simple outer lip, somewhat thickened within, particularly at the lower part, and slightly con- tracted in the middle ; the upper part of the volution slightly convex, sloping outwards, the body of the shell nearly straight, contracting towards the base, with two folds upon the inner lip ; the upper one sharp, prominent, and compressed ; nearly at right * Etym. Conus and ovulum. This name of Melampus has priority, and ought to have been the one employed, but this having been used in my Catalogue is here retained. 12 MOLLUSCA FROM THE CRAG. angles to the axis of the shell, and situate about the middle of the aperture, at the lower part of the body of the shell ; the other upon the columella, midway between the upper fold and the base of the aperture, and is more oblique of the two. The inner lip is thick, especially at the lower part, and reflected, sometimes entirely covering the umbilicus. The specimens are generally quite smooth ; but that I imagine is an acci- dental circumstance, as vestiges of punctured striae, may be occasionally observed within the aperture, or by the removal of the left lip, and the shell was probably, in its recent state, entirely covered with striae. There is one deep ridge round the upper part of the volution a little below the suture, and an incipient sinus at the upper angle of the aperture. I am strongly induced to think that the inhabitant was an animal more inclined to salt water than to fresh, as the specimens from the Red Crag have attained to a greater size, and appear to have received their full development as associates with purely marine forms. 2. CONOVULUS MYOSOTIS (?) Drop. Tab. I, fig. 14, a — b. var. /3, fig. 15. AURICULA MYOSOTIS. Drap. Hist, des Moll. pi. 3, fig. 16, 17, 1805. CONOVULUS BIDENTATUS. Gray. 2d edit. Turt. Man. p. 227, pi. 12, fig. 145, 1840. CONOVULUS MYOSOTIS.