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SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 3 







UPPER CAMBRIAN TRILOBITE FAUNAS 
OF NORTHEASTERN TENNESSEE 

(With 21 Plates) 



By 

FRANCO RASETTI 

The Johns Hopkins University 
Baltimore, Md. 




(Publication 4598) 



CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

June 10, 1965 



,v, .■ 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 3 



l^psf arrl| 3F«ttb 



UPPER CAMBRIAN TRILOBITE FAUNAS 
OF NORTHEASTERN TENNESSEE 

(With 21 Plates) 



By 
FRANCO RASETTI 

The Johns Hopkins University 
Baltimore, Md. 




(Publication 4598) 



CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

June 10, 1965 



<.%'^ 



Q^fii^ 



CONNECTICUT PRINTERS, INC. 
HARTFORD, CONN., U.S.A. 



CONTENTS 



Part I. Stratigraphy and Faunas Pj^ge 

Acknowledgments 3 

Descriptions of Localities and Sections 3 

General statement 3 

Hawkins County 4 

Hamblen County 10 

Grainger County 12 

Jefferson County I5 

Union County 19 

Claiborne County 21 

Knox County 22 

Monroe County 23 

Purchase Ridge, Scott Coimty, Virginia 24 

Index of Localities 25 

Fauna of the Cedaria Zone 26 

Fauna of the Crepicephalus Zone 28 

Fauna of the Aphelaspis Zone 30 



Part II. Systematic Paleontology 

General Statement 38 

Descriptions of Trilobite Genera and Species 

Order AGNOSTIDA 38 

Family AGNOSTIDAE 38 

Order CORYNEXOCHIDA 39 

Family DORYPYGIDAE 39 

Order PTYCHOPARHDA 40 

Family LONCHOCEPHALIDAE 40 

Family CATILLICEPHALIDAE 44 

Family CREPICEPHALIDAE 45 

Family TRI CREPICEPHALIDAE 54 

Family ASAPHISCIDAE 55 

Family KINGSTONIIDAE 60 

Family MENOMONIIDAE 61 

Family NORWOODIIDAE 64 

Family CEDARIIDAE 69 

Family EL VINIIDAE 71 

Family PTEROCEPHALIIDAE 72, 

PTYCHOPARHDA of uncertain affinities 102 

Undetermined trilobites 112 

References 115 

Explanation of Plates 118 



UPPER CAMBRIAN TRILOBITE FAUNAS 
OF NORTHEASTERN TENNESSEE 

By 

FRANCO RASETTI 

The Johns Hopkins University 



PART I. STRATIGRAPHY AND FAUNAS 

The purpose of this paper is both to describe the fossils and to 
present them in their proper stratigraphic setting. In the study of the 
Cambrian of the southern Appalachians, there has been in the past 
little collaboration between geologists and paleontologists. Strati- 
graphic work was done by geologists who had only a secondary inter- 
est in fossil collecting; on the other hand, almost all the species 
described by Walcott and by Resser were derived from old collections 
that bear more or less precise locality labels but no accurate indication 
of the stratigraphic position. In his paper on the Cambrian of the 
southern Appalachians, Resser (1938a) tried to refer the Upper 
Cambrian fossils to several zones. This assignment was essentially 
based on the occurrence of the genera in question in better-understood 
areas of the United States, chiefly the Upper Mississippi valley, and in 
a broad sense succeeded in providing an approximately correct time 
order for the fossils of the southern Appalachians. However, none of 
the finer details of the time succession could be determined. 

The obvious procedure was therefore to locate well-exposed, rela- 
tively undisturbed, fossiliferous sections, to collect fossils from care- 
fully measured horizons, and to rely on these alone, and not on the old 
collections, in establishing the faunal succession. Many of the previ- 
ously known Upper Cambrian trilobites from Tennessee were thus 
collected again from known strata; those that could not be found 
seldom represent more than slightly variant forms related to the ones 
of ascertained age. A number of new forms were discovered. In gen- 
eral, the collections are much larger than the ones previously in ex- 
istence, and provide indications on intraspecific variability in popula- 
tions from a single bed and similar questions that cannot be discussed 
on the basis of a few scattered specimens from different localities. 

SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 148, NO. 3 



2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

On the basis of published records, first a brief reconnaissance was 
made of various areas of Cambrian outcrop in northeastern Tennessee 
and some adjacent areas of Virginia in search for sections that might 
yield the desired biostratigraphic information. Several belts of Cam- 
brian outcrop did not appear promising for either one of two reasons. 
For example, those north of Clinch Mountain yield a few well-exposed 
sections, such as the ones at Thorn Hill, described by Hall and Amick 
(1934), and at Lee Valley, described by Rodgers and Kent (1948). 
However, most of these sections, with the notable exception of the one 
near Washburn, hold few fossiliferous beds of the Crepicephalus and 
Aphelaspis zones, and the preservation leaves much to be desired. On 
the other hand, other Cambrian belts, such as those in the vicinity of 
Greeneville and Morristown, yielded good fossils to the early collec- 
tors, but the sections are fragmentary and poorly exposed. Several 
localities were found that offered undisturbed, well-exposed, and highly 
fossiliferous sections. 

Upper Cambrian fossils occur in northeastern Tennessee chiefly in 
the upper portion of the Maryville limestone and in the Nolichucky 
formation (including the Maynardville limestone). The overlying 
Copper Ridge dolomite, which seems to represent most of the Fran- 
conian and Trempealeauian stages, is almost totally barren. The few 
trilobites collected from this formation are mentioned by Rodgers 
(1953) and Bridge (1956). No search was made in the Copper Ridge 
dolomite. 

Since the purpose of this paper is essentially paleontologic, no at- 
tempt was made to discuss the stratigraphy and nomenclature of the 
formations in question. This problem has been dealt with by Hall and 
Amick (1934), Rodgers and Kent (1948), Rodgers (1953), and 
Bridge (1956). The main points under discussion are whether the 
Maynardville limestone should be recognized as a separate formation 
or considered as the uppermost portion of the Nolichucky shale, and 
where the Maynardville-Copper Ridge contact should be placed. Sev- 
eral sections were measured and are described herein only in order to 
precisely locate the fossiliferous beds and establish the succession of 
the faunules. Questions of stratigraphic nomenclature are of secondary 
importance for these purposes. 

Rodgers' geologic map of northeast Tennessee at the scale of 
1 : 125,000 and the geologic map of the Mascot-Jefferson City zinc 
district by Bridge were found exceedingly useful in searching for 
possible sections and fossil localities. Dr. Charles R. L. Oder, Chief 
Geologist of the American Zinc Company of Tennessee, who has been 
studying the Maynardville limestone for years, showed the writer 
several interesting sections. 

The area under consideration is covered by recent U.S. Geological 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 3 

Survey 7j^-minute quadrangles at the scale of 1 :24,000. Localities 
are always indicated herein by coordinates (x = abscissa, y =: ordi- 
nate) in millimeters, measured from the southeast corner of the map. 

The present study has been limited to trilobites. In the Dresbachian 
formations of Tennessee the brachiopods are, as usual, the next in- 
vertebrate group in order of abundance. The phylum is represented 
mostly by inarticulates. Recent studies, such as those by Palmer 
(1954) and Bell and Ellinwood (1962) in Texas, have shown that 
adequate investigation of these fossils requires extensive etching of 
limestone with acetic or formic acid, since mechanical preparation 
generally yields only the exterior of the shell, of scarce taxonomic 
significance. It is possible that etching of large amounts of limestone 
of the Aphelaspis zone — the only portion of the Upper Cambrian in 
the area where brachiopods are relatively abundant — might yield 
interesting results. For a number of reasons such a program was not 
undertaken. 

The other invertebrates observed are indeterminable echinoderm 
plates, fairly common in certain beds but poorly preserved; a small 
gastropod of the " H elcionella" type, and a few dendroid graptolites in 
shale beds. The description of these groups of fossils would not bring 
any significant contribution to paleontology. 

ACKNOWLEDGMENTS 

The present work was started as part of a research project under a 
grant from the Penrose Bequest of The Geological Society of America. 
This grant had already produced two papers (Rasetti, 1959, 1961) 
on the Cambrian of the central Appalachians, When funds from this 
source were no longer available, the work was continued and com- 
pleted with grant No. 2829-P from the Penrose Fund of the American 
Philosophical Society. The author is greatly indebted to both institu- 
tions for their support. 

Thanks are also due to Dr. Allison R. Palmer for valuable discus- 
sions on problems of taxonomy and biostratigraphy and for communi- 
cating unpublished results of his investigations in the Upper Cambrian 
of the western United States; to Dr. Robert B. Neuman for strati- 
graphic information ; and to Dr. Charles R. L. Oder for communicating 
his unpublished measurements of sections and for accompanying the 
author in some field excursions. 

DESCRIPTIONS OF LOCALITIES AND SECTIONS 
GENERAL STATEMENT 

This part of the paper presents the stratigraphic evidence that was 
used in arranging the Upper Cambrian faunules in their proper time 



4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

order. Sections were measured, and are described in some detail, 
whenever they yielded several faunules in unquestionable stratigraphic 
succession. Descriptions of lithology are generally limited to those 
indications that may be useful to a geologist in order to identify in the 
field the units from which the fossils were collected. In several cases, 
when the topography was not favorable to an accurate measurement 
of the thickness, the section was described qualitatively, by giving the 
succession of the various lithic units and an estimate of their thick- 
nesses. Even in these cases the time order of the fossils collected is 
certain. Sections where any kind of structural complication might 
bring doubt about the sequence of the strata were never used. 

The localities are indicated in the text only approximately with 
respect to towns, roads, etc., since a complete list of the fossil localities 
defined by coordinates on the U.S. Geological Survey topographic 
maps follows. 

Faunal lists given in the descriptions of the sections usually assign 
to each species an indication of relative abundance (cc = very com- 
mon, c =i common, r = rare, rr = very rare). These indications are 
missing when the collection was too small to supply significant data. 
For brevity, author's names are omitted, since all the species listed are 
discussed elsewhere in this paper. An asterisk preceding the name in- 
dicates the type locality for the species. 

Fossil collections are all labeled with the letters en (for Cambrian, 
NoHchucky) followed by a third letter designating the horizon and a 
number indicating the locality. At least for the later collections, the 
same number is applied to all the collections from a given section. 
As far as possible it was attempted to designate by the same letters 
correlative beds in the different sections ; a few discrepancies are in- 
evitable since precise correlation was not always apparent at the time 
when the fossils were labeled. Collections designated by cna to cne 
belong to the Cedaria zone, cnk to cnn to the Crepicephalus zone, and 
cno to cnx to the Aphelaspis zone. 

HAWKINS COUNTY 

Big Creek section, near Rogersville. — The most complete and satis- 
factory section of the entire fossiliferous portion of the Upper Cam- 
brian was found along Big Creek, just south of U.S. Route 11 -W, a 
few miles east of Rogersville, Hawkins County (Burem quadrangle). 
The U.S. National Museum collections contain numerous fossils from 
unspecified horizons in this section; several species were described 
by Walcott (1916a, 1916b) and Resser (1938a). 

A section of the upper portion of the Maryville formation and the 
entire Nolichucky formation were measured chiefly on the hill slopes 
on the east bank of Big Creek ; the rest of the Maryville formation was 
added from complete sections exposed a short distance east along the 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 5 

Strike. This section with its numerous fossil-bearing beds represents 
a standard with which partial sections studied in other areas will be 
correlated. The upper boundary of the Nolichucky formation is here 
set at the first appearance of dolomite beds, which at Big Creek coin- 
cides with the disappearance of limestone. However, Rodgers (1953) 
assigned some of the lower, noncherty dolomite beds to the upper 
portion of the Nolichucky (Maynardville limestone member) rather 
than to the overlying Copper Ridge dolomite. The author, without 
questioning the reasons that prompted this assignment, has provision- 
ally placed all the dolomite in the Copper Ridge formation because this 
boundary was more readily recognized in the field. In other sections 
there is an interval where limestone and dolomite beds alternate, mak- 
ing the definition of the formational boundary more uncertain than 
at Big Creek. 

Big Creek section, measured 3 miles northeast of Rogersville, 
Hawkins County, Tenn. : 

Nolichucky formation Thickness 

Feet 
8. Limestone and shale ; aphanitic, dark-gray, gray-weathering limestone 
in thin, often nodular beds, ribboned with tan-weathering shale 

or dolomite. Some crystalline lenses are fossiliferous 67 

Collection 66 feet above base (cnx/1) : 

Cheilocephalus brachyops r 

Dytremacephalus angulatus c 

Dytremacephalus sulcijrons rr 

Collection 42 feet above base (cnw/1) : 

Aphelaspis tarda r 

Dytremacephalus angulatus c 

Collection 3-4 feet above base (cnv/1) : 

Aphelaspis tarda c 

7. Limestone and shale : similar to preceding unit, with lesser percentage 

of limestone in more distinctly nodular layers 6 

Collection 0-1 feet above base (cnu/1) : 
Aphelaspis tarda c 

6. Shale, lacking limestone beds 16 

5. Shale, with several limestone lenses and nodules 10 

Collection 1 foot below top (cnt/1) : 
Aphelaspis arsoides r 
Aphelaspis tumifrons c 
Pseudagnostus communis r 
Collection 4 feet below top of interval (cns/1) : 
Aphelaspis arsoides c 
Aphelaspis tumifrons c 
4. Limestone : one bed, massive, crystalline and conglomeratic, well ex- 
posed across stream bed 1 

The above portion of the section was measured on the slopes SE of a 
dry creek bed at x = 182, y = 297 mm, Burem quadrangle. 

3. Shale : finely fissile, with a few siltstone beds near the top 40 

2. Limestone: mostly very thick-bedded, light-gray, aphanitic, in part 
crystalline or oolitic, with some intervals of intraformational 



6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Thickness 
Feet 

pebble conglomerate. At the base some thin beds alternating with 

shale. Very sharp contact with overlying shale 156 

Collection in top few inches (cnn/1) : 

Blountia arcuosa r 

Blountia montanensis r 

Coosia alethes c 

Coosia robusta r 

Coosia, sp. undet. r 

Crepicephalus cf. convergens r 

Kingstonia inflata c 

Maryvillia arion c 

Meteoraspis mutica r 

Terranovella dorsalis r 

Trier epic ephalus thoosa c 

Collection from loose blocks in lower third of 
interval (cnk/3) : 

Blountia alexas r 

Dreshachia amata r 

Kingstonia inflata c 

1. Shale : finely fissile, green or tan, with a few siltstone beds in upper- 

most portion. In the lower 15 feet a few lenses of silty or crys- 
talline limestone ^^^ 

Collections in lower 15 feet both in shale and 
limestone lenses (cne/1, cne/2) : 

Genevievella, sp. undet. r 

Kormagnostus simplex c 

Norwoodella saffordi c 

Total thickness of Nolichucky formation 633 

Maryville formation 
3. Dolomite and limestone: massive, gray, gray-weathering dolomite in 
lower part, grading upward to massive, gray, more coarsely crys- 
talline or oolitic limestone. Fossile not rare in top 30 feet, more 

common in top 10 feet 185 

Collections made at various places (cnc/2 to cnc/5) : 

Hyolithes, sp. undet. c 

Bonneterrina appalachia c 

Coenaspis spectabilis rr 

Coosella andreas r 

Genevievella, sp. undet. r 

Holcacephalus praecursor r 

Kormagnostus simplex c 

Menomonia tuberculata r 

Menomonia, sp. undet. r 

Modocia crassimarginata c 

Modocia dubia c 

Modocia ? agatho r 

Norwoodia, sp. undet. r 

Tricrepicephalus, sp. undet. c 

2. Dolomite : very light gray, weathering almost white 67 

1. Dolomite : gray, weathering tan or dark gray 740 

Total thickness of Maryville formation 992 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 7 

The following comments may be made about this section and the 
contained fossils : 

The Maryville formation here consists mostly of dolomite, except 
in the uppermost portion which is rather pure, crystalline or oolitic 
limestone. The contact of the formation with the underlying Rogers- 
ville shale is very sharp. Presumably the Middle-Upper Cambrian 
boundary lies somewhere within the Maryville, since the uppermost 
portion holds a faunule of the Cedarm zone, of very early Dresbachian 
age. The author was unable to find fossils in the lower parts of the 
formation in the Rogersville area. However, a collection in the U.S. 
National Museum (loc. 107x, 11 miles NW. of Knoxville) mentioned 
by Walcott (1916b, p. 394) yielded the types of Asaphiscus glaher 
Walcott and a species of Olenoides. These are undoubted Middle 
Cambrian fossils and were certainly collected from limestone of the 
Maryville formation, or at least its equivalent in the Conasauga group. 

The Nolichuck}'^ formation at Big Creek and in other sections studied 
in the Rogersville outcrop belt, as well as at many other localities, 
consists in ascending order of four members : a shale, a limestone, 
another shale, and the uppermost limestone. The lower limestone mem- 
ber, although very thick and conspicuous in the present section, is 
quite variable in thickness. It is essentially absent from some of the 
sections north of Clinch Mountain, such as the Thorn Hill and Pur- 
chase Ridge sections, and even from the section on Price School road 
which is not far from Rogersville and in the same outcrop belt. At 
several localities this limestone is in part of algal origin (Oder and 
Bumgarner, 1961). Geologists who discussed the stratigraphy of 
northeastern Tennessee generally recognized a Maynardville lime- 
stone, either as a member of the Nolichucky or as a separate formation. 
In the typical area, in the Maynardville quadrangle, there is essentially 
one limestone succession above the shale of the lower Nolichucky, and 
this was named the Maynardville limestone. It includes at least por- 
tions of Crepicephalus and Aphelaspis faunizones (see discussion of 
the Hurricane Hollow section) . The question arises whether in areas 
where the upper Nolichucky consists of two limestone units separated 
by a shale, the name Maynardville should apply to this entire complex, 
or to the upper limestone alone, the characteristic thin-bedded lime- 
stone ribboned with shale and dolomite. Since the author's purpose 
is not to discuss stratigraphic nomenclature, the more noncommittal 
attitude of assigning all the strata in question to the Nolichucky is 
adopted, without implying any judgment on the validity and bound- 
aries of the Maynardville limestone. 

The faunules listed in the section show that the basal Nolichucky 
shale holds essentially the same fossils as the uppermost Maryville 



8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

limestone, indicating no considerable time interval between the deposi- 
tion of the two units. In this section, younger faunules of the Cedaria 
zone such as those found at several localities north of Clinch Mountain 
seem to be absent, probably owing to the lack of limestone beds or 
nodules in the shale. The next higher faunules occur in the lower 
limestone unit, and these belong to the Crepicephalus zone. The upper, 
unfossiliferous 40-foot shale unit separates the uppermost Crepiceph- 
alus zone faunule from the lowest Aphelaspis zone faunule. As shown 
in the later discussion of other sections, the faunules of the lower 
portion of the Aphelaspis zone are here missing, while the faunules 
of the upper Aphelaspis zone are well represented. 

Forgey Creek. — A partial section of the Maryville and NoHchucky 
formations is exposed along Forgey Creek, between Zion Hill and 
Carter Valley road, in the NE. corner of the Burem quadrangle. The 
uppermost beds of the Maryville hold the usual Cedaria zone fauna. 
This was the easternmost locality examined. 

U.S. Route 11-W, dyi miles NE. of Rogersville. — Although the 
section is poorly exposed here, the locality is important for the pres- 
ence of unusual, highly fossiliferous red beds at the base of the Noli- 
chucky shale. The best collecting locality (now deteriorated) was the 
road cut on the S. side of U.S. Route 11-W at the foot of the hill 
located at x = 326, y = 434, Burem quadrangle (U.S.N.M. locality 
27d, author's locality cnd/1). Good collections were also made here 
in the underlying Maryville limestone, about 30 feet below the top of 
the formation (cnc/1 ) . 

Yellow and pink layers, absent in other areas, begin to appear here 
in the upper portion of the Mar)rville. The overlying Nolichucky 
formation consists, for the lower 50 feet, of alternating red shale and 
thick, irregular, partly lenticular beds of limestone. Each limestone 
bed often presents an irregular alternation of aphanitic, brick-red or 
pink limestone and coarse, yellow to light-brown calcarenite. Both 
types of limestone are highly fossiliferous in places. The calcarenite is 
sometimes a coquina of extremely fragmentary trilobite tests, among 
which only the strong, compact pygidia of Ankoura triangularis have 
escaped destruction. The red, aphanitic limestone supplies better- 
preserved fossils, including numerous larval stages of trilobites. A list 
of the species is given in the discussion of the faunas, 

A search was made to ascertain how far along the strike these 
peculiar beds extend. The red beds can be traced eastward, north of 
the highway, to the south flank of the westernmost hill of Miller Ridge, 
about half a mile E. of locality cnd/1. On the next hill, where the 
Maryville-Nolichucky contact is well exposed, the red shale and lime- 
stone have disappeared. West of locality cnd/1, the first exposure 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 9 

of the formational contact occurs at a distance of about half a mile, 
and no trace of red beds is present. In conclusion, the red beds prob- 
ably extend for less than 1 mile along the strike. They were observed 
at no other locality. 

The lower limestone member of the Nolichucky is sharply defined 
near this locality and has an approximate thickness of 180 feet. 

One mile E. of Rogersville. — A good section of the lower limestone 
member of the Nolichucky was measured in a cut on the E. side of the 
road leading to Bell Cemetery. The limestone is 175 feet thick; how- 
ever, the lower 50 feet here alternate with shale. Good fossils were 
collected about 40 feet above the lowest limestone bed (cnk/1). 

Highly fossiliferous beds about 45 feet below the top of the lower 
limestone member of the Nolichucky occur about 0.2 miles SW. of the 
preceding locality, on the hill S. of a dirt road (loc. cnm/2). Loose 
blocks on the hill slope (cnm/3) were partly derived from these beds, 
partly seemingly from a higher horizon, as some hold a faunule more 
similar to that found in the uppermost beds of the lower limestone. 

Guntown Road. — The lower limestone member of the Nolichucky 
is fairly well exposed on the E. side of the Guntown Road, about ^ 
mile S. of Rogersville. Good collections were made from the top beds 
of the lower limestone member of the Nolichucky (loc. cnn/2). 

Crockett Creek. — Partial sections of the Nolichucky are exposed 
on the hills S. of Crockett Creek (Pressmen's Home quadrangle). A 
good section of the lower limestone member was found near the end 
of a dirt road branching off from U.S. Route 11-W near Bench Mark 
SN-113. The limestone is approximately 145 feet thick. Numerous 
fossils were collected from the top beds (loc. cnn/3). 

Price School Road. — A partial section of the Nolichucky formation 
is exposed on the east side of Price School Road (x = 99-102 mm., 
y = 475--485 mm.. Bulls Gap quadrangle). Shale beds a few feet 
above the top of the Maryville limestone yield Kormagnosttts simplex 
and Norwoodella saffordi as do the strata at the same level in the Big 
Creek section. The lower limestone member of the Nolichucky, how- 
ever, is here reduced to a small fraction of the thickness of 150 feet 
observed in all the sections near Rogersville. It consists of about 30 
feet of limestone alternating with shale. This limestone is overlain 
by a thick succession of shale beds with a few, thin limestone lenses. 
A lens 90 feet above the top of the limestone yielded Amiaspisf sp. ; 
one 140 feet above contained Coosina sp. and Crepicephalus sp. ; and 
one 170 feet above, Aphelaspis sp. and Glaphyraspis sp. Even though 
the fossils are scarce and fragmentary, it is clear that the Crepi- 
cephalus-Aphelaspis zone boundary is somewhere between 140 and 
170 feet above the top of the limestone. This is in contrast with the 



10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

relationships at Big Creek and Lost Creek, where the faunizone 
boundary approximately coincides with the limestone-shale contact, 
and on Shields Ridge (Piedmont Road, Russell Gap), where the 
boundary lies within the limestone unit. These observations indicate 
that, in accordance with its erratically varying thickness, the lower 
limestone member of the Nolichucky does not occupy the same time 
span in different sections. Limestone units in the Nolichucky shale 
are developed erratically at different levels, the only persistent one 
being the characteristic "ribbon rock" at the top. 

HAMBLEN COUNTY 

Three Springs. — A section of the upper Nolichucky formation is 
well exposed in a recent road cut on the E. shore of the Three Springs 
embayment of Cherokee Reservoir (Russellville quadrangle). This 
locality is in the same outcrop belt as the Big Creek section and is 14 
miles distant along the strike. Unfortunately, some of the upper ( May- 
nardville) limestone and its contact with the Copper Ridge dolomite 
are obscured by incomplete exposures and structural complications. 
The section was measured in descending order (northward), starting 
near an old stone bridge, where good exposures in the road cut on the 
E. side of the road begin. An undetermined portion of the upper lime- 
stone unit is therefore missing. 

Thickness 
Feet Inches 
22. Limestone, in thin beds ribboned with shale or dolomite, 

somewhat more shaly in lower portion Not measured 

Collection cnv/lS, 0-5 feet above base ; 
Aphelaspis tarda c 

Dytremacephalus angulatus r 

31. Shale 3 6 

30. Shale and limestone, the latter in nodular beds 4 

Collection cnu/15: 
Aphelaspis tarda c 

29. Shale, partly slumped and poorly exposed. A prominent 
lens of knobbly limestone 4 feet below top is exposed 

along road 10-30 

28. Shale, with nodular limestone beds 14 

Collection cnt/15 at top : 
Aphelaspis arsoides c 

Aphelaspis tumifrons c 

Pseudagnostus communis r 

Collection cnt'/15 at base : 
Aphelaspis arsoides r 

Aphelaspis tumifrons cc 

27. Shale 1 

26. Limestone : massive, granular, with tan-weathering 

stringers 2 



NO. 3 



UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 



11 



Thickness 
Feet Inches 



25. Siltstone, with thin Hmestone beds and lenses 2 

Collection cnt'VlS : 

Aphelaspis arsoides c 

Aphelaspis tumifrons cc 

Pseudagnostus communis r 

24. Shale 3 

23. Limestone : massive, one bed 1 

22. Shale 6 

21. Shale, with thin limestone beds 4 

Collection cns"/15, 2 feet above base : 

Aphelaspidella macropyge 

Aphelaspis rotundata 

Paraphelaspis vigilans 

20. Limestone : massive, one bed 2 

19. Shale, with thin-bedded limestone 5 

Collection cns'/15, from limestone lenses at middle 
and top of interval : 

Aphelaspis arses r 

Aphelaspis rotundata c 

Paraphelaspis vigilans c 

18. Limestone : granular, one bed 1 

17. Siltstone 2 

16. Limestone : massive, granular 1 

15. Shale, with some thin siltstone and limestone beds 9 

Collection ens/ 15, 5 feet below top : 

Aphelaspis camiro c 

Aphelaspis laxa r 

Aphelaspis quadrata c 

Aphelaspis washburnensis r 

Aphelaspis, sp. undet. r 

14. Limestone conglomerate : one bed 

13. Shale, with a few thin limestone beds and lenses 10 

Collection cnr'/15, 2 feet below top : 

Aphelaspis laxa c 

12. Limestone : one bed, partly conglomerate 

1 1 . Shale, with a few, thin limestone beds 1 

Collection cnr/15, 8 inches below top : 

Aphelaspis zvalcotti cc 

Glaphyraspis declivis c 

Glaphyraspis oderi c 

10. Limestone : one bed of irregular thickness 

9. Shale 2 

8. Limestone : one bed of irregular thickness, partly conglomerate 1 

7. Shale, finely fissile 2 

6. Limestone : silty, granular, one bed 

5. Shale with thin siltstone and limestone beds, partly lenticular 4 

Collection cnq/15, 6 inches below top: 

Aphelaspis minor cc 

Glaphyraspis ornata r 



2-4 



6-7 



12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Thickness 
Feet Inches 
Collection cnp715, 1 foot below top : 
Aphelaspis lata c 

Aphelaspis walcotti c 

Collection cnp/15, 2 feet below top : 

Aphelaspis lata cc 

Collection cno/15, 3-4 feet below top : 
Aphelaspis buttsi cc 

Coosella perplexa r 

Glaphyraspis parva cc 

4. Limestone : 4 beds several inches thick, separated by shale 

and siltstone 3 4 

3. Shale, siltstone, and limestone : one 3-inch limestone bed in 

middles of unit 5 4 

Collection cnn/15 from loose pieces at foot of cliff, 
presumably derived from this or preceding unit : 
Amiaspis, sp. undet. 
Coosia alethes 
Crepiccphahis, sp. undet 
Terranovella dorsalis 

2. Limestone conglomerate : one bed, well exposed near road 5-7 

1. Shale, siltstone, and limestone in part conglomerate, alter- 
nating as in preceding imits, underlain by massive lime- 
stone. This part of the section was not measured as it 
yielded no fossils, and change in dip affects its lower 
portion. 

As it can be seen from the faunal lists, this section offers one of 
the most complete successions of Aphelaspis zone faunules observed 
anywhere. Noteworthy is the collection cno/14 at the base of the 
Aphelaspis zone, yielding Coosella, a genus more characteristic of the 
Crepicephalus zone, associated with Aphelaspis buttsi, so far known 
only from this locality in Tennessee, where it is believed to be the 
oldest species of the genus. Equivalent beds will be described from 
the Russell Gap section. 

GRAINGER COUNTY 

Smith Hollow. — A continuous section of the upper portion of the 
Nolichucky formation is exposed in a road cut at Smith Hollow, 
Luttrell quadrangle. The writer is indebted to Dr. Oder for leading 
him to this locality and supplying measurements of the section. Collec- 
tions at various levels were made by Dr. Oder and the author. A brief 
description of the section in descending order follows. 

The uppermost part of the Nolichucky is the usual limestone in thin 
beds, ribboned with shale or dolomite, alternating with minor shale 
intervals. This suit is approximately 150 feet thick. 

Oder's collection No. 14A, about 80 feet below top of unit : 
Aphelaspis tarda 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 13 

Oder's collection No. 14, a short distance below the preceding : 

Aphelaspis arsoides 
Aphelaspis tumijrons 

The above unit is underlain by a thick shale interval with minor 
siltstone, limestone, and limestone conglomerate layers. Some of the 
limestone beds are lenticular. The base of this shale rests on massive 
limestone as in the sections of the Rogersville area. The thickness of 
the limestone cannot be accurately measured but seems to be much 
less than in the vicinity of Rogersville. 

The following collections were all made from thin limestone beds 
in the shale unit. 

Collection cns/16 (= Oder's collection No. 13), 
about 100 feet below top of shale : 

Aphelaspis camiro c 

Aphelaspis laxa r 

Aphelaspis quadrata c 

Collection cnq/16, about 2 feet below the preceding : 

Aphelaspis walcotti 

Glaphyraspis ornata 

Glaphyraspis declivis 
Collection cnr/16, about 2 feet below the preceding: 

Aphelaspis walcotti cc 

Glaphyraspis ornata r 

Collection cnn/16, about 145 feet below top of shale : 

Amiaspis erratica 

Amiaspis obsolescens 

Coosia alethes 

Crepicephalus buttsi 

This section affords a good sequence of Aphelaspis faunules and 
confirms the order of the species of this genus observed in other sec- 
tions. The lowest faunule belongs to the Crepicephalus zone. It is 
notable for the presence of the genus Amiaspis. 

Thorn Hill. — The Nolichucky formation exposed in the Thorn Hill 
section, measured by Hall and Amick, is not particularly fossiliferous. 
The author collected from limestone beds interstratified with shale in 
the lower portion of the formation (Cedaria zone, loc. cnd/13) the 
following species : 

Cedaria tennesseensis 

Kormagnostus simplex 
Menomonia, sp. undet. 
Norwoodella walcotti 

Washburn. — A richly fossiliferous and excellently exposed section 
of the beds of the Aphelaspis zone was measured in a cut of the 
Southern Railway about a mile north of Washburn, The locality is in 



14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

the Dutch Valley quadrangle, in the same outcrop belt as the Thorn 
Hill section studied by Hall and Amick, at a distance of 10 miles along 
the strike. The beds dip 42°-A5° S. The Nolichucky-Copper Ridge 
contact is exposed in a ravine on the E. side of the railroad and seems 
to be rather gradational, the dolomite content increasing upward. 
Only the basal part of the upper (Maynardville) limestone member 
of the Nolichucky is exposed in the railroad cut, the best exposures 
being on the E. side. Below the limestone, every bed to the base of the 
Aphelaspis zone is visible. 

Thickness 
Feet 
16. Limestone, ribboned with shale and dolomite, rather poorly exposed 

in ravine ; only lowest 6 feet exposed in railroad cut 70 

Collection cnx/20, 2-6 feet above base : 
Aphelaspis tarda cc 

15. Shale 5 

14. Limestone, ribboned with shale and dolomite 21 

Collection cnw/20, 4-7 feet below top : 

Aphelaspis punctata c 

*Aphelaspis tarda cc 

Cheilocephalus brachyops r 

Dunderbergia tennesseensis r 

13. Shale, finely fissile 12 

12. Shale, with thin limestone beds and lenses 16 

Collection cnt720, 8 feet above base : 
Aphelaspis arsoides c 

Aphelaspis tumifrons cc 

P seudagnostus communis c 

Collection cnt/20, 2 feet above base : 
Aphelaspis tumifrons c 

Pseudagnostus communis r 

11. Shale : finely fissile, lacking limestone beds 14 

10. Shale, with thin limestone beds and lenses ; one thick limestone bed 

at base 10 

Collection cns/20, 0-4 feet below top : 

Aphelaspidella macropyge c 

Aphelaspis arses c 

* Aphelaspis rotundata c 

*Paraphelaspis vigilans c 

9. Shale : finely fissile, lacking limestone beds 9 

8. Shale, with thin limestone lenses 2 

Collection cnr'/20 : 
Aphelaspis camiro c 

Aphelaspis laxa c 

Aphelaspis quadrata c 

Glaphyraspis oderi r 

7. Shale : finely fissile, lacking limestone beds 5 

6. Shale, with thin limestone beds and lenses ; a few limestone beds up to 

4-5 inches thick, one at top 22 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 15 

Thickness 
Feet 
Collection cnr/20 in thin lenses in top 1 foot : 

Aphelaspis camiro c 

Aphelaspis laxa r 

Aphelaspis quadrata c 

Collection cnq'/20 in thin bed 2j^ feet below top : 

*Aphelaspis washburnensis 

Aphelaspis, sp. undet. 

Aphelaspidella macropyge 

Glaphyraspis declivis 

Collection cnq/20 in thin beds and lenses, 10-14 feet above base : 

Aphelaspis walcotti cc 

Glaphyraspis oderi c 

Collection cnp720, in thin beds and lenses 6-8 feet above base : 

Aphelaspis minor c 

Glaphyraspis oderi r 

Collection cnp/20 in lenses and nodules 1-4 feet above base : 

Aphelaspis lata cc 

Cheiloccphalus brevilobus r 

5. Limestone : in rather thick beds, with some shale intervals 7 

4. Shale and thin-bedded limestone 5 

Collection cnn/20, 1 foot above base : 

Crepicephalus, sp. undet. 

Terraiiovella dorsalis 

3. Limestone : in rather thick beds, with some shale intervals 6 

2. Shale, siltstone, and thin-bedded limestone. Unit extends almost to 

northern end of railroad cut 27 

Collection cnm720, 35^ feet below top : 

*Amiaspis obsolescens 

Coosia alethes 

Collection cnm/20, 1 1 feet below top : 

Kingstonia inflata 

The Washburn section supplies one of the most complete successions 
of Aphelaspis faunules observed in Tennessee, and is probably un- 
equaled in the number of fossils of the Aphelaspis zone. The trilobites 
are mostly well preserved, including the extremely numerous larval 
stages of Aphelaspis present in collection cnw/20 (pi. 20, fig. 1). 

JEFFERSON COUNTY 

The Nolichucky formation is partly exposed near the crest of 
Shields Ridge, in the New Market and Jefferson City quadrangles. 
Three localities yielded important fossils and information about the 
faunal succession. 

New Market-Piedmont Road. — The Nolichucky formation is in- 
completely exposed along the road on the N. and S. slopes of Shields 
Ridge. The top of the lower limestone unit crops out where the road 
crosses the summit. This locality yielded numerous trilobites to early 



16 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

collectors, and several of the fossils in the U.S. National Museum 
collections were used as types by Walcott and Resser (U.S.N.M. 
locality 120). In these early collections fossils from the Crepicephalus 
and Aphelaspis zones were indiscriminately mixed. Bridge (1956) 
gave a description of the section in which, however, many intervals 
were stated to be covered. His collection No. 2804, from which the 
new species Aphelaspis hridgei is described herein, was made at this 
locality. 

The general lithology of the Nolichucky is very similar to that 
described for the Rogersville Big Creek section. Thicknesses were not 
measured because of the unfavorable topography and incomplete expo- 
sures. The lower Nolichucky shale is followed by a massive limestone 
unit that bears fossils at least in its upper portion. Fossils of the 
Crepicephalus zone occur (loc. cnn/5) 30-40 feet below the top of the 
limestone (Tricrepicephalus thoosa, Meteoraspis sp.). However, the 
top of the massive limestone belongs in the Aphelaspis zone. Crystal- 
line lenses in aphanitic limestone in the uppermost 1 foot of the unit, 
as well as limestone lenses in the lower few feet of the overlying shale, 
yielded collection cns/2. The species observed are : 

* Aphelaspis arsoides c 

* Aphelaspis inertnis r 
Aphelaspis tumifrons cc 
Cheilocephalus, sp. undet. r 
PseudagnosHis communis r 

Comparison with the faunules of the Big Creek, Three Springs, and 
Washburn sections indicates that the above faunule is fairly high in 
the middle portion of the Aphelaspis zone. The U.S. National Museum 
collection 120 includes the types of Aphelaspis camiro, A. laxa, and 
A. quadrata which, as it appears from other evidence, are somewhat 
older than the species listed above. Collection 2804 of the U.S. Geo- 
logical Survey yielded the types of Aphelaspis hridgei, unknown from 
other localities. Its association with Blountia bristolensis and Glaphyr- 
aspis ornata, species that were found only in the basal beds of the 
Aphelaspis zone at other localities, shows that this collection was 
made from beds still lower than those yielding Aphelaspis camiro, A. 
laxa, and A. quadrata. Unfortunately, the portion of the massive lime- 
stone with interbedded shale intervals, from which all these fossils 
are presumed to come, is now poorly exposed and shows only apha- 
nitic, unfossiliferous beds. 

The massive limestone is overlain by 40 to 50 feet of shale, the lower 
portion of which contains the rare limestone lenses mentioned above. 
The shale is in turn overlain by the usual limestone ribboned with 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 17 

shale and dolomite. Its exposures are not extensive, and no fossils 
were observed. The contact with the Copper Ridge dolomite is exposed 
in a road cut on the S. slope of the ridge. 

Russell Gap. —The lower limestone unit of the Nolichucky is more 
favorably exposed where a dirt road crosses Shields Ridge at Russell 
Gap, in the SW. corner of the New Market quadrangle. The overlying 
shale is poorly exposed in a dip slope in the woods E. of the road. 
The uppermost limestone is partly exposed only in a ravine E. of the 
road. The best exposures of the fossiliferous upper portion of the lower 
limestone unit are located near the crest of the ridge in the woods NE. 
of the gap. Fossils were collected from the following beds in descend- 
ing order. 

Collection cnw/14. — Crystalline beds in lower portion (probably 
lower 10 feet) of upper limestone unit of the Nolichucky. 
These lower beds are predominantly calcareous, with little 
shale or dolomite : 
Aphelaspis tarda r 

*Dunderbergia tennesseensis r 

*Dytremacephalus angulatus c 

*Dytremacephalus sulcifrons rr 

Cheilocephalus hrachyops r 

Collection cnq/14. — Top 1-2 feet of lower limestone unit, under- 
lying the upper shale unit, about 40-50 feet below the pre- 
ceding collection. This and the underlying beds are massive, 
aphanitic limestone with crystalline lenses : 
Aphelaspis minor c 

Blountia bristolensis c 

Cheilocephalus brevilobus cc 

Glaphyraspis ornata r 

Collection cnp/14. — Massive limestone, about 3 feet below the 
preceding, hence 4-5 feet below top of lower limestone unit : 
* Aphelaspis lata c 

Blountia bristolensis cc 

Cheilocephalus brevilobus c 

Glaphyraspis ornata r 

Collection cno/14. — Massive limestone, 11 feet below top: 
Aphelaspis cf. lata (or buttsi) r 

Blountia bristolensis c 

Cheilocephalus brevilobus c 

Coosella perplexa c 

Glaphyraspis parva r 

Tricrepicephalus, sp. undet. r 

Collection cnn/14. — Massive limestone, 14 feet below top : 
Blountia, sp. undet. r 

Blountiella, sp. undet. r 

Coosia alethes r 

Coosina, sp. undet. r 



18 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Kingstonia inflata r 

Metearaspis, sp. undet. r 

Terranovella dorsalis r 

Tricrepicephalus thoosa c 

Collection cnw/14 belongs to the uppermost Aphelaspis zone of 
Tennessee, yielding an assemblage known from a number of sections. 
The middle portion of the faunizone may be represented in the poorly 
exposed shale unit. The underlying, massive limestone ofifers a re- 
markable transition from the Crepicephalus to the Aphelaspis zone 
within a few feet of beds. Collection cnn/14 contains a typical upper 
Crepicephalus zone assemblage. Collection cno/14, only 3 feet higher, 
still includes the typical Crepicephalus zone genera Coosella and Tri- 
crepicephalus, associated with Aphelaspis and Cheilocephalus. The 
specimens of Tricrepicephalus are too fragmentary to be specifically 
identifiable, but the generic characters of the pygidium are unmistak- 
able. An equivalent faunule was collected from the Three Springs 
section, where, however, Tricrepicephalus was not found. 

Lost Creek. — A partial section of the upper Nolichucky was studied 
in a recent road cut near the headwaters of Lost Creek, 0.2 mile W. of 
Tennessee Route 92, about 2 miles S. of Jefferson City. The lower, 
massive limestone unit is partly exposed and is overlain by alternating 
beds of shale, limestone, and limestone conglomerate. The exposed 
section barely reaches the base of the uppermost limestone unit of the 
Nolichucky. Notwithstanding the limited exposure, this locality yielded 
a number of faunules in clear relative stratigraphic order. The section 
is described below. 

Thickness 
Feet Inches 

13. Limestone : massive, crystalline, banded with dolomite 2 4 

12. Shale, with small scattered limestone lenses 12 

Collection cnt/4, 0-2 feet above base : 
Aphelaspis arsoides c 

Aphelaspis tumifrons cc 

Dytremacephalus angulatus rr 

Pseudagnostus communis r 

11. Limestone : crystalline, one bed 1 

10. Shale, with scattered limestone lenses 8 

Collection cns/4, 3-4 feet above base : 
Aphelaspis inermis c 

Aphelaspis arses c 

Aphelaspis cainiro r 

Aphelaspis laxa r 

Cheilocephalus, sp. undet. r 

Pseudagnostus commtmis r 

9. Limestone: coarsely granular, with insoluble stringers; 

one bed 1 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 19 

Thickness 
Feet Inches 

8. Shale 5 

7. Limestone : massive, coarsely granular, with siliceous stringers 3 6 

6. Shale, with thin limestone beds 2 6 

Collection cnr'/4 in limestone bed at top : 

Aphelaspidella macropyge 
Collection cnr/4 in limestone bed at base : 
Aphelaspis arses r 

Aphelaspis cf. lata r 

* Aphelaspidella macropyge c 

Cheilocephalus, sp. undet. r 

Paraphelaspis vigilans r 

5. Limestone : coarsely granular, one bed 2 

4. Shale 2 

3. Limestone pebble conglomerate : one bed 10 

2. Shale, with limestone lenses and thin beds, especially in 

upper portion 18 

Collection cnq"/4 at top : 

Aphelaspis cf. rotundata 
Collection cnq'/4, 13 feet above base : 

Aphelaspis cf. laxa 
Collection cnq/4 in a limestone bed 8 feet above base : 

Aphelaspis walcotti 
Collection cnn/4 in 1-inch limestone bed, 6 inches 
above base : 
Coosia alethes c 
Crepicephalus, sp. undet. No. 1 r 
Maryvillia arion c 
Tricrepicephalns thoosa c 
1. Limestone: massive, granular, aphanitic, or oolitic, poorly 
bedded, with tan-weathering siliceous stringers ; incom- 
pletely exposed 60+ 

Although this section is in the same outcrop belt as the Piedmont 
Road and Russell Gap sections, it shows several differences. Here the 
Crepicephalus zone includes all the lower, massive limestone unit and 
extends a few feet above it. The overlying shale has much more inter- 
bedded limestone. The earliest Aphelaspis zone faunule with Aphelas- 
pis walcotti is younger than the earliest faunules observed in the 
Russell Gap, Three Springs, Washburn, and Hurricane Hollow sec- 
tions. 

UNION COUNTY 

Hurricane Hollow. — A section of the upper portion of the Noli- 
chucky is exposed along the Hurricane Hollow embayment of Norris 
Reservoir ( Maynardville quadrangle) and was measured by Dr. C. R. 
L. Oder, who showed it to the writer. The strata are exposed both 
in the road cut and along the shores on both sides of the embayment. 



20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Dr. Oder measured his section in the road cut, whereas the more 
interesting fossils were found on the E. shore of the embayment, 
where the writer measured a partial section. Difficulty was experienced 
in correlating the road-cut section with the shore section, since the 
strata could not be accurately traced through the intervening area. 
However, all the fossils discussed herein were collected by Dr. Oder 
and the author from the shore beds in unquestionable stratigraphic 
order. The beds dip 25°-30° S. The section in descending order fol- 
lows, beginning with the highest Hmestone beds below the dolomite. 

Thickness 
Feet Inches 

12. Limestone : weathering blue-gray, mostly very massive, at 

top and bottom thin-bedded, in part dolomitic 20 

11. Limestone: very massive, mottled with dolomite, weather- 
ing to rough surfaces 14 

10. Limestone : thin-bedded, aphanitic, with tan-weathering 

partings, weathering to smooth, blue-gray surfaces 6 

9. Limestone: crystalline, massive, with insoluble stringers 

weathering in relief 18 

8. Shale and thin-bedded limestone 2 

Collection cnr717 (= Oder's coll. No. 2) : 
Aphelaspis walcotti 
Blountia mimula 
*Glaphyraspis declivis c 

*Glaphyraspis oderi c 

7. Limestone : crystalline, massive, weathering blue-gray ; 

basal part weathering to spongy residue 2 6 

6. Limestone: massive, mottled with dolomite, weathering to 
rough surfaces ; in lower part with regular, insoluble 

stringers 10 

5. Shale, with Hmestone nodules 1 4 

4. Limestone: massive, mottled with dolomite, weathering to 

rough surfaces 6 

3. Shale, with limestone lenses and nodules 8 

Collection cnr/17, 2 feet below top : 
Aphelaspis, sp. undet. 
2. Limestone and shale: Hmestone in thin, partly lenticular 

beds ; interval grades eastward to almost pure limestone . . 7 

Collections cnq/17, 2J^ feet above base : 
* Aphelaspis minor c 

Glaphyraspis ornata r 

1. Limestone: mostly crystalline, massive, with a few thin- 
bedded intervals. Base of unit forms bottom of ravine 

on lake shore 18 

Collection cnp/17 in thin limestone bed at top : 
*Aphelaspis transversa c 

Blountia hristolensis c 

Cheilocephalus brevilobus r 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 21 

Collection cnn/17, in massive limestone beds 5-8 feet 
below top : 
Coosia, sp. undet. 
Crepicephalns, sp. undet. 
Tricrepicephalus, sp. undet. 

The section extends into lower beds of similar lithology, with alter- 
nating massive and thin-bedded limestones and shale, the latter becom- 
ing more prevalent downward. Occasional very fragmentary fossils 
of the Crepicephalus zone were seen in this lower, unmeasured portion 
of the section. 

This section, like the ones at Three Springs and Russell Gap, is 
interesting for offering an Aphelaspis faunule a few feet above a 
typical Crepicephalus zone faunule. The earliest Aphelaspis here is a 
new species, A. transversa, closely related to A. buttsi and A. lata 
which are the first to appear in the two above-mentioned sections. 

CLAIBORNE COUNTY 

Comby Ridge. — An interesting fossil locality occurs where U.S. 
Route 25-E crosses Comby Ridge (Howard Quarter quadrangle). On 
the E. side of the road and creek, the lower part of the Nolichucky 
formation consists of shale with numerous limestone beds and lenses. 
One such lens collected by Dr. Gunnar Henningsmoen and Dr. Robert 
B. Neuman yielded fossils of the Cedaria zone, some of which are 
illustrated herein. The author found further fossiliferous beds, in 
addition to collecting from the above-mentioned lens. Unfortunately, 
the exposures are poor and some of the fossiliferous lenses are weath- 
ered out of the shale, hence their stratigraphic order is not always 
certain. Lenses or beds believed to occur in ascending order were 
labeled cnb/10, cnd/10, and cne/10. There is a considerable thickness 
of shale underlying these fossiliferous beds but overlying the Mary- 
ville limestone. 

The fossils are for the most part extremely fragmentary in a coarse- 
grained calcarenite. The following faunules were observed. 



Collection cne/10 : 




Cedaria tennesseensis 


c 


Kormagnostus simplex 


r 


Menomonia, sp. undet. 


r 


Norzvoodella walcotti 


cc 


Collection cnd/10 : 




Ankoura triangularis 


r 


Kormagnostus simplex 


c 


Norwoodella halli 


c 


Norwoodella walcotti 


r 



22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Collection cnb/10 : 

Ankoura triangularis c 

Kormagnostus simplex r 

Olenoides, sp. undet. r 

River Ridge. — A section of the uppermost part of the Nolichucky 
formation (Maynardville limestone member) was measured in a deep 
cut on the W. side of U.S. Route 25-E where it crosses River Ridge, 
a short distance N. of the bridge on the Clinch River (Howard Quar- 
ter quadrangle). At the top of the measured section are readily recog- 
nizable, massive beds of dolomite that may be considered the base of 
the Copper Ridge dolomite. 

Thickness 
Feet 

14. Dolomite : mottled, weathering to rough surface. This bed is almost 
at top of exposures on west side of road ; higher beds exposed on 

east side 3 

13. Dolomite : thick-bedded, weathering to smooth surface. This and the 

overlying unit may be referred to the Copper Ridge dolomite 6 

12. Shale 2 

11. Dolomite, one bed 2 

10. Shale: dark gray, hard, not fissile, with some interbedded dolomite 

but very little limestone 7Z 

9. Shale : dark gray, fissile 5 

8. Shale : as unit 10, but containing thin limestone beds and lenses 18 

Collection cnv/21, 10 feet above base : 
Aphelaspis tarda c 

Collection cnu/21, 4 feet above base : 
Aphelaspis tarda c 

7. Shale : dark gray, fissile, with one limestone bed in middle of interval .... 3 
6. Shale, alternating with thin-bedded limestone; more shaly in upper 

5 feet 22 

Collection cnu'/21, in limestone bed at top : 
Aphelaspis tarda 

5. Shale : finely fissile 3 

4. Limestone, ribboned with shale or dolomite 5 

3. Shale, finely fissile. Thickness approximate 20 

2. Limestone, ribboned with shale or dolomite 3j4 

1. Shale: finely fissile, only the uppermost portion exposed. Thin lime- 
stone lenses present 20-25 feet below top not measured 

Collection cnt/21 in limestone lenses : 
Aphelaspis arsoides c 

Aphelaspis tumijrons c 

Pseudagnostus communis c 

KNOX COUNTY 

Copper Ridge. — Numerous Upper Cambrian fossils in the U.S. 
National Museum collections were recovered from beds of the Ce- 
daria, Crepicephalus, and Aphelaspis zones on the NW. slope of Cop- 
per Ridge near Bull Run, south of Heiskell (Powell quadrangle). 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 23 

This area appears to offer now neither the opportunity for measuring 
good sections, nor plentiful fossils. A partial section of the Noli- 
chucky is exposed in the cut of the Southern Railway, and some of 
the material of Norivoodella walcotti illustrated herein was collected 
at this locality (cnd/12). The fossils occurred in thin limestone beds 
in shale, and their stratigraphic position could not be referred to 
readily recognizable lithic units. 

Mascot. — A partial section of the Nolichucky formation is exposed 
in a road cut on the E. side of the road leading N. from Mascot to U.S. 
Route 11-W. The lower limestone unit of the Nolichucky and some 
of the overlying shale with thin-bedded, partly conglomeratic limestone 
beds are exposed. Fossils of the Crepicephalus zone were collected 
from limestone beds in shale about 5 feet above the top of the massive 
limestone (loc. cnn/19). 

MONROE COUNTY 

Owing to flat topography, exposures are generally scarce in the 
southwestern portion of the area investigated. A partial section of the 
Nolichucky formation was studied by A. R. Palmer and R. H. Ray- 
mond in the bluffs on the E. bank of the Little Tennessee River, near 
the E. end of the bridge on U.S. Route 411, Two trilobite collections 
were made. Collection U.S.G.S. 2970 is from a single bed at the top 
of a 38-foot unit of thin-bedded, knobbly limestone ; collection 2969 
is from weathered siltstone about 45 feet higher. The author was able 
to find only fossils of the upper Aphelaspis zone in the higher beds. 

The U.S. Geological Survey collections are interesting because they 
include 3 species not observed elsewhere. The list of species follows. 

Collection 2969 : 

Dytremacephalus angulatus (complete specimens) 
Collection 2970 : 

Aphelaspidella macropyge 

Aphelaspis arses 
* Aphelaspis palmeri 

Cheilocephalus, sp. undet. 
*Dunderbergia longifrons 
*Dytremacephalus strictus 

Paraphelaspis vigilans 

Collection 2970 may be correlated with collection cnr/4 from the 
Lost Creek section and collection cns/20 from the Washburn section, 
having in common with both Aphelaspidella macropyge, Aphelaspis 
arses, Cheilocephalus sp. undet., and Paraphelaspis vigilans. Thus the 
stratigraphic position of the three new species, Aphelaspis palmeri, 
Dimderbergia longifrons, and Dytremacephalus strictus, is at least 
approximately determined in the middle Aphelaspis zone. 



24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

PURCHASE RIDGE, SCOTT COUNTY, VIRGINIA 

Although the section here discussed is outside of Tennessee, it was 
deemed worth mentioning because it is close to the State line, and 
occurs in the northernmost Cambrian outcrop belt in this portion of 
the Appalachians. 

Most of the Maryville and Nolichucky formations are exposed in 
cuts on the road from Pattonsville to Clinchport, Scott County (Duf- 
field quadrangle). The Nolichucky formation is mostly shale excepting 
the upper (Maynardville) limestone unit. The contact with the Copper 
Ridge dolomite is not well exposed. A partial section of the strata 
of the Aphelaspis zone in descending order follows. 

Thickness 
Feet Inches 
11. Limestone: in thin, often nodular beds, mostly aphanitic, 

ribboned with shale or dolomite 75 + 

10. Limestone: similar to unit 11, but more readily weather- 
ing to separate layers 13 

Collection cnv77, one foot below top : 
Aphelaspis tarda c 

9. Shale, with some limestone lenses 3 

Collection cnv/7, 1 foot above base : 
Aphelaspis tarda c 

8. Limestone : thin-bedded, alternating with shale 10 

7. Shale 1 4 

6. Limestone: crystalline, one bed filled with trilobite frag- 
ments 5 

Collection cnu/7 : 
Aphelaspis tarda cc 

Dunderbergia tennesseensis r 

5. Shale, with a few, thin limestone beds 6 

4. Limestone : thick-bedded 2 

3. Shale, with thin limestone beds 5 

2. Limestone : one bed 1 6 

1. Shale, with some siltstone and limestone beds. Seemingly 
several hundred feet thick and extending to limestones 

of basal Nolichucky not measured 

Collection cnt/7 from thin limestone lens 10 feet 
below top : 
Aphelaspis tumifrons cc 

Pseudagnostus communis c 

The upper (Maynardville) limestone unit of the Nolichucky shows 
the same lithology and faunal succession of the upper Aphelaspis zone 
as in the Big Creek section. Fossils of the lower Aphelaspis zone could 
not be found because of the unfavorable shaly lithology of the interval. 
The massive lower limestone of the Nolichucky present in many other 
sections is here lacking or greatly reduced. In most respects the lithol- 
ogy of the Nolichucky is very similar to that described by Hall and 
Amick (1934) for the Thorn Hill section. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 25 

INDEX OF LOCALITIES 
CEDARIA ZONE 

Collection Quadrangle x y County Name of locality 

cnc/1 Burem 325 435 Hawkins U.S. Route 11-W 

cnc/2 " 179 318 " Big Creek 

cnc/3 " 172 312 " Big Creek 

cnc/4 " 168 306 " Big Creek 

cnc/5 " 161 299 " Big Creek 

cnc/6 " 61 181 " Rogersville 

cnc/7 " 437 497 " Forgey Creek 

cnd/1 " 327 436 " U.S. Route 11-W 

cnd/2 " 343 442 " Miller Ridge 

cne/1 " 179 318 " Big Creek 

cne/2 " 168 306 " Big Creek 

cnb/10 1 

cnd/10 I Howard Quarter 16 151 Claiborne Comby Ridge 

cne/10 J 

cne/1 2 Powell 249 248 Knox Copper Ridge 

cne/13 Avondale 227 560 Grainger Thorn Hill 

U.S.G.S. 2407 . . . Howard Quarter = cnd/10 Claiborne Comby Ridge 

U.S.G.S. 2406 . . . " " = cnb/10 " Comby Ridge 

CREPICEPHALUS zone 

Collection Quadrangle x y County Name of locality 

cnk/1 Burem 68 171 Hawkins Rogersville 

cnk/3 " 172 295 " Big Creek 

cnm/3 }••••" 5^ 165 " Rogersville 

cnn/1 " 68-73 171-174 " Big Creek 

cnn/2 " 13 127 " Rogersville 

cnn/3 Pressmens 

Home 367 52 " Crockett Creek 

cnn/4 Jefferson City 91 408 Jefferson Lost Creek 

cnn/5 New Market 295 237 " Piedmont Road 

cnn/14 " " 140 191 " Russell Gap 

cnm/15 \ .Russellville 305 260 Hamblen Three Springs 
cnn/1 5 J 

cnn/16 Luttrell 353 270 Grainger Smith Hollow 

cnn/17 Maynardville 50 129 Union Hurricane Hollow 

cnn/19 Mascot 14 403 Knox Mascot 

cnm/20 1 

cnm720 \ Dutch Valley 98 266 Grainger Washburn 

cnn/20 J 

APHELASPIS ZONE 

Collection Quadrangle x y County Name of locality 

cns/l-cnx/1 Burem 180-183 290-296 Hawkins Big Creek 

cns/2 New Market 292 235 Jefferson Piedmont Road 

cnq/4-cnt/4 Jefferson City 91-94 411 " Lost Creek 

cnt/7-cnv/7 Duffield, Va. 194 277 Scott Purchase Ridge 



26 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 



cno/14-cnq/14 . . . 


, .New Market 


13&-141 


190-193 


Jefferson 


Russell Gap 


cnw/14 


i( <i 


142 


188 


" 


Russell Gap 


cno/15-cnv/15 . . , 


, .Russellville 


305-312 


260-257 


Hamblen 


Three Springs 


cnq/16-cns/16 . . . 


.Luttrell 


354 


271 


Grainger 


Smith Hollow 


cnp/17-cnr/17 . . . 


.Maynardville 


50 


129 


Union 


Hurricane Hollow 


cnp/20-cnx/20 . . 


. Dutch Valley 


98 


266-263 


Grainger 


Washburn 


cnt/21-cnv/21 . . . 


. Howard 












Quarter 


137 


141-139 


Claiborne River Ridge 


U.S.G.S. 2969-70 


. Vonore 


144 


481 


Monroe 


Little Tennessee 
River 



FAUNA OF THE CEDARIA ZONE 
Fossils of the Cedaria zone occur in the uppermost portion of the 
Maryville limestone (only in the Roger sville area) and in the basal 
part of the Nolichucky formation. At all the localities studied, an un- 
fossiliferous interval in the Nolichucky shale separates the uppermost 
beds carrying a Cedaria fauna from the lowermost beds holding a 
Crepicephalus zone fauna. Hence assemblages transitional between 
the two faunizones, as reported by Lochman and Duncan (1944) 
from Montana and Palmer (1954) from Texas, have not been ob- 
served. 

The oldest Upper Cambrian faunule seems to be the one occurring 
in the uppermost 10-30 feet of the Maryville limestone in the Rogers- 
ville outcrop belt. The corresponding interval was examined at several 
other localities but yielded no fossils. Collections were made at several 
localities in the vicinity of Roger sville (author's collections cnc/1 to 
cnc/7; U.S.N.M. localities 102a, 123a). The species known from these 
beds are listed below. An asterisk preceding the name indicates that 
the types were collected from this area and horizon. 

*Bonneterrina appalachia 
*Coenaspis spectabilis 
*Coosella andreas 

Genevievella, sp. undet. 
*Hawk{nsia minuta 
*Holcacephalus praecursor 

Ithycephalus typicalis 

Kormagnostiis simplex 
*Menomonia tuberculata 

Menomonia, sp. undet. 
*Modocia crassimarginata 

Modocia dubia 
*Modocia ? agatho 

N orwoodella, sp. undet. 

Norwoodia, sp. undet. 

Tricrepicephalus, sp. undet. 

The next higher faunule is especially well represented in the red 
limestone beds at the base of the Nolichucky, of very limited extent 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 27 

in the Rogersville area as previously discussed (author's localities 
cnd/1, cnd/2; U.S.N.M. locality 27d). The faunule from these beds, 
excluding a few unrecognizable forms named by Resser, includes : 

*Ankoura triangularis 

Bonneterrina appalachia 

Cedarina, sp. undet. 
*Coosella resseri 

Genevievella, sp. undet. 
*Holcacephalus granulatus 
*Ithycephalus typicalis 
*Kormagnostus simplex 
*Loxoparia obliqua 
*Menomonia prominens 
*Modocia bidentata 

Modocia crassimarginata 
*Modocia dubia 

Nonvoodella saffordi 
*Norzvoodella rotundicollis 
*N orwoodia rogcrsvillensis 

Tricrepicephalus, sp. undet. 

In the equivalent stratigraphic position in other parts of the Rogers- 
ville outcrop belt, the basal beds of the Nolichucky consist of the usual 
gray-green shale with rare lenses of crystalline limestone (author's 
localities cne/1, cne/2; U.S.N.M. localities 103, 124). The species 
collected from these beds include : 

Genevievella, sp. undet. 
Kormagnostus simplex 
Menomonia prominens 
*Norwoodella saffordi 

Outside of the immediate vicinity of Rogersville, fossils of the 
Cedaria zone occur in Tennessee chiefly in the northwestern portion 
of the Cambrian outcrop area, in the belts N. of Clinch Mountain 
from Forked Deer Creek (Thorn Hill section) to Heiskell W. of 
Knoxville. Trilobites occur at scattered localities, usually either in 
shale or in a coarse, glauconitic calcarenite where most of the tests 
have been ground to unrecognizable fragments. Very little information 
about the faunal succession can be determined from these occurrences. 
Species collected from several localities are listed below. 

Seemingly the oldest Upper Cambrian fossils occur in U.S.G.S. 
collection 2406 (= author's collection cnb/10), where the following 
species were identified : 

Ankoura triangularis 
Kormagnostus simplex 
Olenoides, sp. undet. 



28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

The most striking fossil is the Olenoides, unfortunately known only 
from fragmentary pygidia. Notwithstanding the presence of this pre- 
dominantly Middle Cambrian genus, the abundance of Ankoura and 
Kormagnostus suggests about the same age as the red beds at the base 
of the Nolichucky in the Rogersville area. 

Faunules collected from the Comby Ridge localities (end/ 10 =: 
U.S.G.S. collection 2407, cne/10). Thorn Hill (cne/13), and Copper 
Ridge (cne/12) yielded: 

Ankoura triangularis 
Cedaria temiesseensis 
Kormagnostus simplex 
Menomonia, sp. undet. 
Norwoodella halli 
Norwoodella walcotti 

This faunule is presumably somewhat younger than any of those 
of the Cedaria zone collected from the vicinity of Rogersville. 

FAUNA OF THE CREPICEPHALUS ZONE 

In all the sections studied, an unfossiliferous interval separates the 
youngest observed faunule of the Cedaria zone from the oldest fossils 
of the Crepicephalus zone. The lower and middle portions of the Noli- 
chucky formation are in general sparingly fossiliferous, being repre- 
sented either by shales with siltstone beds, or in part by the massive 
lower limestone member. Only when either the shales contain fairly 
pure, crystalline limestone layers, or the massive limestone is partly 
replaced by a thin-bedded limestone, may well-preserved fossils be 
expected. These conditions occur erratically at different localities, 
hence a single section seldom supplies a succession of several faunules, 
and it is difficult to place those collected in different areas in proper 
stratigraphic order. In general, the beds of the Crepicephalus zone 
become more fossiliferous upward, the richest in most sections being 
those that just underlie the Aphelaspis zone. 

Probably the earliest fossils of the Crepicephalus zone collected in 
the area are those from near the base of the lower limestone member 
occurring in the vicinity of Rogersville (collections cnk/1, cnk/3). 
The species include : 

*Blountia alexas 

Blountia montanensis 
*Coosella planicauda 

Coosella, sp. undet. 
*Crepicephalus convergens 

Dreshachia amata 
*Kingstonia inflata 

Maryvillia arion 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 29 

*Meteoraspis brevispinosa 
Tricrepicephalus thoosa 
Undetermined cranidium No. 2 

Most of these species are represented in higher beds except Blountia 
alexas and Meteoraspis brevispinosa, which were not found in the 
highly fossiliferous, higher portions of the same limestone unit. Mary- 
villia arion is very rare in the above faunule, whereas it becomes 
abundant in higher beds. 

A rather large faunule was collected near Rogersville, a short dis- 
tance from locality cnk/1, in beds approximately 45 feet below the top 
of the lower limestone unit of the Nolichucky, hence about 90 feet 
above the beds cnk/1. At other localities no fossils were observed at 
this horizon. The faunule (collection cnm/2) includes : 

Blountia arcuosa 
Blountia montanensis 
Coosella planicauda 
Coosia alethes 
Coosina amage 
Coosina ariston 
Dresbachia amata 
Kingstonia inflata 
Llanoaspis walcotti 
Madarocephalus laetus 
Maryvillia arion 
Meteoraspis mutica 
Tricrepicephalus thoosa 

Finally, the youngest faunule of the Crepicephalus zone is well rep- 
resented at numerous localities. It occurs either near the top of the 
massive lower limestone unit of the Nolichucky, or in thin limestone 
beds near the base of the overlying shale. The transition between the 
Crepicephalus and Aphelaspis zones may occur either within the upper 
portion of the limestone unit, or within the lower part of the overlying 
shale. In some sections, such as at Big Creek, it is possible that the 
faunizone boundary coincides with the lithologic contact. The species 
observed at localities cnn/1, cnn/2, cnn/3, cnn/4, cnn/5, cnn/14, 
cnn/15, cnn/16, cnn/17, cnn/19, and cnmV20 are listed below. These 
collections are lumped together, since age differences between them 
appear insignificant. 

Amiaspis erratica 
*Amiaspis obsolescens 
* Blountia arcuosa 

Blountia lata 

Blountia montanensis 

Blountiella, sp. undet. 

Coosella, sp. undet. 



30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

*Coosia alethes 

Coosia robusta 

Coosia, sp. undet. 

Coosina ariston 

Coosina, sp. undet. 

Crepicephalus buttsi 

Crepicephalus cf. convergens 

Crepicephalus cf. scissilis 

Crepicephalus, sp. undet. No. 1 

Crepicephalus, sp. undet. No. 2 

Kingstonia inflata 

Llanoaspis walcotti 
*Maryvillia arion 

Meteoraspis mutica 

Meteoraspis, sp. undet. 

Pemphigaspis, sp. undet. 

Terranovella dorsalis 
* Tricrepicephalus thoosa 

Undet. cranidium No. 1 

Fossils from the U.S.N.M. localities 24m, 104, 121a, 123b, 125 and 
125a were certainly all collected in the Rogersville area from the 
lower limestone member of the Nolichucky formation, hence from the 
horizons here designated cnk, cnm, and cnn. 

FAUNA OF THE APHELASPIS ZONE 
The faunal succession in the Aphelaspis zone is particularly well 
developed in Tennessee and was studied in great detail in several 
sections. 

At some of the localities there is no gap in fossiliferous beds between 
the Crepicephalus and Aphelaspis zones, hence the change from one 
fauna to the other could be thoroughly investigated. It was shown in 
the preceding section that the latest Crepicephalus zone faunule is 
characterized by species of Coosia, Crepicephalus, Tricrepicephalus, 
Blountia, and Kingstonia, in addition to Maryvillia arion and Terra- 
novella dorsalis. Other genera, such as Amiaspis and Llanoaspis, are 
occasionally present. At Russell Gap, a faunule that is considered to 
belong in the Aphelaspis zone appears about 3 feet above the typical 
Crepicephalus fauna, in a succession of massive limestone beds of 
uniform lithology. This basal Aphelaspis zone faunule (loc. cno/14) 
yielded several species of trilobites representing a holdover of Cre- 
picephalus zone forms with the addition of new elements, which had 
certainly evolved elsewhere since no possible immediate ancestors 
occur in the local Crepicephalus fauna. The Crepicephalus zone genera 
Tricrepicephalus, represented by an undetermined species, and 
Coosella, represented by Coosella perplexa, are associated with the 
typical Aphelaspis zone forms Aphelaspis cf. A. lata and Cheilocephalus 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 31 

brevilobus. Further members of the faunule are Blountia bristolensis 
and Glaphyraspis parva. Blountia bristolensis was not found in the 
Crepicephalus zone but is there represented by the very similar 
Blountia montanensis. Glaphyraspis was not found in Tennessee below 
the Aphelaspis zone. However, the author collected cranidia attributed 
to G. parva in a late Crepicephalus zone faunule from northeastern 
Virginia (Rasetti, 1961). 

In the Hurricane Hollow section, also, an interval of a few feet 
separates the uppermost Crepicephalus zone faunule from the earliest 
Aphelaspis zone faunule in a uniform succession of massive limestone 
beds. Here, however, the only remnant of the Crepicephalus fauna is 
the genus Blountia, represented again by B. bristolensis. It is asso- 
ciated with Aphelaspis transversa and Cheilocephalus brevilobus. 

The transition between the two faunizones is excellently shown in 
the Three Springs section. Here the rock at this level is mostly shale 
with thin fossiliferous limestone beds and lenses. The earliest Aphel- 
aspis zone faunule (loc. cno/15) is essentially the same as at Russell 
Gap, holding in great abundance Aphelaspis buttsi and Glaphyraspis 
parva, with rare specimens of Coosella perplexa. 

At all these localities, Coosella is absent from higher beds, while 
Blountia and Glaphyraspis continue in association with different species 
of Aphelaspis. In this portion of the section faunal changes may occur 
within a few feet of beds, and very accurate determinations of the rela- 
tive positions of beds and lenses are required to avoid mixing forms 
that do not occur together. In the field every single lens was labeled 
separately and its stratigraphic position carefully recorded. In the 
Russell Gap and Three Springs sections, a characteristic faunule (Iocs. 
cnp/14, cnp/15) including innumerable remains of Aphelaspis lata, 
a close relative of A. buttsi, occurs a few feet above the faunule de- 
scribed above. Associated species are Blountia bristolensis, Cheiloce- 
phalus brevilobus, and Glaphyraspis ornata. This faunule is well 
represented also in the Washburn section (loc. cnp/20) . 

In the Three Springs section, in a thin bed 1 foot higher, Aphelaspis 
walcotti appears in association with A. lata. This is an unusually early 
occurrence of that species which is more common in higher strata. 
Still 6 inches higher, another species of Aphelaspsis, A. minor, makes 
its appearance in the Three Springs section and is also common in the 
equivalent position in the Russell Gap and Hurricane Hollow sections 
(Iocs, cnq/15, cnq/14, cnq/17). Associated forms, as in the under- 
lying faunule, are Blountia bristolensis, Cheilocephalus brevilobus, and 
Glaphyraspis ornata. 

The next higher faunule, known from a number of sections, is char- 
acterized by Aphelaspis walcotti, the t3^e species of the genus. The 



32 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

stratigraphic position of the type collection from Saltville, Va., is un- 
known, but in Tennessee the species was found to occur always in the 
same relative position to other forms of Aphelaspis, excepting the un- 
usually early occurrence mentioned above. It was collected at Three 
Springs (cnr/15), Smith Hollow (cnq/16, cnr/16), Lost Creek 
(cnq/4), Hurricane Hollow (cnr/17 = Oder's coll. No. 2), and 
Washburn (cnq/20). Associated species are Glaphyraspis declivis, 
G. oderi, and Blountia mimula, the last found only at Hurricane Hol- 
low. 

This is the latest known occurrence of Blountia in Tennessee. In 
view of this fact and other faunal changes, it seems proper to designate 
the strata so far discussed as the lower portion of the Aphelaspis zone. 

The overlying beds, here assigned to the middle Aphelaspis zone, 
hold various faunules characterized by several species of Aphelaspis 
and related genera. These assemblages do not appear exactly in the 
same order in the different sections, hence we may assume that they 
are essentially of the same age. In the Washburn section, the earliest 
of these faunules (collection cnqV20) consists of Aphelaspis wash- 
burnensis and Glaphyraspis declivis. This is followed by an assem- 
blage of Aphelaspis camiro, A. laxa, and A. quadrata, recognized at 
several localities (U.S.N.M. locality 120, Shields Ridge; cns/15, 
cnsV15, Three Springs; cns/16 (= Oder's collection No. 13), Smith 
Hollow; cnr/20, cnrV20, Washburn). The Washburn section yields 
from somewhat higher beds (cns/20) a very characteristic assemblage 
of Aphelaspidella macropyge, Aphelaspis arses, A. rotundata, and 
Paraphelaspis vigilans. 

However, at Lost Creek we encounter in ascending order a bed with 
rare Aphelaspis cf. laxa (cnqV4), followed by one with A. rotundata 
(cnq'V4). Above the latter are Hmestone beds (cnr/4, cnrV4) with 
an abundance of Aphelaspidella macropyge, accompanied by Aphelaspis 
arses, Aphelaspis cf. lata, Cheilocephalus sp., and Paraphelaspis vigi- 
lans. The still higher beds cns/4 yielded rare Aphelaspis camiro and 
A. laxa, in addition to other species to be mentioned later. In the Three 
Springs section, above a bed (cnr'/lS) with Aphelaspis laxa, collec- 
tion cns/15 yielded Aphelaspis camiro, A. laxa, A. quadrata, A. wash- 
burnensis, and Aphelaspis, sp. undet. (the last two not associated in 
the same stratum with the other three). The still higher beds ens VI 5 
and cns'VlS yielded Aphelaspidella macropyge, Aphelaspis arses, A. 
rotundata, and Paraphelaspis vigilans. These findings indicate that al- 
though the Aphelaspis camiro-laxar-quadrata and the Aphelaspidella 
macropyge-Aphelaspis rotundata-Paraphelaspis vigilans assemblages 
were never observed in the same bed, each may occur either below or 
above the other. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 33 

An approximate equivalent of the last-mentioned assemblage is the 
one collected from Monroe County (U.S.G.S. collection 2970) with 
Aphelaspidella macropyge, Aphelaspis arses, A. palmeri, Cheiloceph- 
alus, sp., Dunderbergia longifrons, Dytremacephalus strictus, and 
Paraphelaspis vigilans. 

In Jefferson County, lenses at the previously mentioned locality 
cns/4 also yield Aphelaspis arses and A. inermis, both also present in 
collection cns/2, accompanied by Cheilocephalus sp. and Pseudagnostus 
communis. 

Above these faunules appears a widespread assemblage characterized 
in all sections where it is known by innumerable examples of Aphel- 
aspis tumifrons. It was collected from Big Creek (cns/1, cnt/1), Lost 
Creek (cnt/4), Shields Ridge (cns/2), Three Springs (cnt/15, 
cntVlS), Smith Hollow (Oder's coll. No. 14), Washburn (cnt/20, 
cnt720), River Ridge (cnt/21), and Purchase Ridge, Va. (cnt/7). 
Here should be mentioned the exceptional occurrence at Lost Creek 
in the collection cnt/4 of very rare specimens of Dytremacephalus 
angulatus, a species that becomes common in strata of the upper 
Aphelaspis zone. Normal associates of Aphelaspis tumifrons are in- 
stead Aphelaspis arsoides, Cheilocephalus sp., and Pseudagnostus 
communis. 

The beds above the Aphelaspis tumifrons faunule and up to the top 
of the fossiliferous sequence, i.e., to the top of the Nolichucky forma- 
tion (or Maynardville limestone), shall be assigned to the upper 
Aphelaspis zone. One faunule seems to occupy this interval, covering 
in the Big Creek section about 70 feet of strata, and the characteristic 
species are Aphelaspis tarda and Dytremacephalus angulatus. Less 
frequent and widespread are Aphelaspis punctata, Cheilocephalus 
hrachyops, Dunderbergia tennesseensis, and the rare Dytremacephalus 
sulcifrons. This Aphelaspis tarda faunule was collected at Big Creek 
(cnu/1, cnv/1, cnw/1, cnx/1). Purchase Ridge (cnu/7, cnv/7, 
cnvV7), Russell Gap (cnw/14). Three Springs (cnu/15, cnv/15), 
Smith Hollow (Oder's coll. No. 14A), Washburn (cnw/20, cnx/20), 
and River Ridge (cnu/21, cnv/21 ) . 

In Tennessee all the higher fossiliferous beds of the Nolichucky, up 
to the top of the formation, have been assigned to the Aphelaspis zone, 
since the faunules are very homogeneous, being dominated by species 
of Aphelaspis. However, the younger of these faunules may be equiva- 
lent to faunules attributed by Palmer to post- Aphelaspis zones in the 
western sections (see later discussion). 

It seems likely that the vertical distribution of genera and species 
described above does not mean that each species only lived for the short 
time span indicated by the thickness of beds through which it was 



34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

collected. Two examples, the presence of Aphelaspis cf. lata at an un- 
usually high horizon in collection cnr/4, and the early occurrence of 
Dytremacephalus angulatus in collection cnt/4, probably indicate that 
while at a given locality each species was abundant for only a very 
limited time, it may have lived at different times at other places. The 
inversion of the order of the Aphelaspis camiro and Aphelaspis rotun- 
dafa assemblages, observed in two sections, even though it does not 
involve a considerable thickness of strata, is another indication that 
the presence or absence of a species at a certain level may have little 
time significance, being determined rather by some ecologic factor, or 
simply a historical accident. 

Even considering these restrictions to its validity, it is clear that 
the above-discussed succession of Aphelaspis faunules is the best docu- 
mented in the entire Cambrian of the Appalachians and may allow the 
stratigrapher to correlate new sections with great precision. As it will 
be pointed out in the discussion of Aphelaspis, a species of that genus 
may not be identifiable from a single individual, even if perfectly pre- 
served, much less from weathered or flattened material. Fortunately, 
however, the strata of the Aphelaspis zone, and especially thin, crystal- 
line limestone lenses in shale, may be so fossiliferous that a small 
sample of rock in many cases supplies sufficient information for the 
clear recognition of one of the faunules described herein. 

In view of the relatively meager knowledge of the biostratigraphy of 
the Aphelaspis zone in North America and of the observed transition 
between the Crepicephalus and Aphelaspis faunas, a comparison with 
recent findings in other areas is of interest. A detailed study of the 
distribution of genera and species of trilobites near and above the 
Crepicephalus-Aphelaspis zone boundary was made by Palmer ( 1954, 
1962b) in Alabama, central Texas, and Nevada. His main conclusions, 
derived from the study of the faunal succession in the Conasauga 
formation at Woodstock and Cedar Bluff, Ala., and in the uppermost 
part of the Hamburg limestone and the overlying Dunderberg shale at 
several localities in Nevada, may be thus summarized : ( 1 ) There is a 
sudden change, often occurring in a few feet of strata, from a faunule 
containing trilobite genera of the Crepicephalus zone ("Crepicephalid 
biofacies") to a faunule with Aphelaspis and other trilobites of the 
Aphelaspis zone ("Pterocephaliid biofacies"). (2) This change in Ne- 
vada coincides with the contact between the relatively pure, massive 
Hamburg limestone and the interstratified siltstone and silty limestone 
beds of the overlying Dunderberg formation. (3) Notwithstanding 
the great faunal change, no appreciable hiatus is believed to be in- 
volved. (4) The replacement of the Crepicephalid biofacies with the 
Pterocephaliid biofacies is believed not to have been synchronous every- 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS RASETTI 35 

where, but to have taken place earlier in the geosynclinal areas and to 
have spread later toward the interior of the continental shelf. Hence 
the use of the term "biofacies" rather than faunizones. (5) The upper- 
most faunule attributed to the Crepicephalid biofacies at McGill, Nev,, 
and a similar faunule collected at Woodstock, Ala., include Cedaria 
prolifica, the type species, or related forms of Cedaria. If the inter- 
pretation is correct, the type species of Cedaria would be a trilobite of 
the Crepicephalus rather than the Cedaria zone. 

In a second, more extensive paper on the Upper Cambrian faunas 
of Nevada, Palmer (1965)^ recognizes in ascending order the Aphel- 
aspis, Dicanthopyge, Prehonsia, Dunderhergia, and Elvinia zones, all 
belonging to a Pterocephaliid "biomere." The vahdity of some of these 
zones may be limited to the Great Basin. 

The observations in Tennessee show several features in common 
with the faunal development in Nevada. The change from the Crepi- 
cephalus to the Aphelaspis fauna is equally sudden, and the writer has 
already expressed agreement with Palmer's conclusion that most of 
the trilobites of the Aphelaspis fauna have no immediate ancestors in 
the Crepicephalus fauna ; hence the change occurred by immigration of 
a new fauna that had been evolving elsewhere, presumably in geosyn- 
clinal areas. In Tennessee the faunal change may occur either within 
the lower, massive limestone member of the Nolichucky formation, or 
coincide with the contact between this limestone unit and the over- 
lying shale with interbedded, thin limestone beds and lenses ; or it may 
occur within the latter lithologic unit. In any case there is no evidence 
whatever that the faunal change is associated with a hiatus. 

The earliest Aphelaspis faunule observed in Tennessee has species 
identical with or closely related to some of the earliest species of the 
Pterocephaliid biofacies found by Palmer in Nevada. In particular, 
Aphelaspis buttsi is the earliest species of the genus appearing both at 
McGill, Nev., and in the Three Springs section in Tennessee. Instead, 
no very close relationship appears between the youngest faunules of 
the Crepicephalid biofacies observed in Nevada and Tennessee; only 
the genus Coosia seems common to both. This fact might be indicative 
of the presence of a hiatus in the Nevada sections. 

It becomes more difficult to correlate younger faunules from Ten- 
nessee with those of the Nevada sections. Several Aphelaspis species 
described from Nevada, A. brachyphasis, haguei, subditus, and longis- 
pina, all closely resemble species from Tennessee, but in view of the 
fact that in either region species of Aphelaspis of rather different ages 



^ The writer is indebted to Dr. Palmer for reading the manuscript before pub- 
lication. 



Aphelaspis buttsi 

lata 

transversa 

minor 

walcotti 

washburnensis 

camiro 

laxa 

quadrata 

rotundata 

palmeri 

arses 

inermis 

arsoides 

tumifrons 

tarda 

punctata 
Aphelaspidella macropyge 
Paraphelaspis vigilans 
Dyt remacephalus angulatus 

strictus 

sulcifrons 
Dunderbergia longifrons 

tennesseensis 
Cheilocephalus brevilobua 

brachyops 

sp, undet. 
Coosella perplexa 
Tricrepicephalus, sp. undet. 
Glaphyraapis parva 

ornata 

declivis 

oderi 
Blountia bristolensis 

mimula 
Pseudagnostus communis 



LOWER 



MIDDLE 



Fig. 1. — ^Range of trilobite species in the Aphelaspis zone of Tennessee. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 37 

may be extremely similar (e.g., in Tennessee the early species A. 
walcotti resembles the late species A. tarda), not much time signifi- 
cance can be attributed to such similarities. In Nevada, Palmer finds 
Tumicephalus (based on a species almost identical with Aphelaspis 
tumifrons) in the ^ost- Aphelaspis, Dicanthopyge zone, species of 
Dytremacephalus in the still younger Prehousia and Dunderbergia 
zones, Cheilocephalus hrachyops and various species of Dunderbergia 
in the Dunderbergia zone. These findings might be taken to indicate 
that part of the middle Aphelaspis zone and all of the upper Aphelaspis 
zone of this paper are equivalent to portions of Palmer's post-Aphel- 
aspis zones in Nevada. On the other hand, these latter zones are char- 
acterized by a large number of genera of Pterocephaliid trilobites 
never observed in Tennessee. Hence it is difficult to decide what fauna 
in Nevada is the equivalent of the youngest Aphelaspis faunule from 
Tennessee, the Aphelaspis tarda faunule, which occurs in the upper- 
most beds of the Nolichucky formation. Perhaps the evidence favors 
equivalence to part of the Prehousia or Dunderbergia zones in Nevada. 

Even in the lower part of the Aphelaspis zone several genera present 
in the early Aphelaspis fauna in Alabama and Nevada were not found 
in Tennessee. Conspicuous among these are Glyptagnostus and other 
agnostid genera, and the Pterocephaliid genus Olenaspella, indistin- 
guishable from Aphelaspis in the cranidial features but characterized 
by the development of one or more pairs of marginal pygidial spines. 
Apparently these trilobites are more characteristic of the geosynclinal 
facies and never migrated far enough within the continental shelf to 
reach northeastern Tennessee. Absence of trilobites of the geosynclinal 
facies is a feature of both the Crepicephalus and Aphelaspis faunas. 

The observations in Tennessee bear no evidence on the question 
whether the replacement of the Crepicephalus fauna with the Aphel- 
aspis fauna was simultaneous or not in different areas, since the locali- 
ties studied are all within a narrow belt parallel to the margin of the 
geosyncline. 

In Tennessee no occurrence of Cedaria or other genera of the 
Cedaria zone close to the base of the Aphelaspis zone, or even a few 
hundred feet below this level, was ever observed. This fact may again 
be related to the "cratonic" rather than geosynclinal environment pre- 
vailing through the entire Upper Cambrian in Tennessee. 



PART II. SYSTEMATIC PALEONTOLOGY 

GENERAL STATEMENT 

Not all the species of trilobites described from the Upper Cambrian 
of Tennessee are treated in this paper. With few exceptions, only those 
collected by the author from measured sections and hence contributing 
to the knowledge of the faunal succession are discussed herein. 

Type catalog numbers and type localities for previously described 
species are given only when the types are from the southern Appala- 
chians. 

Unless otherwise stated, all the described and illustrated specimens 
are preserved in limestone, and show the outer surface of the test, on 
which the description is based. 

The author's localities are often given only by their numbers in this 
descriptive part; their topographic position may be readily identified 
from the locality list, the stratigraphic position from the descriptions 
of the sections. 

All the types and other figured specimens collected by the writer 
were deposited in the U.S. National Museum collections. All the Mu- 
seum numbers beyond 144000 are listed in Paleozoic catalog No. 30. 

DESCRIPTIONS OF TRILOBITE GENERA AND SPECIES 

Order AGNOSTIDA 

Family AGNOSTIDAE McCoy, 1849 

Genus KORMAGNOSTUS Resser, 1938 

Type species. — Korniagnostus simplex Resser. 

KORMAGNOSTUS SIMPLEX Resser 

Plate 1, figures 8, 9 

Korniagnostus simplex Resser, 1938a, p. 49, pi. 9, figs. 11-13. 
Kormagnostus harlanensis Resser, 1938a, p. 49, pi. 10, figs. 11, 12. 
Kormagnostus simplex Resser, Palmer, 1954, p. 718, pi. 76, figs. 8-12 (includes 

complete synonymy). 
Kormagnostus simplex Resser, Lochman and Hu, 1960, p. 822, pi. 99, figs. 5-31. 

Common almost everywhere in the fossiliferous beds at the top of 
the Maryville limestone and the overlying basal Nolichucky shale 
(Cedaria zone) . 

Occurrence. — Type locality for K. simplex is U.S.N.M. 27d ( = 
author's locality cnd/1) ; red beds at the base of the Nolichucky E. 
of Rogersville. Type locality for K. harlanensis is U.S.N.M. locality 

38 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 39 

124, presumably near the top of the Maryville limestone and identical 
with one of the author's localities, cnc/2 to cnc/5. Collected by the 
author at locahties cnc/5, cnc/6, cnd/1, cnd/2, cne/1, cne/2, cnb/10, 
cnd/10, cne/10, cne/13. 

Types. — Cotypes of K. simplex: U.S.N.M. 94842. Cotypes of K. 
harlanensis : U.S.N.M. 94863. Plesiotypes figured herein: U.S.N.M. 
144546. 

Genus PSEUDAGNOSTUS Jaekel, 1909 

Type species. — Agnostus cyclopyge Tullberg. 

PSEUDAGNOSTUS COMMUNIS (Hall & Whitfield) 

Plate 10, figures 23-25 

Agnostus communis Hall and Whitfield, 1877, p. 228, pi. 1, figs. 28, 29. 
Agnostus neon Hall and Whitfield, 1877, p. 229, pi. 1, figs. 26, 27. 
Pseudagnostus communis (Hall and Whitfield) Palmer, 1955, p. 94, pi. 19, figs. 

16, 19-21 ; pi. 20, figs. 4-11, 14 ; 1960, p. 61, pi. 4, figs. 3, 4. 
Pseudagnostus commmiis (Hall and Whitfield) Rasetti, 1961, p. 109, pi. 23, figs. 

13-17. 

A Pseudagnostus that occurs at several localities in beds of the 
Aphelaspis zone does not differ in any observable features from topo- 
type material illustrated by Palmer. The latter is from the Dunder- 
hergia zone of Nevada. The author (Rasetti, 1961) figured specimens 
from the Dunderbergia zone of Maryland, 

Occurrence. — Collected at localities cnt/1, cns/2, cns/4, cnt/4, cnt/7, 
ens/ 15, cnt/1 5. All these collections are from the middle portion of the 
Aphelaspis zone. 

Ty/>^j.— Plesiotypes: U.S.N.M. 144547. 

Order CORYNEXOCHIDA 
Family DORYPYGIDAE Kobayashi, 1935 

Genus OLENOIDES Meek, 1877 

Type species. — Paradoxides nevadensis Meek. 

OLENOIDES, species undetermined 

Plate 5, figtires 12, 13 

Available material. — Two fragmentary pygidia. 

Description. — Pygidium fully typical of the genus, of the four-spined 
group. Axis not preserved except for the terminal portion, almost 
reaching the posterior margin. Pleural regions of low convexity. Three 
pairs of pleural furrows and as many of interpleural grooves about 
equally impressed, regularly curved, all becoming somewhat deeper in 
the indefinite border furrow; each interpleural groove approximately 
parallel to the preceding furrow but diverging from the following fur- 



40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

row. Spines progressively closer to each other ; those of the first two 
pairs strong, the last two progressively more slender. Spines of last 
pair directed straight backward, their distance greater than between 
the third and fourth pairs. Surface of test smooth. 

Discussion. — This form, as far as can be ascertained from the frag- 
mentary material, does not greatly differ from several Middle Cam- 
brian species of the genus, such as O. curticei Walcott, and O. con- 
vexus Rasetti, but is readily distinguished by the course of the pleural 
furrows and the spacing of the marginal spines. The writer (Rasetti, 
1946) described a Dresbachian species of the genus which, however, 
has only 3 pairs of marginal spines. 

Occurrence. — U.S.G.S. collection 2406 (= author's collection 
cnb/10), Comby Ridge. The species occurs in the same piece of rock 
with abundant Ankoura triangularis. 

Disposition of material. — Figured specimens : U.S.N.M. 144548. 

Order PTYCHOPARIIDA 
Family LONCHOCEPHALIDAE Hupe, 1953 

Genus TERRANOVELLA Lochman, 1938 

Type species. — Terranovella ohscura Lochman. 

TERRANOVELLA DORS ALIS (HaU) 

Plate 6, figure 7 

Conocephalites? (Arionellusf) dorsalis Hall, 1863, p. 222. 

Ptychoparia dorsalis (Hall) Vogdes, 1890, p. 141. 

Lonchocephalus sospita Walcott, 1916a, p. 195, pi. 36, figs. 1, la. 

Terranovella htittsi Resser, 1938a, p. 100, pi. 15, figs. 22-26. 

Terranovella dorsalis (Hall) Raasch and Lochman, 1943, p. 234, pi. 35, figs. 

3-10, 17. 
Terranovella dorsalis (Hall) Rasetti, 1961, p. 118, pi. 22, figs. 7-13. 

Occurrence. — Type locahty for T. buttsi is U.S.N.M. 35s, near 
Abingdon, Va. Collected by the author in the uppermost beds of the 
lower limestone member of the Nolichucky (Crepicephalus zone) at 
localities cnn/1, cnn/14, cnn/15, cnn/19, and cnn/20. 

Types.— Uolotype of T. buttsi: U.S.N.M. 94984. Plesiotype: 
U.S.N.M. 144549. 

Genus GLAPHYRASPIS Resser, 1937 

Type species. — Liostracus parvus Walcott. 

GLAPHYRASPIS PARVA (Walcott) 

Plate 10, figures 9-17 

Liostracus parvus Walcott, 1899, p. 463, pi. 65, fig. 6. 
Glaphyraspis parva (Walcott) Resser, 1937, p. 12. 

Raaschella occidentalis Lochman, in Lochman and Duncan, 1944, pi. 43, pi. 4 
figs. 1-5. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 41 

Glaphyraspis parva (Walcott) Rasetti, 1961, p. 112, pi. 22, figs. 14-17. 
Glaphyraspis parva (Walcott) Lochman and Hu, 1962b, p. 438, pi. 68, figs. 7-52. 

A form that occurs in the transition beds between the Crepicephalus 
and Aphelaspis zones is referred to the species. The cranidia are some- 
what variable both in shape and ornamentation. The glabella is typically 
parallel-sided, but in some individuals it is slightly tapered and pro- 
portionately shorter and wider. The depth of the glabellar furrows is 
also variable. The ornamentation of the type material from Yellow- 
stone National Park consists of a dense, extremely fine granulation 
plus scattered, larger granules. Some of the individuals from Tennessee 
match this type of ornamentation; others show granules of one size, 
while some are almost smooth. All these features may be found in 
specimens from a single piece of rock, hence they must be ascribed to 
intraspecific variability. 

Occurrence. — The illustrated material is from locality cno/15, 
Three Springs. Also collected at locality cno/14, Russell Gap. At both 
localities it occurs below the beds yielding other species of Glaphy- 
raspis. 

ry/j^.?.— Plesiotypes: U.S.N.M. 144550. 

GLAPHYRASPIS ORNATA (Lochman) 
Plate 10, figure 8; plate 11, figures 13, 14 

Raaschella ornata Lochman, 1938, p. 82, pi. 18, figs. 6-10. 
Raaschella ornata Lochman, Palmer, 1954, p. 767, pi. 98, figs. 7-9. 
Glaphyraspis ornata (Lochman) Rasetti, 1961, p. 112. 

The species is not rare in the basal beds of the Aphelaspis zone. 
Complete specimens in shale collected by Dr. Oder, one of which is 
illustrated herein, show that the thorax has 8 segments. The axial rings 
have no nodes or spines. The pleurae are flat, straight, and uniformly 
furrowed for most of their course. Near the distal end they bend back- 
ward and downward and possess the peculiar ridges previously ob- 
served in the pygidium. 

Occurrence. — Author's localities cnp/14, cnq/14, cnq/15, cnq/16, 
cnr/16, cnq/17. Also in Oder's collection No. 3 at Hurricane Hollow 
and U.S.G.S. collection 2804 on Shields Ridge. 

Ty/)^:?.— Plesiotypes : U.S.N.M. 144551-2. 

GLAPHYRASPIS ODERI Rasetti, new species 

Plate 10, figures 18-22 

Available material. — Numerous cranidia, free cheeks, and pygidia 
well preserved in limestone. 

Description. — Glabella of same shape as in G. ornata; glabellar 
furrows of usual pattern but exceedingly shallow on outer surface. 



42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Occipital furrow well impressed; occipital ring expanded medially, 
rounded. Fixed cheeks convex, rising somewhat above axial furrow, 
then downsloping. Frontal area short, about one-fiifth the glabellar 
length ; border narrow and poorly defined by a shallow border furrow. 
Ocular ridges faint, transverse in direction ; palpebral lobes narrow and 
short, in advance of glabellar midpoint. Posterior area as in type 
species, steeply downsloping, well furrowed. Free check with border 
well defined anteriorly, poorly marked posteriorly; genal angle 
rounded. 

Pygidium with long axis, showing about 4 distinct rings, reaching 
the posterior margin. Pleural platforms flat; border downsloping. 
Pleural and interpleural furrows both well marked. Each segment has 
the characteristic distal ridge as in other species. 

Surface of cranidium in most of the specimens from the type locality 
with scattered tubercles only in certain areas, more apparent on the 
posterior portion of the fixed cheeks, almost lacking on the glabella. 
Some of the cranidia appear entirely smooth, particularly among those 
from collection cnq/20, and especially from the higher collection 
cnrV20. However, smooth and granulated cranidia occur on the same 
piece of rock, and there are all intermediate forms. 

Length of largest cranidium 3.0 mm. ; length of largest pygidium 1.8 
mm. 

Discussion. — This species resembles both G. parva, from which it 
differs in the somewhat wider and shorter glabella, and G. ornata, from 
which it can be separated by the much weaker ornamentation. 

Occurrence. — The types are from Oder's collection No. 2 at Hurri- 
cane Hollow, in beds immediately overlying those with G. ornata. Also 
present in collections cnr/15, cnpV20, cnq/20, and cnrV20. The spe- 
cies ranges through an appreciable thickness of beds, appearing in the 
Aphelaspis minor, A. walcotti, and the A. camiro, A. laxa, and A. 
quadrata assemblages. 

Ty/)^^.— Holotype : U.S.N.M. 144553. Paratypes: U.S.N.M. 
144554. 

GLAPHYRASPIS DECLIVIS Rasetti, new species 

Plate 14, figures 20-24 

Available material. — Numerous cranidia and free cheeks well pre- 
served in limestone. 

Description. — Glabella subovate, slightly tapered, rounded in front, 
rising well above the cheeks. Posterior glabellar furrows of same shape 
as in G. ornata, very shallow ; other pairs indistinct. Occipital furrow 
moderately impressed ; occipital ring widely subtriangular, bearing an 
indistinct node. Cheeks sloping down steeply from axial furrow ; frontal 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 43 

area about one-fourth the glabellar length, slightly convex, barely 
divided by a trace of a border furrow ; anterior outline somewhat 
pointed medially. Ocular ridges faint ; palpebral area about one-fourth 
the glabellar width ; palpebral lobes very small, at level of anterior third 
of glabella. Anterior section of facial suture convergent immediately in 
front of palpebral lobes; posterior section slightly convex outward, 
gradually curving backward and inward to produce broad, well- 
rounded posterior area. Furrow on posterior area broad and shallow. 
Free cheek rounded at genal angle; border narrow but fairly distinct 
anteriorly, becoming indistinct posteriorly. Surface of test smooth. 
Length of largest cranidium 2.4 mm. 

Discussion. — The pygidium has not been identified. The cranidium 
of G. declivis differs from other species of the genus in the steeply 
downsloping palpebral area and the tendency to obsolescence of all the 
furrows ; however, its close relationship to the more typical forms is un- 
mistakable. 

Occurrence. — The type is from Oder's collection No. 2, Hurricane 
Hollow. Also present in collections cnr/15. Three Springs, and cnr/16. 
Smith Hollow. In all these occurrences it is associated with Aphelaspis 
walcotti. Rare specimens were collected at locality cnqV20, Washburn, 
in somewhat higher beds. 

Types.— RoXoty^e: U.S.N.M. 144556. Paratypes: U.S.N.M. 144- 
557. 

Genus AMIASPIS Lochman, 1944 

Type species. — Amiaspis erratica Lochman. 

AMIASPIS ERRATICA Lochman 

Plate 5, figure 20 

Amiaspis erratica Lochman, in Lochman and Duncan, 1944, p. 68, pi. 8, figs. 
41-46. 

A few cranidia do not appear to differ appreciably from topotype 
material from Montana. 

Occurrence. — Locality cnn/ 16, Smith Hollow. 
7y/>^.—Plesiotype: U.S.N.M. 144558. 

AMIASPIS OBSOLESCENS Rasetti, new species 

Plate 5, figures 21-24 

Available material. — The holotype, a good cranidium, is the only 
specimen from the type locality. Several fragmentary cranidia from 
another locality are also available. 

Description. — Glabella large, somewhat tapered, widely rounded in 
front, unfurrowed, barely defined on the outer surface by a very shallow 



44 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

axial furrow, almost merging with the general convexity of the cepha- 
lon. Occipital furrow very shallow ; occipital ring extended into a long, 
slender, almost horizontal spine. Fixed cheeks convex and down- 
sloping; frontal area short (sag.), not differentiated into preglabellar 
field and border. Ocular ridges barely indicated ; palpebral lobes almost 
indistinct, at level of the anterior fourth of glabella. Posterior area 
broad, strongly downsloping, rounded distally, deeply furrowed in con- 
trast to the shallowness of all other furrows. Margin of posterior border 
showing a geniculation close to the axial furrow. Surface of test com- 
pletely smooth. Length of largest cranidium, exclusive of spine, 2.2 
mm. 

Discussion. — The species differs from the type, with which it is 
associated, in the obsolescence of the axial furrow and the proportion- 
ately larger and unfurrowed glabella. 

Occurrence. — The type locality is cnmV20, Washburn. Also in col- 
lection cnn/16. Smith Hollow. The stratigraphic position is in the up- 
per Crepicephalus zone. 

Types.— RoXoty^t: U.S.N.M. 144559. Paratypes: U.S.N.M. 144- 
560. 

Family CATILLICEPHALIDAE Raymond, 1938 

Genus PEMPfflGASPIS Hall, 1863 

Type species. — Pemphigaspis bullata Hall. 

PEMPHIGASPIS, species undetermined 

Plate 7, figures 23-25 

A few cranidia and pygidia of Pemphigaspis, the latter fragmentary, 
may be identical with the type species but are not sufficient for a satis- 
factory identification. 

Occurrence. — Uppermost beds of lower limestone member of the 
Nolichucky (Crepicephalus zone) at locality cnn/3. 

Disposition of material. — Figured specimens : U.S.N.M. 144562. 

Genus MADAROCEPHALUS Resser, 1938 

Type species. — Madaroccphalus laetus Resser. 

MADAROCEPHALUS LAETUS Resser 

Plate 8, figure 20 

Madaroccphalus laetus Resser, 1938a, p. 87, pi. 10, figs. 51-53. 

A single cranidium agrees with the types, and proves that the species 
belongs to the Crepicephalus zone. 

Occurrence. — Type locality is U.S.N.M. 56v, near McCalla, Ala. 
The author collected the specimen in the upper part of the lower lime- 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 45 

stone member of the Nolichucky {Crepicephalus zone) at locality 
cnm/2. 

Types.— Coiy^QS : U.S.N.M. 94885. Plesiotype : U.S.N.M. 144563. 

Family CREPICEPHALIDAE Kobayashi, 1935 

Genus CREPICEPHALUS Owen, 1852 

Type species. — Dikelocephalus ? iowensis Owen. 

CREPICEPHALUS of. C. SCISSILIS Resser 

Plate 8, figure 30 

Crepicephalus scissilis Resser, 1938a, p. 72, pi. 11, figs. 34, 35. 
Crepicephalus greendalensis Resser, 1938a, p. 7Z, pi. 11, figs. 46, 47. 

A few, exfoliated pygidia resemble this species in the general shape, 
differing in the following minor features. The outline between the 
spines is slightly concave rather than straight; the median profile of 
the pleural region behind the axis is somewhat concave, instead of 
convex as it appears in Resser's specimens. Possibly these differences 
should be attributed specific value when better-preserved and more 
complete material can be found. 

Occurrence. — Type locality for C. scissilis is U.S.N.M. 124a, 4 miles 
NE. of Rogersville. Type locality for C. greendalensis is U.S.N.M. 
36u, near Greendale, Va. The author's material was collected from the 
uppermost beds of the lower limestone member of the Nolichucky 
{Crepicephalus zone) at locality cnn/3. 

Disposition of material. — Figured specimen : U.S.N.M. 144564. 

CREPICEPHALUS BUTTSI Resser 

Plate 6, figures 5, 6 

Crepicephalus buttsi Resser, 1938a, p. 72, pi. 11, figs. 28, 29, 49, SO. 
Crepicephalus expansus Resser, 1938a, p. 75, pi. 11, fig. Z6. 

Crepicephalus buttsi is represented by cranidia and pygidia poorly 
preserved and somewhat flattened in shale, while C. expansus is based 
on a limestone pygidium. No observable differences separate the pygi- 
dia bearing the two names. A form collected by the author and repre- 
sented only by pygidia is identified with this species. The individual 
specimens vary to some extent in possessing straight or somewhat in- 
ward curved spines. Since both types occur in the same bed, these slight 
differences are not attributed specific significance. 

Occurrence. — The type locality of C. buttsi is U.S.N.M. 26s, near 
Cleveland, Va. The type locality of C. expansus is U.S.N.M. 105, near 
Sneedville, Hancock County, Tenn. The specimens figured herein are 
from locality cnn/19. 



46 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Types. — Holotype of C. buttsi (pygidium) : U.S.N.M. 94907. Para- 
types : U.S.N.M. 94908. Holotype of C. expansus: U.S.N.M. 94910. 
Plesiotypes: U.S.N.M. 144565. 

CREPICEPHALUS CONVERGENS Rasetti, new species 

Plate 8, figures 5-8 

Available material. — Several pygidia and cranidia, the former of 
small size, mostly preserving the test. 

Description. — Cranidium fully typical of the genus. Glabella tapered, 
rounded in front, showing 2 pairs of shallow furrows even on the outer 
surface ; occipital furrow straight, occipital ring rounded. Frontal area 
divided into preglabellar field and border of about equal widths (sag.) ; 
border slightly convex. Palpebral area and lobes as in other species of 
the genus ; posterior area not preserved. 

Pygidium represented by better specimens than the cranidium. Axis 
occupying two-thirds of the length, somewhat tapered, extended into 
a short postaxial ridge which reaches the wide, indistinct border fur- 
row. About 2 rings distinct, 1 or 2 more barely indicated. Pleural lobes 
with rounded anterior angles, fairly straight sides converging toward 
the rear, and concave posterior margin between the spines. Pleural 
platforms relatively small, with 3 short, well-marked furrows, no 
interpleural grooves; slope dropping rather steeply to border furrow 
and wide, flat border. Spines rapidly tapered, flat, relatively short. 
Surface finely granulate. Length of largest pygidium 6.5 mm., width 
10.5 mm. 

Discussion. — This form is chiefly characterized by the pygidium, 
which differs in outline, form of the spines, and relative length of axis 
from described species. 

Occurrence. — Lower portion of lower limestone member of the 
Nolichucky (Crepicephalus zone) at locality cnk/1. 

Types. — Holotype (pygidium): U.S.N.M. 144566, Paratypes: 
U.S.N.M. 144567. 

CREPICEPHALUS cf. C. CONVERGENS Rasetti 

Plate 8, figures 9-11 

Several pygidia collected in strata higher than those yielding the types 
of the species differ consistently in several features aside from the 
different manner of preservation (these pygidia are exfoliated). The 
sides are even more strongly convergent than in C. convergens, thus 
bringing the spines closer together ; these are also shorter and more 
obtuse in shape, and the margin between them more definitely notched. 

Occurrence. — Uppermost beds of the lower limestone member 
(Crepicephalus zone) of the Nolichucky (loc. cnn/1, cnn/3). 

Dispostion of material. — Figured specimens: U.S.N.M. 144568-9. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 47 

CREPICEPHALUS, species undetermined No. 1 

Plate 8, figures 17, 18 

Available material. — Represented by incomplete, exfoliated pygidia 
and one poorly preserved cranidium that may belong to the same 
species. 

Description. — Pygidium twice as wide as long. Axis occupying 
about five-sixths of the length, somewhat tapered, showing 3 rings and 
a terminal section. Pleural lobes extended into a pair of broad-based, 
strongly outward-directed, and presumably very long spines. Pleural 
platforms relatively short, with 3 pairs of pleural furrows. Border 
furrow indistinct. 

Discussion. — This form cannot be identified with any described 
species on account of the character of the pleural spines. 

Occurrence. — Uppermost beds of the lower limestone member 
(Crepicephalus zone) of the Nolichucky (loc. cnn/4). 

Disposition of material. — Figured specimens: U.S.N.M. 144570. 

CREPICEPHALUS? species undetermined No. 2 

Plate 8, figures 12, 13 

Available material. — A few cranidia and pygidia tentatively assigned 
to one species, preserved in limestone as internal impressions. 

Description. — Glabella rather strongly convex in both directions, 
straight-sided, tapered, rounded in front, unfurrowed. Occipital furrow 
well impressed, straight; occipital ring lacking node or spine. Pre- 
glabellar field very short ; border sharply elevated, convex, somewhat 
arched transversely ; border furrow lacking depressions. Palpebral area 
slightly upsloping, about 0.25 times glabellar width; palpebral lobes 
small, curved, opposite glabellar midpoint; ocular ridges faintly indi- 
cated. Anterior facial sutures slightly divergent; anterior angles of 
cranidium narrowly rounded. Posterior area not preserved. 

Associated pygidium of the Crepicephalus type, twice as wide as the 
midlength. Axis long, showing 3 rings and a terminal section, extended 
into a short postaxial ridge that reaches the margin. Pleural platforms 
convex and downsloping, with 3 pairs of deep, wide furrows, ending 
at wide, shallow border furrow. Spines continue the straight, slightly 
convergent outline of pygidial sides and are sharply pointed without 
attaining great length ; margin between spines forming a broad curve. 
Length of largest cranidium 16 mm. ; of pygidium 7 mm., width 14 mm. 

Discussion. — The pygidium seems definitely to belong in the genus ; 
the cranidium, however, is unusual in the strongly elevated anterior 
border and slightly upsloping palpebral area. The first of these char- 
acters would rather suggest Meteoraspis, but in that genus the pal- 
pebral area rises above the axial furrow and then slopes downward in 
characteristic fashion. 



48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Occurrence. — Uppermost beds of the lower limestone member of 
the Nolichucky (Crepicephalus zone) ; locality cnn/3. 

Disposition of material. — Figured specimens : U.S.N.M. 144571. 

Genus COOSELLA Lochman, 1936 

Type species. — Coosella prolifica Lochman. 

COOSELLA ANDREAS (Walcott) 

Plate 1, figures 1^ 

Blountia andreas Walcott, 1916b, p. 398, pi. 64, fig. 2. 
Coosella andreas (Walcott) Resser, 1938a, p. 70, pi. 13, fig. 11. 

Available material. — The holotype is a cranidium. Two cranidia and 
two associated pygidia collected by the author allow a more complete 
description. The cranidia differ from the holotype in the slightly less 
downsloping attitude of the anterior border, but such differences are 
common in obviously conspecific populations. 

Description. — The pygidium has a very prominent, tapered, rounded 
axis reaching more than two-thirds of the pygidial midlength ; it shows 
3 rings and a terminal section extended into a low, broad postaxial 
ridge. Pleural lobes with unusually strong convexity, sloping down 
steeply to a narrow, poorly defined, concave border. Pleural platforms 
furrowed for a short distance, with 2 pairs of furrows and 1 pair of 
interpleural grooves indicated, all ending on the line that marks the 
inner edge of the doublure. Posterior margin in dorsal view showing a 
narrow notch between rounded lobes, in posterior view strongly raised 
medially. Surface of test smooth. The strong convexity of the pygidium 
distinguishes the species from all others attributed to the genus. 

Occurrence. — Uppermost beds of Maryville limestone {Cedaria 
zone). Type locality is U.S.N.M. 102a, east of Roger sville. Collected 
by the author at locality cnc/2. 

Types.— Rolotype: U.S.N.M. 62823. Plesiotypes: U.S.N.M. 
144572. 

COOSELLA RESSERI Rasetti, new name 

Plate 1, figures 5-7 

Uncaspis tennesseensis Resser (part), 1938a, p. 105, pi. 9, fig. 20 (only). 

Available material. — The pygidium, holotype of Uncaspis tennes- 
seensis, and 2 additional pygidia, all preserved in limestone but ex- 
foliated. 

Description. — Pygidial axis slightly tapered, very prominent, show- 
ing 3 rings plus a terminal section, extended into a low postaxial ridge. 
Pleural platforms convex and strongly downsloping, showing several 
pairs of shallow furrows and interpleural grooves, all curving back- 
ward. Pleural region extended into a pair of slightly concave, horizon- 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 49 

tal, somewhat falcate lobes separated by a wide, rounded notch. Mid- 
length of pygidium 5 mm., width 10 mm. 

Discussion. — The cranidium referred by Resser to Uncaspis tennes- 
seensis is an example of Modocia duhia, as mentioned in the synonymy 
of that species. The holotype pygidium is certainly not an Uncaspis, 
whatever the characters of this poorly understood genus may be, and 
seems definitely referable to Coosella. This assignment requires a 
change in the trivial name, because the binomial combination Coosella 
tennesseensis was used by Resser for another species. The pygidium 
has fundamentally the same structure as Coosella andreas, but is more 
strongly bilobate, and the notch between the lobes is much wider. 

Occurrence. — Red beds at the base of the Nolichucky (Cedaria 
zone) at U.S.N.M. locality 27d, where it was also collected by the 
author (loc. cnd/1). 

ry/)^.y.— Holotype : U.S.N.M. 94846. Plesiotype: U.S.N.M. 
144573. 

COOSELLA PLANICAUDA Rasetti, new species 

Plate 7, figures 1-5 

Available material. — A few cranidia and numerous pygidia. 

Description. — Glabella of usual shape, with traces of lateral furrows ; 
occipital furrow deep and straight, occipital ring bearing a low node. 
Preglabellar field and border of about equal width (sag.) ; border 
strongly convex, with terrace lines. Palpebral lobes narrow, half the 
glabellar length ; width of palpebral area about 0.3 times the glabellar 
width. Midpoint of palpebral lobes somewhat in advance of glabellar 
midpoint. 

Pygidium with very little overall relief. Axis moderately convex, 
little more than half the pygidial length, moderately tapered, showing 
2 or 3 rings and an unfurrowed terminal section, extended into a brief 
postaxial ridge. Pleural lobes almost flat, showing faint furrows in the 
narrow triangular portions anterior to the inner margin of the wide 
doublure, smooth in the remainder of the broad, slightly concave area ; 
posterior outline well rounded except for a shallow median notch 
between the pair of wide lobes. Surface of test smooth. Length of 
largest pygidium 7.5 mm., width 11 mm. 

Discussion. — This species possibly resembles Coosia more than 
Coosella in the shape of the pygidium, but the cranidial features rather 
indicate the present generic assignment. 

Occurrence. — Lower and middle portions of the lower limestone 
member of the Nolichucky (Crepicephalus zone). Localities cnk/2, 
cnm/2. 

Ty/)^.y.— Holotype : U.S.N.M. 144574. Paratypes: U.S.N.M. 
144575-6. 



50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

COOSELLA PERPLEXA (Palmer) 

Plate IS, figures 19-26 

Crepicephalus? perplexus Palmer, 1954, p. 7Zi, pi. 77, figs. 1, 2, 4. 

Represented in the collections by numerous cranidia and pygidia 
and a few free cheeks. Careful comparison with topotype specimens 
and further material from Nevada identified by Palmer (private com- 
munication) failed to disclose any significant difference, hence the 
identification seems highly reliable. 

Palmer tentatively referred the species to Crepicephalus rather than 
Coosella because of the stratigraphic position rather than morphology. 
The cranidia of the two genera are indistinguishable, and it has been 
customary to refer to Crepicephalus the forms with pygidia extended 
into a pair of lateral spines, to Coosella those with a pair of rounded 
lobes more or less separated by a median notch. Hence the reference 
to Coosella seems indicated in the present case. Other species of Coo- 
sella, e.g., C. planicauda, occur in the upper Crepicephalus zone, hence 
there is no stratigraphic discontinuity in the distribution of the genus. 

Occurrence. — Basal beds of the Aphelaspis zone in collections cno/ 
14, Russell Gap, and cno/15. Three Springs. 

ry/)^j.— Plesiotypes: U.S.N.M. 144577-8. 

COOSELLA, species undetermined 

Plate 6, figure 19 

A single pygidium was collected. It has a short axis and wide, flat 
pleural lobes with a slight median notch in the posterior margin. The 
axis is extended into a long, narrow postaxial ridge. This specimen 
resembles a pygidium of an unnamed species of Coosella figured by 
Palmer (1954, p. 730, pi. 79, fig. 1) but the sides are straighter and 
the posterior angles not so widely rounded. 

Occurrence. — Lower portion of lower limestone member of the 
Nolichucky {Crepicephalus zone) at locality cnk/1. 

Disposition oj material. — Figured specimen : U.S.N.M. 144579. 

Genus COOSINA Rasetti, 1956 

Type species. — Maryvillia ariston Walcott (part) . 

COOSINA AMAGE (Walcott) 

Plate 7, figures 14-22 

Blountia amage Walcott, 1916b, p. 398, pi. 64, figs. 3, 3a. 

Blounfia alethes Walcott (part), 1916b, p. 397, pi. 64, figs, lb, Ic (only). 

Coosella amage (Walcott) Resser, 1938a, p. 70, pi. 13, figs. 12, 13. 

Available material. — Blountia amage was based on a proper com- 
bination of cranidium and pygidium, both represented by specimens 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS RASETTI 51 

preserving the test. Blountia alethes was described on a cranidium of 
Coosia illegitimately combined with an exfoliated pygidium of the pre- 
ceding species. Since Walcott designated the cranidium as the holotype, 
the name alethes belongs to the species of Coosia, as used by Resser. 
The present generic assignment seems the proper one for Blountia 
amage. This species was found to be exceedingly common at one local- 
ity, and the numerous and better preserved material allows a more 
complete description. 

Description. — Glabella defined by a fairly deep axial furrow, strongly 
tapered, rounded in front ; glabellar furrows obsolete on outer surface, 
faint on impression of interior. Occipital furrow wide, occipital ring 
simple. Frontal area as in type species except for the greater distinct- 
ness of the border furrow and border. Palpebral area approximately 
horizontal, about 0.4 times the glabellar width ; palpebral lobes about 
0.4 times the glabellar length. Posterior area somewhat more slender 
and more deeply furrowed than in type species. 

Pygidium 1.4 times as wide as long. Axis elevated, slightly tapered, 
occupying 0.8 of the pygidial length, extended into a brief postaxial 
ridge, with about 5 distinct rings and a terminal section. Pleural lobes 
convex, downsloping to moderately wide concave border. Anterior 
marginal furrow deep and wide, three other pairs of furrows shallow 
even on interior casts, traces of interpleural furrows also visible; all 
furrows end sharply at a line that corresponds to the inner edge of the 
doublure on the ventral side. The lateral and posterior margin with 
almost even curvature, except for a slight indication of flattening 
medially. Surface of test smooth. Length of largest cranidium 14 mm., 
of largest pygidium 10 mm. 

Occurrence. — The type locality is U.S.N.M. 107, 11 miles NW. of 
Knoxville. Type locality for Blountia alethes, U.S.N.M. 123b, near 
Rogersville. Illustrated plesiotypes from the middle portion of the 
lower limestone member of the Nolichucky (Crepicephalus zone) at 
locality cnm/2. 

Ty/)^.?.— Holotype : U.S.N.M. 62824. Paratype: U.S.N.M. 62825. 
Paratype pygidium of Blountia alethes assigned to the species: 
U.S.N.M. 62822. Plesiotypes: U.S.N.M. 144580, 144561. 

COOSINA ARISTON (Walcott) 

Plate 7, figure 27 

Maryvillia ariston Walcott (part), 1916b, p. 401, pi. 64, figs. 5, 5' (not fig. 5a). 
Coosina ariston (Walcott) Rasetti, 1956, p. 1267 (includes complete syn- 
onymy) ; 1961, p. Ill, pi. 21, figs. 12, 13. 

Several pygidia seem identical with this species. The cranidium was 
not identified ; it would be difficult to distinguish from that of the far 
more common associated species C. amage. 



52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Occurrence. — Type locality is U.S.N.M. 120, on Shields Ridge, 
New Market quadrangle. Collected by the writer in the middle portion 
of the lower limestone member of the Nolichucky (Crepicephalus zone) 
at locality cnm/2. 

Types.— Uolotype : U.S.N.M. 62829. Plesiotype : U.S.N.M. 144581. 



Genus COOSIA Walcott, 1911 

Type species. — Coosia superba Walcott. 

COOSIA ALETHES (Walcott) 

Plate 6, figures 15-18; plate 7, figures 6-13 

Blountia alethes Walcott (part), 1916b, p. 397, pi. 64, figs. 1, la (only). 
Coosia alethes (Walcott) Resser, 1938a, p. 71. 

Available material. — Abundant new specimens show that Walcott's 
type cranidium is an immature individual of a species of Coosia that 
attains large dimensions and is common everywhere in the upper 
Crepicephalus zone of the Nolichucky. 

Description. — Glabella well defined by the axial furrow, unfurrowed, 
not changing much in shape in cranidia from 2.3 to 18 mm, in length, 
except for a gradual decrease of the convexity. Occipital furrow 
straight, well impressed, occipital ring simple. Frontal area increasing 
in length relative to the entire cranidium from 0.30 to 0.37 in the above- 
mentioned size range. Border furrow becoming gradually wider and 
shallower ; midlength of preglabellar field about equal to border width 
(sag.) in small cranidia, decreasing to about half of border in adults. 
Palpebral area decreasing in relative width with size ; palpebral lobes 
regularly curved in early stages, becoming somewhat angular later. 
Entire thorax preserved in an immature specimen that may represent 
a holaspid and has 12 segments. The pygidium in this individual has a 
long axis and the pleural lobes show 3 or 4 distinct pairs of furrows. 
In larger pygidia the axis becomes shorter, equaling only half or less 
of the pygidial length, and extends into a postaxial ridge. It is com- 
posed of 3 rings and a terminal section distinct even on the outer 
surface. The pleural lobes are slightly downsloping and furrowed in 
a limited area near the axis, then flatten out into a wide, smooth, some- 
what concave area that corresponds to the extent of the doublure. 
The anterior marginal furrow is the only one that extends almost to 
the lateral margin. The largest fairly complete cranidium is 18 mm. 
long, but fragments indicate larger individuals. A large, incomplete 
pygidium has a length of 22 mm. and a width of 44 mm. Surface of test 
smooth except for wavy terrace lines on cranidial and pygidial borders. 

Discussion. — It may be questioned whether forms of Coosia de- 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 53 

scribed under various names from other areas, such as C. dakotensis 
Resser, C. albertensis Resser, C. modesta Lochman, C. grandis Loch- 
man are distinct from the present species. In any case, the trivial name 
alethes would be the proper one for the species from Tennessee since 
it has priority. 

Occurrence. — Type locality is U.S.N.M. 123b, near Rogersville. 
Common in the uppermost beds of the lower limestone member of the 
Nolichucky (Crepicephalus zone). Localities cnn/1 to cnn/4, cnn/19, 
and cnn/1 6 ; rare in somewhat lower beds (loc. cnm/2) . 

Types.— Kolotype: U.S.N.M. 62821. Plesiotypes: U.S.N.M. 
144582-6. 



COOSIA ROBUSTA Walcott 

Plate 7, figure 26 

Coosia robusta Walcott, 1911, p. 97, pi. 16, figs. 2, 2a. 

Coosia robusta Walcott, Resser, 1938a, p. 70, pi. 11, figs. 12, 13. 

Several pygidia associated with the preceding species seem identical 
with the types ; however, no cranidia could be identified. The pygidium 
differs from that of C. alethes in the longer axis and almost entirely 
convex surface. The largest pygidium found is 25 mm. long and 40 
mm. wide. 

Occurrence. — Type locality is U.S.N.M. 107, NW. of Knoxville. 
Collected from the uppermost beds of the lower limestone member of 
the Nolichucky (Crepicephalus zone) at localities cnn/1, cnn/2. 

Ty/'^.y.— Cotypes : U.S.N.M. 57590, 57591. Plesiotype: U.S.N.M. 
144587. 

COOSIA, species undetermined 

Plate 5, figure 19 

Known from a single pygidium. Axis stout, prominent, slightly 
tapered, rounded posteriorly, somewhat over half the pygidial length, 
extended into a short postaxial ridge. Pleural regions flat, with straight 
anterior and posterior outlines that give the entire pygidium a rec- 
tangular appearance. Pleural furrows, except the first pair, almost 
indistinct, curving backward. Surface of posterior portion of pleural 
regions with transverse wrinkles. Length 3.0 mm., width 8.0 mm. 

This pygidium differs from the associated species of Coosia in its 
subquadrate shape. 

Occurrence. — Upper portion of lower limestone member of the 
Nolichucky (Crepicephalus zone) at locality cnn/1. 

Disposition of material. — Figured specimen : U.S.N.M. 144588. 



54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Family TRICREPICEPHALIDAE Palmer, 1954 

Genus TRICREPICEPHALUS Kobayashi, 1935 

Type species. — Arionellus (Bathyurus) texanus Shumard. 

TRICREPICEPHALUS THOOSA ( Walcott) 

Plate 6, figures 1-4 
Crepicephalus thoosa Walcott, 1916a, p. 214, pi, 31, figs. 1, la-k. 
Paracrepicephalus walcotti Lochman, 1936, p. 39, pi. 9, figs. 29, 31, 33. 
Tricrepicephalus walcotti (Lochman) Resser, 1938a, p. 102, pi. 11, fig. 54. 
Tricrepicephalus thoosa (Walcott) Resser, 1938a, p. 101, pi. 14, fig. 8. 
Tricrepicephalus carta (Walcott) Palmer (part), 1954, p. 755 (includes syn- 
onymy). 

Palmer placed a number of described forms of Tricrepicephalus in 
the synonymy of Tricrepicephalus coria (Walcott), the type of which 
is from the House Range, Utah. He pointed out that the species con- 
strued in this broad sense includes a considerable amount of variation. 

Since the material from the type locality for T. coria is rather poorly 
preserved, the writer prefers to adopt for the southern Appalachians 
form a name based on specimens from that area, and as new material 
was collected from the type locality for T. thoosa, this is the name here 
used. The differences between the type specimens of T. thoosa and 
T. walcotti fall well within the range of variation in cranidial and 
pygidial features observed in individuals from a single bed, hence 
Lochman's name is placed in synonymy. It was also included by Palmer 
in the list of synonyms of T. coria. 

Occurrence. — Type locality for T. thoosa is U.S.N.M. 125a, 4 miles 
NE. of Rogersville (presumably identical with author's locality 
cnn/1). Type locality for T. walcotti is U.S.N.M. 119, S. of Morris- 
town. Collected by the author at localities cnk/1, cnm/2, cnn/1 to 
cnn/5. The species ranges throughout the lower limestone member 
{Crepicephalus zone) of the Nolichucky formation. 

Ty/>^.y.— Holotype of T. thoosa: U.S.N.M. 61654. Holotype and 
paratype of T. walcotti: U.S.N.M. 61655, 61658. Plesiotypes: 
U.S.N.M. 144589-91. 

Genus METEORASPIS Resser, 1935 

Type species. — Ptychoparia metra Walcott. 

METEORASPIS MUTICA Rasetti 

Plate 6, figures 13, 14 
Meteoraspis mutica Rasetti, 1961, p. 116, pi. 21, figs. 25-29. 

The assignment of cranidium and pygidium to the same species is 
made certain by the frequent association in the same bed observed 
in Tennessee. The largest cranidium observed has a length of 11 mm., 
the largest pygidium a length of 5 mm. and a width of 9 mm. 

Occurrence. — The types are from the Conococheague formation 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 55 

near Winchester, Va. Plesiotypes from localities cnm/2 and cnn/1, 
in the upper portion of the lower limestone member of the Nolichucky 
(Crepiceplialus zone) . 
ry/>^j.— Plesiotypes: U.S.N.M. 144592-3. 

METEORASPIS BREVISPINOSA Rasetti, new species 

Plate 6, figures 9-12 

Available material. — Several cranidia and pygidia preserved in lime- 
stone, the larger ones lacking the test. 

Description. — Glabella of usual shape and convexity, unfurrowed, 
defined by a deep axial furrow all around. Occipital furrow deep, occip- 
ital ring rounded, bearing a low node. Preglabellar field and palpebral 
area narrow, convex, downsloping; border elevated, convex, defined 
by a deep border furrow ; the latter with a pair of shallow depressions. 
Posterior area deeply furrowed. 

Pygidium subrectangular, about as wide as long. Axis very promi- 
nent, large, somewhat tapered, rounded posteriorly, almost reaching 
posterior margin ; 3 rings and a terminal section defined by deep fur- 
rows. Pleural lobes steeply downsloping, with fairly straight sides 
slightly convergent backward, extended into a pair of blunt spines; 
margin between spines straight for a considerable length. A few broad 
and shallow pleural furrows indicated on internal impression ; border 
furrow and border indistinct. On the outer surface the pleural lobes 
would probably appear almost entirely smooth, except for the an- 
terior marginal furrow. Length of largest cranidium 11 mm., of 
largest pygidium 1 1 mm. 

Discussion. — The cranidium differs little from M. metra and other 
described species, but the pygidium is characteristic, lacking the long 
spines of other species. The pygidium of M. mutica lacks spines but is 
quite different in other respects. 

Occurrence. — Lower portion of lower limestone member of the 
Nolichucky (Cre pic ephalus zone) at locality cnk/1. 

Types. — Holotype (pygidium): U.S.N.M. 144594. Paratypes: 
U.S.N.M. 144595. 

Family ASAPHISCIDAE Raymond, 1924 

Genus BLOUNTIA Walcott, 1916 

Type species. — Blountia mimula Walcott. 

BLOUNTIA ARCUOSA Resser 

Plate 9, figures 1-8 
Blountia arcuosa Resser, 1938a, p. 64, pi. 12, fig. 25. 

Available material. — The hypodigm contains only cranidia. Excel- 
lent additional material allows a more complete description of the 
species. 



56 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Description. — Glabella very slightly expanding forward in the pos- 
terior half, well rounded anteriorly, exceedingly convex in the anterior 
portion, overhanging the frontal area; occipital furrow exceedingly 
faint on outer surface, occipital ring very short (sag.) ; glabellar fur- 
rows lacking. Preglabellar field vertical; border about as wide (sag.) 
as the preglabellar field, convex, with terrace lines. Anterior sections of 
facial sutures parallel ; posterior section with gentle curvature, defining 
slender, sharply pointed, faintly furrowed posterior area. Palpebral 
lobes small and faintly elevated; palpebral area about 0.2 times the 
glabellar width. 

Pygidium almost twice as wide as long. Axis long, not rising above 
the general convexity; axial furrow shallow. Pleural lobes with con- 
vexity increasing toward the margin, lacking distinct border furrow 
and border, sharply downrolled especially in the posterior portion. 
Furrows obsolete on outer surface ; on interior cast, 6 or 7 rings are 
distinguishable on the axis and 3 faint pairs of furrows on the pleural 
lobes. Surface smooth. 

Occurrence. — Type locality is U.S.N.M. 121a, 4 miles NE. of 
Rogersville. The species is not rare in the upper part of the lower 
limestone member of the Nolichucky formation (Crepicephalus zone) 
in the Rogersville area (localities cnm/1, cnm/2, cnn/2, cnn/3) . 

73;/^^.?.— Holotype : U.S.N.M. 94960. Plesiotypes: U.S.N.M. 
144555. 

BLOUNTIA ALEXAS Walcott 

Plate 9, figures 9-12 

Blountia alexas Walcott, 1916b, p. 398, pi. 61, figs. 5, Sa. 
Blountia alexas Walcott, Resser, 1938a, p. 65, pi. 12, fig. 27. 

Available material. — The hypodigm consists of the holotype crani- 
dium. Additional cranidia and pygidia allow a more complete descrip- 
tion. 

Description. — Glabella of moderate convexity, straight-sided, 
slightly tapered, rounded in front, unfurrowed. Occipital furrow al- 
most indistinct on outer surface, occipital ring very short (sag.). 
Preglabellar field on the average somewhat shorter (sag.) than border, 
the ratio varying somewhat in different individuals; border sHghtly 
convex, wide (sag.), set off from preglabellar field by its upturned 
position. Palpebral area about 0.3 times the width of glabella at same 
level. Anterior facial sutures divergent, anterior angles of cranidium 
well rounded ; posterior section of facial suture with gentle curvature ; 
posterior area falcate, extending farther backward than occipital ring, 
with faint furrow in proximal portion only. 

Pygidium with little convexity. Length 0.6 times width. Axis ta- 
pered, occupying two-thirds of length ; axial furrow shallow laterally, 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 57 

almost obsolete posteriorly. Pleural lobes with faint border furrow 
and wide border. Only traces of segmentation on outer surface. Sur- 
face smooth. 

Occurrence. — Type locality is U.S.N. M. 125, 4 miles NE. of Rogers- 
ville. Plesiotypes from the lower portion of the lower Hmestone mem- 
ber (Crepicephalus zone) of the NoHchucky formation (loc. cnk/1, 
cnk/3, the latter presumably identical with type locaUty). 

Types.— Uolotype: U.S.N.M. 62785. Plesiotypes: U.S.N.M. 
144596, 144701. 

BLOUNTIALATA (Resser) 

Plate 9, figure 21 

Blountiella lata Resser, 1938a, p. 65, pi. 12, fig. Z7. 

Blountia rogersvillensis Resser, 1938a, p. 64, pi. 12, figs. 29, 30. 

The species was described under the two names on the basis of 
cranidia preserving the test or not, respectively, as recognized by 
Lochman and Duncan (1944). This trilobite was found as a rare 
member of the faunule of the upper portion of the lower hmestone 
member of the Nolichucky. The previous descriptions and the illus- 
trations supply the available information about the species. 

Occurrence. — The type locality for Blountiella lata is U.S.N.M. 125 
and that for Blountia rogersvillensis is U.S.N.M. 121a, both 4 miles 
NE. of Rogersville. The author collected the species from the upper- 
most beds of the lower limestone member of the Nolichucky (Crepi- 
cephalus zone) at locality cnn/3. 

Types. — Holotype: U.S.N.M. 94961. Holotype of Blountia rogers- 
villensis: U.S.N.M. 94959. Plesiotype : U.S.N.M. 144597. 

BLOUNTIA MONTANENSIS Duncan 

Plate 9, figures 13-20 

Blountia montanensis Duncan, in Lochman and Duncan, 1944, p. 53, pi. 8, figs. 
29-34. 

This species, described from Montana, is common in the Crepi- 
cephalus zone in Tennessee. There is some variation in the length of 
the preglabellar field, elevation of the anterior border and depth of the 
axial furrow on the cranidium, but since all intermediate forms occur 
in the same beds, these features should be interpreted as intraspecific 
variability. 

Occurrence. — Localities cnk/1, cnm/2, cnn/1, cnn/3. The species 
is more common in the lower portion of the lower limestone member 
of the Nolichucky {Crepicephalus zone) but ranges throughout this 
limestone. 

Ty/j^j.— Plesiotypes: U.S.N.M. 144598-9. 



58 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

BLOUNTIA BRISTOLENSIS Resser 

Plate 10, figures 1, 2; plate 11, figures 9-12 

Blountia bristolensis Resser, 1938a, p. 65, pi. 12, fig. 24. 
Maryvillia bristolensis Resser, 1938a, p. 87, pi. 12, fig. 38. 

Blountia nixonensis Lochman, in Lochman and Duncan, 1944, p. 43, pi. 4, figs. 
7-12. 

Available material. — The hypodigm of B. bristolensis includes the 
holotype pygidium. Maryvillia bristolensis is based on a cranidium 
from the same collection. Blountia nixonensis was described from 
numerous cranidia and pygidia. The author's collections include nu- 
merous fragments and one articulated shield. The latter allows a de- 
scription of the thorax. 

Description. — Entire exoskeleton ovate ; pygidium as large as ceph- 
alon. Thorax of 7 segments, not tapered, as wide as cephalon and 
pygidium. In the specimen, evidently an exuvia as it lacks the free 
cheeks, the cranidium was pushed over the thorax, concealing 
the entire first and part of the second thoracic segment. The entire 
thorax was exposed during preparation when the cranidium broke off. 
In the illustration the cranidium is shown restored. Thoracic axis 
slightly tapered, at much lesser rate than pygidial axis. Axial furrows 
on thorax rather deep. Pleurae unfurrowed, flat and horizontal in 
proximal two-thirds, presenting sharp geniculation and showing an- 
terior facet that allowed enrollment of the animal. Termination of 
pleurae narrowly rounded, sharper in anterior pleurae. Length of exo- 
skeleton, allowing for displacement of cranidium, 17.4 mm., of which 
7.0 belong to the cephalon, 4.4 to the thorax, and 6.0 to the pygidium. 
The individual corresponds almost to the largest size of cranidia and 
pygidia in the author's collections. 

Discussion. — A species of Blountia common in the basal beds of the 
Aphelaspis zone in Tennessee is identified with B. bristolensis. This 
and Maryvillia bristolensis, from the same collection, obviously are 
conspecific. Careful comparison of the author's material with B. nix- 
onensis from Montana failed to reveal any differences. 

The species, like B. mimula, has 7 thoracic segments. In the present 
case one may be certain that the individual is a holaspid. However, it 
should not be inferred that all species of Blountia have 7 segments. 
An undescribed Blountia from the Murphy's Creek formation of the 
Gaspe Peninsula of Quebec, collected by the author, has 9 thoracic 
segments. This Blountia occurs in association with Cedaria and Crepi- 
cephalus and is therefore considerably older. 

Occurrence. — Type locality for Blountia bristolensis and Maryvillia 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 59 

bristolensis is U.S.N.M. 36v, near Bristol, Va. Collected by the author 
at localities cnp/17 (complete specimen), cnp/14, and cnq/14. 

Types. — Holotype of Blountia bristolensis: U.S.N.M. 94942. Holo- 
type of Maryvillia bristolensis: U.S.N.M. 94963. Plesiotypes: 
U.S.N.M. 144600-1. 

BLOUNTIA MIMULA Walcott 

Plate 10, figures Z-7 

Blountia mimula Walcott, 1916b, p. 399, pi. 61, figs. 4, 4a-c. 
Blountia mimula Walcott, Resser, 1938a, p. 63, pi. 12, figs. 18, 19. 

As far as can be determined, a species of Blountia collected from the 
lower Aphelaspis zone seems identifiable with the species. The holo- 
type is an articulated exoskeleton of very small size and is the only 
specimen in the hypodigm that comes from the type locality. The para- 
types are from a different locality and appear conspecific with the 
holotype as far as one can compare immature individuals. The cranidia 
and pygidia illustrated herein are larger than any of the types and 
differ only in the shallower axial furrow around the glabella, a modi- 
fication gradually acquired during the growth of these trilobites. 

Occurrence. — The holotype is from U.S.N.M. locality 120 on Shields 
Ridge. Under this label trilobites from both the Crepicephalus and 
Aphelaspis zones are mixed. The paratypes are from U.S.N.M. locality 
107c, NW, of Knoxville. The specimens illustrated herein are from 
Oder's collection No. 2 in the Hurricane Hollow section, in association 
with Aphelaspis walcotti, in beds higher than those holding Blountia 
bristolensis. 

Types.— RoXoiyp^: U.S.N.M. 62781. Paratypes: U.S.N.M. 
62782-4. Plesiotypes: U.S.N.M. 144602. 

Genus MARYVILLIA Walcott, 1916 

Type species. — Maryvillia arion Walcott. 

MARYVILLIA ARION Walcott 

Plate 9, figures 22-26 

Maryvillia arion Walcott, 1916b, p. 400, pi. 64, figs. 4-4c. 

Maryvillia arion Walcott, Rasetti, 1956, p. 1267 (includes complete synonymy) ; 
1%1, p. 116, pi. 21, figs. 14, 15. 

Occurrence. — Type locality is U.S.N.M. 123b, J^ mile E. of Rogers- 
ville (probably identical with author's locality cnn/2). A common 
and diagnostic fossil of the upper part of the Crepicephalus zone. 
Collected at localities cnk/1 (very rare), cnm/2, cnn/1, cnn/2, cnn/3, 
cnn/4, cnn/14. 



60 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

ry^^^.—Holotype: U.S.N.M. 62826. Plesiotypes: U.S.N.M. 
144603^. 

Family KINGSTONIIDAE Kobayashi, 1933 

Genus KINGSTONIA Walcott, 1924 

Type species. — Kingstonia apion Walcott. 

KINGSTONIA INFLATA Resser 

Plate 8, figures 21-28 

Kingstonia inflata Resser, 1938a, p. 84, pi. 12, figs. 5, 6. 
Kingstonia rotundata Resser, 1938a, p. 83, pi. 12, figs. 9-10. 

Available material. — The two names represent the same species, 
described from the appearance of the outer surface and from internal 
impressions respectively. Abundant material of this exceedingly com- 
mon form allows a more complete description. 

Description. — Cranidium very convex in both directions, barely 
showing a trace of the axial furrow on outer surface. Glabella defined 
on internal impressions, straight-sided, slightly tapered, very wide in 
proportion to cranidial width. Anterior border indicated only by its 
terraced surface, without change in slope from glabella and preglabellar 
field. Palpebral lobes almost indistinct; facial suture showing little 
change of direction before and after palpebral lobes in dorsal view; 
anterior sections strongly convergent ; posterior section gently convex 
outward, defining a stout posterior area ; posterior angles of cranidium 
obtuse. Posterior outline rounded in axial portion, with indentations 
corresponding to the axial furrow; convex along the margin of the 
posterior area. 

Pygidium with axis occupying less than one-third of the maximum 
width, well defined anteriorly but merging with the pleural region 
posteriorly, not tapered. Pleural lobes increasingly convex toward the 
margin. Facet at anterior angles very distinct. Five axial rings and 

3 or 4 broad, shallow pleural furrows visible on interior impressions. 
Length of largest cranidia 4.5 mm. 

Several cranidia, one of which is figured, show through the dark 
surface of the test a regular pattern of yellow stains that presumably 
represent muscle attachments on the inner surface. 

Occurrence. — Type localities for K. inflata are U.S.N.M. 121a, 125, 

4 miles NE. of Rogersville. Type locality for K. rotundata is U.S.N.M. 
123b, near Rogersville. Found by the writer throughout the lower 
limestone member of the Nolichucky (Crepicephalus zone) in the 
Rogersville area (Iocs, cnk/1, cnk/3, cnm/2, cnm/3, cnn/1, cnn/3). 

Types.— Cotypes of K. inflata: U.S.N.M. 94934, 94953. Cotypes 
K. rotundata: U.S.N.M. 94935. Plesiotypes : U.S.N.M. 144605-7. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 61 

Genus ANKOURA Resser, 1938 

Type species. — Ankoura triangularis Resser. 

ANKOURA TRIANGULARIS Resser 

Plate 3, figures 15-21 

Ankoura triangularis Resser, 1938a, p. 58, pi. 9, fig. 33. 

Available material. — Although the pygidia are quite common at the 
type locality, the much more fragile cranidia are difficult to obtain. 
Resser figured a fragmentary cranidium, from which the precise char- 
acters were not clearly understood. Lochman (1940) attributed to 
the species good limestone material from the Bonneterre dolomite; 
however, her form belongs to a different species. Hence a brief descrip- 
tion of the cranidium of Ankoura triangularis is in order. This descrip- 
tion is based on exfoliated topotype material, plus specimens preserving 
the test from another locality. 

Description. — Glabella parallel-sided, rounded in front, well defined 
on internal impressions but barely indicated on the outer surface. 
Occipital furrow almost obsolete on outer surface ; occipital ring very 
short, lacking a spine. Frontal area convex and downsloping; border 
barely represented on outer surface by a narrow striated band as in 
many species of Kingstonia. On internal impressions there is a shallow 
border furrow. Furrow on posterior area almost obsolete on outer 
surface. 

Discussion. — The species differs from the material identified by 
Lochman in two important characters: the simple occipital ring and 
the absence of a flat border. 

Occurrence. — The type locality is U.S.N.M. 27d; red beds at the 
base of the Nolichucky (Cedaria zone) E. of Rogersville. The speci- 
mens figured herein are partly from the type locality, partly from a 
limestone lens at an unspecified level near the base of the NoHchucky 
on Comby Ridge, Howard Quarter quadrangle (author's locality cnb/ 
10). 

Ty/^^.?.— Cotypes : U.S.N.M. 94851. Plesiotypes: U.S.N.M. 
144608-9, 144702. 

Family MENOMONIIDAE Walcott, 1916 

Genus DRESBACHIA Walcott, 1916 

Type species. — Dresbachia amata Walcott. 

DRESBACfflA AMATA Walcott 

Plate 8, figures 1-4 

Dresbachia amata Walcott, 1916a, p. 167, pi. 26, figs. 5, 5a-c. 
Dresbachia appalachia Resser, 1938, p. 74, pi. 10, figs. 32-34. 
Dresbachia amata Walcott, Lochman, 1950, p. 338, pi. 48, figs. 11-14. 



62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

A few cranidia and more numerous free cheeks were collected from 
the lower limestone member of the Nolichucky {Crepicephalus zone) 
at localities cnk/1, cnk/3, cnm/2. 

Types. — Holotype of D. appalachia (from loc. U.S.N.M. 22z, near 
Greendale, Va.) : U.S.N.M. 94875. Plesiotypes: U.S.N.M. 144694. 

Genus MENOMONIA Walcott, 1916 

Type species. — Conocephalites calymenoides Whitfield. 

MENOMONIA PROMINENS Resser 

Plate 5, figures 14-17 

Menomonia prominens Resser, 1938a, p. 88, pi. 9, figs. 42, 43. 
Dresbachia speciosa Resser, 1938a, p. 75, pi. 9, figs. 28, 29. 

Available material. — Resser's two names were based on the cranidia 
and free cheeks of the same species. Additional material allows a more 
complete description. 

Description. — Glabella straight-sided, tapered, rounded in front, 
with 2 pairs of short lateral furrows ; occipital furrow well impressed, 
occipital ring rounded. Preglabellar field slightly arched transversely, 
fairly long (sag.) ; border upturned, arched transversely. Palpebral 
lobes with their midpoint at the level of the anterior end of the glabella, 
strongly upsloping, rising higher than glabella. Posterior area tapered, 
large, strongly downsloping and hence giving strong relief to the 
cranidium, deeply furrowed ; posterior cranidial margin curving back- 
ward. Free cheek with border well defined only anteriorly, almost 
parallel-sided, well rounded at the genal angle. The surface characters 
are described as they appear on internal impressions, as none of the 
specimens preserve the test. Large tubercles on the glabella are ar- 
ranged more or less regularly in 4—5 pairs. Tubercles of the same size 
are irregularly scattered on the fixed cheeks, decreasing in number 
toward the distal end of the posterior area. The tubercles are more 
crowded on the anterior border. The free cheeks have larger granules 
near the eye and finer granules distally. The largest cranidium has a 
length of 4.8 mm. 

Occurrence. — Type locality is U.S.N.M, 27d; red beds at the base 
of the Nolichucky E. of Rogersville (Cedaria zone). Collected by the 
author at the same locality (cnd/1) . 

Types. — Holotype and paratypes: U.S.N.M. 94857. Plesiotypes: 
U.S.N.M. 144695. 

MENOMONIA TUBERCULATA Rasetti, new species 

Plate 2, figures 19-24 

Available material. — Several cranidia and free cheeks in limestone. 
Description. — Glabella and occipital ring similar to preceding spc 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 63 

cies. Preglabellar field about as long (sag.) as border width (sag.) ; 
border elevated, arched transversely. Palpebral area almost as wide as 
anterior portion of glabella, less upsloping than in M. prominens ; pal- 
pebral lobe moderately upsloping, not extending much farther forward 
than the anterior end of the glabella. Posterior area much less tapered 
than in M. prominens, more rounded distally, bearing a deep, wide 
furrow. Posterior outline of cranidium transverse; posterolateral 
angles not extending farther backward than occipital ring. 

Free cheek almost subtriangular. Border distinct for more than half 
the length of the margin. Anterior section of facial suture much longer 
than in M. prominens, corresponding to the more posterior position 
of the eye. Posterior section with slight sigmoidal curvature, cutting 
posterior margin closer to genal angle than in preceding species. Ele- 
vated portions of surface covered with coarse tubercles, possibly repre- 
senting the base of broken spines, those on the glabella being arranged 
more or less regularly in several rows. Length of largest cranidium 
5 mm. 

Discussion. — The present species resembles M. calymenoides rather 
than M. prominens, the differences from the latter having been already 
pointed out in the description. An accurate comparison with topotypes 
of M. calymenoides is not very significant because of the poor preser- 
vation of these small trilobites as internal casts in the Eau Claire sand- 
stone. One definite difference seems to be that in AI. calymenoides the 
anterior border has almost even width, whereas in the present species 
it tapers at the sides. The palpebral area seems to be proportionately 
wider. 

Occurrence. — Uppermost beds of the Maryville limestone (Cedaria 
zone) at localities cnc/1 to cnc/6. 

Ty/^^.y.— Holotype : U.S.N.M. 144696. Paratypes: U.S.N.M. 
144697-8. 

MENOMONIA, species undetermined 

Plate 2, figures 25-27 

A few incomplete cranidia and several free cheeks apparently repre- 
sent a form of Menomonia different from the two previously discussed 
species. 

Most of the cranidial features agree with M. tuberculata, except in 
the somewhat more anterior position of the eyes, narrower palpebral 
area, and lack of tubercles on the posterior area, where the surface is 
finely wrinkled. The free cheek resembles more closely that of M. 
prominens in general shape and also shows a wrinkled surface with, 
in addition, a few tubercles on the anterior part of the border. 



64 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Occurrence. — Uppermost beds of the Maryville limestone {Cedaria 
zone) at localities cnc/4, cnc/6. 

Disposition of material. — Figured specimens: U.S.N.M. 144699- 
700. 

Family NORWOODIIDAE Walcott, 1916 

Genus NORWOODIA Walcott, 1916 

Type species. — N orwoodia gracilis Walcott. 

NORWOODIA ROGERSVILLENSIS Resser 

Plate 4, figures 25, 26 

Norzvoodia rogersvillensis Resser, 1938a, p. 91, pi. 9, figs. 25, 26. 
Norwoodia harlanensis Resser, 1938a, p. 91, pi. 9, fig. 31. 

Available material. — The hypodigms consist of cranidia from the 
same locality. In addition to further cranidia, pygidia occur in the 
author's collection. 

Description. — Glabella tapered, rounded in front, rather convex, 
defined by a well-impressed axial furrow. Glabellar furrows probably 
obsolete on outer surface. Occipital furrow shallow ; occipital ring ex- 
tended into a large, horizontal spine longer than the glabella. Frontal 
area as long as glabella, mostly consisting of downsloping preglabellar 
field; border wide (sag.), upturned. Palpebral area about half the 
glabellar width; ocular ridges distinct. Anterior sections of facial 
sutures very slightly divergent; posterior section directed outward 
and somewhat forward, reaching the margin well in advance of genal 
angle. Posterior area slightly expanding distally, well furrowed, ex- 
tended into a slender and moderately long genal spine. 

The pygidia are attributed to the species because of the close simi- 
larity to N. gracilis and other closely related species. Pygidium twice 
as wide as long, convex. Axis defined laterally, merging with the 
pleural region posteriorly, of 3 distinct rings. Pleural lobes convex, 
with 3 pairs of shallow furrows ; border narrow but distinct. All the 
described cranidial and pygidial features refer to the impression of the 
interior since none of the specimens preserves the test. 

Discussion. — Among the species of the southern Appalachians, the 
present one resembles N. gracilis Walcott, differing mainly in the 
proportionately wider and shorter glabella, shorter occipital spine, and 
different shape of the posterior area and genal spine. 

Occurrence. — Found only in the red beds {Cedaria zone) at the 
base of the Nolichucky. Type locality is U.S.N.M. 27d, the same as 
the author's locality cnd/1. 

Types. — Holotype : U.S.N.M. 94847. Holotype of A'', harlanensis: 
U.S.N.M. 94850. Plesiotypes : U.S.N.M. 144610. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 65 

NORWOODIA, species undetermined 

Plate 4, figure 24 

Cranidia of Norwoodia, too incomplete for specific identification but 
certainly very close to the preceding species, are present in the upper- 
most beds of the Maryville limestone in the Rogersville area. 

Occurrence. — Mar3rville limestone {Cedaria zone) ; localities cnc/2, 
cnc/4, cnc/6. 

Disposition of material. — Figured specimen: U.S.N.M. 144611. 

Genus NORWOODELLA Resser, 1938 

Type species. — Norwoodia saffordi Walcott. 

NORWOODELLA SAFFORDI (Walcott) 

Plate 3, figures 1-6 

Norwoodia saffordi Walcott, 1916a, p. 171, pi. 27, figs. 1-lf. 

Norwoodella saffordi (Walcott) Resser, 1938a, p. 89, pi. 10, figs. 40, 41, 49, 50. 

This species is readily distinguished from all others of the genus 
by the depth of the axial furrow and the fixed cheeks which rise above 
the furrow itself instead of sloping down from it. Limestone specimens 
are figured, in addition to the complete holotype exoskeleton flattened 
in shale. The thorax of this individual seemingly has 9 segments, not 
8 as stated by Walcott. The material from Missouri attributed to this 
species by Lochman (1940) was incorrectly identified. 

Occurrence. — Type locality is U.S.N.M. 103, near Rogersville. The 
species is common in the basal beds of the Nolichucky shale and inter- 
stratified limestone lenses (Cedaria zone) . Collected at localities cnd/1, 
cne/1, cne/2. 

Types. — Lectotype (herein designated) : U.S.N.M. 61595. Para- 
types: U.S.N.M. 61596-600. Plesiotypes: U.S.N.M. 144612-3. 

NORWOODELLA ROTUNDICOLLIS Rasetti, new species 

Plate 4, figures 1-7 

Available material. — Numerous cranidia and a few free cheeks and 
pygidia, preserved in limestone but mostly lacking the test. 

Description. — Glabella tapered, straight-sided, rounded in front, 
fairly convex, rising above the cheeks, unfurrowed on outer surface. 
Axial furrow on outer surface impressed laterally but obsolete in front ; 
on interior impressions well defined all around. Occipital furrow im- 
pressed throughout ; occipital ring subtriangular but rounded, lacking 
a spine. Frontal area convex and downsloping, somewhat over one- 
third the glabellar length, undivided by a border furrow even on inter- 
nal impressions. Palpebral area downsloping, about 0.3 times the 
glabellar width; ocular ridges faint. Posterior area wide (exsag.). 



66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

parallel-sided, with a distinct furrow even on outer surface. Genal 
spine slightly curved, of moderate length. Free cheek as in other 
species of the genus. Surface of test perfectly smooth ; internal impres- 
sions show fine anastomosing lines on frontal area and free cheeks. 
Length of largest cranidium 8 mm. 

The pygidia attributed to the species are so similar to N. saffordi, 
which occurs in the same beds, that some doubt remains concerning 
their assignment. Pygidium somewhat fan-shaped, with regularly 
curved pleurae and anterior margin. Axis prominent, long, tapered, 
showing 3 rings plus a terminal section. Pleurae poorly fused, with 3 
pairs of wide furrows and as many narrow interpleural grooves, all 
furrows and grooves extending to the margin, where the separate 
endings of the pleurae form a wavy outline. Border furrow and border 
lacking. 

Discussion. — The cranidium resembles N. decUvis Resser, which 
also appears to lack an occipital spine. However, this condition in the 
type material in shale may be due to imperfect preservation, and there- 
fore it was deemed preferable not to attempt identification with that 
species. The pygidium resembles, besides A^. saffordi, pygidia associ- 
ated with the type cranidia of N. kingstonensis Resser. All these py- 
gidia strongly differ from those of other species of the genus, such as 
N. walcotti and A^. halli illustrated herein, which have well-fused 
pleural regions, a smooth posterior margin, and a border furrow, much 
like pygidia of Norzvoodia. 

Occurrence. — Red beds at the base of the Nolichucky (Cedaria 
zone) at locality end/ 1 (= U.S.N.M. loc. 27d). 

Types.— Uolotype: U.S.N.M. 144614. Paratypes: U.S.N.M. 
144615. 

NORWOODELLA WALCOTTI Resser 

Plate 4, figures 16-23 

Norzvoodella walcotti Resser, 1938a, p. 89, pi. 10, figs. 42, 54. 

Available material. — The hypodigm consists of cranidia flattened 
in shale. Good cranidia, free checks, and pygidia in limestone occur in 
the U.S.G.S. and author's collections. 

Description. — Glabella entirely undefined on upper surface, except 
for a faint indication of its anterior boundary. Occipital furrow obso- 
lete; occipital ring extended into a slender, horizontal spine. Frontal 
area undifferentiated, somewhat downsloping. Palpebral area, as de- 
terminable on exfoliated specimens, very narrow. Palpebral lobes 
small, somewhat elevated. Anterior sections of facial suture convergent, 
making the frontal portion of the cranidium very narrow, well rounded. 
Posterior section directed almost straight outward from palpebral lobe, 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS RASETTI 67 

almost parallel to posterior cranidial margin, sharply curving back- 
ward, cutting margin near base of genal spine. Genal spine slender, of 
moderate length. Furrow on posterior area obsolete on outer surface, 
impressed on interior cast. Free cheek completely lacking border fur- 
row on outer surface, entirely convex, extended into a short, slender 
strip that simulates a genal spine, but actually contributes to the 
cephalic margin in a region in advance of the base of the genal spine 
borne by the cranidium. Visual surface of eye convex, bean-shaped; 
facets indistinguishable. 

Pygidium approximately semicircular, twice as wide as long. Facets 
well developed. Posterior outline with uniform curvature. Axis well 
defined anteriorly but merging with the pleural lobes posteriorly, 
showing 2 rings plus a terminal indistinctly segmented section. Pleural 
lobes entirely convex, lacking any furrows, showing barely a trace of 
differentiated border. Surface of cranidium and free cheeks perfectly 
smooth. Pleural lobes of pygidium with very fine, transverse terrace 
lines only visible under conditions of perfect preservation. 

Discussion. — This species is quite distinctive in the lack of all 
furrows on the outer surface, and especially the narrowing of the 
cranidium in front of the eyes. The pygidium is much like Norwoodia 
gracilis and N. rogersvillensis and unlike Norwoodella safjordi, N. 
kingstonensis, and N. rotundicollis. This fact would perhaps justify 
redistributing the species hitherto referred to Norwoodia and Nor- 
woodella on the basis of the pygidia, rather than the questionable 
character of the structure of the frontal area. This revision should only 
be undertaken when the pygidia of most species of this group are 
known with certainty. For the present species the assignment is cer- 
tain, since only one species of the Norwoodiidae occurred in the beds 
yielding the material illustrated herein. 

Occurrence. — Basal portion of the Nolichucky (Cedaria zone). 
The type locality is U.S.N.M. 107a, NW. of Knoxville. The specimens 
illustrated are from the collections cne/10, Comby Ridge (= U.S.G.S. 
collection 2407), and cne/12 near Heiskell (the latter presumably 
close to or identical with the type locality) . 

Types. — Holotype and paratypes: U.S.N.M. 94880. Plesiotypes: 
U.S.N.M. 144616-8. 

NORWOODELLA HALLI Resser 

Plate 4, figures 8-15 

Norwoodella halli Resser, 1938a, p. 90, pi. 10, figs. 45, 46. 
Norwoodella halli Resser, Lochman, 1940, p. 47, pi. 5, figs. 31-36. 

The types are cranidia preserved in shale. Lochman gave a detailed 
description of the species and figured unflattened limestone material 



68 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

from Missouri, including the pygidium. The assignment of the two 
parts of the shield is confirmed by the specimens illustrated herein. 

Occurrence. — The type locality is U.S.N.M. 22t in the Thorn Hill 
section, in the interval 45-133 feet above the base of the formation. 
Also in author's collection cnd/10, Comby Ridge. 

Types. — Holotype and paratypes: U.S.N.M. 94883. Plesiotypes: 
U.S.N.M. 144619. 

Genus HOLCACEPHALUS Resser, 1939 

Type species. — Holcacephalus granulatus Resser. 

HOLCACEPHALUS GRANULATUS Resser 

Plate 3, figures 12-14 

Holcacephalus granulatus Resser, 1938a, p. 81, pi. 9, figs. 15-17. 

Available material. — The species, quite common at the type locality, 
was not found elsewhere. All the available specimens lack the test. 

Description. — Glabella definitely tapered, defined by a deep axial 
furrow, with two pairs of short, but deep lateral furrows, and another 
pair less distinct. Occipital furrow deep, occipital ring long (sag.), 
bearing a short, very slender spine. Preglabellar field downsloping, 
border narrow, well defined by the border furrow. Ocular ridges trans- 
verse ; palpebral lobes at level of anterior third of glabella ; palpebral 
area almost as wide as anterior portion of glabella. Posterior area 
slender, slightly expanded distally, bearing a genal spine that is broken 
off in almost all available specimens. Surface covered with relatively 
large granules. 

Pygidium twice as wide as long, subelliptical ; with posterior outline 
slightly indented medially. Axis occupying almost entire length, with 
4 prominent rings. Pleural lobes slightly convex, lacking border furrow 
or border. Three pairs of pleurae are clearly separated by interpleural 
grooves ; each pleura is furrowed and the posterior band bears a row 
of tubercles like those on the cranidium. 

Discussion. — This species differs considerably from all others hith- 
erto attributed to the genus in the tapered, deeply furrowed glabella. 

Occurrence. — Red limestone beds at the base of the Nolichucky 
(Cedaria zone) at U.S.N.M. locality 27d (= author's locality cnd/1), 

Ty/^^.?.—Cotypes: U.S.N.M. 94844. Plesiotypes: U.S.N.M. 144620. 

HOLCACEPHALUS PRAECURSOR Rasetti, new species 

Plate 3, fig-ures 10, 11 

Available material. — Several cranidia and pygidia. 

Description. — Owing to the similarity to the preceding species, it is 
sufficient to point out the differences. The anterior border is somewhat 
wider and flat instead of convex ; the ocular ridges are more prominent ; 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 69 

the cranidial surface has fewer and smaller granules than H. granu- 
latus; these are barely apparent on the glabella and frontal area, being 
more conspicuous on the palpebral and posterior areas. The pygidium 
has the same structure as in H. granulatus, but here again the granules 
are indistinct. The species attains a larger size, with cranidia 3^ mm. 
in length. This form may be ancestral to H. granulatus. 

Occurrence. — Uppermost beds of Maryville limestone {Cedaria 
zone) at locality cnc/1. 

Tj;/)^.?.— Holotype : U.S.N.M. 144621. Paratypes: U.S.N.M. 
144622. 

Family CEDARIIDAE Raymond, 1937 

Genus CEDARIA Walcott, 1924 

Type species. — Cedaria prolifica Walcott. 

CEDARIA TENNESSEENSIS Walcott 

Plate 5, figures 4-8 

Cedaria tennesseensis Walcott, 1925, p. 79, pi. 17, figs. 22-25. 
Cedaria tennesseensis Walcott, Resser, 1938a, p. 68, pi. 11, figs. 3-5. 

Available material. — The types are cranidia, free cheeks, and py- 
gidia flattened in shale. Fragmentary material in limestone was col- 
lected by the writer. 

Description. — Cranidium of moderate convexity. Glabella as in other 
species of the genus. Frontal area sharply divided into preglabellar 
field and border by a narrow border furrow ; border flat, its sagittal 
length more than half the length of the preglabellar field. Palpebral 
area and lobe without specific features. Posterior area broad (exsag.), 
the posterior section of the facial suture running outward and slightly 
forward ; border furrow on posterior area turning forward for a con- 
siderable distance. Anterior sections of facial suture less divergent 
than in most other species of the genus. Free cheek with ocular plat- 
form and border of about equal widths, separated by sharp border 
furrow, Genal spine long and strong as in other species of Cedaria. 

Pygidium 1.6 times as wide as long, almost elliptical, with anterior 
angles widely rounded. Axis short, in larger individuals not exceeding 
half of the pygidial length, showing about 3 rings plus a terminal sec- 
tion. Pleural regions almost flat, wide, with 3 pairs of broad, shallow 
furrows and a trace of a fourth, and indistinct interpleural grooves. 
The furrows run straight through the pleural platform, change to a 
more backward direction in passing onto the wide, slightly concave 
border, and almost reach the pygidial margin. Pygidial doublure very 
wide, its anterior margin well visible as an impression on the dorsal 
side. Pygidial border with very fine, wavy lines. 

Discussion. — This species differs considerably from the type species, 



70 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

C. prolifica, in the lesser divergence of the anterior section of the facial 
suture, wider cephalic border, broader (exsag.) posterior area, py- 
gidium more transverse, with shorter axis, fewer pleural segments, 
and much wider border and doublure. 

Occurrence. — The type locality is U.S.N.M. 107a, Copper Ridge, 
NW. of Knoxville (very close to author's locality cne/12). Collected 
by the writer at localities cne/10, cne/12, cne/13. All the limestone 
material is fragmentary, especially the cranidia. 

73;/'^.?.— Lectotype (designated herein) : U.S.N.M. 70270. Para- 
types : U.S.N.M. 70271-3. Plesiotypes : U.S.N.M. 144623. 

Genus CEDARINA Lochman, 1940 

Type species. — Cedarina vale Lochman. 

CEDARINA, species undetermined 

Plate 5, figure 18 

Available material. — A few pygidia, all lacking the test. 

Description. — Pygidium almost 3 times as wide as long. Axis ele- 
vated, tapered, composed of 3 rings plus a terminal section, almost 
reaching the posterior pygidial margin. Anterior outline of pleural 
lobes slightly curved, anterior angles sharp, posterior margin with 
shallow, rounded median notch. Three pairs of pleural furrows well 
impressed, shallow interpleural grooves distinct near border. Border 
furrow indistinct, border flat, narrow. Length of largest pygidium 
3.3 mm., width 9.2 mm. 

Discussion. — The pygidium closely resembles that of Cedarina vale 
Lochman from Missouri. The pygidia of other species of the genus 
described by Lochman from the West are all proportionately longer. 
No definite identification can be made without the cranidium. 

Occurrence. — Rare in the red beds at the base of the Nolichucky 
(Cedaria zone) at locality end/ 1. 

Disposition of material. — Figured specimen: U.S.N.M. 144624. 

Genus LLANOASPIS Lochman, 1938 

Type species. — Llanoaspis modesta Lochman. 

LLANOASPIS WALCOTTI (Resser) 

Plate 8, figures 14-16 

Gencvievella walcotti Resser, 1938a, p. 77, pi. 15, figs. 3-5. 
Genevievclla rogersvillensis Resser, 1938a, p. 78, pi. 15, figs. 16-18. 
Rogersvillia rogersvillensis (Resser) Hupe, 1953, p. 182, fig. 159. 

Palmer (1954) placed a number of described species of the genus, 
including zvalcotti, in the synonymy of the type species. While the 
writer agrees that not all the described forms are distinguishable, he 
believes that the one here discussed is readily separable by the shape 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 71 

of the pygidium, which completely lacks the lateral expansion of the 
posterior border clearly apparent in the specimens of L. modesta fig- 
ured by Lochman (1938) and Palmer (1954). 

The type specimens of walcotti are preserved in limestone, while 
those of rogersvillensis are flattened in shale, but there seems to be no 
specific difference between the two. 

Occurrence. — Type locality for L. rogersvillensis is U.S.N.M. 24m, 
near Rogersville. Type locality for L. walcotti is U.S.N.M. 107, NW. 
of Knoxville. The figured specimens are from the uppermost beds of 
the lower limestone member of the Nolichucky (Crepicephalus zone) 
at locality cnn/3. 

Types. — Holotype and paratypes of L. rogersvillensis: U.S.N.M. 
94974-5. Holotype and paratypes of L. walcotti: U.S.N.M. 94970-1. 
Plesiotypes : U.S.N.M. 144625. 

Genus GENEVIEVELLA Lochman, 1936 

Type species. — Genevievella neunia Lochman. 

GENEVIEVELLA, species undetermined 

Plate 5, figures 9-11 

Known from several cranidia. The shape and convexity of glabella, 
frontal area and posterior area are about the same as in the type spe- 
cies. However, the present form lacks the strong elevation of the 
palpebral area and palpebral lobes present in G. neunia. As the material 
is scarce, imperfectly preserved, and from different localities, it does 
not warrant naming a new species. 

Occurrence. — A large cranidium was collected from locality cnc/4, 
and another from locality cnc/2, both in the uppermost Maryville 
limestone. Further material was collected in limestone beds or lenses 
at the base of the Nolichucky (localities cnd/1, cne/2). All these beds 
belong in the Cedaria zone. 

Disposition of material. — Figured specimens : U.S.N.M. 144626-7. 

Family ELVINIIDAE Kobayashi, 1935 

Genus DUNDERBERGIA Walcott, 1924 

Type species. — Crepicephalus (Loganellus)nitidus Hall and Whit- 
field. 

DUNDERBERGIA TENNESSEENSIS Rasetti, new species 

Plate IS, figures 1-12 

Available material. — Several cranidia and free cheeks, two pygidia, 
and one tentatively assigned hypostome. 

Description. — Glabella of fairly strong convexity, straight-sided, 
tapered, somewhat truncate in front, defined by deep axial furrows 
laterally, shallower furrow in front. Three pairs of lateral furrows; 



72 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

posterior pair very oblique, moderately deep ; third pair shorter and 
shallower, directed slightly backward; second pair very short and 
shallow, directed slightly forward. Occipital furrow deep, occipital ring 
bearing a node. Preglabellar field slightly convex longitudinally and 
more or less downsloping in different individuals. Border furrow well 
impressed, in some cranidia showing an indication of the median angle 
more marked in several other species of the genus. Border somewhat 
convex, not greatly tapered laterally ; midlength (sag.) of border about 
half the length of preglabellar field. In anterior view the border appears 
fairly arched transversely in some cranidia, especially the larger ones, 
rather flat in smaller individuals. It was considered whether this might 
be a specific distinction ; however, since the two kinds are mixed in the 
collections from both localities where the species was found, it was 
thought more likely that the differences are due either to growth 
stages, to intraspecific variability, or both. Palpebral area somewhat 
convex, on average horizontal, half as wide as glabella. Ocular ridges 
straight, slanted backward, more strongly so in the larger cranidia. 
Palpebral lobe defined by deep furrow even on upper surface, narrow, 
strongly curved, somewhat convex transversely, 0.20 to 0.25 times as 
long as glabella; distance from posterior margin greater than length 
of lobe. Anterior section of facial suture as divergent as in an average 
Aphelaspis. Posterior area slender, somewhat narrower (tr.) than 
occipital ring. Ocular platform moderately convex. Border on free 
cheek of uniform width, almost flat, defined by shallow furrow ; genal 
spine strong, of moderate length. 

All portions of the cranidial surface except in the furrows covered 
with granules, usually of two sizes, although in some of the cranidia 
only the larger granules are distinct. The border of the free cheek has, 
in addition to dense, fine granules, a few scattered, somewhat larger 
granules. Length of largest (holotype) cranidium 15 mm. 

Pygidium twice as wide as long. Axis large, wider than the pleural 
lobe, elevated, subcylindrical, rounded at the extremity, extended into 
a short postaxial ridge reaching the posterior margin. First two axial 
rings well defined, the rest merging into a terminal section. Pleural 
platforms without much relief, with 2 pairs of broad, rather indefinite 
furrows. Border rather narrow, flat, poorly defined. In posterior view 
the posterior margin appears elevated medially. Surface finely granu- 
late. 

Discussion. — The cranidium seems definitely referable to Dunder- 
bergia and shows most similarity to D. bigranulosa Palmer (1960) 
and D. anytus (Hall and Whitfield), both from Nevada. The pygidium 
also closely agrees with pygidia of Dunderhergia figured by Palmer. 
D. bigranulosa is from the Dunderbergia zone, while the stratigraphic 
position of D. anytus, does not seem to be known with certainty. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 72i 

Occurrence. — Uppermost Aphelaspis zone, in association with 
Aphelaspis tarda. The type locality is cnw/14. Shields Ridge. Also in 
collections cnw/20, Washburn, and cnu/7, Purchase Ridge, Scott 
County, Va. 

ry/^^.y.— Holotype : U.S.N.M. 144628. Paratypes: U.S.N.M. 
144629-31. 

DUNDERBERGIA LONGEFRONS Rasetti, new species 

Plate 15, figures 13-18 

Available material. — Several cranidia and one pygidium. 

Description. — Glabella strongly convex transversely and fairly con- 
vex longitudinally, slightly tapered, rounded in front, with 2 pairs of 
shallow lateral furrows. Occipital furrow deep, occipital ring lacking a 
distinct node. Frontal area relatively short ; preglabellar field steeply 
downsloping; border convex, elevated. Palpebral area convex trans- 
versely, on the average horizontal ; ocular ridges low and broad ; pal- 
pebral lobes well defined by furrow even on outer surface, slightly more 
anterior with respect to the glabella than in the preceding species. 
Anterior section of facial suture weakly divergent; posterior section 
and posterior area not entirely preserved. 

Pygidial axis broad, elevated, showing two very distinct rings and 
a terminal section with a third shallow ring furrow ; axis extended into 
a broad postaxial ridge. Pleural regions with 3 distinct pairs of broad 
furrows; interpleural grooves lacking. Border furrow broad, border 
narrow, poorly defined. The posterior outline shows a faint median 
notch in dorsal view and is elevated medially in posterior view. 

Surface of both shields covered with moderately elevated granules. 
Length of largest (holotype) cranidium 6 mm. Length of pygidium 
L3 mm., width 2.4 mm. 

Discussion. — The species differs from D. tennesseensis and most 
other forms of the genus in the proportionately longer glabella relative 
to the entire cranidium. 

Occurrence. — U.S.G.S. collection 2970, Monroe County. The asso- 
ciation of species at that locality indicates the middle Aphelaspis zone. 

Ty/'^.y.— Holotype : U.S.N.M. 144632. Paratypes: U.S.N.M. 
144633. 

Family PTEROCEPHALIIDAE Kobayashi, 1935 

Genus APHELASPIS Resser, 1935 

Type species. — Aphelaspis walcotti Resser. 

The study of the species of Aphelaspis, from the southern Appala- 
chians presents such taxonomic problems as may be expected when 
thousands of individuals from numerous localities and slightly differ- 



74 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

ent horizons are available. Each thin limestone bed or lens, where the 
well-preserved material occurs, shows a population with a certain 
range of variability, but often statistically distinguishable from those 
occurring in lower or higher beds. In certain cases the range of varia- 
tion within a population is such that extreme individuals overlap in 
several features those of different populations. Nevertheless, as mate- 
rial from a larger number of localities was studied, 17 well-character- 
ized species emerged. Most of these could be found at a number of 
different localities in the same stratigraphic order, hence are valuable 
for correlation. 

A favorable factor in the study of this difficult genus was offered 
by the frequent occurrence in a single bed or lens of a coquina of 
fragments of a single species. Hence the various parts could be 
assigned unequivocally for all the species described herein. Less fre- 
quently 2 species occurred in the same bed, and only 1 association of 3 
species (A. camiro, laxa, and quadrata) was observed. 

Difficulties in identification resulted from the presence in some beds 
of only immature forms of species that occur in much larger sizes 
at other localities. Cranidia less than 4 or 5 mm. in length are often 
indeterminable. Exfoliated specimens are difficult to compare accu- 
rately with individuals preserving the test; the latter were chosen 
almost exclusively for the descriptions and illustrations. Material pre- 
served in shale or siltstone can seldom be specifically identified. 

Virtually all the specimens collected could be assigned to the species 
discussed herein. However, it is to be expected that future collections 
from new localities will yield further new species, owing to the fact 
that fossiliferous limestone beds in shale may occur at slightly different 
horizons at different places. 

In agreement with Palmer (1962b), Proaulacopleura Kobayashi, 
1936, C lev eland ella Resser, 1938, and Labiostria Palmer, 1954, are 
here considered subjective synonyms of Aphelaspis. 

The characters of the genus have been described in great detail by 
Palmer (1954, 1962b). Only one point concerning ornamentation will 
be mentioned here. The upper surface of the test in the southern Ap- 
palachian species is either perfectly smooth, or finely punctate, in 
.some species only in the furrows {A. inerniis, A. arsoides, A. pal- 
meri). The inner surface is invariably very finely granulate, and the 
internal impression therefore finely and densely pitted. Lack of com- 
ment on ornamentation in the specific descriptions means that the 
outer surface is entirely smooth. 

The characters most frequently used for specific discrimination are 
the following. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS RASETTI 75 

( 1 ) The width of the palpebral area relative to the glabellar width 
at the same level. 

(2) The sagittal length of the frontal area relative to the length 
of glabella, including the occipital ring. 

(3) The relative sagittal lengths of preglabellar field and border. 
This ratio and the preceding one, although of undoubted statistical 
significance, were found variable within a population for some of the 
species (e.g., A tarda, A. camiro). Such variations appeared uncor- 
related with either stratigraphic position or size of the cranidia. 

(4) The (exsagittal) length of the palpebral lobes relative to the 
length of glabella inclusive of occipital ring. 

(5) The (exsagittal) length of the palpebral lobe relative to the 
exsagittal distance between the posterior end of the palpebral lobe 
and the posterior cranidial margin. 

(6) The (transverse) width of the posterior area relative to the 
width of the occipital ring. 

(7) The angle of divergence of the anterior sections of the facial 
suture and the more or less sharp change of direction of the suture 
in crossing the anterior border furrow. The posterior section of the 
facial suture has the same course in all species. 

(8) The slope of the palpebral area, also a somewhat variable 
feature within a population. 

(9) The slope and convexity of the preglabellar field and the 
more or less sharp angle formed by the border with respect to the pre- 
glabellar field. These features show large intraspecific variability, 
e.g., in A. laxa and A. tarda. 

(10) The free cheeks in some cases offered useful characteristics 
in the features of the border and genal spine. 

(11) The pygidia may be virtually indistinguishable for several 
species. In other cases species whose cranidia are very similar may 
show quite different pygidia. 

All the species previously described from Virginia and Tennessee 
by Walcott (1916a) and Resser (1938a) could be found again, repre- 
sented by more abundant and better preserved material, and with 
three exceptions are discussed herein. Saratogia aruno Walcott and 
Clevelandclla nitida Resser are specifically undetermined forms of 
Aphelaspis possessing an occipital spine, presumably identical with 
either A. arses or A. arsoides. Aphelaspis hamhlenensis is based on a 
complete exoskeleton flattened and weathered in shale ; since individ- 
uals so preserved do not preserve the specific features, the name should 
be restricted to the holotype. In these three cases the stratigraphic 
position of the type specimens is unknown. 



76 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

APHELASPIS WALCOTTI Resser 

Plate 18, figures 10-20 

Aphelaspis zvalcotti Resser, 1938a, p. 59, pi. 13, fig. 14, 

Aphelaspis walcotti Resser, Palmer, 1962b, p. 33, pi. 4, figs. 24, 28, 33. 

Aphelaspis simulans Resser, 1938a, p. 59, pi. 13, figs. 19-21. 

Available material. — The hypodigm of A. walcotti consists of sev- 
eral cranidia, free cheeks, and pygidia, moderately well preserved and 
exfoliated. The types of A. simulans also include cranidia, free cheeks, 
and pygidia. Abundant material from the author's collections at various 
localities is also available. 

Description. — Cranidium with less relief than average in the genus. 
Glabella defined by a shallow axial furrow on outer surface, weakly 
convex. Preglabellar field moderately downsloping and somewhat 
convex. Border fiat, forming sharp angle with preglabellar field. 
Frontal area on average 0.6 times the length of glabella plus occipital 
ring. Sagittal length of border averaging slightly less than the length 
of preglabellar field. Palpebral area of average width, from slightly 
upsloping to horizontal. Ocular ridges very faint, almost transverse 
to slightly slanted backward. Palpebral lobe averaging somewhat more 
than one-third the length of glabella plus occipital ring ; distance from 
posterior end of palpebral lobe to posterior margin greater than length 
of palpebral lobe. Anterior section of facial suture with average diver- 
gence ; anterior angles of cranidium more widely rounded than in most 
species. Width (tr.) of posterior area less than width of occipital ring. 

Free cheek with ocular platform of low convexity. Border slightly 
concave, upturned, not defined by furrow or sharp change in slope. 
Genal spine flat on upper side, of less than average length, rather 
rapidly tapered. 

Pygidium 3 times as wide as long. Anterior margin almost straight ; 
anterior angles sharp. Axis short, showing 2 or 3 rings plus a terminal 
section. Pleural lobes flat, with furrows and interpleural grooves, 
almost indistinct on outer surface, well marked on internal impression. 
Border flat, very narrow medially. 

Length of largest cranidium collected 15 mm. 

Discussion. — Careful examination of the types of Aphelaspis simu- 
lans and additional topotype material preserved in the U.S. National 
Museum indicates that the species may be definitely synonymized 
with A. walcotti. Aphelaspis simulans is based on a population show- 
ing a slightly greater relief of the cranidial parts than the average in 
A. walcotti, in particular, definitely upsloping palpebral area; however, 
the differences are not consistent among individual cranidia and fall 
within the range of variability observed within a single population. 
The pygidium also fully agrees with that of typical A. walcotti. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 77 

The species is closest to A. bridgei, A. quadrata, and A. tarda. The 
differences will be discussed in describing these species. 

Palmer (1954) assigned to Aphelaspis walcotti material from Texas 
which seems to include excessive variation to represent a single spe- 
cies. The Texas pygidia differ considerably from the Tennessee forms, 
hence it appears doubtful that the species exists in Texas. Cranidia 
from Wyoming illustrated by Shaw (1956) certainly do not belong 
to the species. 

Occurrence. — The type locality is U.S.N.M. lOu, near Saltville, Va. 
The type locality for A. simulans is U.S.N.M. 117d, near Washburn, 
Grainger County. Collected by the author at localities cnq/4, cnr/15, 
cnr/16, cnq/16, cnrV17, and cnq/20. 

Types. — Holotype and paratypes : U.S.N.M. 94923. Holotype and 
paratypes of Aphelaspis simulans: U.S.N.M. 94925-6. Plesiotypes: 
U.S.N.M. 144632-4. 

APHELASPIS BRIDGEI Rasetti, new species 

Plate 13, figures 1-7 

Available material. — Large numbers of cranidia and less numerous 
free cheeks and pygidia well preserved in limestone. 

Description. — Glabella defined by a shallow axial furrow, of usual 
shape. Occipital furrow shallow, occipital ring bearing a small node. 
Frontal area about 0.55 times as long as glabella. Preglabellar field 
somewhat convex longitudinally ; border sharply defined by border 
furrow and change in slope, slightly convex, approximately horizon- 
tal; sagittal length of border almost equaling preglabellar field. Pal- 
pebral area slightly downsloping, 0.4 times as wide as glabella. Aver- 
age exsagittal length of palpebral lobe 0.34 times length of glabella 
plus occipital ring and 0.84 times distance from posterior end of 
palpebral lobe to posterior cranidial margin. Ocular ridges faint, 
somewhat slanted backward. Width (tr.) of posterior area 0.8 times 
the width of the occipital ring. 

Free cheek with flat border defined by shallow border furrow ; genal 
spine flat on upper side, of moderate length. 

Pygidium about 2.8 times as wide as long. Axis tapered, showing 
2 or 3 well-defined rings and a terminal section. Anterior outline of 
pleural region almost straight, without apparent geniculation. Anterior 
angles rounded, posterior margin regularly curved. Three pairs of 
pleural furrows very distinct ; interpleural grooves faint. Furrows and 
grooves not extending to narrow, flat border. 

Surface of all parts of test smooth. Length of large cranidium 
10 mm. Length of largest pygidium 4.3 mm., width 12 mm. 

Discussion. — This species is very close to A. walcotti, from which 



78 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

it may be distinguished, at least statistically, by the slightly down- 
sloping palpebral area, flat rather than concave border of the free 
cheeks, and more deeply furrowed pygidium. In some respects the 
species is transitional between A. lata and A. walcotti. 

Occurrence. — U.S.G.S. collection 2804, from N. slope of Shields 
Ridge on New Market-Piedmont road, in upper part of lower lime- 
stone unit of the Nolichucky. The association with Blountia bristolen- 
sis and Glaphyraspis ornata shows that the species belongs to the 
lower portion of the Aphelaspis zone. The author was unable to 
collect fossils from this portion of the zone at the locality. The nearby 
locality at Russell Gap yielded fossils of the basal Aphelaspis zone, 
including, in ascending order, Aphelaspis lata and A. minor. The 
present species presumably occurs in higher beds, but lower than 
those which yielded Aphelaspis camiro, A. laxa, and A. quadrata at 
their type locality, U.S.N.M. 120, which is also on the New Market- 
Piedmont road. 

T3;/>?.y.— Holotype : U.S.N.M. 144635. Paratypes: U.S.N.M. 
144636. 

APHELASPIS QUADRATA Resser 

Plate 18, figures 1-9 
Aphelaspis quadrata Resser, 1938a, p. 59, pi. 13, figs. 16-17. 

Available material. — The holotype is a large, somewhat incomplete 
cranidium. The collection from the type locality includes several 
cranidia and pygidia, from which a clear picture of the specific char- 
acters can be gathered. The species was collected by Dr. Oder and the 
writer from the Three Springs, Washburn, and Smith Hollow sec- 
tions. Free cheek and pygidium were unequivocally identified. 

Description. — Glabella of average shape and convexity, defined by 
a well-impressed axial furrow. Preglabellar field downsloping, of 
moderate and fairly uniform convexity. Border averaging two-thirds 
of the sagittal length of preglabellar field, upturned and hence forming 
a sharp angle with the preglabellar field, almost flat ; border furrow 
uniformly curved. Frontal area on average 0.50 times as long as 
glabella inclusive of occipital ring. Palpebral area slightly convex, 
horizontal to slightly upsloping. Ocular ridges definitely slanted back- 
ward. Length of palpebral lobe 0.25 times length of glabella plus 
occipital ring, and 0.7 times distance from posterior end of palpebral 
lobe to posterior margin. Anterior section of facial suture with average 
divergence. Width (tr.) of posterior area equals width of occipital 
ring. 

Free cheek with fairly convex ocular platform. Border flat, up- 
turned. Genal spine relatively short, rapidly tapered. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 79 

Pygidium 2.3 times as wide as long. Anterior margin definitely 
curving backward. Axis elevated, tapered, showing 3 rings plus a 
terminal section. Pleural lobes with distinct furrows and shallower 
interpleural grooves even on outer surface. Border flat, narrower 
medially ; margin with slight median inbend. 

Length of largest cranidium about 15 mm. 

Discussion. — This species may be compared with A. laxa and A. 
walcotti. From laxa it differs consistently in the somewhat more con- 
vex glabella, less bulging preglabellar field, more posterior position 
of the eyes, and shorter (tr.) posterior area. The pygidium is propor- 
tionately narrower and more strongly furrowed. Compared with A. 
walcotti, A. quadrata has a cranidium with greater relief, lesser rela- 
tive sagittal length of border relative to preglabellar field, and the 
pygidium has a more curved anterior margin. 

Occurrence. — The type locality is U.S.N.M. 120, Shields Ridge. 
Although material under this label includes collections from different 
horizons, the association of the species with A. camiro and A. laxa is 
proved by the occurrence of the three species on the same piece of 
rock. Also collected by the author at localities cns/15, cns/16, cnr/20 
and cnrV20, in association with the equally common A. camiro and 
rare specimens of A. laxa. 

Types. — Holotype and paratypes: U.S.N.M. 94924. Plesiotypes: 
U.S.N.M. 144637-8. 

APHELASPIS TARDA Rasetti, new species 

Plate 20, figures 1-18 

Available material. — Large numbers of cranidia, free cheeks, and 
pygidia from several localities, both preserving the test and exfoliated. 

Description. — Glabella of average shape and convexity; occipital 
ring bearing a median node. Frontal area averaging 0.65 times the 
glabellar length, but showing wide variation in this ratio, uncorrelated 
with size, locality, or horizon. Preglabellar field more or less convex 
longitudinally ; border flat, forming sharp angle with preglabellar field. 
Sagittal length of border on average half of that of preglabellar field ; 
this ratio is also highly variable. Palpebral area and lobe always more 
or less upsloping; palpebral area from 0.3 to 0.4 times as wide as 
glabella. Ocular ridges transverse to slightly slanted backward. Length 
of palpebral lobe about 0.4 times glabellar length and equal to distance 
to posterior margin. Width (tr.) of posterior area 0.8 times the width 
of occipital ring. 

Free cheeks with border furrow distinct and border of variable 
width, flat to somewhat convex. Genal spine subcylindrical, rather flat 
on upper side, wide at the base, of moderate length. 



80 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Pygidium 2.5 times as wide as long. Axis showing 2 or 3 distinct 
rings on outer surface. Anterior outline of pleural lobes gradually 
curving backward without sharp geniculation, anterior angles more 
or less rounded. Pleural platforms with very faint furrows on outer 
surface ; border furrow and border indefinite. 

Length of largest cranidium 18 mm. Length of largest pygidium 
4 mm., width 10 mm. 

Discussion. — The numerous populations of this species observed 
show individual variability, especially in the relative proportions of 
border, preglabellar field, and glabellar length. Single cranidia with 
short preglabellar field and long border may be confused with A. wal- 
cotti and possibly other species. However, statistically the species is 
fairly well defined. The considerable length of the preglabellar field 
in most individuals, the upsloping palpebral area, definite flat border 
and border furrow on the free cheeks, and the characteristic pygidium 
with well-rounded anterior angles clearly distinguish a population of 
A. tarda from one of A. walcotti. The two species are rather widely 
separated stratigraphically, and no transition forms were observed in 
intermediate beds. 

Occurrence. — Common at every locality where fossiliferous beds 
of the upper Aphelaspis zone are developed. The type locality is 
cnw/20, Washburn. Also present in collections cnu/1, cnv/1, cnw/1, 
cnw/14, cnu/15, cnv/15, cnx/20, cnu/21, cnv/21 and Oder's collec- 
tion No. 14A. The species is also common in beds cnu/7, cnv/7 and 
cnvV7 in the Purchase Ridge section, Scott County, Va. 

Ty/'^^.— Holotype : U.S.N.M. 144639. Paratypes: U.S.N.M. 
144640-2. 

APHELASPIS LAXA Resser 

Plate 12, figures 18-21 ; plate 13, figures 8-15 

Aphelaspis laxa Resser, 1938a, p. 60, pi. 13, fig. 18. 

Available material. — The holotype is an exfoliated cranidium lack- 
ing the palpebral lobes and part of the anterior border. Several para- 
type cranidia are much better preserved, and further topotype material 
exists in the U.S. National Museum collections. The species also 
occurs in several of the author's collections, represented by cranidia, 
free cheeks, and pygidia. 

Description. — Glabella of low convexity, rising little above the level 
of the cheeks, but defined at least laterally by a rather deep axial 
furrow. Frontal area about 0.6 times the glabellar length. Preglabellar 
field strongly convex longitudinally, hence sloping down steeply to 
border furrow. Border almost flat, horizontal ; sagittal length of border 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 81 

more than half the length of preglabellar field. Palpebral area 0.4 
times as wide as glabella, approximately horizontal; ocular ridges 
faint, with transverse course. Sagittal length of palpebral lobe 0.3 
times the glabellar length, and about 0.6 times the distance from pos- 
terior end of palpebral lobe to posterior margin. Width (tr.) of 
posterior area 1.1 times the width of occipital ring. 

Free cheek with relatively convex ocular platform, and wide, flat 
border upturned with respect to platform. Genal spine broad at base, 
rather rapidly tapered, flat on upper side, in most specimens somewhat 
curving upward. Depression at end of posterior border furrow deeper 
than in most species of the genus. 

Pygidium definitely identified from collections where the species 
occurs alone. Pygidium about 3 times as wide as long ; anterior margin 
fairly straight, anterior angles narrowly rounded. Axis tapered, show- 
ing 2 and sometimes 3 rings plus a terminal section. Two or three 
pairs of broad, shallow pleural furrows usually visible; some speci- 
mens also show a trace of interpleural grooves. 

Length of largest cranidia 16 mm. Length of largest pygidium 5 
mm., width 15 mm. 

Discussion. — The species is well distinguished, at least statistically, 
by the low glabella, strongly convex preglabellar field, anterior posi- 
tion of the eyes, and considerable width (tr.) of the posterior area. 
However, single cranidia, especially if incompletely preserved, may 
be confused with such species as A. walcotti, A. quadrata, and A. 
tarda. The pygidium resembles those of A. walcotti and A. hridgei. 

Occurrence. — The type locality is U.S.N.M, 120 on Shields Ridge ; 
beds holding this species are not now exposed at that locality. The 
stratigraphic position of the species is well established by its occur- 
rence in the author's collections cns/4, cns/15, cns/16, cnsVlS, 
cnr/20, and cnrV20. 

Types. — Holotype and paratypes: U.S.N.M, 94929. Plesiotypes: 
U.S.N.M. 144643-5. 

APHELASPIS PALMERI Rasetti, new species 

Plate 14, figures 13-19 

Available material. — Several cranidia, free cheeks, hypostomes, and 
pygidia. 

Description. — Glabella of average shape and convexity; occipital 
ring bearing a small node. Preglabellar field convex longitudinally, 
steeply downsloping in anterior portion, forming sharp angle with 
horizontal, slightly convex border. Preglabellar field about one and 
one-half times as long (sag.) as border; entire frontal area about 



82 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

three-fourths the length of glabella plus occipital ring. Border furrow 
showing in most specimens a slight median inbend. Palpebral area 
half of the glabellar width, slightly upsloping ; ocular ridge transverse. 
Palpebral lobe 0.4 times the length of glabella plus occipital ring; 
distance to posterior cranidial margin slightly greater than length of 
palpebral lobe. Anterior facial sutures slightly more divergent than 
the average in the genus ; anterior angles of cranidium more widely 
rounded than in most species. Posterior area as wide (tr.) as occipital 
ring. Free cheek with wide border well defined anteriorly, the border 
furrow fading out posteriorly ; genal spine convex on upper face, 
rather long, somewhat curving inward. 

Pygidium somewhat more than twice as wide as long. Axis occupy- 
ing somewhat less than a third of the width, tapered, showing at least 
on internal impression 3 rings plus a terminal section, extended into 
a broad, low postaxial ridge. Anterior outline of pleural lobes and 
furrows curving backward, producing well-rounded anterior angles. 
Doublure fairly wide laterally, reduced medially. Posterior margin 
rather straight in median portion, with suggestion of a slight median 
notch. 

Surface of cranidium and free cheeks punctate in the furrows, 
especially in the anterior border furrow where the puncta are larger. 
Length of largest (holotype) cranidium 20 mm. Length of pygidium 
2.6 mm., width 5.5 mm. 

Discussion. — The cranidium is somewhat similar to A. laxa in the 
longitudinal profile of the frontal area, differing from that species in 
the proportionately longer (sag.) border, more widely rounded anter- 
ior angles, longer palpebral lobe, lesser distance from palpebral lobe 
to posterior margin, narrower (tr.) posterior area, and punctate sur- 
face. The pygidium is unlike A. laxa and much more like A. tarda in 
the lesser relative width and rounded sides. The rather strong diver- 
gence of the anterior facial sutures and median inbend of the border 
furrow give the cranidia of this species some resemblance to Aphelaspi- 
della macropyge, but the pygidium is definitely of the Aphelaspis type. 

Occurrence. — The type locality is U.S.G.S. 2970, Monroe County, 
where it occurs in association with Aphelaspidella macropyge, Aphe- 
laspis arses, and Paraphelaspis vigilans. These species indicate the 
lower portion of the middle Aphelaspis zone. A few, imperfect cranidia 
in the collection cnqV4 from the Lost Creek section may belong to 
this species, but, especially in the absence of the pygidia, cannot be 
distinguished with certainty from A. laxa. The stratigraphic position 
would confirm the assignment indicated above. 

Ty/'^.y.— Holotype : U.S.N.M. 144646. Paratypes: U.S.N.M. 
144647. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 83 

APHELASPIS CAMIRO (Walcott) 

Plate 12, figures 1-17 

Crepicephahis cmniro Walcott (part), 1916a, p. 205, pi. 32, figs. 2, 2'. 
Uncaspis camiro (Walcott) Kobayashi, 1935, p. 279. 
Aphelaspis camiro (Walcott) Resser, 1938a, p. 60, pi. 13, fig. 27. 

Available material. — Resser properly restricted the name to Wal- 
cott's holotype cranidium, excluding the pygidium which not only does 
not belong to the species, but probably is a trilobite of the Crepiceph- 
alus zone. The hypodigm includes a number of paratype cranidia well 
preserved in limestone. The species was collected at other localities 
by Dr. Oder and the author. From these collections the proper free 
cheek and pygidium could be identified unequivocally. Many of these 
pygidia were then discovered in the collection from the type locality 
in the U.S. National Museum. 

Description. — Glabella somewhat smaller in proportion to the cra- 
nidium than in other species of the genus. Occipital ring bearing a 
small node near the posterior margin. Frontal area unusually long, 
averaging 0.8 times the glabellar length ; as in other species, however, 
this ratio varies considerably among the individuals from one bed. 
Anterior sections of facial sutures diverging at average angle, making 
the cranidium very wide between the anterior angles. Border furrow 
better impressed than usual in the genus. Border slightly convex, its 
sagittal length averaging two-thirds the length of preglabellar field; 
border furrow showing in most, but not all, specimens a definite 
median inbend, and generally pitted on the outer surface. Preglabellar 
field as a whole rather flat, showing a low median boss. Palpebral area 
upsloping, about half the glabellar width. Ocular ridges transverse 
to slightly slanted backward. Palpebral lobe averaging 0.3 times the 
glabellar length, and about 0.5 times the distance from posterior end 
of palpebral lobe to posterior margin. Posterior area at least as wide 
(tr). as occipital ring. Length of largest observed cranidium 22 mm. 

Free cheek with distinct, flat border set ofif by definite furrow, 
deeper in anterior portion, and long, slowly tapered genal spine, flat 
on the upper side. 

Pygidium on average 1.75 times as wide as long, with a somewhat 
pointed shape. Axis relatively large, prominent, tapered, rounded pos- 
teriorly, showing 3 very distinct rings plus a terminal section. Anterior 
outline of pleural lobes after a short transverse course turning back- 
ward like the first pair of pleural furrows. Two other pairs of furrows 
may be faintly indicated. Border furrow and border poorly defined. 
Length of largest pygidium 3.8 mm., width 6.8 mm. 

Discussion. — This is one of the most distinctive species of Aphe- 
laspis. Larger cranidia may be distinguished by the long frontal area. 



84 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

upsloping palpebral area, flat preglabellar field with a more or less 
distinct preglabellar boss, and anterior position of the eyes. The 
pygidium is unique in its relatively long and narrow shape and well- 
rounded sides. Immature cranidia, however, are not always easily 
distinguishable from those of associated species. 

Occurrence. — The type locality is U.S.N.M. 120, Shields Ridge 
(see discussion of A. quadrata and A. laxa). Also collected by the 
author at localities cns/4, cns/15, cns/16, cnr/20, and cnrV20. 

Types. — Holotype and paratypes: U.S.N.M. 61672. Plesiotypes: 
U.S.N.M. 144648-51. 

APHELASPIS ROTUNDATA Rasetti, new species 

Plate 14, figures 1-12 

Available material. — Numerous cranidia, free cheeks, and pygidia, 
and a few hypostomes. Most of the specimens lack the test. 

Description. — Cranidium with low relief. Glabella and occipital 
ring without distinctive features. Preglabellar field slightly down- 
sloping, with little convexity; border furrow better defined than in 
most species; border elevated, somewhat convex. Total length (sag.) 
of frontal area averaging 0.6 times the length of glabella plus occipital 
ring; midlength (sag.) of border about 0.3 times the midlength of 
preglabellar field. Palpebral area averaging somewhat less than half 
the glabellar width, upsloping; palpebral lobe also upsloping, defined 
by shallow furrow even on outer surface. Exsagittal length of pal- 
pebral lobe about 0.4 times the length of glabella plus occipital ring ; 
exsagittal distance to posterior margin equal to length of palpebral 
lobe. Posterior area slender, about as wide (tr.) as occipital ring. 
Anterior sections of facial suture on the average more divergent than 
in most species, but there is considerable variability in this character 
among the population from a single thin bed. Free cheek with well- 
defined, flat border; genal spine flat dorsally at least in basal part, 
very long. 

Pygidium twice as wide as long. Outline oval, lacking definite 
geniculation on anterior margin, widely rounded laterally, not notched 
but elevated medially. Axis stout, composed of 3 rings plus a terminal 
section, extended into a broad postaxial ridge that reaches the margin. 
Pleural platforms downsloping, giving pygidium considerable relief 
compared to other species. Pleural furrows and grooves shallow, the 
first furrow curving backward to follow the curvature of the margin. 
Border flat, poorly defined ; doublure wide laterally, tapering medially. 

Surface of test smooth, except for the genal coeca showing faintly 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 85 

on outer surface on preglabellar field and ocular platform, well marked 
on internal impression. Length of largest cranidium 21 mm. ; length 
of largest pygidium 7 mm., width 14 mm. 

Discussion. — This is a large species, whose cranidia somewhat re- 
semble A. camiro. They differ in the narrower and more elevated 
anterior border, proportionately longer palpebral lobes, and lesser 
width (tr.) of the posterior area. The free cheek and genal spine are 
also very similar to that species. The pygidium is quite distinctive, 
with a proportionately narrower axis and regularly oval rather than 
subtrapezoidal outline. 

Unless careful attention is paid to the divergence of the anterior 
sections of the facial suture, cranidia of Aphelaspis rohindata may be 
confused with those of the associated species Aphelaspidella macro- 
pyge. Even though there is some variability in the divergence of the 
sutures in either species, usually well-preserved cranidia can be classi- 
fied on this character alone. The pygidia are immediately distinguish- 
able, although the pygidium of Aphelaspis rotundata, with its doublure 
wider than in most species of the genus, approaches in shape the 
pygidium of Aphelaspidella. 

Occurrence. — Medial portion of the Aphelaspis zone, in association 
with Aphelaspis arses, Aphelaspidella macropyge, and Paraphelaspis 
vigilans. The type locality is cns/20, Washburn. Also present in col- 
lections cns/20a, Washburn, cnq'V4, Lost Creek, and ens'/ 15, cns'V 
15, Three Springs. 

Tv/'^.y.— Holotype : U.S.N.M. 144652. Paratypes: U.S.N.M. 
144653-4. 

APHELASPIS WASHBURNENSIS Rasetti, new species 

Plate 17, figures 15-23 

Available material. — Several cranidia, free cheeks, and pygidia. 

Description. — Glabella relatively small in proportion to cranidium, 
of low convexity but defined by a fairly deep axial furrow. Frontal 
area averaging 0.75 times the length of glabella plus occipital ring. 
Preglabellar field tumid, strongly downsloping in anterior portion; 
border well defined by sharp change in slope, about half as long (sag.) 
as preglabellar field. Palpebral area somewhat upsloping, unusually 
wide (somewhat more than half the glabellar width) ; ocular ridges 
transverse ; palpebral lobes about 0.3 times the length of glabella plus 
occipital ring; distance from posterior end of palpebral lobe to pos- 
terior margin about equaling length of palpebral lobe. Anterior section 
of facial suture diverging at average angle; anterior angles of era- 



86 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

nidium fairly sharp. Posterior area slender, considerably wider (tr.) 
than occipital ring. 

Free check with relatively narrow and well-defined border ; border 
furrow becoming obsolete along posterior portion of lateral margin. 
Genal spine rather broad-based, flat on dorsal side, of average length. 

Pygidium slightly more than twice as wide as long ; axis prominent, 
showing 2 rings plus a terminal, indistinctly segmented section, oc- 
cupying more than two-thirds of pygidial length. Pleural regions with 
2 pairs of broad pleural furrows and traces of interpleural grooves; 
border flat, fairly wide. 

Surface of test smooth except for more or less distinct puncta in 
the depressions, especially the anterior border furrow. Length of holo- 
type cranidium 15 mm. 

Discussion. — The combination of cranidium and pygidium forms a 
distinctive species. The cranidium differs from most of the known 
species of Aphelaspis in the relative width of the palpebral area ; other 
species that have a wide palpebral area {A. lata, A. buttsi) are quite 
different in other cranidial features. The low glabella and tumid pre- 
glabellar field recall A. laxa, in which, however, the palpebral area is 
narrow and the palpebral lobes are more anteriorly situated. The 
pygidium resembles none of the above-mentioned species, being simi- 
lar to A. rotundata and A. palmeri. 

As far as can be ascertained from the scarce and mostly fragmentary 
material, the species is rather variable in most of its features. At both 
localities where it was collected, A. washburnensis occurs in associa- 
tion with another species of Aphelaspis, possibly the same in both 
cases. This second species seems somewhat intermediate between A. 
walcotti and A. quadrata, but the material was deemed insufficient 
to decide whether it should be identified with either of these two 
species or described as a new one. Therefore this form appears as 
Aphelaspis sp. undet. in the faunal lists. 

Occurrence. — The type locality is cnqV20, Washburn. In this sec- 
tion the species occurs in association with Aphelaspidella macropyge 
and Glaphyraspis declivis, above the strata holding A. walcotti and 
below those with A. caniiro, A. laxa, and A. quadrata. In the Three 
Springs section, a limestone lens holding Aphelaspis washburnensis 
and possibly Aphelaspidella macropyge was collected at the same level 
(cns/15) as beds yielding Aphelaspis camiro, A. laxa, and A. quad- 
rata, but the latter 3 species were not associated with A. washburnensis 
in the same lens. From this evidence it is clear that A. washburnensis 
occurs near the base of the middle Aphelaspis zone. 

Types.— RoXoiy^t: U.S.N.M. 144655. Paratypes: U.S.N.M. 
144656-7. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 87 

APHELASPIS BUTTSI (Kobayashi) 

Plate 16, figures 1-7 

Olenus cf. truncatus (Briinnich) Butts, 1926, pi. 9, figs. 6, 7. 
Proaulacopleura buttsi Kobayashi, 1936, p. 93, pi. 15, fig. 6. 
Proaulacoplenra buttsi Kobayashi, Resser, 1938a, p. 95, pi. 16, fig. 18. 
Aphelaspis buttsi (Kobayashi) Palmer, 1962b, p. 35, pi. 4, figs. 23, 26, 31, 32; 
pi. 6, fig. 15. 

Large numbers of specimens, many of them complete exoskeletons 
like the holotype, are available from the type locality in Alabama. 
This material is all flattened in shale, hence identification with lime- 
stone specimens inevitably leaves some uncertainty. However, all the 
features of cranidium, free cheek, and pygidium, excepting the con- 
vexity that cannot be compared, match so perfectly that reference of 
the Tennessee material to the species seems justified. Palmer (1962b) 
referred to A. buttsi, his excellent limestone specimens from Nevada, 
which are identical in all respects with those from the writer's collec- 
tions. 

Occurrence. — The species is very abundant in collection cno/15, 
Three Springs, from beds containing a mixture of genera of the Crepi- 
cephalus and Aphelaspis zones. Cranidia of an Aphelaspis collected 
from the essentially equivalent beds cno/14 at Russell Gap may belong 
to the species, but they cannot be distinguished with certainty from 
A. lata in the absence of associated pygidia. This is the oldest Aphe- 
laspis species found in Tennessee. The type locality is U.S.N.M. 91o, 
near Center, Ala. 

ry/)^.?.— Holotype : U.S.N.M. 93048. Plesiotypes: U.S.N.M. 
144658. 

APHELASPIS LATA Rasetti, new species 

Plate 16, figures 8-20 

Available material. — Large numbers of cranidia and several free 
cheeks and pygidia, both preserving the test and exfoliated. 

Description. — Cranidium proportionately wide and short, its sagit- 
tal length equaling the width between the palpebral lobes, which is 
slightly greater than the width between the anterior angles. Glabella 
somewhat wider and shorter than in most species, of moderate con- 
vexity. Fixed cheeks not rising above the level of the axial furrow. 
Preglabellar field of moderate, uniform longitudinal convexity ; border 
somewhat convex, defined by change in slope and shallow border 
furrow. Length of frontal area 0.6 times the length of glabella; 
sagittal length of border slightly less than half the length of pre- 
glabellar field. Border furrow somewhat angular on midline. Pal- 
pebral area horizontal to slightly downsloping, wider than in most 



88 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Species, half as wide as glabella. Ocular ridges transverse or even 
slightly slanted forward. Palpebral lobe averaging 0.4 times the gla- 
bellar length. Distance from posterior end of palpebral lobe to posterior 
margin equal to length of palpebral lobe. Anterior section of facial 
suture of average divergence. Posterior area as wide (tr.) as occipital 
ring. 

Free cheek with slightly convex border like the cranidium; genal 
spine flat, of average length. 

Pygidium somewhat less than 3 times as wide as long, transversely 
subelliptical. Axis relatively long, showing 2 or 3 rings plus a ter- 
minal section, well defined on outer surface. Pleural lobes with well- 
impressed furrows and very shallow interpleural grooves visible on 
outer surface. Posterior margin slightly indented medially. 

Length of largest cranidium collected 8 mm. Length of largest pygi- 
dium 3.6 mm., width 10 mm. 

Discussion. — The cranidium of this species is almost indistinguish- 
able from A. huttsi except for the shallower glabellar and axial fur- 
rows. Even this difference can be determined statistically only when 
numerous well-preserved specimens in limestone are available. The 
pygidium, however, is markedly distinct in possessing one less seg- 
ment both in the axis and pleural lobes, and in its posterior outline 
which is slightly notched medially, like A. walcotti and several other 
species, rather than somewhat pointed as in ^. huttsi. The interpleural 
grooves are less distinct than in that species. 

Occurrence. — The type locality is cnp/14. Shields Ridge. Also 
collected at localities cnp/15. Three Springs, and cnp/20, Washburn. 
A few, small cranidia apparently identical with topotypes of the same 
size were recovered from considerably higher beds at locality cnr/4, 
Lost Creek. Since several species of Aphelaspis are distinguishable 
only from the pygidia, the identification must be considered tentative. 

Types.— Ro\oty^&: U.S.N.M. 144659. Paratypes: U.S.N.M. 
144660-2, 144734. 

APHELASPIS TRANSVERSA Rasetti, new species 

Plate 16, figures 21-27 

Description. — Cranidium wide and short, of the same general 
proportions as in A. lata. Glabella of considerable transverse con- 
vexity, defined by a rather deep axial furrow at the sides, a shallower 
furrow in front, truncate. Occipital furrow deeper than usual in the 
genus; occipital ring bearing a small node. Preglabellar field with 
considerable convexity on midline ; border furrow straight at the sides, 
forming a rounded, obtuse angle medially. Border sharply upturned 
from preglabellar field, almost flat; sagittal border length two-thirds 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 89 

of length of preglabellar field. Frontal area averaging slightly over 0.6 
times the glabellar length. Palpebral area rising above the axial fur- 
row, somewhat convex, on average somewhat upsloping, half as wide 
as glabella. Ocular ridges stronger than in most species, transverse 
to slightly slanted forward. Palpebral lobes 0.4 times the glabellar 
length ; distance from posterior end of palpebral lobe to posterior 
margin equal to length of palpebral lobe. Posterior area as wide (tr.) 
as occipital ring. Free cheek with flat genal spine of average rate of 
tapering. 

Pygidium about 3 times as wide as long. Axis with 2 rings plus a 
terminal section. Pleural lobes showing only 1 distinct pair of pleural 
furrows. 

Length of largest cranidium observed 7 mm. 

Discussion. — This species resembles A. lata but is clearly distin- 
guished by the depth of the axial furrow, convexity of the palpebral 
area, wider anterior border, and smoother pygidium. 

Occurrence. — Locality cnp/17, Hurricane Hollow, in the basal bed 
of the Aphelaspis zone, a few feet above strata with typical Crepi- 
cephalus fauna. 

Ty/)^.r.— Holotype : U.S.N.M. 144663. Paratypes: U.S.N.M. 
144664. 

APHELASPIS MINOR Rasetti, new species 

Plate 19, figures 18-25 

Available material. — Large numbers of cranidia and free cheeks, 
and a few pygidia. 

Description. — Glabella of average shape and convexity; occipital 
furrow fairly well impressed, occipital ring bearing a low node. Pre- 
glabellar field moderately convex longitudinally; border furrow well 
impressed, slightly angular on midline; border convex, its midlength 
(sag.) less than the length of preglabellar field. Length of frontal area 
averaging 0.50 times length of glabella plus occipital ring. Palpebral 
area upsloping ; palpebral lobes slightly elevated above palpebral area, 
set off by shallow furrow, half the length of glabella plus occipital ring. 
Distance from posterior end of palpebral lobe to posterior cranidial 
margin less than length of palpebral lobe. Ocular ridges transverse. 
Anterior sections of facial suture with average divergence. Posterior 
area about as wide (tr.) as occipital ring. Free cheek with rather flat 
border defined by sharp change in slope. Genal spine relatively long, 
rather flat on dorsal side. 

Pygidium exactly 3 times as wide as long. Axis well tapered, 
rounded posteriorly, showing 2 rings plus a terminal section, reaching 
the border furrow. Pleural platforms rather convex, faintly furrowed. 



90 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Anterior outline without definite geniculation. Border and doublure 
very narrow throughout. 

Length of largest of hundreds of cranidia observed, 7 mm. Length 
of largest pygidium 2.5 mm., width 7.5 mm. 

Discussion. — The cranidia may not be easy to distinguish from 
immature examples of some of the larger species, but the combination 
of cranidium and pygidium characterizes the species as definitely dis- 
tinct from all others. The cranidium is extremely similar to that of 
A. inermis, the distinguishing features being pointed out in the de- 
scription of that species. The pygidium instead is very much like 
A. walcotti and A. hridgei. 

Occurrence. — Lower part of the Aphelaspis zone, above the beds 
with A. lata and below those carrying A. walcotti. Type locality is 
cnq/17. Hurricane Hollow. Also in collections cnq/14, Shields Ridge, 
cnq/15. Three Springs, and cnpV20, Washburn. 

Types.— Ro\oiy^&: U.S.N.M. 144665. Paratypes: U.S.N.M. 
144666-8. 

APHELASPIS INERMIS Rasetti, new species 

Plate 19, figures 8-17 

Available material. — Numerous cranidia and free cheeks, and a few 
tentatively assigned pygidia. 

Description. — Glabella of average shape and convexity; occipital 
furrow shallow ; occipital ring bearing a node, lacking spine. Frontal 
area averaging slightly less than half the glabellar length. Preglabellar 
field somewhat convex longitudinally especially on midline. Border 
defined by shallow furrow and change in slope, slightly convex, rather 
narrow for the genus. Anterior section of facial suture moderately 
divergent, straight to border furrow. Palpebral area slightly upsloping, 
about 0.3 times the glabellar width. Palpebral lobes set off by very 
shallow furrow, somewhat elevated, averaging 0.3 times the glabellar 
length and somewhat less than distance from posterior margin. Width 
(tr.) of posterior area equal to width of occipital ring. Free cheek 
with slightly convex border defined by shallow furrow. Genal spine 
oval in cross section, rather thick and long. 

Pygidia associated with the cranidia in more than one collection are 
transversely subelliptical, about 2.5 times as wide as long. Axis very 
prominent, equally long and wide, rounded posteriorly, with 1 distinct 
ring. Pleural lobes with 2 pairs of furrows and indistinct interpleural 
grooves, all ending in flat border which is wider laterally than medially. 

Surface of test pitted in furrows of cranidium and free cheek, but 
not as coarsely as in ^. arsoides. Length of unusually large cranidium 
9 mm. Most of the specimens do not exceed 6 mm. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 91 

Discussion. — This species is very similar to A. arsoides in all pro- 
portions. Apart from lack of an occipital spine, it may be distinguished 
at least statistically by the lesser divergence of the anterior section of 
the facial suture, greater convexity of the preglabellar field, slightly 
upsloping palpebral area, and convex instead of flat genal spine. It is 
also very similar to A. minor, with which it had been confused before 
large collections were made. It may be distinguished from that species 
by the usually slanted instead of transverse course of the ocular ridge, 
sharper anterior angles of the cranidium, slightly smaller palpebral 
lobe, and lesser average slope of the palpebral area. The pygidia are 
quite different, the one of A. minor being proportionately shorter and 
wider, with narrower border and furrows extending almost to the 
margin. The pygidium of A. inermis is more like that of A. arses. 
The present species and A. minor occupy different stratigraphic posi- 
tions, and no transition forms are known from intermediate beds. 

Occurrence. — The type locality is cns/2. Shields Ridge. Also present 
in collections cnr/4, cns/4 and cnt/4. It occurs in association with A. 
tumifrons or A. arsoides. 

Types.— Uolotype: U.S.N.M. 144669. Paratypes: U.S.N.M. 
144670-1. 

APHELASPIS TUMIFRONS Resser 

Plate 19, figures 1-7 
Aphelaspis tumifrons Resser, 1938a, p. 60, pi. 13, fig. 15. 

Available material. — The hypodigm includes the holotype and sev- 
eral other cranidia in fair state of preservation. Abundant and well- 
preserved new specimens from various localities allow a more complete 
description. 

Description. — Glabella poorly defined on upper surface by a very- 
shallow axial furrow. Occipital furrow shallow ; occipital ring bearing 
a node. Frontal area averaging 0.45 times the glabellar length. Pre- 
glabellar field with definite median boss. Border defined by somewhat 
gradual change in slope, of average width medially, almost vanishing 
at the sides. Anterior cranidial margin slightly pointed medially. Pal- 
pebral area approximately horizontal, about 0.3 times the glabellar 
width ; palpebral lobe more or less upsloping, not defined by palpebral 
furrow on outer surface. Average exsagittal length of palpebral lobe 
0.4 times the glabellar length and 0.8 times the distance to posterior 
margin. Ocular ridges wide, almost undefined on outer surface, some- 
what slanted backward. Transverse width of posterior area 0.8 times 
width of occipital ring. Free cheek with somewhat convex ocular plat- 
form, broad and vaguely defined border furrow, and fairly long, 
cylindrical genal spine. 



92 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Pygidium more than twice as wide as long. Axis strongly tapered, 
usually showing 1 distinct ring plus a terminal unsegmented section, 
almost reaching posterior margin. Anterior outline of pleural lobe 
with sharp geniculation situated about midway from axial furrow to 
anterior angle. Two pairs of broad pleural furrows and somewhat 
indistinct pleural grooves are visible on upper surface. Border narrow 
all along posterior margin, poorly defined by shallow border furrow. 

In some specimens fine puncta are present in the furrows on cra- 
nidium and free cheeks. Length of largest cranidium observed among 
several hundred specimens 10 mm. The overwhelming majority of the 
cranidia do not exceed 7 mm. Length of largest pygidium 1.6 mm., 
width 4.0 mm. 

Discussion. — This is a distinctive species, that can seldom be con- 
fused with other forms of Aphelaspis even if only a small sample is 
available. The main characteristics are the shallowness of the axial 
furrow, the tumid preglabellar field, the poorly defined anterior border, 
and the relatively anterior position of the eyes. 

Occurrence. — The species is usually extremely abundant when 
present, and represents an excellent index fossil for the upper portion 
of the middle Aphelaspis zone. The type locality is U.S.N.M. 119, 
S. of Morristown, Hamblen County. Present in the author's collec- 
tions cns/1, cnt/1, cns/2, cnt/4, cnt/7, cns/15, cnt/15, cntVlS, cnt/20, 
cnt/21, and in Oder's collection No. 14. 

Types.— Ro\oiy^&: U.S.N.M. 94927. Plesiotypes: U.S.N.M. 
144672. 

APHELASPIS PUNCTATA Rasetti, new species 

Plate 18, figures 21-29 

Available material. — Numerous cranidia and free cheeks and a few 
pygidia. 

Description. — Glabella of usual shape and convexity; axial furrow 
with deep pits at anterior corners of glabella. Frontal area markedly 
convex in front of glabella; border furrow well impressed, forming 
rounded angle on midline; border convex, averaging in midlength 
(sag.) one-third of length of preglabellar field. Entire frontal area 
over half the length of glabella plus occipital ring. Palpebral area 
somewhat upsloping; palpebral lobes elevated above palpebral area, 
half the glabellar length, defined by distinct furrow. Distance from 
posterior end of palpebral lobe to posterior cranidial margin less than 
length of palpebral lobe. Anterior sections of facial suture with aver- 
age divergence; anterior angles of cranidium very sharp. Posterior 
area equal in width (tr.) to occipital ring. Free cheek with narrow, 
convex border. Genal spine rapidly tapered, fairly flat on dorsal side ; 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 93 

posterior border furrow with shallow extension on proximal portion 
of genal spine. 

Associated pygidium with large axis, wider than pleural lobes, ele- 
vated, rounded at the extremity, showing 3 poorly defined rings plus 
a terminal section. Anterior outline of pleural lobes showing genicula- 
tion not far from axial furrow, then bending backward rather sharply ; 
posterior margin with maximum curvature on midline. One pair of 
pleural furrows well impressed, two other pairs shallow and rather 
indistinct. Border narrow, poorly defined by border furrow. 

Surface of cranidium and free cheeks almost entirely covered with 
fine, dense puncta. Surface of pygidium also punctate. Length of 
largest cranidium 8 mm. Length of pygidium 2.1 mm., width 3.7 mm. 

Discussion. — The cranidium of this species would be distinctive 
even without the unique feature of the punctate surface because of 
the deep pits in the axial furrow, the roll in front of the glabella, and 
the elevated palpebral lobes. All these features tend to give the species 
an aspect approaching Dytremacephalus angulatus. The pygidium is 
also distinctive in shape, having a proportionately larger axis than 
other species of Aphelaspis. 

Occurrence. — Uppermost beds of the Aphelaspis zone, in associa- 
tion with Aphelaspis tarda. The type locality is cnw/14. Shields Ridge, 
but the species is less rare at locality cnw/20, Washburn. 

Ty/'^.y.— Holotype : U.S.N.M. 144673. Paratypes: U.S.N.M. 
14467^5. 

APHELASPIS ARSES (Walcott) 

Plate 13, figures 16-23 

Saratogia arses Walcott, 1916a, p. 196, pi. 35, figs. 4-4b. 
Clevelandella arses (Walcott) Resser, 1938a, p. 69, pi. 13, fig. 22. 

Available material. — The hypodigm consists exclusively of the holo- 
type, a good cranidium in limestone. Collections by the author sup- 
plied numerous cranidia and free cheeks and a few pygidia. 

Description. — Glabella of average shape and convexity. Occipital 
furrow well defined throughout, deeper than in most species of the 
genus. Occipital ring bearing a small node and, in addition, a long, 
slender, somewhat upturned spine. Frontal area averaging half the 
length of glabella (exclusive of spine). Preglabellar field slightly con- 
vex longitudinally. Border narrow, defined by shallow furrow and 
change in slope, in most specimens definitely convex. Anterior sections 
of facial suture quite straight from palpebral lobe to border furrow. 
Palpebral area slightly convex, horizontal to slightly upsloping, aver- 
aging 0.3 times the glabellar width. Ocular ridges broad but distinct, 
slanted backward. Palpebral lobes set off by distinct furrow on upper 



94 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

surface, relatively narrow, about 0.3 times the glabellar length and 
equaling the distance to posterior cranidial margin. Posterior area 
about as wide (tr.) as occipital ring. Free cheek with slightly convex 
border defined by shallow furrow; genal spine oval in cross section, 
fairly long, tapering to sharp point. 

Pygidium associated with the cranidia transversely subelliptical, 
twice as wide as long. Axis prominent, showing 2 rings plus a termi- 
nal section, almost reaching margin. Pleural lobes with 2 more or less 
distinct pairs of broad furrows and very weak interpleural grooves. 
Anterior outline regularly curved, anterior angles rounded. Border 
furrow and border undefined. 

Surface of test smooth. Length of largest cranidium (exclusive of 
spine) 7 mm. Length of pygidium 2 mm., width 4 mm. 

Discussion. — The assignment of the species to Aphelaspis was justi- 
fied in the discussion of the genus. Aphelaspis arses may be distin- 
guished from most species of the genus, apart from the occipital spine, 
by the better than average definition of the occipital ring and palpebral 
lobe. The closest relatives are two species described herein, A. arsoides 
and A. inermis; the differences are mentioned in their discussion. 

Occurrence. — The type locality is U.S.N.M. 173, near Maryville. 
The exposures in that area were very poor and may now be concealed 
in built-up areas. The author's material was collected from localities 
cnr/4 and cns/4. Lost Creek, cns/20, Washburn, and cnsVlS, Three 
Springs. 

Types.— Holotype: U.S.N.M. 61617. Plesiotypes: U.S.N.M. 
144676, 144733. 

APHELASPIS ARSOIDES Rasetti, new species 

Plate 11, figures 15-21 ; plate 12, figure 22 

Available material. — Large numbers of cranidia and free cheeks 
from several localities, and a few pygidia. 

Description. — Glabella rather flat, defined by shallow axial furrow. 
Occipital furrow shallow ; occipital ring extended into long, slender, 
almost horizontal spine, not bearing a node. Frontal area from 0.5 to 
0.7 times the glabellar length. Preglabellar field with very slight longi- 
tudinal convexity ; border of average width, defined by furrow and 
change in slope, more or less convex. Anterior sections of facial suture 
straight to border furrow, diverging at somewhat greater angle than 
in most species, including A. arses. Palpebral area horizontal to 
slightly downsloping, about 0.3 times the glabellar width. Ocular 
ridges distinct, slanted backward. Palpebral lobe almost undefined by 
furrow on upper surface, about 0.3 times the glabellar length, and 
equaling the distance to posterior margin. Posterior area somewhat 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 95 

narrower (tr.) than occipital ring. Free cheek with flat border well 
defined by lateral border furrow, which, however, becomes indistinct 
before meeting posterior border furrow, as in all species of Aphelaspis. 
Genal spine flat, of average length. Facial suture cutting posterior 
margin somewhat farther from genal angle than in A. arses. 

Surface distinctly pitted in furrows on cranidium and free cheeks, 
especially in border furrow. Length of unusually large cranidium 
exclusive of spine, 13 mm. ; the majority do not exceed 8 mm. 

Pygidium transversely ovate, two and one-half times as wide as 
long. Axis stout, showing 2 rings and a terminal section, almost reach- 
ing the margin. Pleural lobes almost flat and horizontal. Anterior and 
posterior outlines slightly and regularly curved, lateral angles well 
rounded. Anterior pleural furrow distinct, distally curving backward 
to parallel the margin ; another pair of furrows indistinct. The surface 
in the depressions in some specimens is pitted as in the cranidium and 
free cheeks. Length of largest pygidium 3.5 mm., width 8.5 mm. 

Discussion. — This species can be distinguished from the closely 
related A. arses by the shallower axial furrow, almost horizontal pal- 
pebral area, indistinct palpebral furrow, the characteristic pitted sur- 
face in the depressions of the test, and somewhat different shape and 
flat border of the free cheek. 

Occurrence. — This species occupies a somewhat higher stratigraphic 
position than A. arses and is frequently associated with A. tumifrons. 
The type locality is cns/2. Also present in collections cns/1, cnt/1, 
cnt/4, cns/15, cnt/15, cntV15, cnt/20, cntV20, cnt/21, and Oder's 
collection No. 14. 

Types.— Uolotype: U.S.N.M. 144677. Paratypes: U.S.N.M. 
144678-80. 

Genus APHELASPIDELLA Rasetti, new genus 

Description. — Cranidium similar to Aphelaspis, except in the very 
strong divergence of the anterior sections of the facial suture. Free 
cheek as in Aphelaspis, with long genal spine. Pygidium proportion- 
ately much larger than in Aphelaspis. Axis occupying less than half 
the length, extended into a postaxial ridge. Pleural lobes wide, with 
little relief, with shallow furrows and grooves and a wide, concave 
border ; doublure very wide. 

Discussion. — The very close relationship to Aphelaspis is obvious. 
However, the different course of the anterior section of the facial 
suture and the pygidial characters are important enough to deserve 
generic recognition. 

Type species. — Aphelaspidella macropyge Rasetti, n. sp. 

Occurrence. — Aphelaspis zone of the southern Appalachians. 



96 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

APHELASPIDELLA MACROPYGE Rasetti, new species 

Plate 11, figures 1-8 

Available material. — Numerous cranidia, free cheeks, and pygidia 
excellently preserved in limestone. 

Description. — Cranidium of low general convexity. Glabella 
straight-sided, subtruncate in front, of low convexity, defined by a 
shallow axial furrow. Glabellar furrows barely indicated on outer 
surface; occipital furrow shallow, occipital ring short (sag.) and 
simple. Frontal area 0.8 times the glabellar length ; preglabellar field 
convex, slightly downsloping; border furrow deep, with a median 
inbend; border somewhat convex, wide medially, tapering in width 
at the sides. Palpebral area half as wide as the glabella, slightly up- 
sloping. Ocular ridges faint, transverse. Palpebral lobes 0.3 times the 
length of glabella plus occipital ring, defined by a very shallow pal- 
pebral furrow. Anterior sections of facial suture forming an angle of 
almost 60° with the median line ; anterior angles of cranidium more 
widely rounded than in any species of Aphelaspis ; marginal portion of 
suture about one-third the length of anterior cranidial margin, as in 
most Aphelaspis species. Posterior section of facial suture first directed 
backward, curving outward, then again somewhat backward, defining 
slender posterior area identical with that of most Aphelaspis species. 
Free cheek with well-defined lateral border. 

Pygidium twice as wide as long, subelliptical. Axis rapidly tapered, 
showing 3 rings and a terminal section, less than half the pygidial 
length, extended into a long postaxial ridge. Three pairs of increas- 
ingly shallow pleural furrows and less distinct interpleural grooves 
are visible ; the furrows extend, very broad and shallow, even across 
the wide, concave border. The inner edge of the doublure is clearly 
apparent on the upper surface. 

Surface of test smooth, except for a dense row of puncta in the 
anterior border furrow. Length of largest cranidium 18 mm. Length 
of largest pygidium 9 mm., width 18 mm. 

Occurrence. — The type locality is author's locality cnr/4, Lost 
Creek. Also common in collections cns/20, cns/20a, Washburn, and 
present in collections cns"/15, Three Springs, and U.S.G.S. 2970. In 
the U.S. National Museum there is a collection of cranidia and pygidia 
of the species from locality 173, marked "Maryville, Tenn." which 
is also the type locality for Aphelaspis arses. 

Types.— B.o\oiy^e\ U.S.N.M. 144681. Paratypes: U.S.N.M. 
144682. 

Genus PARAPHELASPIS Rasetti, new genus 

Description. — Cranidium with considerable relief. Glabella well ta- 
pered, truncate in front, fairly convex transversely, defined by a deep 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — ^RASETTI 97 

axial furrow laterally. Occipital furrow and ring as in Aphelaspis. 
Frontal area less than half the glabellar length, downsloping. Pregla- 
bellar field slightly convex ; border narrow, elevated. Palpebral area 
narrow, upsloping; palpebral lobe elevated, opposite anterior third of 
glabella. Posterior area narrower (tr.) than occipital ring, broadly 
triangular, rather strongly downsloping. Anterior section of facial 
suture as in Aphelaspis. Free cheek wide, steeply downsloping ; ocular 
platform somewhat convex ; border narrow. Facial suture cutting pos- 
terior margin rather far from genal angle; genal spine short and 
slender. Size small. Surface smooth except for puncta in the depres- 
sions. 

Discussion. — The close affinity with Aphelaspis is obvious. Never- 
theless the genus appears to deserve recognition because of the greater 
relief of the cranidial parts, in particular the elevation of the palpebral 
area and lobe and the downsloping attitude of the free cheek and 
posterior area. Another distinguishing feature is the anterior position 
of the eyes. The cranidia of Paraphelaspis resemble immature cranidia 
of Aphelaspis rather than adult individuals of that genus. Possibly 
we have a case of paedogenesis, Paraphelaspis representing an offshoot 
of the Aphelaspis stock preserving immature features in sexually ma- 
ture individuals. 

One should also mention the resemblance of the genus to Kujandas- 
pis Ivshin (type species: Kujandaspis kujandensis Ivshin, 1956), 
which seems also to represent another close relative of Aphelaspis. In 
Kujandaspis the glabella is relatively smaller and the eyes do not have 
such an anterior position as in Paraphelaspis. 

Type species. — Paraphelaspis vigilans Rasetti, n. sp. 

Occurrence. — Aphelaspis zone of the southern Appalachians. 

PARAPHELASPIS VIGILANS Rasetti, new species 

Plate 21, figures 14-28 

Available material. — Numerous cranidia and free cheeks. 

Description. — Glabella strongly tapered, truncate in front, defined 
by a deep axial furrow at the sides, a shallower furrow in front. One 
or two shallow pairs of lateral furrows visible even on outer surface, 
of the same pattern as in Aphelaspis. Occipital furrow well marked ; 
occipital ring bearing a node. Frontal area 0.4 to 0.5 times as long as 
glabella plus occipital ring, proportionately longer in larger cranidia. 
Preglabellar field with a more or less pronounced convexity in front 
of the glabella; border furrow regularly curved; border length (sag.) 
less than half the preglabellar field ; border convex, elevated. Pal- 
pebral area very narrow, proportionately wider in larger cranidia, 
more or less strongly upsloping; ocular ridges distinct, very short, 
directed somewhat forward. Palpebral lobe somewhat less than 0.3 



98 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

times as long as glabella plus occipital ring, set off by shallow but 
distinct furrow even on outer surface ; its anterior end almost at the 
level of the front of the glabella, its posterior end slightly anterior to 
level of glabellar midpoint. Distance to posterior margin about twice 
length of palpebral lobe. Anterior section of facial suture straight to 
border furrow, divergent as the average in Aphelaspis ; posterior sec- 
tion directed straight outward and backward, curving rather sharply 
backward before cutting posterior margin at right angle, defining much 
longer (exsag.) and narrower (tr.) posterior area than in Aphelaspis 
species ; width of posterior area less than width of occipital ring. 

Free cheek proportionately wide, evidently steeply sloping. Ocular 
platform convex near the eye. Border furrow shallow and broad; 
border narrow, convex as in cranidium. Facial suture cutting margin 
at considerable distance from short, slender genal spine. The pygidium 
has not been identified. 

Length of largest among hundreds of cranidia observed 5.5 mm. 

Discussion. — It was mentioned in the generic description that Para- 
phelaspis resembles immature individuals of Aphelaspis in several 
respects. This also agrees with the fact, apparent from the description 
and the illustrations, that the similarity to Aphelaspis increases with 
increasing size of the cranidia of Par aphelaspis, especially in the fea- 
tures of greater relative length of the frontal area and width of the 
palpebral area. Nevertheless, there are still considerable differences 
between the largest cranidia of Paraphelaspis vigilans and individuals 
of the same size of all the known species of Aphelaspis. In particular, 
immature cranidia of the two species of Aphelaspis that occur in asso- 
ciation with Paraphelaspis are known and are quite different from 
Paraphelaspis. Of all species of Aphelaspis, A. inermis is possibly 
closest to Paraphelaspis. 

Occurrence. — The type locality is cns/20, Washburn. Also present 
in collections cns/20a, Washburn, cnr/4. Lost Creek, ens VI 5, cns'V 
15, Three Springs, and U.S.G.S. 2970. The species has been found 
only in association with Aphelaspidella macropyge. 

Types.— Holotype: U.S.N.M. 144683. Paratypes: U.S.N.M. 
144684-5. 

Genus DYTREMACEPHALUS Palmer, 1954 

Type species. — Dytremacephalus granulosus Palmer. 

DYTREMACEPHALUS ANGULATUS Rasetti, new species 

Plate 21, figures 1-9 

Available material. — Large numbers of cranidia, a few free cheeks 
and pygidia in excellent state of preservation. 

Description. — Glabella tapered, straight-sided, truncate in front, of 
moderate convexity, defined by deep axial furrows at the sides, a 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 99 

shallow furrow in front. A pair of deep pits in furrow at anterior 
corners of glabella. Three shallow pairs of lateral furrows visible on 
upper surface. Occipital furrow deep at the sides, shallow medially; 
occipital ring long (sag.), bearing a node. Preglabellar field swollen 
in posterior portion, rising above the frontal portion of the axial fur- 
row, downsloping in anterior portion ; border furrow wide with strong 
curvature on midline, giving it an angular aspect. Border about half 
as long (sag.) as preglabellar field, upturned, convex, tapering at the 
sides. Entire frontal area half as long as glabella inclusive of occipital 
ring. Palpebral area slightly more than half as wide as glabella, slightly 
convex and upsloping from the axial furrow. Ocular ridges distinct, 
moderately slanted backward. Palpebral lobes defined by furrow even 
on outer surface, fairly wide, not rising above palpebral area, 0.4 times 
as long as glabella. Distance from palpebral lobe to posterior cranidial 
margin considerably shorter than palpebral lobe. Anterior sections of 
facial suture moderately divergent as in Aphelaspis, straight to border 
furrow. Posterior area as in Aphelaspis, narrower (tr.) than occipital 
ring. Free cheek with well-defined, convex border and border furrow ; 
ocular platform more convex than in species of Aphelaspis ; genal 
spine short, rapidly tapered, flat on upper side. 

Thorax preserved in complete exoskeletons in shale. One small 
individual appears to have 12 segments; however, the larger thorax 
illustrated herein, attached to the pygidium but lacking the cephalon, 
shows 13 segments, and this seems to be the number in the holaspid, 
as in the species of Aphelaspis where the thorax is known. The pleurae 
are straight proximally, curving backward to short falcate extension 
distally, and are furrowed through all their length, much as in Aphe- 
laspis. 

Pygidium with considerable convexity. Axis occupying one-third 
of the width, almost reaching margin, strongly elevated, showing 3 to 
5 distinct rings plus terminal section, rounded posteriorly. Pleural 
platforms steeply downsloping, with strong furrows and distinct inter- 
pleural grooves. Border flat, wide at the sides, almost vanishing 
medially, as the axis almost attains the margin. Anterior margin curv- 
ing backward, almost attaining longitudinal course; angles fairly 
sharp; posterior margin straight laterally, forming fairly sharp angle 
medially. 

Surface of cranidium finely and densely granulate except in the 
furrows. Border of cranidium and free cheek with terrace lines. Ocular 
platform granulate like the cranidium. Ornamentation of pygidium 
indistinct. Length of largest cranidium 6.5 mm. Fragments indicate 
that the species attains a somewhat larger size. Length of largest 
pygidium 2.4 mm., width 6 mm. 

Discussion. — This trilobite, obviously a very close relative of Aphe- 










D 





Fig. 2. — A, Dytremacephalus angulatus Rasetti, n. sp. Cranidium, pygidium. B, 
Aphelaspidella macropyge Rasetti, n. gen., n. sp. Cranidium, free cheek, pygi- 
dium. C, Loxoparia obliqua Rasetti, n. gen., n. sp. Frontal, dorsal, and lateral 
views of cranidium. D, Hawkinsia miniita Rasetti, n. gen., n. sp. Dorsal, frontal, 
and lateral views of cranidium. E, Paraphelaspis vigilans Rasetti, n. gen., n. sp. 
Frontal and dorsal views of cranidium. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 101 

laspis, seems best referred to Dytremacephalus, although the palpebral 
area is wider than in D. granulosus and the palpebral lobe larger and 
more posterior in position. The frontal and palpebral areas are more 
like D. laevis Palmer (1954). In Nevada, Palmer (1965) finds two 
species of Dytremacephalus in the lower part of the Dunderhergia 
zone. In view of the somewhat questionable assignment of the present 
species to the genus, this fact should not be attributed much signifi- 
cance for correlation. Dytremacephalus angulatus differs from all spe- 
cies of Aphelaspis in the deep axial furrows, more posterior position 
of the eyes, granulate surface, and shortness of the genal spine. 

One should also note the considerable similarity of the cranidia of 
this trilobite to Acrocephalaspis fidus Ivshin (1956) from Kazakhstan, 
where it occurs in association with Aphelaspis, and hence may be taken 
to be approximately of the same age as the present species. Unfortu- 
nately Ivshin's material includes only cranidia. Ivshin compared Acro- 
cephalaspis with Acrocephalites, but, judging from the illustrations, 
his new genus seems very close to Aphelaspis. It is also possible that 
Aphelaspis and Acrocephalites are closely related. 

Occurrence. — Mainly characteristic of the uppermost portion of the 
Aphelaspis zone in Tennessee, usually associated with Aphelaspis 
tarda. The type locality is cnw/14, Shields Ridge. Also present in col- 
lections cnw/1, cnx/1, cnv/15, and U.S.G.S. 2969. A single specimen 
was found in the collection cnt/4, from somewhat lower beds here 
assigned to the upper portion of the middle Aphelaspis zone. 

Types.— Kolotype: U.S.N.M. 144686. Paratypes: U.S.N.M. 
144687-9. 



DYTREMACEPHALUS SULCIFRONS Rasetti, new species 

Plate 12, figures 23-25 

Available material. — ^Two cranidia from different localities. 

Description. — Cranidium as a whole and glabella with greater longi- 
tudinal convexity than in preceding species. Glabella with 2 fairly deep 
pairs of lateral furrows, a third pair very short and shallow, more 
rounded anteriorly than in D. angulatus. Shallow portion of axial 
furrow shorter than in preceding species. Palpebral area, palpebral 
lobes, and course of facial sutures as in D. angulatus. Surface orna- 
mentation of the same type. Length of cranidium 6 mm. 

Discussion. — The differences from D. angulatus were pointed out 
in the description. This may be an extreme case of variation within 
that species ; however, in the absence of intermediate forms, it is de- 
scribed as a representative of an associated, rare species. It resembles 
the type species of the genus. 



102 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Occurrence. — The holotype is from collection cnw/14, Shields 
Ridge; the paratype from collection cnx/1, Big Creek. 

T3,^^^._Holotype : U.S.N.M. 144690. Paratype: U.S.N.M. 
144691. 

DYTREMACEPHALUS STRICTUS Rasetti, new species 

Plate 21, figures 10-13 

Available material. — Several cranidia and one tentatively assigned 
pygidium. 

Description. — Glabella as in D. angulatus, defined by a deeper fur- 
row in front. Occipital ring unusually short (sag.), set off by a deep 
occipital furrow, bearing a small node. Pits at anterior corners of 
glabella marked in some individuals. Preglabellar field convex longi- 
tudinally, somewhat shorter than in D. angulatus; border furrow not 
distinctly angulate as in that species ; border somewhat less elevated. 
Palpebral area somewhat convex, upsloping, from one-third to one- 
half the glabellar width ; ocular ridges slightly slanted backward. Pal- 
pebral lobe, posterior area, and facial sutures as in D. angulatus. 
Granulation of surface rather indistinct. 

The pygidium tentatively assigned to the species is proportionately 
shorter and wider than D. angulatus and has fewer segments both in 
the axis and the pleural lobes. 

Discussion. — The species was compared in the description with D. 
angulatus, from which the cranidium differs essentially in the propor- 
tionately larger glabella. As it appears from the illustrations, consider- 
able variation occurs among the specimens, all from one small piece 
of rock. 

Occurrence. — Locality U.S.G.S. 2970, Vonore quadrangle, Monroe 
County, in association with Aphelaspidella macropyge, Aphelaspis 
palmeri, and other species. 

Ty/^^j.— Holotype : U.S.N.M. 144692. Paratypes: U.S.N.M. 
144693. 

PTYCHOPARIIDA OF UNCERTAIN AFFINITIES 

Genus BONNETERRINA Lochman, 1936 

Type species. — Bonneterrina prima Lochman. 

BONNETERRINA APPAL ACHIA (Walcott) 

Plate 2, figures 10-18 

Lonchocephalus appalachia Walcott, part, 1916a, p. 190, pi. 35, figs. 6, 6a, 6c. 
Lonchocephalus appalachia Walcott, Resser, 1938a, p. 86, pi. 10, fig. 30. 
Bonneterrina appalachia (Walcott) Palmer, 1954, p. 726, pi. 80, fig. 9. 

The species is one of the most common and readily recognizable 
fossils of the uppermost beds of the Maryville formation in the Rogers- 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 103 

ville area. A considerable amount of variability is present in the 
cranidia; since the various forms intergrade and occur in the same 
bed, it would be improper to split the species, even though the ex- 
tremes in the range of variation might suggest such action. 

The main variable features are the convexity of the glabella and 
the entire cranidium; the depth of the axial furrow; the direction of 
the occipital spine, varying from almost horizontal to upturned at 45 
degrees ; the distinctness of the occipital furrow ; the relative width 
and convexity of the anterior border. The figured cranidia show some 
of these features. The largest cranidium has a length of 15 mm. exclu- 
sive of the spine. 

The pygidium, although less common than the cranidium, can be 
assigned with virtual certainty. It is about twice as wide as long, 
regularly rounded posteriorly. Axis occupying almost entire length, 
tapered, with 3 prominent rings and a terminal section, bearing a large 
upright spine on the first ring. Pleural lobes convex and downsloping, 
with 3 pairs of broad pleural furrows and 2 pairs of narrower inter- 
pleural grooves, all reaching almost to the margin; border furrow 
shallow, border narrow, poorly defined. Length of largest pygidium 
9 mm,, width 18 mm. 

The pygidium closely resembles that of Shickshockia cristata (Ra- 
setti, 1946), and the cranidium also has similar features. It is ques- 
tionable whether Shickshockia should be maintained as a distinct 
genus. 

Occurrence. — Uppermost beds of Maryville and basal beds of Noli- 
chucky formation (Cedaria zone). Type locality is U.S.N.M. 123a, 
4 miles NE. of Rogersville. Collected by the author at localities cnc/1 
to cnc/6 in the Maryville limestone and localities cnd/1, cnd/2 in the 
red beds of the Nolichucky. 

7^;/?^.^.— Holotype : U.S.N.M. 61719. Paratypes: U.S.N.M. 
61721, 61722. Plesiotypes: U.S.N.M. 144703-6. 

Genus CHEILOCEPHALUS Berkey, 1898 

Type species. — Cheilocephalus stcroixensis Berkey. 

CHEILOCEPHALUS BREVILOBUS (Walcott) 

Plate 17, figures 1-5 

Lisania? hreviloba Walcott, 1916b, p. 404, pi. 66, figs. 3-3c. 

Pseudolisania breviloba (Walcott) Kobayashi, 1935, p. 162. 

Pseudolisania breviloba (Walcott) Resser, 1938a, p. 96, pi. 16, fig. 17. 

Cheilocephalus breviloba (Walcott) Palmer, 1954, p. 759, pi. 88, figs. 1-4 (in- 
cludes complete synonymy up to 1954) . 

Cheilocephalus brevilobus (Walcott) Lochman and Hu, 1962b, p. 436, pi. 69, 
figs. 1-24. 



104 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

The species is common in the basal beds of the Aphelaspis zone in 
Tennessee. The largest cranidium observed has a length of 20 mm. 
and a width between the tips of the posterior area of 40 mm. The 
largest pygidium has a length of 21 mm. and a width of 34 mm. 

The free cheek has never been described. Fragments are common 
in association with other parts of the exoskeleton, but it is difficult 
to prepare good specimens. The free cheek has a concave border not 
differentiated from the ocular platform by a furrow. The facial suture 
cuts the posterior margin very close to the genal angle. This is ex- 
tended into a short, flat, triangular genal spine. Hence the suture does 
not have a proparian course, as some authors have conjectured. 

Occurrence. — The types are from an unspecified horizon in the 
Nolichucky formation at U.S.N.M. locality 118a, near Greeneville, 
Greene County. Collected by the author at localities cno/14, cnp/14, 
cnq/14, cnp/17. 

Types.— Holotype: U.S.N.M. 62852. Paratypes: U.S.N.M. 
62853^. Plesiotypes: U.S.N.M. 144707-8. 

CHEILOCEPHALUS BRACHYOPS Palmer 

Plate 17, figures 6-11 

Cheilocephalus brachyops Palmer, 1965, p. 105, pi. 1, figs. 12-15, 17. 

A species of Cheilocephalus that occurs in the upper Aphelaspis 
zone fully agrees in all characters of cranidium and pygidium with the 
species, described from the Dunderbergia zone in Nevada. 

Occurrence. — Collections cnx/1, Big Creek, and cnw/14, Shields 
Ridge. 

T3>/>^5.— Plesiotypes: U.S.N.M. 144709-10. 

CHEILOCEPHALUS, species undetermined 

Plate 17, figures 12-14 

Rare specimens of Cheilocephalus that occur in the middle portion 
of the Aphelaspis zone possess a frontal area short as in C. brachyops, 
but flat and lacking the raised border of that species. The surface 
shows indistinct ornamentation. The pygidium is like both C. brevi- 
lobus and C. brachyops. A close comparison is made uncertain by the 
fact that all the specimens in question are small and obviously imma- 
ture. Hence it will be left undecided whether this form should be 
assigned to a new species. 

Occurrence. — The figured specimens are from locality cnr/4. Lost 
Creek. Also present in collections cns/4, cns/2, and U.S.G.S. 2970. 

Disposition of material. — Figured specimens: U.S.N.M. 144711. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 105 

Genus COENASPIS Resser, 1938 

Type species. — Coenaspis spectabilis Resser. 

COENASPIS SPECTABILIS Resser 

Plate 5, figures 1-3 

Coenaspis spectabilis Resser, 1938a, p. 69, pi. 16, fig. 9. 

The only new information about this rare trilobite is its stratigraphic 
position. 

Occurrence. — Beds of the lower Cedaria zone at the top of the 
Maryville formation. The type locality is U.S.N.M. 123a, near Rogers- 
ville. One cranidium was collected by the writer at locality cnc/3, 
close to or identical with the preceding. 

Types.— Uolotype : U.S.N.M. 94978. 

Genus HAWKINSIA Rasetti, new genus 

Description. — Very small trilobites. Cranidium subtrapezoidal, 
rather convex. Glabella moderately convex, defined by deep axial 
furrow, tapered, with short, shallow lateral furrows. Occipital furrow 
deep, occipital ring simple. Frontal area short (sag.), convex and 
downsloping, barely differentiated into preglabellar field and border. 
Ocular ridges well marked, subtransverse, curved. Palpebral area 
convex, as wide as glabella ; palpebral lobes small and inconspicuous, 
situated far in advance of glabellar midpoint. Posterior area large, 
deeply furrowed. Facial sutures showing little change of direction 
between anterior and posterior section in dorsal view ; in lateral view 
there is a marked angle. Anterior sections convergent, curving inward, 
rounding off the anterior cranidial outline. Posterior section first run- 
ning outward and backward, gradually curving backward and finally 
slightly inward, giving the cranidium a sharp posterolateral angle. 

Type species. — Hawkinsia minuta Rasetti, n. sp. 

Discussion. — Although the known specimens of the type species are 
quite small, the fact that they are all about the same size suggests that 
they are not immature. In any case, Hazvkinsia could not be the im- 
mature form of any of the larger trilobites known from the same beds. 
No plausible affinities of the genus can be suggested. The name is 
derived from Hawkins County, where the type species occurs. 

Occurrence. — Upper Cambrian {Cedaria zone) of the southern 
Appalachians. 

HAWKINSIA MINUTA Rasetti, new species 

Plate 3, figures 22-25 

Available material. — Several cranidia preserved in limestone. 
Description. — The generic description includes most of the known 



106 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

characters of the species. The glabella shows 2 pairs of short, rather 
shallow lateral furrows; those of the posterior pair show a tendency 
to bifurcate. The occipital ring is rounded, lacking spine or node. The 
frontal area is divided about equally into preglabellar field and border 
by an excessively shallow furrow, which becomes obsolete medially. 
The surface of the test is very finely granulate. Length of holotype 
cranidium 2.2 mm., width at posterior end 3.3 mm. 

Occurrence. — Uppermost beds of the Maryville limestone (Cedaria 
zone) at locality cnc/1. 

Types.— Holotype: U.S.N.M. 144712. Paratypes: U.S.N.M. 
144713. 

Genus ITHYCEPHALUS Resser, 1939 

Type species. — Ithycephalus typicalis Resser. 

ITHYCEPHALUS TYPICALIS Resser 

Plate 1, figures 10-12 

Ithycephalus typicalis Resser, 1938a, p. 82, pi. 9, fig. 10. 

A perfect cranidium of this rare species is figured. 

Occurrence. — Type locality U.S.N.M. 27d ; red beds at the base of 
the Nolichucky {Cedaria zone) east of Rogersville. The figured speci- 
men is from the same beds and locality (author's locality cnd/1). One 
specimen was also collected from the underlying uppermost beds of 
the Maryville limestone (loc. cnc/1). 

Ty/'^.?.— Holotype : U.S.N.M. 94841. Plesiotype: U.S.N.M. 
144714. 

Genus MODOCIA Walcott, 1924 

Type species. — Arionellus (Crepicephalus) oweni Meek and Hay- 
den. 

Three genera have been considered synonyms of Modocia: Armonia 
Walcott, 1924 (type species, Armonia pelops Walcott) ; Metisia 
Resser, 1937 (type species, Ptychoparia metisensis Walcott) ; and 
Semnocephalus Resser, 1942 (type species, Solenopleura? weedi 
Walcott (part) ) . 

A question arises concerning the status of the genus Syspacheilus 
Resser, 1938 (type species, Syspacheilus typicalis Resser). Palmer 
(1954) discussed the problem of assigning a pygidium to Syspacheilus. 
He attributed to cranidia identified as Syspacheilus camurus Lochman 
pygidia indistinguishable from Coosella. Lochman and Hu (1961) 
attributed to 6". dunoirensis (Miller) and a new species, Syspacheilus 
praecedens, short pygidia of the generalized ptychoparioid type. 

The latter assignment seems unquestionable, in view of the abun- 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 107 

dance of the material and of the almost identical association of cranidia 
and pygidia observed by the author in other areas. Then, if Palmer's 
pygidium is correctly attributed, we must conclude that there are two 
genera of trilobites with indistinguishable cranidia and very different 
pygidia, not an unusual situation. In that case it would be impossible 
at present to decide which one is Syspacheilus, since there is no reliable 
assignment of a pygidium to the type species. 

Whatever the solution of this problem may be, the author sees no 
reason to maintain the use of Syspacheilus for the species with a short 
pygidium, typified by Syspacheilus praecedens, which are almost iden- 
tical with Metisia metisensis (Rasetti, 1963). If these forms are 
sufficiently distinct from Modocia oweni to warrant generic recogni- 
tion, then they should be referred to Metisia accepted as a valid genus. 
Possibly the same arguments apply to Talbotina (at least as repre- 
sented by T. juweli Lochman, in Lochman and Duncan, 1944) and 
Ithyektyphus Shaw (1956), (Lochman and Hu, 1960). 

In conclusion, it seems best at present to restrict the use of Sys- 
pacheilus to the type species until the characters of the genus are 
clarified. 

MODOCIA DUBIA (Resser) 
Plate 1, figures 22-26 

Asaphiscus? agatho Walcott (part), 1916b, p. 391, pi. 62i, fig. 9a (only). 

Ehmania dubia Resser, 1938a, p. 75, pi. 9, figs. 18, 19. 

Uncaspis tennesseensis Resser, 1938a (part), p. 105, pi. 9, fig. 21 (only). 

Three species of Modocia are common in the red beds at the base 
of the Nolichucky, and two of them were also collected at various 
localities in the underlying beds of the Maryville formation. Through 
association in several instances it was possible to obtain an unambigu- 
ous assignment of the pygidia to the respective cranidia. 

Description. — Entire cranidium of moderate convexity. Glabella 
moderately convex, proportionately wide and short, strongly tapered, 
rounded in front, bearing a trace of furrows on outer surface. Pregla- 
bellar field flat ; border not greatly elevated or convex, about as wide 
(sag.) medially as the preglabellar field. Palpebral area slightly convex 
and downsloping; ocular ridges faint; palpebral lobes one-third the 
glabellar length, placed about parallel to the axial furrow, defined by 
a sharp palpebral furrow, situated well in advance of glabellar mid- 
point. Posterior area long (exsag.), deeply furrowed. The anterior 
sections of the facial sutures are barely divergent. The surface of the 
test is densely and finely granulate. Length of larger cranidia 12 mm. 

Pygidium twice as wide as long. Axis stout and prominent, showing 
two distinct rings, and in some specimens a less distinct third ring. 



108 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

plus a terminal section, almost reaching posterior margin. Pleural re- 
gions of low convexity, with almost equally deep pleural furrows and 
interpleural grooves, curving back distally and almost reaching the 
margin. Border furrow and border almost indistinct. Length of a large 
pygidium 6.5 mm., width 13 mm. 

Discussion. — This form differs from the type species in many details 
of the cranidium, such as the lesser prominence of the glabella, lesser 
divergence of the anterior sections of the facial suture, and more 
anterior position of the eyes. 

Occurrence. — The type locality is U.S.N.M. 27d; red beds at the 
base of the Nolichucky {Cedaria zone) near Roger sville. Collected by 
the author at the same locality (cnd/1) and also in the uppermost beds 
of the underlying Maryville limestone (localities cnc/1 to cnc/6) . 

Types. — Holotype and paratypes: U.S.N.M. 94845. Paratype of 
Asaphiscus ? agatho: U.S.N.M. 62820. Paratype of Uncaspis tennes- 
seensis: U.S.N.M. 94846. Plesiotypes figured herein: U.S.N.M. 
144715-6. 

MODOCIA BIDENTATA Rasetti, new species 

Plate 1, figures 13-21 

Available material. — Numerous cranidia and pygidia in limestone. 

Description. — Glabella rather convex, rising above the cheeks, rela- 
tively narrow and long, unfurrowed. Occipital furrow well marked; 
occipital ring short, simple. Frontal and palpebral areas downsloping ; 
preglabellar field longer (sag.) than border width ; border well defined, 
slightly convex, tapered in width at the sides. Palpebral area about 
half the glabellar width; ocular ridges faint; palpebral lobes located 
somewhat in advance of glabellar midpoint. Anterior sections of facial 
suture somewhat divergent ; posterior section curving backward, pro- 
ducing blunt posterior area. 

Pygidium of same general proportions as in preceding species, not 
greatly convex transversely. Axis as in preceding species. Pleural 
regions with pleural furrows and interpleural grooves of progressively 
decreasing strength. First pleural segment extended into a pair of 
short, backward-directed marginal spines. 

Surface of test smooth. Length of largest cranidium 17 mm. Length 
of largest pygidium 8.5 mm., width 17 mm. 

Discussion. — The cranidial proportions are fully typical of Modocia. 
The chief distinguishing feature is the pair of short pygidial spines. 
This character is not uncommon in several genera of late Medial Cam- 
brian and Dresbachian ptychoparioid trilobites, e.g., in species of 
Ehmaniella. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 109 

Occurrence. — Red beds at the base of the NoHchucky (Cedaria 
zone) E. of Rogersville (locality cnd/1). 

Types. — Holotype (pygidium) : U.S.N.M. 144717. Paratypes: 
144718. 

MODOCIA CRASSIMARGINATA Rasetti, new species 

Plate 2, figures 1-9 

Available material. — Numerous cranidia and pygidia well preserved 
in limestone. 

Description. — Glabella rather plump, defined by a deep axial furrow, 
rounded in front, unfurrowed; occipital furrow well impressed, occi- 
pital ring simple. Preglabellar field downsloping, short (sag.), on the 
average shorter than the border width (sag.), although there is vari- 
ability in this character. Border convex, wide (sag.). Ocular ridges 
faintly indicated ; palpebral lobes narrow, defined by a shallow palpe- 
bral furrow, about 0.3 times the glabellar length, somewhat in advance 
of level of glabellar midpoint. Palpebral area convex, on average down- 
sloping, 0.4 times the glabellar width. Anterior sections of facial suture 
somewhat divergent, curving inward after crossing the border furrow, 
rounding off the anterior cranidial angles. Posterior section first di- 
rected outward, curving backward, rounding off the extremity of the 
posterior area which is deeply furrowed. 

Pygidium with a stout, barely tapered, well-rounded axis showing 
3 rings and a terminal section, not reaching the margin. Pleural re- 
gions transversely downsloping and convex longitudinally, showing 3 
pairs of well-impressed furrows and 2 pairs of slightly shallower inter- 
pleural grooves, all fading out toward the margin without the presence 
of any defined border furrow or border. 

Surface of test with inconspicuous ornamentation. Some of the 
cranidia show a punctate surface, the puncta being small and so dense 
as to produce the effect of a fine granulation ; other cranidia appear al- 
most smooth. Pygidia where the test is preserved show a very fine 
granulation. 

Length of the largest cranidia 17mm. Length of largest pygidium 
6.5 mm., width 14 mm. 

Discussion. — Species of this type were assigned to Syspacheilus (see 
discussion of Modocia) ; for example, the present form does not seem 
to differ greatly from Syspacheilus camurus Lochman (1940), S. 
dunoirensis (Miller), as figured by Lochman and Hu (1961), and 5. 
praecedens Lochman and Hu (1961). From the latter two forms, 
where the pygidium is known, the present species differs in the more 
deeply furrowed pleural lobes. Armonia pelops Walcott is also close to 



110 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

the present species, but an accurate comparison is difficult since all the 
type material is more or less flattened. It would seem that Armonia 
pelops has a proportionately narrower glabella and a more nearly tri- 
angular pygidium. Metisia metisensis (Walcott) is almost identical in 
the proportions and convexity of all the cranidial parts, but the surface 
ornamentation is coarser, and the pygidium has a definite border and 
is not turned down marginally as in the present form. 

Occurrence. — Uppermost beds of Maryville limestone (Cedaria 
zone). Type locality cnc/2; also common at localities cnc/1, cnc/3 to 
cnc/6. Also occurring in the red beds at the base of the Nolichucky at 
locality end/ 1. 

Ty^^^.—Holotype : U.S.N.M. 144719. Paratypes: U.S.N.M. 144- 
720-23. 

MODOCIA ? AGATHO ( Walcott ) 

Plate 1, figures 27-30 

Asaphiscus? agatho Walcott (part), 1916b, p. 391, pi. 63, fig. 9 (only). 
Ehmania? agatho (Walcott) Resser, 1938b, p. 29. 

Available material. — Walcott based the species on the holotype 
cranidium and assigned to it a pygidium on the same piece of limestone. 
The author's collections, however, indicate that the pygidium belongs 
to the more common, associated species Modocia dubia. A pygidium 
believed to belong to the species is present in the collection from the 
type locality. The author collected several cranidia and one pygidium. 

Description. — Glabella of moderate convexity, fairly straight-sided, 
moderately tapered, rounded in front, with a bare trace of lateral fur- 
rows on outer surface. Occipital furrow well marked; occipital ring 
subtriangular, rounded. Frontal area downsloping, rather flat, divided 
into preglabellar field and border by a shallow furrow, not accom- 
panied by much change in slope. Ocular ridges present ; palpebral area 
convex, on average horizontal, one-third the glabellar width. Palpebral 
lobes 0.3 times the glabellar length, narrow, defined by shallow palpe- 
bral furrow, situated at the level of glabellar midpoint and hence more 
posterior in position than in the 3 preceding species. Anterior sections 
of facial suture definitely divergent ; posterior section directed outward 
from palpebral lobe, curving backward distally ; posterior area almost 
parallel-sided, rounded distally, deeply furrowed ; surface smooth. 

Pygidium tentatively assigned to the species 2.2 times as wide as 
long. Anterior margin fairly straight. Axis stout, not greatly tapered, 
showing 2 rings plus a terminal section. Pleural regions with little con- 
vexity, almost horizontal, showing several pairs of furrows and inter- 
pleural grooves ; only the first pair of furrows fairly deep. All furrows 
and grooves extend to a shallow border furrow that sets off a slightly 
elevated border. Surface very finely granulate. 



NO, 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 111 

Length of largest cranidium 6 mm. Length of pygidium 3.5 mm., 
width 7.5 mm. 

Discussion. — This species cannot be given a satisfactory generic 
assignment. The cranidium differs from typical Modocia in the lack of 
a convex anterior border, horizontal rather than downsloping palpe- 
bral area, more posterior position of the eyes, and parallel-sided rather 
than tapered posterior area. In all these features it closely resembles 
cranidia of Marjumia typa. However, if the pygidium is correctly as- 
signed, it is rather indicative of Modocia; spinose pygidia of the Mar- 
jumia type were not recovered from the Maryville formation. 

Occurrence. — The type locaHty is U.S.N.M. 123a, near Rogersville. 
Also collected by the author in the same area at localities cnc/2 to 
cnc/5. The species belongs to the lower Cedaria zone faunule of the 
uppermost Maryville limestone. 

Types.— Roloiy^e: U.S.N.M. 62819. Plesiotypes: U.S.N.M. 144- 
72-^^-6. 

Genus LOXOPARIA Rasetti, new genus 

Description. — Cranidium subtrapezoidal, moderately convex. Gla- 
bella moderately convex, unfurrowed, rising above the cheeks, with 
slightly concave side outline, subtruncate in front, reaching the border. 
Occipital furrow well marked ; occipital ring extended into spine. 
Frontal area flat, consisting only of border ; border furrow present at 
the sides, merging with axial furrow medially. Palpebral area some- 
what over half the glabellar width, convex, downsloping ; ocular ridges 
barely distinct, strongly slanted ; palpebral lobes short and narrow, in- 
conspicuous, situated in advance of glabellar midpoint. Anterior sec- 
tions of facial sutures directed forward from palpebral lobes, curving 
inward ; anterior angles of cranidium widely rounded. Posterior sec- 
tion of facial suture directed outward and backward, fairly straight for 
half its course, then curving backward and finally somewhat inward. 
Posterior area of fixed cheeks large, downsloping, extending back- 
ward much farther than glabella, sharply pointed. Furrow on posterior 
area deep, first directed outward and then curving forward ; posterior 
margin of posterior area straight, strongly slanted outward and back- 
ward. 

Type species. — Loxoparia obliqua Rasetti, n. sp. 

Discussion. — The shape of the glabella and frontal area are sug- 
gestive of Llanoaspis and related forms ; however, the characters of 
the palpebral area, palpebral lobes, and course of the posterior section 
of the facial sutures are radically different. The affinities of this tri- 
lobite are obscure. 

Occurrence. — Upper Cambrian (Cedaria zone) of the southern Ap- 
palachians. 



112 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

LOXOPARIA OBLIQUA Rasetti, new species 

Plate 3, figures 7-9 

Available material. — Three cranidia preserved in limestone. 

Description. — The generic description and the illustrations present 
all the observable characters of the species. The axial and border fur- 
rows are shallow on the outer surface. The occipital ring has a subtri- 
angular shape, extending into a broad-based, short spine. Surface of 
test perfectly smooth. Length of largest cranidium 7 mm. 

Occurrence. — Red beds at the base of the Nolichucky {Cedaria 
zone) at locality end/ 1. 

73;/)^.?.— Holotype : U.S.N.M. 144727. Paratypes: U.S.N.M. 144- 
728. 

UNDETERMINED TRILOBITES 

Undetermined Cranidium No. 1 
Plate 8, figure 29 

Known from a single, incomplete specimen. Glabella large, rising 
well above the cheeks, almost straight-sided, strongly tapered, rounded 
in front. Occipital furrow deep and straight ; occipital ring short (sag.), 
extended into an uptilted spine of unknown length. Posterior glabellar 
furrows fairly deep, bifurcated, with the shorter anterior branch trans- 
verse, the longer posterior branch turning backward. Two other pairs 
of lateral furrows short, the anteriormost one very shallow. Preglabel- 
lar field almost vanishing medially ; border slightly convex, not greatly 
arched transversely. Palpebral area and lobe not preserved. Incom- 
plete posterior area deeply furrowed, the furrow turning forward in 
the distal part. Surface covered with medium-sized granules. Length 
of cranidium, exclusive of occipital spine, 4 mm. 

Although this trilobite cannot be referred to any described genus, 
the incomplete material does not warrant a new name. Possibly the 
nearest known forms are certain species of Genevievella. 

Occurrence. — Uppermost beds of the lower limestone member of 
Nolichucky {Cr e pic ephalus zone) at locality cnn/3. 

Disposition of material. — Figured specimen: U.S.N.M. 144729. 

Undetermined Cranidium No. 2 
Plate 8, figure 19 

Known from a single, incomplete specimen. Glabella very convex, 
defined by a deep axial furrow, strongly tapered to a pointed anterior 
end which is somewhat truncate. Surface of glabella mostly broken off ; 
lateral furrows, if present, must have been very shallow. Occipital fur- 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 113 

row broad and deep; occipital ring short (sag.), but extended into a 
very long, uptilted spine. Frontal area consisting of convex, down- 
sloping, preglabellar field and elevated, convex, transversely arched 
border. Ocular ridges wide and fairly prominent, directed slightly 
forward from the glabella, curving slightly to assume a transverse di- 
rection. Palpebral area somewhat wider than glabella, rising above the 
axial furrow and strongly convex transversely. Palpebral lobes and 
posterior area not preserved. Surface of glabella and fixed cheeks cov- 
ered with granules of different sizes. Length of cranidium 4.2 mm. 
exclusive of occipital spine. 

This cranidium, remarkable for the pointed glabella, wide palpebral 
area, and forward-directed ocular ridges, cannot be assigned to any 
described genus. No affinities can be suggested, beyond its inclusion in 
the great ptychoparioid group. 

Occurrence. — Lower portion of lower limestone member of the Noli- 
chucky (Crepicephalus zone) at locality cnk/1. 

Disposition of material. — Figured specimen: U.S.N.M. 144730. 

Undetermined Pygidium No. 1 
Plate 6, figure 8 

Known from a single example. Pygidium 2.5 times as wide as long. 
Axis prominent, tapered, showing 3 rings plus a terminal section, 
reaching the border furrow. Pleural region with a straight anterior 
outline, rounded anterior angles, and posterior margin fairly straight 
on either side, slightly pointed medially. Three pairs of rather deep 
pleural furrows and shallow interpleural grooves are present. Border 
furrow shallow, border very narrow. 

This pygidium somewhat resembles the pygidia of Llanoaspis, dif- 
fering in its shortness and small number of pleural furrows. No cran- 
idium to which it may be assigned was collected from the same beds. 

Occurrence. — Lower portion of lower limestone member of the Noli- 
chucky {Crepicephalus zont) at locality cnk/1. 

Disposition oj material. — Figured specimen: U.S.N.M. 144731. 

Undetermined Pygidium No. 2 
Plate 6, figures 20, 21 

Known from several examples. Pygidium of low convexity, 1.75 
times as wide as long. Axis long, tapered, straight-sided, extended into 
a sharp postaxial ridge that reaches the posterior margin. Seven or 
eight axial rings separated by shallow furrows are distinguishable. 
Pleural regions with straight anterior outline, well-rounded anterior 
angles, and regularly semicircular posterior margin except for a shal- 



114 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

low median notch. Five pairs of shallow, broad pleural furrows end 
very sharply on the line corresponding to the margin of the doublure. 
The remaining portion of the pleural regions is smooth and flat or 
slightly concave. Surface of test smooth. Length of largest pygidium 
6 mm., width 10.7 mm. 

This pygidium may belong to Coosia or a related trilobite. It differs 
from the usual pygidia of Coosia in the great relative length of the axis. 
No corresponding cranidium was collected. 

Occurrence. — Upper portion of lower limestone member of the Noli- 
chucky (Crepicephalus zone) at locality cnm/2. One specimen was col- 
lected from the lower portion of the same limestone at locality cnk/1. 

Disposition of material. — Figured specimens : U.S.N.M. 144732. 



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EXPLANATION OF PLATES 
Plate 1 

Page 

Figs. 1-4. Coosella andreas (Walcott) 48 

1, Cranidium, x4. 2-4, Dorsal, lateral, and posterior views of pygidium, 
X4 (coll. cnc/2) ; U.S.N.M. 144572, plesiotypes. 

Figs. 5-7. Coosella resseri Rasetti, new name 48 

5-7, Lateral, posterior, and dorsal views of pygidium lacking test, x2 
(coll. cnd/1) ; U.S.N.M. 144573, plesiotype. 

Figs. 8, 9. Kormagnostus simplex Resser 38 

8, Cephalon, xS. 9, Pygidium, x5 (coll. cnc/S) ; U.S.N.M. 144546, 
plesiotypes. 

Figs. 10-12. Ithycephalus typicalis Resser 106 

10-12, Dorsal, lateral, and anterior views of cranidium, x5 (coll. 
cnd/1) ; U.S.N.M. 144714, plesiotype. 

Figs. 13-21. Modocia bidentata Rasetti, n. sp 108 

14-16, Dorsal, lateral, and posterior views of pygidium, x2 (coll. 
cnd/1) ; U.S.N.M. 144717, holotype. 13, Cranidium, xl.5. 17, Pygid- 
ium, x2. 18, Cranidium, x2. 19-21, Dorsal, frontal, and lateral views 
of cranidium, x2 (coll. cnd/1) ; U.S.N.M. 144718, paratypes. All 
specimens lacking test. 

Figs. 22-26. Modocia dubia (Resser) 107 

22, 23, Dorsal and lateral views of cranidium, x2. 24, Free cheek, x2. 
26, Pygidium, x2 (coll. cnc/5) ; U.S.N.M. 144715, plesiotypes. 25, 
Exfoliated cranidium, x2 (coll. cnd/1) ; U.S.N.M. 144716, plesiotype. 

Figs. 27-30. Modocia? agatho (Walcott) 110 

27, 28, Lateral and dorsal views of cranidium, x4 (coll. cnc/5) ; U.S.- 
N.M. 144724, plesiotype. 29, Pygidium, x3 (coll. cnc/2) ; U.S.N.M. 

144725, plesiotype. 30, Cranidium, x4 (coll. cnc/4) ; U.S.N.M. 

144726, plesiotype. 

Plate 2 
Figs. 1-9. Modocia crassimarginata Rasetti, n. sp 109 

1-3, Dorsal, lateral, and frontal views of cranidium, x2 (coll. cnc/2) ; 
U.S.N.M. 144719, holotype. 4, 5, Exfoliated cranidia, x2 (coll. 
cnc/1) ; U.S.N.M. 144721, paratypes. 6, 7, Dorsal and posterior views 
of pygidium, x2 (coll. cnc/3) ; U.S.N.M. 144722, paratype. 9, Ex- 
foliated pygidium, x2 (coll. cnd/1) ; U.S.N.M. 144723, paratype. 
8, Partly exfoliated cranidium, x2 (coll. cnd/1) ; U.S.N.M. 144723, 
paratype. 
Figs. lChl8. Bonnet errina appalachia (Walcott) 102 

10, Large cranidium, xl-5 (coll. cnc/6) ; U.S.N.M. 144703, plesio- 
type. 11, 12, Dorsal and lateral views of cranidium with strong relief, 
X2 (coll. cnc/5) ; U.S.N.M. 144704, plesiotype. 13, Free cheek, x2 
(coll. cnc/5) ; U.S.N.M. 144704, plesiotype. 14, 15, Dorsal and lateral 
views of pygidium, x4 (coll. cnc/1) ; U.S.N.M. 144705, plesiotype. 
16, 17, Lateral and dorsal views of cranidium with weak relief and 
shallow occipital furrow, x2 (coll. cnd/1) ; U.S.N.M. 144706, plesio- 

118 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 119 

Page 

type. 18, Exfoliated pygidium, x2 (coll. cnd/1) ; U.S.N.M. 144706, 
plesiotype. 

Figs. 19-24. M enomonia tuber culata Rasetti, n. sp 62 

19-21, Dorsal, lateral, and frontal views of cranidium, x5 (coll. cnc/2) ; 
U.S.N.M. 144696, holotype. 22, Free cheek, x5 (coll. cnc/2) ; U.S.- 
N.M. 144697, paratype. 23, 24, Lateral and dorsal views of cranidium 
with somewhat shorter preglabellar field, x5 (coll. cnc/5) ; U.S.N.M. 
144698, paratype. 

Figs. 25-27. M enomonia, sp. undet 63 

25, 26, Dorsal and lateral views of cranidium, x5 (coll. cnc/4) ; U.S.- 
N.M. 144699. 27, Free cheek, x5 (coll. cnc/6) ; U.S.N.M. 144700. 

Plate 3 

Figs. 1-6. Norwoodella saffordi (Walcott) 65 

1, Artificial cast of counterpart of holotype, x3 (U.S.N.M. coll. 103) ; 
U.S.N.M. 61595. 2, 3, Exfoliated cranidia, x5 (coll. cnd/1); U.S.- 
N.M. 144612, plesiotypes. 4, Cranidium, X5. 5, 6, Pygidia, X7.5 (coll. 
cne/2) ; U.S.N.M. 144613, plesiotypes. 

Figs. 7-9. Loxoparia obliqua Rasetti, n. gen., n. sp 112 

Dorsal, frontal, and lateral views of cranidium, x5 (coll. cnd/1) ; 
U.S.N.M. 144727, holotype. 

Figs. 10, 11. Holcacephalus praecursor Rasetti, n. sp 68 

10, Partly exfoliated cranidium, x7.5 (coll. cnc/1) ; U.S.N.M. 144621, 
holotype. 11, Exfoliated pygidium, xlO (coll. cnc/1); U.S.N.M. 
144622, paratype. 

Figs. 12-14. Holcacephalus granulatus Resser 68 

12, 13, Exfoliated cranidia, X 10. 14, Exfoliated pygidium, xlO (coll. 
cnd/1) ; U.S.N.M. 144620, plesiotypes. 

Figs. 15-21. Ankoura triangularis Resser 61 

15, 16, Dorsal and lateral views of exfoliated pygidium, x7.5. 17, Ex- 
foliated pygidium, x7.5 (coll. U.S.N.M. 27d) ; U.S.N.M. 144702, 
plesiotypes. 18, 19, Lateral and dorsal views of exfoliated cranidium, 
X7.5 (coll. U.S.N.M. 27d) ; U.S.N.M. 144608, plesiotype. 20, Incom- 
plete cranidium preserving test, x7.5. 21, Pygidium, x7.5 (coll. cnb/ 
10) ; U.S.N.M. 144609, plesiotypes. 

Figs. 22-25. Hawkinsia minuta Rasetti, n. gen. n. sp 105 

22, Cranidium, X 10 (coll. cnc/1); U.S.N.M. 144713, paratype. 23-25, 
Frontal, lateral, and dorsal views of cranidium, xlO (coll. cnc/1); 
U.S.N.M. 144712, holotype. 

Plate 4 

Figs. 1-7. Norwoodella rotundicollis Rasetti, n. sp 65 

1, 2, Dorsal and lateral views of exfoliated cranidium, x3 (coll. cnd/1) ; 
U.S.N.M. 144614, holotype. 3, Exfoliated cranidia, x3. 4, Free check, 
X5. 5, Cranidium, x5. 6, Exfoliated pygidium, XlO. 7, Exfoliated py- 
gidium, x8 (coll. cnd/1) ; U.S.N.M. 144615, paratypes. 

Figs. 8-15. Norzvoodella halli Resser 67 

8-10, Frontal, lateral, and dorsal views of cranidium, X7.5. 11, 12, Free 
cheeks, x5. 13-15, Pygidia, x7.5 (coll. cnd/10) ; U.S.N.M. 144619, 
plesiotypes. 



120 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Page 

Figs. 16-23. Norwoodella walcotti Resser 66 

16-18, Dorsal, lateral, and frontal views of cranidium, x4. 19, 20, Py- 
gidia, X5. 21, Free cheek, x5 (coll. cne/10) ; U.S.N.M. 144616, 
plesiotypes. 22, Free cheek, x5 (coll. cne/12) ; U.S.N.M. 144617, 
plesiotype. 23, Cranidium, x4 (coll. U.S.G.S. 2407) ; U.S.N.M. 
144618, plesiotype. 

Fig. 24. Norwoodia, sp. undet 65 

Incomplete, exfoliated cranidium, x4 (coll. cnc/4) ; U.S.N.M. 144611. 

Figs. 25, 26. Norwoodia rogersvillensis Resser 64 

25, Exfoliated cranidium, xS. 26, Exfoliated pygidium, XlO (coll. 
cnd/1) ; U.S.N.M. 144610, plesiotypes. 

Plate 5 

Figs. 1-3. Coenaspis spectabilis Resser 105 

Dorsal, frontal, and dorsolateral views of rubber reproduction of par- 
tially exfoliated holotype cranidium, x4 (coll. U.S.N.M. 123a) ; 
U.S.N.M. 94978. 
Figs. 4-8. Cedaria tennesseensis Walcott 69 

4, 5, Cranidia flattened in shale, x2 (coll. U.S.N.M. 107a) ; U.S.N.M. 
70273, paratypes. 6, Free cheek, x3. 7, Exfoliated pygidium, x2. 8, 
Pygidium, x3 (coll. cne/10) ; U.S.N.M. 144623, plesiotypes. 

Figs. 9-11. Genevievella, sp. undet 71 

9, 10, Dorsal and lateral views of cranidium, x3 (coll. cnc/4) ; U.S.- 
N.M. 144626. 11, Exfoliated cranidium, x5 (coll. cnd/1) ; U.S.N.M. 
144627. 

Figs. 12, 13. Olenoides, sp. undet 39 

Pygidia, X4 (coll. U.S.G.S. 2406) ; U.S.N.M. 144548. 

Figs. 14-17. Menomonia prominens Resser 62 

14, Exfoliated cranidium, X5. 15, 16, Lateral and posterior views of 
cranidium, x5. 17, Free cheek, x5 (coll. cnd/1) ; U.S.N.M. 144695, 
plesiotypes. 

Fig. 18. Cedarina, sp. undet 70 

Exfoliated pygidium, x3 (coll. cnd/1) ; U.S.N.M. 144624. 

Fig. 19. Coosia, sp. undet 53 

Pygidium, x5 (coll. cnn/1) ; U.S.N.M. 144588. 

Fig. 20. Amiaspis erratica Lochman 43 

Cranidium, xlO (coll. cnn/16) ; U.S.N.M. 144558, plesiotype. 

Figs. 21-24. Amiaspis obsolescens Rasetti, n. sp 43 

21-23, Dorsal, lateral, and frontal views of cranidium, x8 (coll. cnmV 
20) ; U.S.N.M. 144559, holotype. 24, Cranidium, x8 (coll. cnn/16) ; 
U.S.N.M. 144560, paratype. 

Plate 6 

Figs. 1-4. Tricrepicephalus thoosa (Walcott) 54 

1, Exfoliated cranidium, Xl.5, coll. cnn/3) ; U.S.N.M. 144589, plesio- 
type. 2, Exfoliated pygidium, x2.2 (coll. cnn/3) ; U.S.N.M. 144589, 
plesiotype. 3, Cranidium, x2 (coll. cnn/14) ; U.S.N.M. 144590, plesio- 
type. 4, pygidium preserving unusually smooth test on pleural regions, 
X2.2 (coll. cnm/2) ; U.S.N.M. 144591, plesiotype. 
Figs. 5, 6. Crepicephalus buftsi Resser 45 

5, Exfoliated pygidium, xl- 6, Exfoliated pygidium, Xl.5 (coll. cnn/19) ; 
U.S.N.M. 144565, plesiotypes. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 121 

Page 

Fig. 7. Terranovella dorsalis (Hall) 40 

Cranidium, X 10 (coll. cnn/19) ; U.S.N.M. 144549, plesiotype. 

Fig. 8. Undetermined pygidium No. 1 113 

Pygidium, X5 (coll. cnk/1) ; U.S.N.M. 144731. 

Figs. 9-12. Meteoraspis brevispinosa Rasetti, n. sp 55 

9, 10, Lateral and dorsal views of exfoliated pygidium, X2 (coll. cnk/1) ; 
U.S.N.M. 144594, holotype. 11, Small cranidium, x5. 12, Exfoliated 
cranidium, x2 (coll. cnk/1) ; U.S.N.M. 144595, paratypes. 

Figs. 13, 14. Meteoraspis mutica Rasetti 54 

13, Cast of impression of cranidium, x3. 14, Exfoliated pygidium, x3 
(coll. cnm/2) ; U.S.N.M. 144592-3, plesiotypes. 

Figs. 15-18. Coosia alethes (Walcott) 52 

15, Exfoliated cranidium, x2. 16, 17, Exfoliated hypostomes, x2. 18, 
Pygidium, X3 (coll. cnn/16) ; U.S.N.M. 144582, plesiotypes. (See 
also pi. 7.) 

Fig. 19. Coosella, sp. undet 50 

Partly exfoliated pygidium, x2 (coll. cnk/1) ; U.S.N.M. 144579. 

Figs. 20, 21. Undetermined pygidium No. 2 113 

20, Pygidium, x5. 21, Exfoliated pygidium, X3 (coll. cnm/2) ; U.S.- 
N.M. 144732. 

Plate 7 

Figs. 1-5. Coosella planicauda Rasetti, n. sp 49 

1, Cranidium, x3. 2, Cranidium, X5 (coll. cnk/1) ; U.S.N.M. 144576, 
paratypes. 3, Exfoliated pygidium, x2. 4, Pygidium, X3 (coll. cnm/ 
2) ; U.S.N.M. 144575, paratype. 5, Pygidium, x4 (coll. cnm/2) ; 
U.S.N.M. 144574, holotype. 

Figs. 6-13. Coosia alethes (Walcott) 52 

6, Internal rubber cast of pygidium, xl-5 (coll. cnn/1) ; U.S.N.M. 
144583, plesiotype. 7, Exfoliated cranidium, Xl.5 (coll. cnn/4) ; U.S.- 
N.M. 144584, plesiotype. 8, Small, exfoliated cranidium, X5. 9, Ex- 
foliated cranidium, Xl-S. 10, Internal rubber cast of cranidium, Xl.5. 
11, Exfoliated pygidium, x2 (coll. cnn/3) ; U.S.N.M. 144585, ple- 
siotypes. 12, 13, Two views of immature, partially enrolled exoskeleton 
lacking only the free cheeks, X 10 (coll. cnm/2) ; U.S.N.M. 144586, 
plesiotype. 

Figs. 14-22. Coosina amage (Walcott) 50 

14-16, Dorsal, lateral, and frontal views of exfoliated cranidium, x2. 
17, Cranidium, x3. 19-21, Dorsal, lateral, and posterior views of py- 
gidium, x2. 22, Internal rubber cast of pygidium, X2 (coll. cnm/2) ; 
U.S.N.M. 144580, plesiotypes. 18, Pygidium, X2 (coll. cnm/3) ; 
U.S.N.M. 144561, plesiotype. 

Figs. 23-25. Pemphigaspis, sp. undet 44 

23, 24, Lateral and dorsal views of cranidium, X5. 25, Ventral view of 
pygidium, x5 (coll. cnn/3) ; U.S.N.M. 144562. 

Fig. 26. Coosia robusta Walcott 53 

Rubber cast of interior surface of pygidium, Xl.5 (coll. cnn/1) ; U.S.- 
N.M. 144587, plesiotype. 

Fig. 27. Coosina ariston (Walcott) 51 

Exfoliated pygidium, X2 (coll. cnm/2) ; U.S.N.M. 144581, plesiotype. 

Plate 8 
Figs. 1-4. Dresbachia amata Walcott 61 



122 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Page 
1, 2, Lateral and dorsal views of incomplete cranidium, X4, 3, 4, Free 
cheeks, x4 (coll. cnk/1) ; U.S.N.M. 144694, plesiotypes. 

Figs. 5-8. Crepicephalus convergcns Rasetti, n. sp 46 

5, Pygidium, x2 (coll. cnk/1) ; U.S.N.M. 144567, paratype. 6, Pygid- 
ium, X2 (coll. cnk/1) ; U.S.N.M. 144566, holotype. 7, Exfoliated 
cranidium, x5. 8, Portion of cranidium showing ornamentation, XS 
(coll. cnk/1) ; U.S.N.M. 144567, paratypes. 

Figs. 9-11. Crepicephalus cf. convergcns Rasetti 46 

9, 11, Exfoliated pygidia, x2 (coll. cnn/3) ; U.S.N.M. 144568. 10, Ex- 
foliated pygidium, x2 (coll. cnn/1) ; U.S.N.M. 144569. 
Figs. 12, 13. Crepicephalus ? sp. undet. No. 2 47 

12, Rubber cast of internal surface of cranidium, X2. 13, Exfoliated 
pygidium, x2 (coll. cnn/3) ; U.S.N.M. 144571. 

Figs. 14-16. Llanoaspis walcotti Resser 70 

14, Rubber cast of external impression of cranidium, xS. 15, 16, Py- 
gidia, X5 (coll. cnn/3) ; U.S.N.M. 144625, plesiotypes. 

Figs. 17, 18. Crepicephalus, sp. undet. No. 1 47 

17, Rubber cast of internal surface of pygidium, x2. 18, Exfoliated py- 
gidium, X2 (coll. cnn/4) ; U.S.N.M. 144570. 

Fig. 19. Undetermined cranidium No. 2 112 

Cranidium, X5 (coll. cnk/1) ; U.S.N.M. 144730. 

Fig. 20. Madarocephalus laetus Resser 44 

Cranidium, XlO (coll. cnm/2) ; U.S.N.M. 144563, plesiotype. 

Figs. 21-28. Kingstonia inflata Resser 60 

21, 22, Lateral and dorsal views of pygidium, x5. 25, Pygidium, X5. 
26, Photograph of cranidium taken under water, x5, showing lighter 
stains probably corresponding to muscle attachments on interior sur- 
face (coll. cnm/2) ; U.S.N.M. 144605, plesiotypes. 23, Exfoliated py- 
gidium, x5 (coll. cnn/1) ; U.S.N.M. 144606, plesiotype. 24, 28, Lateral 
and dorsal views of cranidium, x5. 27, Cranidium, x5 (coll. cnk/1) ; 
U.S.N.M. 144607, plesiotype. 

Fig. 29. Undetermined cranidium No. 1 112 

Cranidium, x5 (coll. cnn/3) ; U.S.N.M. 144729. 

Fig. 30. Crepicephalus cf. scissilis Resser 45 

Exfoliated pygidium, X2 (coll. cnn/3) ; U.S.N.M. 144564. 

Plate 9 

Figs. 1-8. Blountia arcuosa Resser 55 

1, 2, Dorsal and frontal views of cranidium, X 5. 3, 4, Dorsal and lateral 
views of cranidium, x5. 5, Pygidium, x4. 6, Exfoliated pygidium, 
X5. 7, 8, Dorsal and lateral views of pygidium, x5 (coll. cnm/3) ; 
U.S.N.M. 144555, plesiotypes. 

Figs. 9-12. Blountia alexas Walcott 56 

9, Cranidium, x5. 10, 11, Dorsal and lateral views of cranidium, x5 
(coll. cnk/1) ; U.S.N.M. 144596, plesiotypes. 12, Pygidium, xS 
(coll. cnk/3) ; U.S.N.M. 144701, plesiotype. 
Figs. 13-20. Blountia montanensis Duncan 57 

13, 16, Dorsal and lateral views of cranidium, x5. 14, Free cheek, x5. 
15, Pygidium, x5 (coll. cnk/1); U.S.N.M. 144598, plesiotypes. 17, 
Lateral view of large cranidium, x3. 18, Pygidium, x5. 19, Ex- 
foliated pygidium, x2. 20, Cranidium, xS (coll. cnm/2) ; U.S.N.M. 
144599, plesiotypes. 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 123 

Page 

Fig. 21. Blountia lata (Resser) 57 

Rubber impression of internal surface of cranidium, x5 (coll. cnn/3) ; 
U.S.N.M. 144597, plesiotype. 
Figs. 22-26. Maryvillia arion Walcott 59 

22, 23, Dorsal and lateral views of exfoliated cranidium, x2. 24, Py- 
gidium, xl-5. 25, Exfoliated pygidium, xl-5 (coll. cnm/2) ; U.S.- 
N.M. 144603, plesiotypes. 26, Partly exfoliated pygidium, X2 (coll. 
cnn/1) ; U.S.N.M. 144604, plesiotype. 

Plate 10 

Figs. 1, 2. Blountia hristolensis Resser 58 

1, 2, Dorsal and lateral views of exoskeleton lacking free cheeks, x4 
(coll. cnp/17) ; U.S.N.M. 144600, plesiotype. (See also pi. 11.) 

Figs. Z-7. Blountia mimula Walcott 59 

3, Cranidium, X3. 4, 5, Dorsal and lateral views of cranidium, X3. 6, 
Exfoliated pygidium, X3. 7, Pygidium, X3 (coll. Oder No. 2) ; U.S.- 
N.M. 144602, plesiotypes. 

Fig. 8. Glaphyraspis ornata (Lochman) 41 

Rubber cast of external impression of exoskeleton in shale, XlO (coll. 
Oder No. 3) ; U.S.N.M. 144551, plesiotype. (See also pi. 11.) 

Figs. 9-17. Glaphyraspis parva (Walcott) 40 

9-12, 14, Cranidia, x7.5. 13, Free cheek, X5. 15-17, pygidia, X5 (coll. 
cno/15) ; U.S.N.M. 144550, plesiotypes. 

Figs. 18-22. Glaphyraspis oderi Rasetti, n. sp 41 

18, Cranidia, the one at left being the holotype, X7.5, U.S.N.M. 144553. 
19, Lateral view of holotype cranidium. 20, Cranidium, x7.5. 21, Free 
cheek, x7.5. 22, Pygidium x7.5 (all specimens from coll. Oder No. 2; 
U.S.N.M. 144554, paratypes. 
Figs. 23-25. Pseudagnostus communis (Hall and Whitfield) 39 

23, Exfoliated cephalon, x4. 24, 25, Exfoliated pygidia, x4 (coll. ens/ 
2) ; U.S.N.M. 144547, plesiotypes. 

Plate 11 

Figs. 1-8. Aphelaspidella macropyge Rasetti, n. gen., n. sp 96 

7, 8, Dorsal and frontal views of cranidium, x3 (coll. cnr/4) ; U.S.N.M. 
144681, holotype. 1, 2, Cranidia, x3. 3, 4, Pygidia, x2. 5, 6, Free 
cheeks, X2 (coll. cnr/4) ; U.S.N.M. 144682, paratypes. 

Figs. 9-12. Blountia hristolensis Resser S% 

9, 11, Cranidia, X4. 10, 12, Pygidia. X4 (coll. cnp/14) ; U.S.N.M. 
144601, plesiotypes. (See also pi. 10.) 

Figs. 13, 14. Glaphyraspis ornata (Lochman) 41 

13, Pygidium, x7.5. 14, Cranidium, x7.5 (U.S.G.S. coll. 2804) ; U.S.- 
N.M. 144552, plesiotypes. (See also pi. 10.) 

Figs. 15-21. Aphelaspis arsoides Rasetti, n. sp 94 

15-17, Dorsal, frontal, and lateral views of cranidium, X4 (coll. cns/2) ; 
U.S.N.M. 144677, holotype. 18, 19, Cranidia, X4 (coll. cns/2) ; U.S.- 
N.M. 144678, paratypes. 20, 21, Free cheeks, X4 (coll. cnt/4) ; U.S.- 
N.M. 144679, paratypes. (See also pi. 12.) 

Plate 12 

Figs. 1-17. Aphelaspis camiro (Walcott) 83 

1, 2, Dorsal and frontal views of cranidium, X3. 3-5, Dorsal, lateral. 



124 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Page 
and frontal views of cranidium, x2. 6-8, Pygidia, X4 (U.S.N.M. coll. 
120) ; U.S.N.M. 144648, plesiotypes. 9, Cranidium, x2.5. 10, Free 
cheek, X2 (coll. cnr720) ; U.S.N.M. 144649, plesiotypes. 11, Hypos- 
tome, x3 (coll. cnr/15) ; U.S.N.M. 144650, plesiotype. 12, 13, Dorsal 
and frontal views of cranidium, x4. 14, Free cheek, x4. 15, Hypos- 
tome, x4. 16, Cranidium, X2. 17, Exfoliated cranidium, X2 (coll. 
cns/16) ; U.S.N.M. 144651, plesiotypes. 

Figs. 18-21. Aphelaspis laxa Resser 80 

18, Exfoliated free cheek, xl-S. 19, Cranidium, x4 (coll. cns/16) ; U.S.- 
N.M. 144643, plesiotypes. 20, Free cheek, xl.5. 21, Pygidium, x4 
(coll. cnr720) ; U.S.N.M. 144644, plesiotypes. (See also pi. 13.) 

Fig. 22. Aphelaspis arsoides Rasetti, n. sp 94 

Pygidium, x3 (coll. cnt/20) ; U.S.N.M. 144680, paratype. (See also pi. 

11.) 

Figs. 23-25. Dytremacephalus sulcifrons Rasetti, n. sp 101 

Dorsal, lateral, and frontal views of cranidium, X4 (coll. cnw/14) ; 
U.S.N.M. 144690, holotype. 

Plate 13 

Figs. 1-7. Aphelaspis hridgei Rasetti, n. sp 77 

1-3, Dorsal, frontal, and lateral views of cranidium, X3 (coll. U.S.G.S. 
2804) ; U.S.N.M. 144635, holotype. 4, Cranidium, X3. 5, Free cheek, 
X3. 6, 7, Pygidia, x3 (coll. U.S.G.S. 2804) ; U.S.N.M. 144636, para- 
types. 

Figs. 8-15. Aphelaspis laxa Resser 80 

8, Cranidium, x3. 9-11, Dorsal, frontal, and lateral views of cranidium, 
X4. 13, 15, Pygidia, X2. 14, Lateral view of cranidium, X2 (coll. 
U.S.N.M. 120) ; U.S.N.M. 144645, plesiotypes. 12, Free cheek, x2 
(coll. cnr720) ; U.S.N.M. 144644, plesiotype. (See also pi. 12.) 

Figs. 16-23. Aphelaspis arses (Walcott) 93 

16-18, Dorsal, frontal, and lateral views of cranidium, x4. 19, Cranid- 
ium, X4. 20, Pygidium, X4. 21, Free cheek, x4. 22, Free cheek and 
pygidium, x4 (coll. cns/4) ; U.S.N.M. 144676, plesiotypes. 23, Cran- 
idium, X4 (coll. cnr/4) ; U.S.N.M. 144733, plesiotype. 

Plate 14 

Figs. 1-12. Aphelaspis rotundata Rasetti, n. sp 84 

1-3, Dorsal, lateral, and frontal views of partly exfoliated cranidium, 
X2.8 (coll. cns/20) ; U.S.N.M. 144652, holotype. 5, 6, Exfoliated 
cranidia, Xl-5. 4, Exfoliated hypostome, X4. 7, Free cheek, x3. 8, 
Exfoliated free cheek, x3. 9, Exfoliated pygidium, x2. 10, 11, Lateral 
and dorsal views of exfoliated pygidium, X2.5 (coll. cns/20) ; U.S.- 
N.M. 144653, paratypes. 12, Pygidium attributed to the species, X3 
(coll. cnq'74) ; U.S.N.M. 144654, paratype. 

Figs. 13-19. Aphelaspis palmeri Rasetti, n. sp 81 

13-15, Dorsal, lateral, and frontal views of cranidium, x2 (coll. U.S.- 
G.S. 2970) ; U.S.N.M. 144646, holotype. 16, Free cheek, X3. 17, Partly 
exfoliated cranidium, x4. 18, 19, Exfoliated pygidia, X4 (coll. U.S.- 
G.S. 2970) ; U.S.N.M. 144647, paratypes. 

Figs. 20-24. Glaphyraspis declivis Rasetti, n. sp 42 

20-22, Lateral, dorsal, and frontal views of cranidium, x7.5 (coll. Oder 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 125 

Page 

No. 2); U.S.N.M. 144556, holotype. 23, Cranidium, x7.5. 24, Free 
cheek, x7.S (coll. Oder No. 2) ; U.S.N.M. 144557, paratypes. 

Plate 15 

Figs. 1-12. Dunderbergia tennesseensis Rasetti, n. sp 71 

1-3, Dorsal, lateral, and frontal views of cranidium, X2 (coll. cnw/14) ; 
U.S.N.M. 144628, holotype. 4, Cranidium, x3. 5, Cranidium, xS. 6, 
Free cheek, x2 (coll. cnw/14) ; U.S.N.M. 144629, paratypes. 7, 
Hypostome tentatively attributed to the species, X 10. 8, Cranidium, 
X5. 9, 10, Dorsal and posterior views of pygidium, x3. 11, Pygidium, 
X5 (coll. cnw/20) ; U.S.N.M. 144630, paratypes. 12, Free cheek, x3 
(coll. cnu/7) ; U.S.N.M. 144631, paratype. 

Figs. 13-18. Dunderbergia longijrons Rasetti, n. sp 7Z 

13-15, Dorsal, frontal, and lateral views of cranidium, X5 (coll. U.S.- 
G.S. 2970) ; U.S.N.M. 144632, holotype. 16, Cranidium, X5. 17, Ex- 
foliated cranidium, x4. 18, Pygidium, XlO (coll. U.S.G.S. 2970); 
U.S.N.M. 144633, paratypes. 

Figs. 19-26. Coosella perplexa ( Palmer) 50 

19-21, Dorsal, lateral, and frontal views of cranidium, x3. 22, 23, Py- 
gidia, X3 (coll. cno/14) ; U.S.N.M. 144577, plesiotypes. 24, Exfoliated 
pygidium, Xl-5. 25, Free cheek, X3. 26, Exfoliated cranidium, x3 
(coll. cno/15) ; U.S.N.M. 144578, plesiotypes. 

Plate 16 

Figs. 1-7. Aphelaspis buttsi (Kobayashi) 87 

1, 6, 7, Cranidia, x4. 2, 4, Pygidia, X2. 3, Pygidium, x4. 5, Free cheek, 
X4 (coll. cno/15) ; U.S.N.M. 144658, plesiotypes. 

Figs. 8-20. Aphelaspis lata Rasetti, n. sp 87 

8-10, Dorsal, frontal, and lateral views of cranidium, X4 (coll. cnp/14) ; 
U.S.N.M. 144659, holotype. 11, Free cheek, x4. 12-14, Pygidia, X4 
(coll. cnp/14) ; U.S.N.M. 144660, paratypes. 15, Cranidium, x3. 16, 
Exfoliated cranidium, X3. 17, Pygidium, x4 (coll. cnp/20) ; U.S.- 
N.M. 144661, paratypes. 18, Pygidium, X4 (coll. cnp/15) ; U.S.N.M. 
144662, paratype. 19, 20, Cranidia tentatively attributed to the species, 
X4 (coll. cnr/4) ; U.S.N.M. 144734, paratypes. 

Figs. 21-27. Aphelaspis transversa Rasetti, n. sp 88 

21-23, Lateral, frontal, and dorsal views of cranidium, X4 (coll. cnp/ 
17) ; U.S.N.M. 144663, holotype. 24, Exfoliated free cheek, x2. 25, 27, 
Cranidia, X3. 26, Pygidium, x4 (coll. cnp/17) ; U.S.N.M. 144664, 
paratypes. 

Plate 17 

Figs. 1-5. Cheilocephalus brevilobus (Walcott) 103 

1, Pygidium, x2. 2, Small cranidium, x5. 4, Free cheek, x3 (coll. cnq/ 
14) ; U.S.N.M. 144707, plesiotypes. 3, Small cranidium, with pygidium 
of Blountia bristolensis, X3 (coll. cnp/17) ; U.S.N.M. 144708, plesio- 
type. 5, Small pygidium, x3 (coll. cno/14) ; U.S.N.M. 144735, plesio- 
type. 
Figs. 6-11. Cheilocephalus brachyops Palmer 104 

6, Cranidium, x5. 7, Pygidium, X3. 8, Cranidium, X3 (coll. cnw/14) ; 
U.S.N.M. 144709, plesiotypes. 9, Hypostome, x5. 10, Pygidium, x5. 
11, Cranidium, X5 (coll. cnx/1) ; U.S.N.M. 414710, plesiotypes. 



126 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 

Page 
Figs. 12-14. Cheilocephalus, sp. undet 104 

12, Cranidium, X4. 13, 14, Pygidia, X4 (coll. cnr/4) ; U.S.N.M. 144711. 

Figs. 15-23. Aphclaspis zvashburnensis Rasetti, n. sp 85 

15-17, Dolsal, lateral, and frontal views of cranidium, x2 (coll. cnqV 

20) ; U.S.N.M. 144655, holotype. 18, Cranidium, xl.5. 19, Free cheek, 

X4. 20, Pygidium, x2 (coll. cnq720) ; U.S.N.M. 144656, paratypes. 

21, 22, Partly exfoliated cranidium, X3. 23, Pygidium, x3 (coll. ens/ 

15) ; U.S.N.M. 144657, paratypes. 

Plate 18 

Figs. 1-9. Aphelaspis quadrata Resser 78 

1-3, Small cranidium, X4. 4, Exfoliated free cheek, X2. 5, Free cheek, 
X2. 6, 7, Exfoliated pygidia, X3. 8, Pygidium, x4 (coll. cns/16) ; 
U.S.N.M. 144637, plesiotypes. 9, Pygidium, x4 (coll. U.S.N.M. 120; 
U.S.N.M. 144638, plesiotype. 

Figs. 10-20. Aphclaspis walcotti Resser 76 

10, Cranidium, X3. 11, Free cheek and partly exfoliated cranidium, x4. 
12, Exfoliated pygidium, x2. 16, Cranidium, x4 (coll. cnq/16) ; U.S.- 
N.M. 144632, plesiotypes. 13-15, Lateral, frontal, and dorsal views of 
cranidium, X2. 20, Pygidium, x3 (coll. cnq/20) ; U.S.N.M. 144633, 
plesiotypes. 17, Free cheek, x3. 18, Pygidium, X4. 19, Free cheek, 
X2 (coll. cnr/15) ; U.S.N.M. 144634, plesiotypes. 

Figs. 21-29. Aphelaspis punctata Rasetti, n. sp 92 

21, 22, 24, Frontal, dorsal, and lateral views of cranidium, X4 (coll. 
cnw/14) ; U.S.N.M. 144673, holotype. 23, Cranidium, x4 (coll. cnw/ 
14) ; U.S.N.M. 144674, paratype. 25, 29, Free cheeks, X4. 26, cranid- 
ium, X3. 27, Cranidium, x4. 28, Pygidium, x5 (coll. cnw/20) ; U.S.- 
N.M. 144675, paratypes. 

Plate 19 

Figs. 1-7. Aphelaspis tumifrons Resser 91 

1, 2, Dorsal and frontal views of cranidium, x4. 3, 4, Lateral and dorsal 
views of cranidium, x4. 5, Free cheek, X4. 6, 7, Pygidia, x4 (coll. 
cnt/4) ; U.S.N.M. 144672, plesiotypes. 

Figs. 8-17. Aphelaspis inermis Rasetti, n. sp 90 

8, 9, Frontal and dorsal views of cranidium, x4 (coll. cns/2) ; U.S.N.M. 
144669, holotype. 10-12, Dorsal, lateral, and frontal views of cranidium, 
X4. 13, Frontal view of large, partly exfoliated cranidium, X2. 14, 
Dorsal view of the same specimen, X3. 15, Free cheek, X3 (coll. ens/ 
2) ; U.S.N.M. 144670, paratypes. 16, Pygidium, X4. 17, Cranidium, 
X2 (coll. cns/4) ; U.S.N.M. 144671, paratypes. 

Figs. 18-25. Aphelaspis minor Rasetti, n. sp 89 

18-20, Dorsal, frontal, and lateral views of cranidium, x4 (coll. cnq/ 
17) ; U.S.N.M. 144665, holotype. 21, Cranidium, X4. 22, 23, Frontal 
and dorsal views of cranidium, X4. 24, Pygidium, x4 (coll. cnq/14) ; 
U.S.N.M. 144667, paratypes. 25, Free cheek, x4 (coll. cnq/15) ; U.S.- 
N.M. 144668, paratype. 

Plate 20 

Figs. 1-18. Aphelaspis tarda Rasetti, n. sp 79 

5, Several cranidia, the one at left preserving one free cheek being the 
holotype, X3. 6, Cranidium, X5; U.S.N.M. 144639, holotype. 1, Num- 



NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 127 

Page 

erous meraspid cranidia in various stages, X7.5. 2, 3, Dorsal and 
frontal views of cranidium, X3. 4, Cranidium, X4. 7, Free cheek, x2. 
8, 17, Free cheeks, x3. 9, Hypostome, x5. 10-12, Pygidia, X4 (all 
above specimens from collection cnw/20) ; U.S.N.M. 144640, para- 
types. 13-15, Dorsal, lateral, and frontal views of cranidium, x2 (coll. 
cnu/1) ; U.S.N.M. 144641, paratype. 16, Pygidium, x3 (coll. cnu/7) ; 
U.S.N.M. 144642, paratype. 18, Pygidium, x3 (coll. cnv/7) ; U.S.- 
N.M. 144642, paratype. 

Plate 21 

Figs. 1-9. Dytremacephalus angulatus Rasetti, n. sp 98 

1-3, Dorsal, lateral, and frontal views of cranidium, x5 (coll. cnw/14) ; 
U.S.N.M. 144686, holotype. 4, Cranidium, x5. 7, Pygidium, x5 (coll. 
cnw/14) ; U.S.N.M. 144687, paratypes. 5, Free cheek, x5. 6, 8, Py- 
gidia, x5 (coll. cnx/1) ; U.S.N.M. 144688, paratypes. 9, Rubber cast 
of impression of thorax and pygidium, x4 (coll. U.S.G.S. 2969) ; 
U.S.N.M. 144689, paratype. 

Figs. 10-13. Dytremacephalus strictus Rasetti, n. sp 102 

10, Cranidium, xS (coll. U.S.G.S. 2970) ; U.S.N.M. 144692, holotype. 
11-12, Cranidia, xS. 13, Exfoliated cranidium, xS (coll. U.S.G.S. 
2970) ; U.S.N.M. 144693, paratypes. 

Figs. 14-28. Paraphelaspis vigilans Rasetti, n. gen., n. sp 97 

14-16, Dorsal, lateral, and frontal views of cranidium, x6 (coll. ens/ 
20) ; U.S.N.M. 144683, holotype. 17, Exfoliated free cheek, x4. 18, 
19, Frontal and dorsal views of cranidium, X7.5. 20, 21, Dorsal and 
frontal views of cranidium, x5. 22, Cranidium, X7.5. 23, Exfoliated 
cranidium, x5. 24, 25, Free cheeks, X5 (coll. cns/20) ; U.S.N.M. 
144684, paratypes. 26, 27, Lateral and dorsal views of cranidium, x7.5. 
27, Cranidium, X4 (coll. cnr/4) ; U.S.N.M. 144685, paratypes. 



THSONIAN MISCELLANEOUS COLLECTIONS 



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Trilobites of the Cedaria zone. 

(see explanation of plates at end of text.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148, NO. 3. PL. 




Trilobites of the Cedaria Zone. 

(see explanation of plates at end of text.) 



ITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. 3 




Trilobites of the Cedaria Zone. 

(see explanation of plates at end of text.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3 PL. 




Triuobites of the Cedaria zone. 

(see explanation of plates at end of text.) 



MITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. M8. NO. 3. PL. 5 





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(see explanation of plates at end of text.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3, PL. 6 







Triuobites of the Crepicephalus zone. 

(see explanation of plates at end of text.) 



V1ITHS0NIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. 7 




Triuobites of the Crepicephalus Zone. 

(see explanation of PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3, PL. 8 




TRILOBITES of the CREPICEPhALUS ZONE. 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



ITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. 9 




Trilobites of the Crepicephalus Zone. 

(see explanation of plates at end of text.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. 1 





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ITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. II 




Triuobites of the aphelaspis Zone. 

(see explanation of plates at end of text.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. I 




TRIUOBITES of the APHELASPIS ZONE. 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



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MITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. 13 




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ITHSONIAN MISCELLANEOUS COLLECTIONS 



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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



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TRILOBITES of the APHEL.ASPIS ZONE. 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



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ITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. 17 




Trilobites of the aphelaspis Zone. 

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VOL. 148. NO. 3. PL. 1! 









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trilobites of the aphelaspis Zone. 

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VOL. 148. NO. 3. PL. 19 




triuobites of the apheuaspis Zone. 

(see explanation of plates at end of text.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. 2' 




Trilobites of the aphelaspis Zone. 

(see explanation of plates at end of text.) 



THSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 3. PL. 21 




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SMITHSONIAN MISCELLANEOUS COLLECTIONS 

VOLUME 148, NUMBER 4 



CljarlEsi B. anb iWarp "^aux Malcott 
J&ej^earcl) jTunb 



PLANKTONIC FORAMINIFERA FROM 
THE WESTERN NORTH ATLANTIC 



(With Nine Plates) 



By 
RICHARD CIFELLI 

U. S. National Museum 
Smithsonian Institution 







(Publication 4599) 



CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

FEBRUARY 23, 1965 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 4 



Cljarleg ©. anb iWarp "^aux OTalcott 
3^e£iearcl) Jf unb 



PLANKTONIC FORAMINIFERA FROM 
THE WESTERN NORTH ATLANTIC 

(With Nine Plates) 



By 

RICHARD CIFELLI 

U. S. National Museum 
Smithsonian Institution 






(Publication 4599) 



CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

FEBRUARY 23, 1965 



PORT CITY PRESS, INC. 
BALTIMORE, WID., U. S. A. 



Cljarles; ©. anb JHarp ^m\ OTalcott 
Eej^earcl) Jf unb 



PLANKTONIC FORAMINIFERA FROM THE 
WESTERN NORTH ATLANTIC 

By RICHARD CIFELLI 

U. S. National Museuvt, Smithsonian Institution 

(With Nine Plates) 

INTRODUCTION 

The present paper describes and records the distribution of Fo- 
raminifera collected in plankton tows from four seasonal traverses 
between Cape Cod and Bermuda. Plankton stations were occupied 
in the shelf waters, slope waters, Gulf Stream and Sargasso Sea (see 
Appendix for details). The Gulf Stream stations, except for the fall 
traverse, were determined by bathythermograph at the times of collec- 
tion and were encountered at approximately longitude 69° W. In this 
part of the North Atlantic the Gulf Stream is an important hydro- 
graphic boundary, separating the temperate slope waters from the 
subtropical Sargasso Sea. The chief purpose of this study was to 
determine the influence of this boundary on the distribution of 
planktonic Foraminifera. 

The four seasonal cruises were made in 1960 and 1961 aboard the 
Woods Hole Oceanographic Institution vessels Chain and Crazvford; 
the position of the stations are shown in figure 1. The summer and 
winter stations are the ones that have been regularly occupied by the 
Woods Hole Oceanographic Institution over a period of years in a 
continuing program to study the biology and chemistry of the western 
North Atlantic. The distribution of epizooplankton from those sta- 
tions has been reported on by Grice and Hart (1962). 

The collections were obtained in oblique tows with a No. 10 
plankton net having a |-meter open-mouth diameter. At shallow sta- 
tions the net was lowered as close as possible to the bottom, and 
beyond the shelf it was lowered to 2(X) meters. The ship's speed during 

SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 148, NO. 4 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

80* 75* 70* 65* 60" 




75° 70* 65« 

Fig. 1. — Location of stations. 



towing was approximately 2 knots. The samples were preserved in 
5-percent formalin, buffered with hexamethylenamine. 

Acknowledgments. — Travel, ship-time, and facilities for this work 
were provided by the Woods Hole Oceanographic Institution, sup- 
ported variously by the Office of Naval Research under contract 
Nonr-2196 and the Atomic Energy Commission under grant AT 
(30-1) -1918. I am grateful to the Woods Hole Oceanographic In- 
stitution staff for making this study possible, for their assistance 
aboard ship, and for the collateral data that they made available. This 
is Woods Hole Oceanographic Institution Contributions No. 1498. 

HYDROGRAPHIC SETTING 

Between Cape Cod and Bermuda the subtropical waters of the 
Sargasso Sea are in close proximity to the temperate shelf and slope 



NO. 4 PLANKTONIC FORAM IXIF ERA CIFELLI 3 

waters of the North Atlantic. Separating these water bodies is the 
Gulf Stream, a well-defined band of currents originating in the straits 
of Florida that moves clockwise and can be traced as far north and 
east as the Grand Banks. Significant short- and long-period variations 
occur in the velocity and position of the Gulf Stream, but throughout 
the year it forms a sharp pressure gradient between the slope waters 
and the Sargasso Sea (Iselin, 1936). Because of this pressure 
gradient the slope waters and the Sargasso Sea maintain their more or 
less unique hydrographic properties. 

The waters in the Sargasso Sea are warm, and surface temperatures 
remain relatively uniform throughout the year, ranging from about 
19° C. to 27° C. In contrast, the surface temperatures of the shelf and 
slope waters range from about 12° C. in March, the coldest month, 
to about 26° C. in September, the warmest month (Stommel, 1958, 
fig. 5). During the warmer months there is a pronounced stratified 
surficial layer in the Sargasso Sea with a summer thermocline de- 
veloping between 40 and 70 meters (Cifelli, 1962, figs. 3, 6). In the 
slope and shelf waters the summer thermocline develops between 10 
and 40 meters, but there is relatively little surficial stratification. The 
summer warming afifects mostly the upper 100 meters ; below that 
depth there is little change, and at 200 meters the temperature remains 
relatively constant throughout the year, which is generally between 
9° and 12° C. in the slope waters and between 19° and 21° C. in the 
Sargasso Sea. Lateral variations in temperature are more common 
in the slope waters than in the Sargasso Sea and, moreover, subsur- 
face temperature inversions occur in the former (Grice and Hart, 
1962, p. 289). 

The Sargasso Sea is more saline than the shelf and slope waters. 
In the Sargasso Sea salinities are between 36-37 o/oo, while those in 
the slope waters normally range between 34-36 o/oo. The shelf waters 
tend to be even less saline, with salinities as low as 25-31 o/oo having 
been recorded at the location of the inshore shelf stations (Grice and 
Hart, 1962, p. 289). 

The hydrographic differences between the shelf slope waters and 
the Sargasso Sea are reflected in the composition of their planktonic 
foramini feral faunas. In the vicinity of the Gulf Stream is located 
the boundary between the temperate and the subtropical faunas. 

DISTRIBUTION 

Tables 1-4 show the percentage of total population at the stations 
sampled expressed in number of specimens per half-hour tow. 

The principal features of the distribution and the faunal changes 
observed in the traverses studied as ascertained from these tables 



4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

have been discussed in a previous paper (Cifelli, 1962). Briefly, these 
features may be summarized as follows : 

Abundance. — Considerable areal variation in numerical abundance 
of specimens was observed, even between nearby stations. Some of 
this variation is probably more apparent than real, since, in the 
absence of a current meter, the actual amount of water filtered at the 
towing stations is unknown, and the length of towing time is an inexact 
and variable expression of this quantity. For the most part, however, 
the differences in abundances between stations in the same water body 
reflect the patchiness of distribution, a phenomenon that has long 
been known to be characteristic of planktonic organisms. Patchiness 
of distribution among planktonic Foraminifera has been recognized 
in the Pacific by Bradshaw (1959) and Smith (1963). In general, 
of the waters sampled the Sargasso Sea was the most uniform in the 
abundance of specimens. 

The slope waters yielded the richest concentrations of specimens, 
whereas the Sargasso Sea was generally impoverished. The shelf 
waters were the most variable, and planktonic Foraminifera appear 
to be rare and sparsely distributed at the inner part of the shelf. 
Seasonally, the highest concentrations of specimens were obtained in 
the fall and in the spring. The poorest concentrations were obtained 
in the summer. 

Fauna! composition. — That the Gulf Stream is a boundary of 
major biogeographic importance can be seen in the changes in faunal 
composition of planktonic Foraminifera along the traverses studied. 
On the shelf and inner slope the fauna is distinctly temperate in 
character, being composed throughout the year almost exclusively of 
species of Globigerina. The dominant species are Globigerina bulloides 
and G. pachyderma incompta, but relative frequencies were found 
to be variable and G. inflata and G. aff. qiiinqueloba are also common. 
To the south Globigerina is replaced by a diverse subtropical group of 
species that characterize the Sargasso Sea. The dominant subtropical 
species are Globigerinoides ruber, G. trilobus trilohns, Globigerinella 
aequilateralis, Globorotalia truncatiilinoides, and Piilleniatina obli- 
quiloculata. The relative frequencies of these species, however, were 
inconstant along the traverses and varied considerably throughout the 
year. The position of the boundary between the temperate and sub- 
tropical faunas also changed throughout the year but was always 
observed on the north side of the Gulf Stream. It was closest inshore 
in the fall and farthest offshore between winter and spring. Insofar 
as could be observed, the Gulf Stream contained no endemic elements, 



NO. 4 



PLANKTONIC FOKAMINIFERA — CIFELLI 






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NO. 4 TLANKTONIC FORAMINIFERA — CIFELLI 9 

and its fauna was identical with that of the Sargasso Sea. The 
boundai^y is transitional in faunal character and contains a mixture of 
Glohigerina and subtropical species. The mixed character of the as- 
semblage strongly suggests that mixing of surficial waters occurs 
across the Gulf Stream and that the subtropical species occurring 
with Glohigerina in the slope waters are expatriates. 

Seasonal changes in faunal composition. — Clearly, seasonal cycles 
cannot be described, nor, even, can the fact be established that such 
cycles exist on the basis of only four seasonal traverses. However, 
some marked changes were observed in composition of the subtropical 
fauna from traverse to traverse and there can be no doubt that some 
species of that fauna undergo considerable changes in relative fre- 
quencies throughout the year. The most remarkable change noted 
was the sharp increase of Globorotalia truncatulinoides in the winter. 
Mostly rare or absent in the spring and summer stations, that species 
showed some increase in the fall and was dominant in the winter when, 
at one station (II), it occurred at a frequency of 55 percent. This 
winter increase in Globorotalia truncatulinoides was mainly at the 
expense of Glohigerinoides species (mostly G. ruber and G. trilobus 
trilobus), which were relatively rare then but were dominant or im- 
portant elements of the subtropical fauna at the other seasons. Pul- 
leniatina ohliquiloculata also showed a considerable increase in the 
winter. Globigerinella aequilaferalis attained its highest frequency in 
the spring (60 percent at station 2) but remained fairly common 
through all the seasons. 

It is more difficult to determine whether changes in frequencies of 
species occur throughout the year within the temperate Glohigerina 
fauna because of the considerable lateral changes in frequencies that 
occur from station to station and also, possibly, because of the 
morphologic variation of the Glohigerina species, which are sometimes 
difficult to separate. The indications are that the relative frequencies 
of the Glohigerina species are fairly stable throughout the year except 
for Glohigerina aff. quinqueloha, which appears to increase appreciably 
in the winter. 

SYSTEMATICS 

Since the primary purpose of this work was to determine the dis- 
tribution of planktonic Foraminifera in a limited sector of the North 
Atlantic, no attempt is made to treat the species monographically. 
Only the original and a few pertinent references are given in the 
synonymies. Extensive synonymies can be found in the works of 
Cushman, Todd, Parker, and others. 



lO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

In a group as highly variable as the planktonic Foraminifera it is 
perhaps inevitable that opinions will vary as to the morphologic limits 
of species. Some workers vv^ill tend to split more finely than others, 
and in the absence of quantitative treatments of population structures 
and the lack of data on the biology of the animal, judgments on the 
limits of species are bound to be subjective. The poHcy here has been 
to group together in a single species those forms that occur together 
with intermediaries among which no line of demarcation could be 
perceived. Admittedly, further taxonomic refinements are possible, 
but it is believed that with the morphologic limits recognized here, an 
internal consistency in identification has for the most part been main- 
tained and further refinements would not significantly change the 
distributional patterns presented. The specimens used for illustration 
were chosen to show the range of forms included in the species, and 
the descriptive remarks under the species refer to the specimens 
actually examined, with the emphasis on those characters that were 
found particularly useful for identification. 

Generic as well as specific characters are variable in the planktonic 
Foraminifera, and some species include end forms showing close af- 
finities to species placed in other genera. In fact, Glohigerina inflata 
shows a transition from Glohigerina to Glohorotalia. Such continuous 
variability across established generic boundaries suggests that the Re- 
cent planktonic Foraminifera comprise a closely related group. There- 
fore, they are included here in a single family, the Globigerinidae. 
The species are grouped into eight commonly recognized genera, 
though, admittedly, the genera serve in some cases, owing to a lack 
of exclusive characters, more as conveniences than as representations 
of genetic affinities. 

In the use of specific names an attempt has been made to conform 
with the present Code of Zoological Nomenclature ( 1961 ) . As pointed 
out by Todd (1961, 1963) this code now limits the application of 
priority in the naming of species. However, it is not clear from the 
provision of conservation (article 23b) what these limitations are, 
and, in fact, there is some question as to whether that provision can 
actually be interpreted. Therefore, it would appear that the code 
serves as a guide rather than a "cook book," and the individual is not 
relieved of the responsibility of exercising individual judgment in 
serving the interests of nomenclatural stability. As a result, some 
arbitrary decisions were found necessary in the choice of names, and 
these are discussed under the species concerned. 



NO. 4 PLANKTONIC FORAMINIFERA — CIFELLI II 

Family GLOBIGERINIDAE Carpenter, Parker, and Jones, 1862 

Genus GLOBIGERINA d'Orbigny, 1826 

Globigerina bulloides d'Orbigny 

Plate 1 ; figures 1-3, 5 

Globigerina bulloides d'Orbigny, 1826, Ann. Sci. Nat., vol. 7, p. 777, Nos. 76, 
17. — Bradshaw, 1959, Contr. Cushnian Found. Foram. Res., vol. 10, pt. 2, 
p. 33, pi. 6, figs. 1-4.— Be, 1959, Micropaleontol., vol. 5, No. 1, pi. 1, figs. 
15-17. — Banner and Blow, 1960, Contr. Cushman Found. Foram. Res., 
vol. 11, pt. 1, p. 3, figs. 1, 4. — Parker, 1962, Micropaleontol., vol. 8, No. 2, 
p. 221, pi. 1, figs. 1-8. 

Most of the specimens have bulbous chambers and broad, rounded 
apertures that join in the center of the ventral side to form a large, 
open umbilicus. The species, however, shows continuous gradation to 
small compact forms with restricted apertures and reduced umbilical 
areas (pi. 1, fig. 2b). These latter forms are relatively scarce but are 
included in G. bulloides because of the continuous gradation. 

The final chamber in Globigerina bulloides and other species of 
Globigerinidae shows considerable variation and, as noted by Parker 
(1962, p. 246), sometimes covers the umbilicus and is reduced in size. 
I agree with Parker that a bulla is often nothing more than a much- 
reduced final chamber covering the umbilicus. A specimen of G. 
bulloides with a well-defined bulla is figured here (pi. 1, fig. 5b). 
Other specimens with the final chamber covering the umbilicus and 
grading from bulla size to normal size were also observed. An effect 
of the final chamber covering the umbilicus is that the aperture is 
reduced to a narrow slit or is completely absent. 

Distribution. — Overall, Globigerina bidloides was observed to be 
the dominant species in the shelf and slope waters. The highest fre- 
quency was 70 percent at winter shelf station C. Along with other 
species of Globigerina it diminishes in importance in the vicinity of 
the Gulf Stream and was found to be rare or absent in most of the 
Gulf Stream and Sargasso Sea stations. 

GLOBIGERINA PACHYDERMA INCOMPTA Cifelli 
Plate 1, figures 4, 6 

Globigerina incompta Cifelli, 1961, Contr. Cushman Found. Foram. Res., vol. 12, 
pt. 3, p. 84, pi. 4, figs. 1-7. 

This problematic form, which is characterized mainly by its sim- 
plicity and paucity of distinctive characters, varies in the amount of 



12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

inflation of the test and in nature of the final chamber. As in G. 
hulloides, the test is sometimes compact, and the final chamber oc- 
casionally deviates from the axis of coiling and partially covers the 
umbilicus. Also, the last chamber is often reduced in size. Specimens 
with a compact test and a reduced final chamber covering the umbilicus 
are identical with G. pachyderma. Several such specimens have been 
observed in a few of the samples studied, and two are figured here. 
These specimens show that G. incompta grades into G. pachyderma. 
However, they are of rare occurrence in the region studied, and it is 
useful to retain G. incompta as a subspecies. Parker (1962, p. 224) 
has shown that in Recent Pacific bottom sediments G. incompta 
grades into G. pachyderma, with G. pachyderma dominating in the 
high latitudes. The transition is further shown by Smith (1963) from 
northeastern Pacific plankton tows. The form that Smith figures (pi. 
1, figs. 12-14) as a Globigerina pachyderma-eggeri intergrade is 
identical with G. pachyderma incompta. The relationships, however, 
with G. eggeri { — G. dutertrei) are not yet completely clear. 

Distribution. — Globigerina pachyderma incompta is next in domi- 
nance to G. bnlloides in the shelf and slope waters. The highest fre- 
quencies were observed in the summer (50 percent at stations B and 
E) and the fall (63 percent at station 2). 

GLOBIGERINA DUTERTREI d'Orbigny 

Plate 2, figures 1, 2 

Globigerina eggeri Rhumbi.er, 1900, Nordische Plankton, pt. 14, Foraminiferen, 

p. 19, text figs. 20a-c. 
Globigerina eggeri Bradshaw, 1959 (part), Contr. Cusliman Found. Foram. 

Res., vol. 10, pt. 2, p. 35, figs. 5, 10 only.— Be, 1959, Micropaleontol., vol. 5, 

No. 1, pi. 2, figs. 1-3. 
Globigerina dutertrei d'Orbigny, 1839. — Banner and Blow, 1960, Contr. Cush- 

man Found. Foram. Res., vol. 11, pt. 1, p. 11, pi. 2, fig. 1. 

This species closely resembles botli Globigerina pachyderma in- 
compta and the early stages of Ptdleniatina obliquiloculata. G. 
dutertrei is distinguishable from G. pachyderma incompta by its rela- 
tively high trochoid spire and its broad, open umbilicus. The differ- 
ences are slight, however (Cifelli, 1961), and future studies of addi- 
tional material, particularly from the warmer waters, may show that 
G. dutertrei belongs to the G. pachyderma species group. 

The coiling in G. dutertrei is trochoid throughout except, occasion- 
ally, for the last chamber, which, like other Globigerina species, tends 
to deviate toward the umbilicus. Thus, in the last whorl the chambers 



NO. 4 PLANKTONIC FORAMINIFERA — CIFELLI I3 

tend to wrap around the umbilicus, rather than overlap it as they do 
in Pnlleniatina obliquilocnlata. 

In view of the close morphologic aflinities of G. dutertrei to G. 
pachyderma incompta and Pnlleniatina obliqnilocidata, I disagree with 
Parker (1962, pp. 221, 242) in removing G. dutertrei from the genus 
Glohigerina and placing it in the genus Glohoquadrina, family 
Globorotaliidae. At least, I can find no consistent difference in wall 
surface between G. dutertrei and other species of Glohigerina. Nor 
can a separation be made by the presence or absence of spines, since, 
as Parker points out (Parker, 1962, p. 224), Glohigerina pachyderma 
only sometimes has spines. The fact that spines may be present or 
absent in a single species weakens considerably the argument that 
spines are a character of sufficient importance to separate otherwise 
similar species into different families. 

Distrihution. — Glohigerina dutertrei appears to be relatively rare 
among the Glohigerina in the northwestern part of the Atlantic. In 
the summer, the maximum frequency was 5 percent (station HH') 
and in the fall, 9 percent (station 6). It was not recorded in the 
winter, and in the spring the maximum frequency was only 2 percent 
(station 3). 

GLOBIGERINA aff. G. QUINQUELOBA Natland 
Plate 2, figures 3, 4 

Glohigerina of. quinqueloba Todd and Bronniman, 1957, Cushman Found. 

Foram. Res. Spec. Publ. No. 3, p. 40, pi. 12, fig. 2. 
Glohigerina aff. quinqueloba Be, 1959, Micropaleontol., vol. 5, No. 1, pi. 1, figs. 

21, 22. 

The test is small, and there are 4 to 6 chambers visible on the 
ventral side. The periphery is lobulate, and the final chamber deviates 
slightly from the trochoid spiral, projecting over the umbilicus. The 
wall is thin and translucent. The aperture is a rounded umbilical 
opening that is sometimes partially obscured by a thin, weakly de- 
veloped chamber. The coiling is both sinistral and dextral, but the 
sinistral mode is dominant. 

The specimens included here and those in the figures cited closely 
resemble G. quinqueloha but differ in having a thinner wall and a less 
developed lip. 

The present specimens also resemble in general form and outline 
Glohigerina concinna Reuss and G. diplostoma Reuss (which appears 
to be identical with G. concinna) as originally figured. Those figures, 
however, are lacking in diagnostic detail, and G. concinna and G. 



14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

diplostoma have been interpreted in so many different ways that they 
include a mixed bag of specimens ranging in age from Lower Tertiary 
to Recent. Clarification of these species is needed before the form 
designated here as Globigerina aft. G. quinqueloba can be definitely 
assigned taxonomically. 

Distribution. — This species appears to be relatively scarce in the 
summer (a maximum of 4 percent at station G) but common or 
abundant at other times of the year. A maximum frequency of 57 
percent was recorded at winter station D. 

GLOBIGERINA INFLATA d'Orbigny 
Plate 4, figures 1-3 

Globigerina inflata d'Orbigny, 1839, in Barker-Webb and Berthelot, Hist. Nat. 
lies Canaries, vol. 2, pt. 2, Foraminiferes, p. 134, pi. 2, figs. 7-9. — Bradshaw, 
1959, Contr. Cushman Found. Foram. Res., vol. 10, pt. 2, p. 36, pi. 6, 
figs. 16-18.— Be, 1959, Micropaleontol., vol. 5, No. 1, pi. 1, figs. 12-14. 

Globorotalia inflata (d'Orbigny) Parker, 1962, Micropaleontol., vol. 8, No. 2, 
p. 236, pi. 5, figs. 6-9. 

This is an interesting species as it bridges the morphologic gap 
between Globigerina and Globorotalia. Suites of specimens range 
from a globigerine form with highly inflated chambers, a rounded 
periphery and a large umbilical aperture to a globorotalid form with 
compressed chambers, an angular periphery and a relatively low, 
elongate, extra-umbilical aperture. The surface of the wall is also 
variable, ranging from smooth to rough, with blunt spines. Radiating 
spines, however, are absent. 

Since this species is transitional between Globigerina and 
Globorotalia, the generic assignment becomes somewhat arbitrary. 
The species has been referred to both genera, l)ut most commonly to 
Globigerina. In the samples studied the globigerine form appears to 
be dominant, and the species has a distribution like that of the 
Globigerina species. 

The angular, globorotalid form of Globigerina inflata closely ap- 
proaches Globorotalia punctidata, which is distinguishable by its 
lower, slitlike aperture and its sharper, more angular periphery. These 
characters, however, are variable and end forms are sometimes dif- 
ficult to distinguish. 

Distribution. — Globigerina inflata is common in the shelf and slope 
waters but apparently is not one of the dominant temperate species. 
The highest frequency recorded v.'as Z^ percent, at fall station 4. In 



NO. 4 PLANKTONIC FORAMINIFERA — CIFELLI I5 

the winter it was recorded in the Sargasso Sea as far south as station 
00 with a frequency of 2 percent. 

GLOBIGERINA sp. 

Plate 2, figures 5, 6 

The test is small and relatively high trochospirally. In the last 
whorl the final 1 or 2 chambers tend to bend over the umbilicus. In 
some specimens the umbilicus is covered with a small bubblelike 
chamber with a narrow aperture at the margin. The surface of the 
test is spinose. 

In general form this species resembles Glohigerinita glutinata, but 
the surface is spinose and the chambers are more inflated. 

Distribution. — This form was recorded in frequencies of less than 1 
percent at summer stations HH", MM ; fall stations 4, 9; spring sta- 
tion 2. 

Genus PULLENIATINA Cushman, 1927 

PULLENIATINA OBLIQUILOCULATA (Parker and Jones) 

Plate 3, figures 1, 3; text figure 2 

Pullenia sphaeroides (d'Orbigny) var. ohliquiloculata Parker and Jones, 1865, 
Philos. Trans. Roy. Soc. London, vol. 155, pp. 365, 368, pi. 19, figs. 4a-b. 

Pulleniatina ohliquiloculata (Parker and Jones) Bradshaw, 1959, Contr. Cush- 
man Found. Foram. Res., vol. 10, pt. 2, p. 49, pi. 8, figs. 19, 20.— Be, 1959, 
Micropaleontol., vol. 5, No. 1, pi. 2, figs. 4-6. 

Pullenia sphaeroides (d'Orbigny) var. obliquiloculata Banner and Blow, 1960, 
Contr. Cushman Found. Foram. Res., vol. 11, pt. 1, p. 25, pi. 7, figs. 4a-c. 

In this species the coiling changes during growth from trochospiral 
to streptospiral (Bolli, Loeblich, and Tappan, 1957, p. 39). The 
change in the axis of coiling becomes apparent at about the end of the 
second whorl, and the last 2 or 3 chambers overlap the umbilical 
area. Some of the stages in development are shown in figure 2. 
Stages 1-4 comprise the majority of forms, and stages 5-7, which are 
like the typical form, make up only about 20 percent of the present 
total populations in this species. Stages 5-7 appear to represent varia- 
tions in the degree of overlap of the final chamber over the umbilicus 
rather than successive periods of development. In stage 7, the 
umbilicus is completely covered and the aperture is an extra-umbilical, 
crescent-shaped arch. The highly polished surface occurs only in the 
final 1 or 2 chambers, in stages 6-7. In the earlier stages the surface 
is hispid, but no spines were observed. 



i6 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



In its early stages this species closely resembles Globigerina 
dutertrei in having a broad, open umbilicus and a large umbilical 
aperture. However, at about the end of the second whorl the 
streptospiral coiling of Pulleniatina ohliquilocidata becomes apparent 
and the chambers in the final whorl can be seen to deviate from the 
axis of coiling of the earlier chambers when the test is viewed from 
the dorsal side. Also, the later chambers of P. ohliquiloculata tend to 
be elongate in their axis of coiling. 




5 6 7 

Fig. 2. — Some developmental stages in Pulleniatina obliquiloculata. 

Distribution. — This species was recorded mostly from the southern 
stations and was most common in the winter, when it reached a 
maximum frequency of 34 percent at station II. It was extremely 
scarce in the summer and was recorded at only two stations (LL and 
J J) with frequencies of 1 and less than 1 percent respectively. 

Genus GLOBIGERINITA Bronnimann, 1951 

GLOBIGERINITA GLUTINATA (Egger) 

Plate 3, figures 2, 4, 5 

Globigerina gluHnata Egger, 1893, Abhandl. K. Wiss. Miinchen, CI. II, vol. 18, 

p. 371, pi. 13, figs. 19-21. 
Globigerinita glutinata Bradshaw, 1959, Contr. Cushman Found. Foram. Res., 

vol. 10, pt. 2, p. 40, pi. 7, figs, 7, 8.— Be, 1959, Micropaleontol., vol. 5, No. 1, 

pi. 1, figs. 25-26.— Parker, 1962, Micropaleontol., vol. 8, No. 2, p. 246, 

pi. 9, figs. 1-16. 



Globigerinita glutinata is distinguishable mainly by its smoothly 
polished surface and low umbilical aperture. The bulla and dorsal 



NO. 4 PLANKTONIC FORAMINIFERA- — CIFELLI I7 

aperture, characters diagnostic of the genus Globigerinita, are poorly 
developed in the studied assemblages of this species, and neither 
character appeared on more than about 1 percent of the specimens. No 
single specimen was observed that combined both bulla and dorsal 
aperture. 

To me, the relationship of Globigerinita whh the Globigerinidae 
seems clear enough, and I see no need in placing that genus in Incertae 
Familiae (Parker, 1962, p. 244). The test of Globigerinita is distinctly 
globigerine in form, and there is not a known character in its species 
that is not found in the Globigerinidae. The bulla, or modified last 
chamber, occurs in variants of both Globigerina and Globigerinoides 
species, and the dorsal aperture is a diagnostic feature of Globig- 
erinoides. Nor is the nonspinose, smooth, finely perforate wall hard 
to come by in the Globigerinidae, as Pulleniutina obliquiloculala lacks 
spines and, in its final stage, has a smooth wall, comparable to that of 
Globigerinita glutinata. 

Distribution. — Globigerinita glutinata appears to be a euryopic 
species. In the traverses studied, this species ranged from the shelf 
waters to the Sargasso Sea in about equal abundances. Frequencies 
were low to moderate, the highest being 16 percent at the winter shelf 
station F. In the summer a maximum frequency of 12 percent was 
recorded at both shelf station B and Sargasso Sea station M]\I. 

Genus ORBULINA d'Orbigny, 1839 

ORBULINA UNIVERSA d'Orbigny 

Plate 3, figures 6, 7 

Orbulina unhersa d'Orbigny, 1839, in De la Sagra, Hist. Phys. Pol. Nat. Cuba, 
Foraminiferes, p. 3, pi. 1, fig. 1. — Bradshaw, 1959, Contr. Cushman Found. 
Foram. Res., vol. 10, pt. 2, p. 49, pi. 8, figs. 17, 18.— Be, 1959, Micropaleon- 
tol., vol. 5, No. 1, pi. 2, fig. 18. 

The test is highly porous, with the pores being of two sizes 
evenly scattered throughout the surface. The wall of the inner 
globigerine stage is highly fragile and was seldom found preserved 
in the material studied. Mostly all that was visible of this early stage 
was protoplasm roughly retaining the shape of the chambers and 
some spiny remnants of the wall. The globigerine stage is highly 
spinose, and the spines radiate out into the outer chamber, sometimes 
penetrating through the wall. 

The wall of the outer chamber is variable in thickness and almost 
always single layered. However, on a few specimens the wall was 



l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

observed to be double layered, with the layers loosely attached like 
the concentric rings of an onion. On these specimens the outer layer 
could easily be separated from the inner one with a dissecting needle. 

The bichambered form, Biorbulina hilohata of some authors, is 
regarded here as a variant form of Orbulina imiversa. It is very 
rare and vi^as observed at only one station (Sargasso Sea, summer 
station KK). 

Distribution. — This species occurs mostly in the Sargasso Sea and 
Gulf Stream in low to moderately high frequencies. The lowest fre- 
quencies were recorded in the winter, with less than 2 percent at all 
stations. The summer traverse yielded the highest frequencies, reach- 
ing 18 percent at station KK. 

Genus GLOBOROTALIA Cushman, 1927 
GLOBOROTALIA PUNCTULATA (d'Orbigny) 

Plate 4, figure 4 ; plate 5, figure 1 

Globigerina punctulata d'Orbigny, 1826, Ann. Sci. Nat., vol. 7, p. 277, No. 8. — 

FoRNASiNi, 1898, Paleontol., Ital., vol. 4, p. 210, text fig. 5. 
Globorotalia punctulata Phleger, Parker and Peirson, 1953, Rep. Swedish 

Deep-Sea Exped., vol. 7, No. 1, p. 20, pi. 4, figs. 8-12.— Be, 1959, Micro- 

paleontol., vol. 5, No. 1, pi. 1, figs. 9-12. 
Globorotalia crassajormis (Galloway and Wissler, 1927). Parker, 1962, Micro- 

paleontol, vol. 8, No. 2, p. 35, pi. 4, figs. 17-18, 20-21. 

The test of this species is characterized by its flattened dorsal side 
and its relatively high spire. The periphery is angular and, occasion- 
ally, thinly keeled. The aperture is slitlike and extends from the 
umbilicus to the vicinity of the periphery. On some specimens there 
is a thin lip above the aperture. 

The close morphologic affinities between Globorotalia punctulata 
and Globigerina inflata were mentioned under the latter. It is pos- 
sible that somewhere in their geographic and stratigraphic ranges 
these forms intergrade, and they may eventually prove to be con- 
specific subspecies. 

There has been considerable confusion concerning the rightful name 
of this species, but no attempt is made here to resolve this complicated 
legal problem which has been dealt with by Parker (1958, p. 281 ; 
1962, p. 235) and Banner and Blow (1960, p. 15). Suffice it to say 
that the present specimens are identical with G. punctulata as figured 
by Fornasini. However, they are not identical with the single lecto- 
type for both G. puncticulata and G. punctulata designated by Banner 
and Blow. That lectotype clearly is not the same specimen figured by 



NO. 4 TLANKTONIC FOKAMIiVIFERA CIFELLI I9 

Fornasini as G. pimctulata and in fact, as figured, appears referable 
to G. injlata. Therefore, the lectotype is a potential source of taxo- 
nomic confusion. With G. punctuculata as the senior synonym of G. 
pimctulata and G. inflata, the past records of two commonly occurring, 
related species having different distributional patterns would become 
virtually uninterpretable. 

Distribution. — This species occurred mostly in the southern sta- 
tions. Frequencies were low throughout the year. A maximum fre- 
quency of 4 percent was recorded in the summer at station MM in 
the Sargasso Sea and in the winter at station NN, also in the 
Sargasso Sea. The fall maximum was 3 percent (station 5, slope 
waters), and the spring maximum was 1 percent (station 6, slope 
waters ) . 

GLOBOROTALIA HIRSUTA (d'Orbigny) 

Plate 5, figures 2, 3 

Rotalina hirsuta d'Orbigny, 1939, in Barker-Webb and Berthelot, Hist. Nat. 

lies Canaries, vol. 2, pt. 2, Foraminiferes, p. 131, pi. 1, figs. 37-39. 
Globorotalia hirsuta Bradshaw, 1959, Contr. Cushman Found. Foram. Res., 

vol. 10, pt. 2, p. 44, pi. 8, figs. 1, 2. 

This species is convex on the dorsal side and flattened on the 
ventral side. The periphery is subacute and slightly keeled. The 
aperture is a narrow opening extending beyond the umbilicus and 
sometimes reaching the periphery. The surface of the test is coarsely, 
but irregularly, spinose and punctate, closely resembling the surface 
of G. truncatulinoides , G. punctiilata, and some representatives of 
Glohigerina inflata. 

The spire of Globorotalia hirsuta is much compressed, and the test 
has the appearance of a G. pimctulata that has been flattened on the 
ventral side and expanded somewhat on the dorsal side. 

Distribution. — This species was observed to occur rarely and was 
found only in the stations south of the Gulf Stream. It was most 
abundant in the winter at station OO, where the frequency was 4 
percent. 

GLOBOROTALIA MENARDII (d'Orbigny) 
Plate 6, figures 3, 4 

Rotalia menardii d'Orbigny, 1826, Ann. Sci. Nat., vol. 7, p. 273, No. 26; Mo- 

deles, No. 10. 
Globorotalia ivcnardii Bradshaw, 1959, Contr. Cushman Found. Foram. Res., 

vol. 10, pt. 2, p. 44, pi. 8, figs. 3, 4.— B6, 1959, Micropaleontol., vol. 5, No. 1, 

pi. 1, figs. 1-3. 



20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Globorotalia cultrata (d'Orbigny, 1839) Parker, 1962, Micropaleontol., vol. 8, 
No. 2, p. 235, pi. 5, figs. 3-5. 

The present specimens were compared with representatives of this 
species from plankton tows collected in the Lesser Antilles region of 
the Caribbean. Although the present Central Atlantic forms are 
clearly identical with Caribbean forms, some small general differences 
were noted, as follows : 

1, The Central Atlantic form, on the average, appears to be of 
smaller size. 

2, In the Central Atlantic form the test is smooth with few or no 
pustules on the surface. In the Caribbean form the test ranges from 
smooth to rough, with many pustules or, occasionally, an additional 
coating of calcite on the surface. 

3, The keel of the Central Atlantic form is thin and smooth with 
little or no denticulation. In the Caribbean form the keel is more 
variable and includes forms with thickened and crenulate keels. 

In general, the Central Atlantic form is simpler and shows less 
variation than the Caribbean form. 

Distribution. — This species was observed mostly in the Sargasso 
Sea stations. The highest frequency was recorded in the summer at 
station KK (7 percent). However, most of the records were 1 percent 
or less, suggesting that the stations occupied are beyond the optimum 
range of G. menardii. It was particularly scarce in the stations from 
the winter and spring traverses. 

GLOBOROTALIA TRUNCATULINOIDES (d'Orbigny) 

Plate 6, figures 1, 2; text figure 3 

Rotalina truncatnlinoides d'Orbigny, 1939, in Barker-Webb and Berthelot, Hist. 

Nat. lies Canaries, vol. 2, pt. 2, Foraminiferes, p. 132, pi, 2, figs. 25-27. 
Globorotalia truncatulinoides Bradshaw, 1959, Contr. Cushman Found. Foram. 

Res., vol. 10, pt. 2, p. 44, pi. 8, figs. 7, 8.— Bf, 1959, Micropaleontol., vol, 5, 

No. 1, pi. 1, figs. 5-7. 

Globorotalia truncatulinoides is a distinctive and easily recognizable 
species. In the adult form the test is high spired and has the shape of 
a truncated cone, flattened on the dorsal side and with 5 chambers 
visible on the ventral side. The periphery is subrounded in side view, 
slightly keeled and denticulate. The aperture is a narrow, basal slit 
that extends to a deep, narrow umbilicus; above the aperture there 
is a well-defined lip. The projections of the lips of apertures on the 
chambers surrounding the umbilicus form weak umbilical teeth. 



NO. 4 



PLANKTONIC FORAMINIFERA — CIFELLI 



21 



Pustules or blunt spines are distributed over the entire surface but 
are concentrated mostly beneath the aperture of the final chamber. 
The young form of this species does not have an umbilicus, and 
the ventral cone is much lower than in the adult form. The truncated 
conical shape of the test with an umbilicus is achieved during the 
ontogeny, at about the end of the second whorl, where there is a 
sudden relative increase in size of the lateral dimensions of the 
chamber. The lateral slope at this stage is less acute than in the early 
stage and tends to flare out with respect to the axial dimension of 
the chamber (fig. 3). 




Fig. 3. — Relative increase in lateral slope of Globorotalia truncatulinoides. 
Left, mature form. Right, immature form. 

In the material studied, this species showed a decided preference 
for sinistral coiling. However, specimens were not available in suf- 
ficient numbers from the summer and fall traverses to determine 
possible seasonal differences in coiling ratios. 

Distribution. — Globorotalia truncatulinoides was the dominant 
species in the southern stations (JJ through OO) in the winter. The 
highest frequency was 55 percent at station JJ. At other seasons this 
species was rare or absent at most stations, the highest frequency 
being 3 percent in the fall at station 5. 



Genus CANDEINA d'Orbigny, 1839 
CANDEINA NITIDA d'Orbigny 

Plate 5, figure 4 

Candeina nitida d'Orbigny, 1839, in De la Sagra, Hist. Phys. Pol. Nat. Cuba, 
Foraminiferes, p. 108, pi. 2, figs. 27-28. — Bradshaw, 1959, Contr. Cushman 
Found. Foram. Res., vol. 10, pt. 2, p. 32, pi. 7, fig. 19.— Be, 1959, Micro- 
paleontol., vol, 5, No. 1, pi. 2, figs. 19, 20. 



22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Candeina nitida is a very distinctive species, having 3 large, highly 
inflated final chambers that envelop most of the previous part of 
the test. Pores are distributed along the sutures of the last 3 chambers. 

Distribution. — This species is very rare in the northwestern part of 
the Atlantic and was recorded only in the Sargasso Sea, at summer 
station KK and spring station 3. At both stations the frequencies were 
less than 1 percent. 

Genus GLOBIGERINELLA Cushman, 1927 

GLOBIGERINELLA AEQUILATERALIS (Brady) 

Plate 7, figures 3-5 

Globigerina aequilateralis Brady, 1884, Rep. Voy. Challenger, Zool., vol. 9, 

p. 605, pi. 80, figs. 18-21. 
Globigerinella aequilateralis Bradshaw, 1959, Contr. Cushman Found. Foram. 

Res., vol. 10, pt. 2, p. 38, pi. 7, figs. 1, 2.— Be, 1959. Micropaleontol., vol. 5, 

No. 1, pi. 1, figs. 19, 20, 27. 
Globigerinella siphonijera (d'Orbigny, 1839) Parker, 1962, Micropaleontol., 

vol. 8, No. 2, p. 228, pi. 2, figs. 22-28. 

In its early stages this species is distinctly trochospiral and evolute. 
As growth proceeds the coiling becomes planispiral and the test 
partially involute with the later chambers overlapping and sometimes 
obscuring the trochospiral portion of the test. The large, inflated 
forms, however, are variable in coil and some tend to uncoil and 
grow erratically, with the final 1 or 2 chambers sometimes being 
added on either the dorsal or ventral side. 

The wall is lacking in the axial region of the chambers so that the 
sides of the chambers in the later stages do not touch the previous 
whorl. As a result the aperture is usually a basal slit but is variable in 
size and extends entirely around the final chamber. It is often visible 
around the margins of the previous 1 or 2 chambers. In the larger 
forms that are partially uncoiled, the axial regions of the last few 
chambers are entirely exposed. 

Banner and Blow (1960, p. 22) have resurrected the name H. 
siphonijera (d'Orbigny) for this species. However, this unnecessary 
name change is based on an uncertain type specimen (Todd, 1963, 
p. 110) and is contrary to the present principle of conservation of the 
International Code of Zoological Nomenclature. 

Distribution. — Globigerinella aequilateralis is one of the dominant 
species of the subtropical assemblages. In the spring it reached a 
maximum frequency of 60 percent in the Sargasso Sea at station 2. 
In the summer the maximum frequency was 28 percent at station 



NO. 4 PLANKTONIC FORAMINIFERA — CIFELLI 23 

LL. The percentages dropped in the fall, when the maximum was 
only 9 percent (station 9, in the Sargasso Sea) but increased in the 
winter, when the maximum was 17 percent (Sargasso Sea station 
MM). 

Genus HASTIGERINA Thompson, 1876 
HASTIGERINA PELAGICA (d'Orbigny) 

Plate 7, figures 1, 2 

Nonionina pelagica d'Orbigny, 1838, Foram. Anier. Merid., p. 27, pi. 3, figs. 

13, 14. 
Hastigerina murrayi Thompson, 1876, Bolli, Loebuch, and Tappax, 1957, 

U. S. Nat. Mus. Bull. 215, p. 29, pi. 3, figs. l-3b. 
Hastigerina pelagica Bradshaw, 1959, Contr. Cushman Found. Foram. Res., 

vol. 10, pt. 2, p. 47, pi. 8, figs. 14, 15.— Be, 1959, Micropaleontol., vol. 5, 

No. 1, pi. 2, figs. 21-22. — Banner and Blow, 1960, Micropaleontol., vol. 6, 

p. 20, text fig. 1. 

The test consists of a highly involute, biumbihcate planispiral coil 
of inflated chambers that is sometimes compressed laterally. A 
trochoid stage was not observed. The aperture is an equatorial open- 
ing at the base of the last chamber that varies in size from a slit to a 
broad arch. Above the aperture is a thin lip. The wall of the test is 
very thin and extremely fragile, and specimens are often in a poor 
state of preservation, even from plankton tows. The spines are few 
in number but are coarse and triradiate (Banner and Blow, 1960, 
p. 21). The spines extend into, and even through, the walls of the 
chambers from the previous whorl. 

Hastigerina pelagica is one of the most distinctive and easily 
recognizable Recent planktonic species. It is most readily comparable 
with GlobigerineUa aeqtiilaterlaUs, but I agree with Parker (1962, p. 
228) in retaining these two species in separate genera. As Parker 
states, a much better case can be made for combining H. pelagica with 
Hastigerinella digitata, as these two latter species are unique in their 
spinosity. 

Distribution. — This species reached a maximum frequency of 24 
percent in the summer at Sargasso Sea station (LL) but otherwise 
occurred mostly in low percentages. The winter maximum was 13 
percent (Sargasso Sea station KK), but the fall maximum was only 
3 percent and the spring maximum only 1 percent. 

Genus GLOBIGERINOIDES Cushman, 1927 

The genus Glohigerinoides includes a distinctive group of species 
with peculiar chamber arrangements that tend to deviate considerably 



24 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



from the trochospiral coil as seen in Globigerina. The chamber ar- 
rangements, though sometimes difficult to express geometrically, are 
useful in distinguishing the species of Globigerinoides. Illustrations 
of chamber arrangements in Recent species of Globigerinoides are 
shown in figure 4. 







jjjjwnrt;^-^ 





4d 

Fig. 4, — Chamber arrangements and positions of primary apertures in some 
species of Globigerinoides. 4a, G. ruber, ventral view. 4b, G. conglobatus, im- 
mature form, ventral view. 4c, G. conglobatus, mature form, ventral view. 
4d, G. trilobus trilobus, edge view. 4e, G. trilobus trilobus, ventral view. 



In Globigerinoides conglobatus the chambers are coiled in a fashion 
similar to that in Pulleniatina obliquiloculata, with the early chambers 
added in a trochoid spiral and the final chambers added streptospirally, 
overlapping the umbilicus. In the final stage of development the last 
chamber completely covers the umbilicus. 

In Globigerinoides ruber there is a pronounced shift in the axis of 
the chambers as they are added ; in fact, it is somewhat difficult to 
think of the chambers actually forming a coil. Each chamber is added 
directly above the aperture of the earlier chamber. The aperture of 
the new chamber is 90 degrees apart from the aperture of the pre- 



NO. 4 TLANKTONIC FORAMINIFERA — CIFELLI 25 

vious chamber. This arrangement of chambers might possibly be 
thought of as an extreme streptospiral coil, with the coil changing 90 
degrees in direction with the addition of each chamber. The test is 
nonumbilicate, as in the mature G. conglobatus. The chamber ar- 
rangement of G. elongatiis is identical with that of G. ruber. 

The chamber arrangement in Globigerinoides trilobus is more ob- 
scure. In edge view the test is rather flattened and the chambers ap- 
pear to adhere to the trochospiral coil as in Globigerina. At the same 
time, however, portions of the new chambers overlap the ventral side 
of the test considerably, so that the umbilicus is almost obscured and 
the aperture is low and elongate. In overall appearance G. trilobus 
is similar to G. ruber when viewed from the ventral side, where 3 
chambers are visible with 1 larger chamber set above 2 smaller, earlier 
chambers. However, in G. ruber the primary aperture is symmetrical 
above the 2 earlier chambers, while in G. trilobus it is asymmetrical 
(Bolli, 1957, p. 112). 

GLOBIGERINOIDES ELONGATUS (d'Orbigny) 

Plate 8, figures 1, 4 

Globigerina rubra d'Orbigny, 1839, in De la Sagra, Hist. Phys. Pol. Nat. Cuba, 

Foraminiferes, p. 82, pi. 4, figs. 12-14. — Banner and Blow, 1960, Contr. 

Cushman Foratn. Res., vol. 11, pt. 1, p. 19, pi. 3, figs. 8a, b. 
Globigerinoides rubra Bradshaw, 1959, Contr. Cushman Found. Forani. Res., 

vol. 10, pt. 2, p. 42, pi. 7, figs. 12, 13.— Be, 1959, Micropaleontol., vol. 5, 

No. 1, pi. 2, figs. 16, 17. 

This species is nonumbilicate, and each new chamber is added above 
the primary aperture of the earlier chamber. The final chamber is 
sometimes reduced in size, appearing like a small bubble on the pre- 
vious part of the test. The primary aperture is a broad arched open- 
ing at the base of the last chamber, which is symmetrically located 
above the 2 earlier chambers. There are 2 supplementary apertures 
on the side of the chamber opposite to the primary aperture. The 
supplementary apertures vary from low slits to broad, rounded 
openings; on some of the smaller specimens they are barely per- 
ceptible. When well developed, the supplementary apertures can be 
seen on the last 2 or 3 chambers. 

The color in Globigerinoides ruber ranges from white through 
various shades of pink to bright red. Most often, the red or pink 
color is confined, appearing only in part, particularly the early part, 
of the test. In the summer traverse over 75 percent of the specimens 
were red or pink in color, and most of these were bright red. In the 



26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

winter traverse the white forms predominated, accounting for over 
50 percent of this species. The winter-colored specimens included only 
shades of pink, and bright red forms were lacking. In the fall and 
spring traverses the colors were intermediate between summer and 
winter. 

Distribution, — Overall, Glohigerinoides ruber is the most abundant 
species of Globigerinoides in the traverses studied. It was also one 
of the dominant species of the subtropical assemblages. The highest 
frequency recorded was 43 percent at the summer slope station HH. 
Along with other species of Globigerinoides, the frequency dropped 
considerably in the winter, reaching a maximum of only 8 percent 
(station II). 

GLOBIGERINOIDES ELONGATUS (d'Orbigny) 
Plate 9, figure 5 

Globigerina elongata d'Orbigiiy, 1826, Banner and Blow, 1960, Coiitr. Cushman 
Found. Foram. Res., vol. 11, pt. 1, p. 12, pi. 3, figs. lOa-c. 

This species closely resembles and may turn out to be a variant 
form of Globigerinoides ruber. However, the test is more compact 
than in G. ruber, and the final chambers are compressed, almost 
flattened, as in G. conglobatus. 

The primary aperture is symmetrically located above the two earlier 
chambers in G. elongatus but is less broad than in G. ruber. The 
present specimens agree with the lectotype of G. elongatus as figured 
by Banner and Blow. 

Distribution. — This species is rare and was recorded only from 
Sargasso Sea stations. In all cases the frequencies were less than 1 
percent. 

GLOBIGERINOIDES TRILOBUS TRILOBUS (Reuss) 
Plate 9, figures 1-3 

Globigerina triloba Reuss, 1850, Deiikr. K. Akad. Wiss. Wien, vol. 1, p. 374, 

pi. 47, fig. 11. 
Globigerinoides sacculijer (Brady, 1877), Be, 1959, Micropaleontol., vol. 5, pi. 2, 

figs. 13-15. 

In this species the final chamber is set above the two preceding ones, 
as in Globigerinoides ruber. However, the coiling of G. trilobus 
trilobus is essentially trochospiral, and the final chamber does not 
completely cover the umbilicus, so that the primary aperture is a 
narrow slit at the base of the chamber. On the dorsal side of the 



NO. 4 PLANKTONIC FORAMIN'IFERA CIFELLI 2/ 

chamber there is a single supplementary aperture, in contrast to G. 
ruber in which there are two supplementary apertures on the chamber. 
This species shows variation in the size of the supplementary 
aperture and in the development of the final saclike chamber. The fol- 
lowing forms which are completely transitional were recognized in 
the material studied. 

1, Supplementary aperture small, saclike final chamber lacking. 

2, Supplementary aperture large, saclike final chamber lacking. 

3, Supplementary aperture small, saclike final chamber present. 

4, Supplementary aperture large, saclike final chamber present. 

Form 1 occurs most commonly, but form 2 is also present in 
appreciable numbers. Form 3 and particularly form 4 are relatively 
scarce. The specimens agree very well and are identical with Miocene 
topotypes of Glohigerina trilohus Reuss in the U. S. National Museum 
collections, which include both forms 1 and 2, with dominance of 
form 1. They differ from G. saccuUfer Brady in having smaller sup- 
plementary apertures and less-developed saclike final chambers. Speci- 
mens of G. saccuUfer from Recent Pacific bottom sediments studied 
for comparison included the same range of forms as G. trilohus but 
showed a dominance of forms 3 and 4. Moreover, the Pacific sac- 
culifer includes a form with an elongate saclike final chamber (Brady, 
1884, pi. 80, fig. 4) that was not observed in the North Atlantic 
material. 

Thus, G. trilohus and G. saccuUfer represent overlapping parts of 
a gradational series, a fact noted by several earlier workers, and as 
such are distinguishable only at the subspecific level. Although called 
subspecies, however, trilohus and saccuUfer are not subspecies in the 
geographic sense of the neontologist, since G. trilohus sensu lato has 
a long, complex fossil record. Additional difficulties in applying the 
neontological subspecies concept are introduced by the fact that the 
species has a pelagic habitat. The isolating mechanisms in the open 
ocean are much less understood than those on land or even on the 
ocean bottom. 

It would be convenient if the gradational series between trilohus 
and saccuUfer also represented an evolutionary series, as then it would 
be an easy matter to divide the series into vertical subspecies, in the 
sense of the paleontologist. Unfortunately, such a simple phyletic 
trend does not characterize this lineage. The present North Atlantic 
assemblages show a closer morphologic affinity to the Miocene as- 
semblages of trilohus than to Recent assemblages of saccuUfer. Thus, 
G. trilohus will not yield gracefully to a vertical division of subspecies. 



28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Vertical subspecies could not be identified without knowing the age 
of the assemblage. 

There are, in the fossil record, several additional forms that can 
be linked to the trilobus-sacculifer gradational series, such as G. 
altiapertura and G. immatura. These forms have been treated in 
different ways by various authors, but the treatment thus far has been 
dominantly typological. As a result, the range of forms in G. trilobus 
sensu lato is reasonably well known, but there is still a poor under- 
standing of the nature of population structures at the various strati- 
graphic levels. Parker (1962, p. 219) pointed out the necessity of 
treating assemblages as populations, and it could be added that this 
particular problem lends itself to a quantitative analysis, since the 
distinctions between the subspecies involve gradational characters. In 
order to determine the actual changes that have occurred in G. trilobus 
sensu lato since the Miocene, it will be necessary to analyze statistically 
the character of many assemblages from widely separated localities 
ranging from Miocene to Recent; a formidable task, but only in this 
way can a complete and realistic alignment of subspecies be attained. 

Thus, any present arrangement of subspecies must be considered 
tentative and incomplete. It seems unnecessarily pretentious to force 
subspecies into horizontal or vertical strait jackets, and it is much more 
compatible with the evidence at hand to recognize subspecies as 
dynamic populations in which the range of variation fluctuates through 
time and space. 

Distribution. — Although Globigerinoides trilobus trilobus was not 
as common, overall, as G. ruber, the ratio between the two species 
varied considerably from station to station, and at a few stations G. 
trilobus trilobus was the dominant species of Globigerinoides. Its 
highest frequency was 45 percent, which was recorded in the fall at 
station 8, in the Sargasso Sea. 

GLOBIGERINOIDES CONGLOBATUS (Brady) 
Plate 8, figures 2, 3 

Globigerina conglobata Brady, 1884, Rep. Voy. Challenger, Zoo!., vol. 9, p. 603, 

pi. 80, figs. 1-5, pi. 82, fig. 5. 
Globigerinoides conglobata Bradshaw, 1959, Contr. Cushman Found. Foram. 

Res., vol. 10, pt. 2, p. 40, pi. 7, figs. 5, 6.— B6, 1959, Micropaleontol., vol. 5, 

No. 1, pi. 2, figs. 7-12. 
Globigerinoides sp. Bradshaw, 1959, Contr. Cushman Found. Foram. Res., 

vol. 10, pt. 2, pi. 7, figs. 16, 17. 

Throughout most of the test the coiling is trochospiral, but in the 
last whorl the final 2 chambers overlap the umbilicus. In many 



NO. 4 PLANKTONIC FORAMINIFERA — CIFELLI 29 

Specimens the last chamber completely covers the umbilicus, and the 
primary aperture is a small, rounded opening symmetrically located 
above 2 earlier chambers. The last chamber is compressed and 
flattened in appearance. In the early stages this species has an open 
umbilicus and in coiling closely resembles species of Glohigerina. The 
specimen that Bradshaw (1959, pi. 7, figs. 16, 17) figured as Globig- 
erinoides sp. is considered here to be an early stage of G. conglobatus. 
The wall of this species is relatively thick for a Glohigerinoides and 
the surface is coarsely spinose. 

Distribution. — This is a characteristic species in the subtropical as- 
semblages but was found mostly at frequencies of less than 5 per- 
cent. However, at Sargasso Sea summer station KK it was recorded 
at a frequency of 15 percent and was the dominant species of 
Globigerinoides. 



APPENDIX 

Table 5. — Positions of plankton-collecting stations, summer traverse, 
August 1960. Water depths are given for the shelf stations only. 

Water _ Depth in Latitude N. Longitude W. 

body Station meters o / o / 

Shelf waters A 36 40 58 7149 

B 64 40 44 71 41 

C 67 40 31 71 35 

D 77 40 18 71 28 

E 314 40 DO 71 19 

Slope waters F 39 48 71 12 

G 39 36 71 06 

HH 38 46 70 12 

HH' 38 39 69 33 

HH" 38 12 69 18 

Gulf Stream II 38 00 69 32 

Sargasso Sea JJ 37 12 68 48 

KK 36 23 68 04 

LL 35 35 67 20 

MM 34 47 66 29 



Table 6. — Positions of plankton-collecting stations, fall traverse, 
October 1960. Water depths are given for the shelf stations only. 

Water _ Depth in Latitude N. Longitude W. 

body Station meters o > o / 

Shelf waters 1 36 4103 7129 

2 65 40 48 71 25 

3 68 40 28 71 21 

4 122 40 06 71 15 

Slope waters 5 39 17 7103 

6 38 27 70 53 

Gulf Stream* 7 37 38 70 41 

Sargasso Sea 8 36 58 70 08 

9 36 14 69 18 

* A bathythermograph was not available on this cruise and the position of 
Gulf Stream was estimated by the set of the ship. 



50 



NO, 4 I'LANKTONIC FORAMIXIFERA — CJFELLI 3I 



Table 7. — Positions of plankton-collecting stations, ivinter traverse, 
January 1961. Water depths are given for the shelf stations only. 

Water DcptJt In Latitude N. Longitude W 

body Station meters o » o > 

Shelf waters A 36 40 59 7151 

B 65 40 44 71 41 

C 70 40 31 71 36 

D 77 40 18 71 28 

E 342 39 56 71 18 

Slope waters F 39 48 7112 

G 39 37 71 06 

HH 38 46 70 19 

Gulf Stream II 37 46 69 20 

Sargasso Sea )] 37 10 68 38 

KK 36 23 68 05 

LL 35 35 67 21 

MM 34 43 66 22 

NN 33 56 65 51 

00 33 06 65 03 



Table 8. — Positions of plankton-collecting stations, spring traverse, 

May 1961. Water depths are given for the shelf stations only. 

Water _ Depth in Latitude N. Longitude W. 

body Station meters » » o » 

Shelf waters 9 52 40 45 70 30 

8 58 40 31 70 20 

Slope waters 7 39 51 69 47 

6 39 07 69 14 

5 38 35 68 50 

4 38 00 68 26 

Gulf Stream 3 37 20 67 51 

Sargasso Sea 2 36 06 67 06 



REFERENCES 

Banner, F. T., and Blow, W. H. 

1959. The classification and stratigraphical distribution of the Globigerina- 

ceae. Pt. 1. Palaeontol. (Paleontol. Assoc. London), vol. 2, pt. 1, 
pp. 1-27, pis. 1-3. 

1960. Some primary types of species belonging to the superfamily Globig- 

erinaceae. Contr. Cushman Found, Foram. Res., vol. 11, pt. 1, 
pp. 1-41, pis. 1-8. 
1960a. The taxonomy, morphology, and affinities of the genera included in 
the subfamily Hastigerininae. Micropaleontol., vol. 6, pp. 19-31, 
figs. 1-11. 
Be, a. W. H. 

1959. Ecology of Recent planktonic foraminif era : Pt. 1, Areal distribution 

in the western North Atlantic. Micropaleontol., vol. 5, No. 1, pp. 11- 
100, pis. 1-2, text figs. 1-52, tables 1-2. 

1960. Ecology of Recent planktonic foraminifera : Pt. 2, Bathymetric and 

seasonal distributions in the Sargasso Sea off Bermuda. Micro- 
paleontol., vol. 6, No. 4, pp. 373-392, text figs. 1-19, tables 1-6. 
BoLLi, H. M. 

1957. Planktonic Foraminifera from the Oligocene-Miocene Cipero and 
Lengua formations of Trinidad, B.W.I. U.S. Nat. Mus. Bull. 215, 
pp. 97-121, pis. 22-29. 
BoLLi, H. M., LoEBLicH, A. R., and Tappan, H. 

1957. Planktonic foraminif eral families Hankteninidae, Orbulinidae, Glo- 
borotaliidae, and Globotruncanidae. U.S. Nat. Mus. Bull. 215, 
pp. 3-50, pis. 1-11, text figs. 1-9. 
Bradshaw, J. S. 

1959. Ecology of living planlctonic foraminifera of the North and Equa- 
torial Pacific Ocean. Contr. Cushman Found. Foram. Res., vol. 10, 
pt. 2, pp. 25-63, pis. 6-8. 
Brady, H. B. 

1884. Report on the Foraminifera m Report on the scientific results of 
H.M.S. Challenger during the years 1873-76. Zoology, vol. 9, 
pp. 1-814, pis. 1-115. 

ClFELLI, R. 

1961. Globigerina incompta, a new species of pelagic Foraminifera from 

the North Atlantic. Contr. Cushman Found. Foram. Res., vol. 12, 
pt. 3, pp. 83-86, pi. 4. 

1962. Some dynamic aspects of the distribution of planktonic Foraminifera 

in the western North Atlantic, Sears Found. Journ. Marine Res., 
vol. 20, No. 3, pp. 201-213. 
Grice, G. D., and Hart, D. H. 

1962. The abundance, seasonal occurrence and distribution of the epizoo- 
plankton between New York and Bermuda. Ecological Monogr., 
vol. 32, pp. 287-309. 

32 



NO. 4 PLANKTONIC FOKAMINIFERA — CIFELLI 33 

ISELIN, C. O'D. 

1936. A study of the circulation of the western North Atlantic. Massachu- 
setts Inst. Techn., Woods Hole Oceanogr. Inst., Pap. Phys. 
Oceanogr. and Meteorol., vol. 4, No. 4, pp. 1-101. 
Parker, F. L. 

1958. Eastern Mediterranean Foraminifera. Swedish Deep Sea Exped. 
Reps., vol. 8, pp. 219-283, pis. 1-6. 

1962. Planktonic foraminiferal species in Pacific sediments. Micropaleontol., 

vol. 8, No. 2, pp. 219-254, pis. 1-10. 
Smith, A. B. 

1963. Distribution of living planktonic Foraminifera in the northeastern 

Pacific. Contr. Cushman Found. Foram. Res., vol. 14, pp. 1-15, 
pis. 1-2. 
Stommel, H. 

1958. The Gulf Stream — a physical and dynamical description. California 
Univ. Press, 202 pp. Berkeley and Los Angeles. 
Todd, R. 

1961. On selection of lectotypes and neotypes. Contr. Cushman Found. 

Foram. Res., vol. 12, pp. 121-122. 
1963. Nomenclature of Foraminifera. Contr. Cushman Found. Foram. Res., 
vol. 14, pp. 109-111. 



EXPLANATION OF PLATES 
Plate 1 

Fig. 1. Glohigerina buUoides d'Orbigny. Summer slope station HH". U.S.N.M. 

641307. a, Dorsal view, b, Ventral view. X93. 
Fig. 2. Glohigerina bulloides d'Orbigny. Fall shelf station 3. U.S.N.M. 641308. 

a, Dorsal view, b, Ventral view. X93. 
Fig. 3. Glohigerina bulloides d'Orbigny. Spring slope station 4. U.S.N.M. 

641309. a, Ventral view, b, Dorsal view. X93. 

Fig. 4. Glohigerina pachyderma incompta Cifelli. Fall slope station 5. U.S.N.M. 

641310. a, Ventral view, b, Dorsal view. Xl48. 

Fig. 5. Glohigerina bulloides d'Orbigny. Summer slope station F. U.S.N.M. 

641311. a, Dorsal view, b, Ventral view. X93. 

Fig. 6. Glohigerina pachyderma incompta Cifelli. Fall slope station 6. U.S.N.M. 

641312. a, Dorsal view, b, Ventral view. Xl48. 

Plate 2 

Fig. 1. Glohigerina didertrei d'Orbigny. Summer slope station HH'. U.S.N.M. 

641313. a, Dorsal view, b, Ventral view. X6S. 

Fig. 2. Glohigerina dntertrei d'Orbigny. Fall slope station 6. U.S.N.M. 641314. 

a, Ventral view, b, Dorsal view. X65. 
Fig. 3. Glohigerina aflf. G. qninqueloba Natland. Winter shelf station B. 

U.S.N.M. 641315. a, Ventral side, b, Dorsal side. X214. 
Fig. 4. Glohigerina aflf. G. qninqueloba Natland. Winter shelf station B. 

U.S.N.M. 641316. a, Ventral side, b, Dorsal side. X214. 
Fig. 5. Glohigerina sp. Winter shelf station D. U.S.N.M. 641317. a, Ventral 

side, b, Dorsal side. Xl48. 
Fig. 6. Glohigerina sp. Winter shelf station D. U.S.N.M. 641318. a, Dorsal 

side, b, Ventral side. X148. 

Plate 3 



Fig. 1. Piilleniatina ohliqniloculafa (Parker and Jones). Winter slope sta 
tion HH. U.S.N.M. 641319. a, Dorsal view, b, Ventral view. X93. 

Fig. 2. Globigcrinita glutinata (Egger). Spring Gulf Stream station 3. 
U.S.N.M. 641320. a, Ventral view, b, Dorsal view. Xl48. 

Fig. 3. Pulleniatina ohliqttilociilata (Parker and Jones). Winter slope sta- 
tion HH. U.S.N.M. 641321. a, Dorsal view, b, Ventral view. X93. 

Fig. 4. Glohigerinita glutinata (Egger). Spring slope station 4. U.S.N.M. 

641322. a, Ventral view, b, Dorsal view. Xl48. 

Fig. 5. Glohigerinita glutinata (Egger). Spring slope station 4. U.S.N.M. 

641323. a, Ventral view, b, Dorsal view. Xl48. 

Fig. 6. Orbulina universa d'Orbigny. Summer Sargasso Sea station KK. 

U.S.N.M. 641324. Bichambered form. X46. 
Fig. 7. Orbulina universa d'Orbigny. Fall Sargasso Sea station 9. U.S.N.^L 

641325. X46. 

34 



NO. 4 PLANKTONIC FORAMINIFERA — CIFELLI 35 

Plate 4 

Fig. 1. Globigerina inflata d'Orbigny. Spring slope station 5. U.S.N.M. 641326. 

a, Ventral view, b, Edge view, c, Dorsal view. X93. 
Fig. 2. Globigerina inflata d'Orbigny. Fall slope station 5. U.S.N.M. 641327. 

a, Ventral view, b, Edge view, c, Dorsal view. X93. 
Fig. 3. Globigerina inflata d'Orbigny. Fall slope station 6. U.S.N.M. 641328. 

a, Ventral view, b, Dorsal view. X93. 
Fig. 4. Globorotalia punctulata (d'Orbigny). Summer Sargasso Sea station 

KK. U.S.N.M. 641329. a, Ventral view, b, Exlge view, c, Dorsal view. 

X93. 

Plate 5 

Fig. 1. Globorotalia punctulata (d'Orbigny). Summer Sargasso Sea station 

KK. U.S.N.M. 641330. a, Ventral view, b, Edge view, c, Dorsal view. 

X93. 
Fig. 2. Globorotalia hirsuta (d'Orbigny). Winter Sargasso Sea station OO. 

U.S.N.M. 641331. a, Dorsal view, b, Ventral view. X65. 
Fig. 3. Globorotalia hirsuta (d'Orbigny). Spring Sargasso Sea station 2. 

U.S.N.M. 641332. a, Dorsal view, b, Edge view, c, Ventral view. X65. 
Fig. 4. Candeina nitida d'Orbigny. Summer Sargasso Sea station KK. 

U.S.N.M. 641333. a, Ventral view, b, Dorsal view. X93. 

Plate 6 

Fig. 1. Globorotalia truncalulinoides (d'Orbigny). Winter Sargasso Sea sta- 
tion NN. U.S.N.M. 641334. a, Ventral view, b, Dorsal view. X93. 

Fig. 2. Globorotalia truncatulinoides (d'Orbigny). Fall slope station 5. 
U.S.N.M. 641335. a, Dorsal view, b, Ventral view, X93. 

Fig. 3. Globorotalia menardii (d'Orbigny). Summer Sargasso Sea station LL. 
U.S.N.M. 641336. a, Ventral view, b, Dorsal view. X93. 

Fig. 4. Globorotalia menardii (d'Orbigny). Fall Sargasso Sea station 9. 
U.S.N.M. 641337. a, Ventral view, b, Dorsal view. X93. 

Plate 7 

Fig. 1. Hastigcrina pelagica (d'Orbigny). Winter Sargasso Sea station MM. 

U.S.N.M. 641338. a, Side view, b, Edge view. X65. 
Fig. 2. Hastigerina pelagica (d'Orbigny). Summer Sargasso Sea station LL. 

U.S.N.M. 641339. a, Edge view, b, Side view. X65. 
Fig. 3. Globigerinella aequilaferalis (Brady). Winter Sargasso Sea station NN. 

U.S.N.M. 641340. a, Ventral view, b, Dorsal view. X65. 
Fig. 4. Globigerinella aequilateralis (Brady). Spring Gulf Stream station 3. 

U.S.N.M. 641341. a, Dorsal view, b, Ventral view. X65. 
Fig. 5. Globigerinella aequilateralis (Brady). Spring Gulf Stream station 3. 

U.S.N.M. 641342. a, Dorsal view, b, Ventral view. X65. 

Plate 8 

Fig. 1. Globigerinoides ruber (d'Orbigny). Spring Gulf Stream station 3. 
U.S.N.M. 641343. a, Ventral view, b, Dorsal view. X93 



2)6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Fig. 2, Globigerinoides conglobatus (Brady). Fall slope station 6. U.S.N.M. 

641344. a, Ventral view, b, Dorsal view. X65. 
Fig. 3. Globigerinoides conglobatus (Brady). Summer Sargasso Sea station 

LL. U.S.N.M. 641345. a, Dorsal view, b, Ventral view. X93. 
Fig. 4. Globigerinoides ruber (d'Orbigny). Spring Gulf Stream station 3. 

U.S.N.M. 641346. a, Dorsal view, b, Ventral view. X93. 

Plate 9 

Fig. 1. Globigerinoides trilobus trilobus (Reus). Fall slope station 6. U.S.N.M. 
641347. a, Ventral view, b, Dorsal view. X65. 

Fig. 2. Globigerinoides trilobus irilobus (Reus). Summer Sargasso Sea sta- 
tion KK. U.S.N.M. 641348. a, Ventral view, b, Dorsal view. X65. 

Fig. 3. Globigerinoides trilobus trilobus (Reus). Summer Sargasso Sea sta- 
tion KK. U.S.N.M. 641349. a, Ventral view, b, Dorsal view. X65. 

Fig. 4. Globigerinoides trilobus trilobus (Reus). Summer slope station HH'. 
U.S.N.M. 641350. a, Ventral view, b, Dorsal view. X65. 

Fig. 5. Globigerinoides elongatus (d'Orbigny). Winter Sargasso Sea sta- 
tion NN. U.S.N.M. 641351. a, Ventral view, b, Dorsal view. X148. 



HSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 4. PL. 1 




Globigerina 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL, 148. NO. 



'0>: 



'■^M; 




Si 




''^m 



.itM 




Globigerina 



HSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 4, PL. 3 




PULLENIATINA. GLOBIGERINITA, ORBULINA 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL, 143. NO. 4, P 




Globigerina, Globorotalia 



ITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 4. PL. 5 




Globorotalia. Candeina 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 4. 




Globorotauia 



)NIAN MISCELLANEOUS COLLECTIONS 



VOL. 148, NO. 4. PL. 7 




Hastigerina, Globigerinella 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 4. PL. 




Globigerinoides 



MITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 143. NO. 4. PL. 9 




Globigerinoides 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 5 



Cfjarles; ». anb ilarp IrJaux OTakott 
i^esiearcf) Jf unb 



HEXAHEDRIJES 

(With Four Plates) 



By 



\ 



EDWARD P. HENDERSON 

U. S. National Museum V 
Smithsonian Institution i 

\ 







(Publication 4601) 



/. O <o 



CITY OF WASHINGTON 
PUBLISHED BY THE SMITHSONIAN INSTITUTION 

JUNE 14, 1965 



Gift \ 

Copy 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 5 



Cjjarles; JB. anb iilarp IJaux OTalcott 
i^esiearcl) Jf unb 



HEXAHEDRITES 



(With FotrR Plates) 



By 
EDWARD P. HENDERSON 

U. S. National Museum 
Smithsonian Institution 




(Publication 4601) 



CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

JUNE 14, 1965 



PORT CITY PRESS, INC. 
BALTIMORE, MD., U. S. A. 



Cfjadcfii B. anb iWarp "^aux ajialcott l^efiearcfj Jfunb 
HEXAHEDRITES 

By EDWARD P. HENDERSON 

U. S. National Museum 
Smithsonian Institution 

(With Four Plates) 

INTRODUCTION 

Hexahedrites are the simplest of the iron meteorites and a com- 
paratively easy type to recognize, yet many have been incorrectly 
classified. In several places these irons were found distributed in 
such a manner that they seem to have fallen as a shower. This 
investigation of the worldwide distribution of hexahedrites was made 
to determine how general these local concentrations are. In assem- 
bling the geographic data, certain characteristics were noted which 
could have a bearing on the scatter of these irons. 

Acknowledgments. — Because these topics were discussed with 
many investigators in diverse disciplines over the years, it is difficult 
to credit specific points to the proper source. The author realizes 
that some names probably have been overlooked and to them he 
offers apologies. The following persons have made substantial con- 
tributions to this study: H. J. Axon, University of Manchester, 
Manchester, England; Harrison Brown, California Institution of 
Technology, Pasadena, Calif. ; V. Buchwald, Technical University, 
Copenhagen, Denmark ; Walter Corvello, National Museum, Rio de 
Janeiro, Brazil ; Roy S. Clarke, Jr., U. S. National Museum, Washing- 
ton, D. C. ; M. E. Lipschultz, Goddard Space Flight Center, National 
Aeronautics and Space Administration, Washington, D. C. ; Brian 
Mason, American Museum of Natural History, New York City ; 
Charles Olivier, formerly of Flower Observatory, University of 
Pennsylvania, Philadelphia, Pa.; Sharat Roy (deceased), Chicago 
Museum of Natural History, Chicago, 111. ; Harold Urey, University 
of California, La Jolla, Cahf . ; H. Wanke, Max Planck Institute, 
Mainz, Germany. 

SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 148, NO. 5 



2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

HEXAHEDRITES AND THE NICKEI^IRON SYSTEM 

The three types of iron meteorites, hexahedrites, octahedrites, and 
ataxites, are accounted for by the nickel-iron phase diagram, fig. 1 ; 
however, there are no clearly defined separations between the dif- 



900 



800 - 



700 - 



o 



K 600 



5 

q: 

Q. 



LU 



500 I 



400 - 



300 - 



200 




30 40 
% NICKEL 



Fig. 1. — Nickel-iron phase diagram. The hexahedrites and nickel-poor 
ataxites fall into the same area, i.e., left of the line AB and usually within the 
area defined by the two dotted lines. A hexahedrite should consist of one nickel- 
iron alloy, kamacite or alpha iron. 



ferent types. The hexahedrite group is located to the left of the 
line AB in figure 1. These should consist of a single phase, alpha 
iron or kamacite. The octahedrites fall in the area between AB and 
AC and consist of two phases of nickel-iron alloys, kamacite (alpha 
iron) and taenite (gamma iron). The third group, ataxites, should 



NO. 5 HEXAHEDRITES — HENDERSON 3 

occupy the area to the right of AC and chiefly consist of taenite, but 
usually also contain an appreciable quantity of alpha iron, kamacite. 

Meteorites lying along the borderlines of groups are difficult to 
classify. Thus, any list of hexahedrites compiled by one investi- 
gator will contain irons that another compiler might regard as coarse 
octahedrites. 

The Ni-Fe diagram (fig. 1) shows the conditions under which 
kamacite (alpha iron), the sole constituent of a hexahedrite, forms. 
The two dotted vertical lines at 5.5 and 6.0 percent Ni define the 
range within which hexahedrites grade into coarse octahedrites. 
Thus, no hexahedrite has a nickel value to the right of these dotted 
lines, and most hexahedrites lie either on or slightly to the left of the 
5.5 line. 

The different classes of meteorites — hexahedrites, nickel-poor 
ataxites, octahedrites, and nickel-rich ataxites — do not correspond 
to the diagram for 1 atmosphere of pressure, as stated by Uhlig 
(1954) and by Henderson and Perry (1954). According to Uhlig, 
this is due to the fact that meteorites form under pressures greater 
than 1 atmosphere. 

If a horizontal line is drawn in figure 1 at 490° C, and if it is as- 
sumed that no changes take place below this temperature, the modified 
diagram more faithfully depicts the structures in iron meteorites. 
Following a 490° line from left to right, the hexahedrites, which 
consist of one component, lie to the left of the line AB while the 
octahedrites and nickel-rich ataxites lie between AB and AC. 

The chemical composition reported for the hexahedrites and 
nickel-poor ataxites only represents an average composition of the 
area selected for analysis and not the entire meteorite. Since the 
Ni values of hexahedrites range from about 4 to 6 percent, there is 
no valid chemical reason for continuing the use of the term nickel- 
poor ataxite. This term should be dropped. 

The available analyses of the nickel-rich ataxites, hereafter referred 
to as ataxites, show nickel values which can be located on the 490° 
line to the left of where it crosses the AC line. Actually most of the 
Ni percentages lie nearer to the AB than the AC line. Thus, 
kamacite should be a common constituent in ataxites, and indeed, 
kamacite spindles are recognizable in these meteorites. The struc- 
tures of ataxites are more confused than the structures in the 
octahedrites and hexahedrites. 

An interesting relationship was noted in the range of Ni percentages 
of the three groups of meteorites. The difference between the 



4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

lowest and highest nickel value in the hexahedrites is about 2 
percent, in octahedrites the range is about 6 percent, while in ataxites 
it is nearer 18 percent. 

DESCRIBED HEXAHEDRITES 

Table 1 lists all known hexahedrites as of July 1962, together with 
their weights and dates of fall or find. Synonyms are not numbered. 

Table 1. — List of described hexahedrites. 

Weight, Date of Date of 

Name kilograms discovery fall 

Angela (see La Primitiva) 

Aragon, Ga. (see Cedar town) 

1. Aswan, Egypt ? 1953 

2. Auburn, Ala 3.6 1867 

3. Avce, Italy 1.23 Mar. 31, 1908 

4. Barraba, Australia (Bingara) 1.36 unknown 

5. Bellsbank, S. Africa 38 1950 ( ?) 

6. Bennet Co., S. Dak 89 1934 

7. Bingara, N. S. Wales 1.1 & 6.4 1880 

8. Boguslavka, Siberia 199 & 57 Oct. 18, 1916 

9. Braunau, Czechoslovakia 22 & 17 July 14, 1847 

10. Bruno, Canada 13 1913 

11. Cedartown, Ga 11.3 before 1898 

12. Central Missouri i 25 1885 

13. Chesterville, S. C 16.5 1848 

14. Chico Mountain, Tex 2,000 2 before 1915 

15. Chinguetti, French W. Africa — s 1920 

16. Cincinnati, Ohio unknown 1870 

17. Coahuila, Mexico 1,000 1837 

18. Corrego do Areado, Brazil 32 1925 

19. Coya Norte, Chile 17.9 1927 

20. Edmonton, Canada 7.34 1939 

El Mocovi (see Otumpa) 

21. Filomena, Chile 21.1 1941 

Fort Duncan (see Coahuila) 

22. Forsyth County, N. C 17 1891 

Gressk, Russia (see Hressk) 

23. Hex River, Africa 60 1882 

24. Holland's Store, Ga 12.27 1887 

25. Hressk, Russia 11.9 1954 

26. Indian Valley, Va 14 1887 

27. Iredell, Tex 1.5 1898 

^Usually this iron is listed as a coarse octahedrite, but Perry (1944) consid- 
ered it a granulated hexahedrite. See plate 4. 

2 Sample lost, weight unconfirmed. 

3 Reported as 100 meters long, 45 meters high. These figures probably were 
intended to be centimeters, not meters. 



NO. 5 HEXAHEDRITES — HENDERSON 5 

Table 1. — Continued 

28. Keen Mt., Va 6.7 1950 

29. Kendall County, Tex 21 1887 

30. La Primitiva, Chile 3.1,4,1.5, 1888 

4.3, 9 

31. Lick Creek, N. C 1.24 1879 

32. Locust Grove, Ga 10 1857 

33. Lombard, Mont unknown ? 

34. Mayodan, N. C 16 1950 

35. Mejillones, Chile — * 1875 

Mejillones, Chile 14.5 1905 

36. Murphy, N. C 8 1889 

37. Mt. Joy, Pa 385 1887 

38. Navajo, Ariz 1499 1921-1926 

680 

39. Nedagolla, India ^ 4.5 Jan. 23, 1870 

40. Negrillos, Chile 28.5 before 1936 

41. Nenntmannsdorf, Saxony 12.5 1872 

42. Okano, Japan 4.74 Apr. 7, 1904 

43. Opavo, Czechoslovakia 7.4, 5.8, 1925 

1.0, 0.1 

44. Otumpa, Argentina (15 tons, 1576 

est.) 

45. Pima County, Ariz 0.21 before 1947 

46. Pirapora, Brazil ^ 2.56 

47. Puripica, Chile 19 1929 

■* "A cart would be required for its carriage," G. A. Daubree, Compt. Rend., 
Acad. Sci. Paris, vol. 81, p. 597, 1875. 

5 Although reported as a nickel -poor ataxite, the analyses show 6.2 and 6.1 
percent of Ni. These values are above the Ni content of hexahedrites. This 
iron, which has exceptionally fine flight markings, obviously fell as an orientated 
individual. A cross section through its short dimension shows two well-defined 
heat-altered zones about 2.5-3.0 mm. wide. The metal between these thermally 
altered zones displays a pattern like that formed when metal is rapidly quenched 
(Axon, 1962). This structure is visible at low magnifications (6X to lOX) ; 
however, at higher magnifications a granular texture is noticeable. Both struc- 
tures existed before this meteorite entered our atmosphere. 

All witnessed falls of hexahedrites (table 2) occurred in the morning. Neda- 
golla fell at 7 p.m. Meteorites falling in the morning are oncoming ones, thus 
enter the atmosphere with higher velocities than those which fall in the afternoon 
hours. Hence, the Nedagolla differs from the witnessed hexahedrite falls not 
only in its metallography and chemistry, but also in the time of fall. 

To combine two interpretations, one from its chemistry and the other from 
its metallography, to explain its past history, is difficult. The structure, notice- 
able at low magnifications, is that of a metal which solidified quickly, but the 
granular texture, visible at higher magnifications, is suggestive of later reheat- 
ing to about 800° C. Where and when these events took place is unknown, but 
they happened prior to its fall in 1870. From its chemical composition this iron 
might represent a melted coarse octahedrite, and it is definitely unlike all other 
hexahedrites. 

' The Pirapora, Brazil, iron was reported in private communications from 
Dr. Walter Curvello, Museum Nacional, Rio dc Janeiro. No additional data 
are available. 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I48 



Table 1. — Con tinned 

48. Quillagua, Chile 78 

49. Richland, Tex 15.4 

50. Rio Loa, Chile 4 

51. Sakouchi, Japan ^ 4.18 

52. San Francisco del Mezquital, 

Mexico 7.5 

53. San Martin, Chile 29 

54. Scottsville, Ky 10 

55. Sierra Gorda, Chile 22.0 

56. Sikhote Alin, E. Siberia ^ (many 

tons) 

57. Siratik, W. Africa — » 

.S8. Smithonia, Ga.'" 70 

59. Soper, Okla X7 

60. Summitt, Ala 1 

61. Tandil, Argentina 0.98 

62. Tocopilla, Chile 75 

63. Tombigbee, Ala 43 

64. Union, Chile 22 

65. Uwet, Nigeria 54 

66. Villanueva del Fresno, Spain 0.35 ^^ 

67. Walker County, Ala 75 

68. Warialda, N. S. Wales (Bingera) . . .2.8 

69. Wathena, Kans 0.56 

70. Yarroweyah, Victoria, Australia 9.5 



1938 

1951 

1915 

1913 Apr. 13, 1913 

before 1868 

before 1924 

1867 

1898 



Feb. 12, 1947 



1716 
1940 
1938 
1890 

1927 

1859-86 

1930 

1903 

not given 

1832 

1919 

1939 

1903 



1916-1919 



''Since Kanda (1952) lists the Sakouchi as a hexahedrite, it is included 
in this list. The information about this meteorite is incomplete and conflicting. 

* The composition lies along the border between the hexahedrites and the 
coarse octahedrites. Because there is an absence of a noticeable octahedral 
arrangement in these specimens, this iron is classified as a hexahedrite. 

3 This meteorite needs restudy. Although a large mass was found, only about 
1.7 kg. is known today. 

10 When Roy and Wyant (1950) studied the Smithonia, Ga., iron, they found 
no Neumann lines, the nickel content below 6 percent, and hence classified it as 
a nickel-poor ataxite. In a later cut, which penetrated deeper into the meteorite, 
Henderson and Furcron (1957) observed Neumann lines which established this 
iron as a normal hexahedrite. 

^1 Weight not reported, but was calculated from the dimensions. 



METEORITES INCORRECTLY IDENTIFIED AND EXCLUDED 
FROM THE HEXAHEDRITES 

Not included in the foregoing list of hexahedrites are seven 
specimens incorrectly listed as hexahedrites. These are : 

1. Chihuahua City, Mexico. Although this iron was listed by 
Hey (1953) as a brecciated hexahedrite, Nininger (1931) reported 
it as having "a fine octahedral crystallization," Also Nininger 



NO. 5 HEXAHEDRITES — HENDERSON 7 

published an analysis by F. C. Hawley which reported 6.96 percent 
Ni. Again in 1950 Nininger classified this iron as a brecciated 
octahedrite. Goldberg and others (1951) published two nickel 
determinations, 6.97 and 6.85 percent. Thus, three analyses report 
values in excess of those for a hexahedrite. 

2. Dorofeevka, U.S.S.R. Illustrations of this iron published by 
Zavaritsky (1954) show both narrow kamacite lamellae and plessite 
areas. In the text Zavaritsky mentions that this iron resembles a 
nickel-rich ataxite. 

3. Granado, Ariz. Nininger and Nininger (1950) reported this 
38-gram iron as a hexahedrite, but H. H. Nininger now regards it as a 
piece of Canyon Diablo (personal communications). 

4. Lake Murray, Carter County, Okla. Classified as a coarse 
octahedrite. This specimen, weighing 272.7 kg., was found about 
1932 but not excavated and recovered until 1952. La Paz con- 
sidered it an intermediate member between the hexahedrites and 
octahedrites and proposed the term "hexaoctahedrite." Plate 1 
shows a portion of a cut through the Lake Murray meteorite. In 
several areas wide kamacite bands are arranged in an octahedral 
pattern. The octahedral structure in other parts of this section is 
disrupted by the growth of large skeletons of schreibersite inclusions, 
some measuring more than 6 cm. in length and 4 cm. in width. 

5. New Mexico. This 130-gram specimen was found in 1923 
at approximately 34°3r N. and 107° W. Nininger and Nininger 
(1950) listed it as a hexahedrite and said it had been fashioned into 
an ax. Obviously man had something to do with this iron. Since 
the Sandia Mountains, N. Mex., iron has kamacite grains of about 
this size and shape, H. H. Nininger now regards the New Mexico 
specimen as a man-worked fragment of the Sandia Mountains iron 
(personal communications). 

6. Sulechow, Poland. Although typed as a hexahedrite by 
Pokrzywnicki (1959), the Ni value in analysis is within the range of 
the octahedrites. 

7. Western Arkansas. Merrill (1927) reported an analysis with 
a nickel value within the range of the hexahedrites but did not 
classify the meteorite. Merrill's published analysis is inconsistent 
with the structure of this specimen. Also the analysis of the mete- 
orite with which Merrill compared the analysis of the Western 
Arkansas was proved to be inaccurate. The Western Arkansas, 
therefore, is definitely not a hexahedrite. 



8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, 1 48 

PHENOMENA OF HEXAHEDRITE FALLS 
WITNESSED FALLS OF HEXAHEDRITES 

The first observed fall of a hexahedrite took place near Braunau, 
Czechoslovakia, in 1847, Since then, falls of five other hexahedrites 
have been witnessed. Six of the seven meteorites in table 2 fell 
north of the Equator in the Eastern Hemisphere, while one (Tandil) 
fell in the Western Hemisphere south of the Equator (table 2) , 

Since the two pieces of the Braunau iron, 22 and 17 kg., fell in 
1847, two other hexahedrites have been recovered within 100 miles 
of Braunau (see fig. 7), Perhaps, therefore, the 1847 fall was a 
shower of hexahedrites. 

Table 2. — Witnessed falls of hexahedrites arranged chronologically. 
(The Nedagolla iron, which is not a true 
hexahedrite, is included for comparison.) 

Name Country Date of fall and hour Coordinates 

Braunau Czechoslo- July 14, 1847—3 :45 a.m. 56.6° N. 16.3° E. 

vakia 

Nedagolla 1 ...India Jan. 23, 1870— 7:00 p.m. 18°41' N. 83°20' E. 

Okano Japan Apr. 7, 1904— 6:35 a.m. 35°4' N. 135°13'E. 

Avce Italy Mar. 31, 1908—8 :45 a.m. 46° N. 13.5° E. 

Boguslavka ...Siberia Oct. 18, 1916— 11 :47 a.m. 44°33' N. 131°38'E. 

Tandil Argentina Between 1916-1919— ? 37°17' S. 59°6' E. 

Sikhote-Alin ..Siberia Feb. 12, 1947— 10:38 a.m. 46°9.6' N. 134°39.2' E. 

1 See footnote 5 to table 1. 

Another interesting fact about these witnessed falls is that five 
occurred in the morning, with the Boguslavka iron falling only 13 
minutes before noon. The Nedagolla, which has structural features 
and a chemical composition unlike a hexahedrite, fell in the after- 
noon. The time of fall of the Tandil iron was not recorded. The 
fact that these irons, with the possible exception of the Tandil 
meteorite, fell in the morning may not be a coincidence, 

CLUSTERING OF HEXAHEDRITES 

The clustered occurrence of hexahedrites was once assumed to be 
due to transportation by man. Fletcher (1890) concluded that 
because iron meteorites were useful as anvils and for other purposes, 
man gathered them for use and later discarded them in places 
distant from where they fell. This point of view is no longer popu- 
lar either with those who study meteorites or with archeologists. 

In the late 19th century local concentrations of hexahedrites 



NO. 5 HEXAHEDRITES — HENDERSON 9 

prompted the question, "Are these irons related?" Farrington (1915) 
said : "Early writers are inclined to group into one fall similar 
meteorites, even though separated by thousands of miles of distance, 
but later observations have failed to confirm this view." 

Several widely scattered large hexahedrites are known from north- 
ern Mexico. Many of these have been sectioned and now are con- 
sidered to be parts of the Coahuila meteorite. Thus, names given to 
individual masses, such as Sanchez Estate, Hacienda, Potosi, Fort 
Duncan, etc., are now relegated to synonomy, and all are collectively 
known as the Coahuila meteorite. Farrington (1915) accepted the 
Coahuila group as a shower and said, "In the State of Coahuila, 
Mexico, numbers of meteoritic irons of a rare class, hexahedrites, are 
found one or two hundred miles apart. It hardly seems likely that 
separate falls of these rare meteorites would occur within such a 
limited area." 

Twenty-five hexahedrites have been found since Farrington wrote 
as he did in 1915. A number of these coincide with some of the 
geographic groupings noted by earlier writers. Of the new geo- 
graphic groups found since Farrington's time, the most important is 
the Chilean group. In general, the places where hexahedrites were 
found suggest the probability that they fell as showers. 

It is assumed that all the Coahuila meteorites come from latitude 
28°40' N. and longitude 102°50' W., a midpoint in the scatter of 
those specimens in northern Coahuila. Earlier writers even sug- 
gested that some hexahedrites from Virginia, Georgia, and Kentucl<y 
were related to the Coahuila irons. Although it is possible that the 
hexahedrites from these eastern States are part of the Coahuila 
shower, this study lists them as hexahedrites from southeastern 
United States (see table 6). 

If it is reasonable for Fletcher (1890) to regard the Coahuila irons 
as a shower, it would seem equally admissable to include some of 
the hexahedrites found slightly north and east of Coahuila in Texas 
and toward the Oklahoma border, as part of the same shower. 
Since the hexahedrites in this portion of Texas are as closely spaced 
as the hexahedrites in other geographic areas, they are grouped 
with the irons scattered around Coahuila (see table 5). 

MECHANISM FOR SCATTERING METEORITES 

The above distribution of hexahedrites would be accounted for if 
two or more large hexahedrites approached the earth on essentially 
parallel trajectories. Under these circumstances the second or third 



10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

masses to enter our atmosphere and fall would scatter pieces in 
different places from those where the first or second one fell. Thus, 
the distance between the strewn fields would depend upon the 
interval that separated the arrival of the individual masses into the 
atmosphere and upon the trajectories along which they were travel- 
ing. For meteorites to approach the earth in such a manner prob- 
ably would require the fragmentation of a larger object relatively 
close to the earth. Any mass fragmenting far out in space would 
scatter, and thus few pieces would have parallel orbits. 

Many spectacular fireballs have been tracked across North America, 
and from some of them meteorites have fallen. Since the distance 
traversed by some fireballs exceeds the distance over which clustered 
hexahedrites have been found scattered, a few of these events will 
be briefly reviewed. 

When Smith (1877) described the Rochester fireball of 1876, he 
may have considered a mechanism similar to that described above 
when he wrote : 

The Bolide made its appearance about 9 o'clock p.m., December 21, 1876, and 
was of extraordinary magnificence. It passed eastward over the States of 
Kansas, Missouri, Illinois, Indiana, Ohio, and parts of Pennsylvania and New 
York. Although no observations were made in the last two mentioned states, 
still Professor Kirwood is doubtless correct in defining this as its course. At 
Bloomington, its elevation was 15 degrees. According to the calculations, the 
length of its observed track was from lOOO to 1100 miles, one of the longest on 
record. Its height is supposed to have been 38 miles above the place where the 
small fragments fell from it. 

The Canadian fireball of February 9, 1913, which was named 
Cyrillid by O'Keefe (1961), also made an unusually long streak 
across the country. Detonations were heard all the way from 
Toronto, Ontario, to Towanda, Pa., a distance of 200 miles. If more 
observations had been collected immediately after its passage, this 
distance possibly would have been extended. O'Keefe quotes ob- 
servers as saying, "Before the astonishment aroused by the first 
meteor had subsided, other bodies were seen coming from the 
northwest, emerging from precisely the same place as the first one. 
Onward they moved, at the same deliberate pace, in twos or threes 
or fours, with trails streaming behind." 

The Pasamonte meteorite, which fell March 24, 1933, also made 
a brilliant display over several states. Nininger (1934) interviewed 
observers in the area from near Wichita, Kan., to New Mexico, where 
the specimens were recovered. This fireball was seen for approxi- 
mately 400 miles, but the objects known to have fallen from it are 
confined to a distance of about 4 miles. 



NO. 5 HEXAHEDRITES — HENDERSON II 

The three foregoing events happened within 57 years, and in two 
cases the observed flights extended 1,000 to 1,100 miles and 
about 400 miles, respectively. Witnesses of the 1913 fireball re- 
ported that more than one object was seen moving through the 
sky. Meteorites are usually considered to be single objects when 
they enter our atmosphere, but it appears on the basis of the 1913 
observation that several objects can enter the atmosphere at slightly 
different times and along the same trajectory. If more than one 
object was involved in the 1913 fireball, probably some were higher 
in the sky than others, although all appeared to be moving on the 
same or only slightly different trajectories. 

Before leaving the subject of fireballs, some comments seem neces- 
sary on recurring meteor showers that appear from year to year. 
Elliott (1804) wrote about the November 12, 1799, display as 
follows : 

November 12, 1799, about three o'clock a.m., I was called up to see the shooting 
stars. The phenomenon was grand and awful, the whole heavens appeared as if 
illuminated by sky rockets, which disappeared only by the light of the sun after 
daybreak. The meteors which appeared at any one instant as numerous as stars, 
flew in all possible directions except from the earth towards which they are 
inclined more or less, and some of them descended perpendicularly over the 
vessel we were in. So that I was in constant expectation of their falling among 
us. We were in latitude 25° N. and SE. of Kay Largo near the edge of the 
Gulph Stream. I have since been informed that the phenomenon extended over 
a large proportion of the West India Islands and as far north of Mary's in 
latitude 30°42', when it appeared as brilliant as with us off Cape Florida.^ 

Although it is frequently stated that meteorites do not fall from 
reappearing meteor showers, such as the Leonid showers in No- 
vember, this may be incorrect, for the records show that from 1800 
to the present time (January 1963), 43 meteorites have fallen in 
November. The greatest number of meteorites to fall on any day 
in November is 5, and this number fell on the 12th day of the month. 
Thus, until more information is available, we cannot be sure that 
these recurring meteor showers do not bring an occasional meteorite. 
However, one phenomenal shower like that observed in 1799 could 
have delivered most of these hexahedrites. 

Between 1800 and mid-1962, 218 meteorites fell and were 
recovered in August, September, October, and November. The 
distribution of these falls is shown in figure 2 by listing the year and 
the day of the month on which the fall occurred.^ The Bali, West 



1 Humboldt, the German naturalist, who was in South America in 1799, also 
observed this meteor display. 

- Seventeen falls were reported by year and month, but the day was not given. 



12 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



AUGUST 



SEPTEMBER 



I 

2 

3 

4 

5 

6 

7 

8 

9 

10 

II 

12 

13 

I — 15 
<I6 
Cl|7 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 
30 
31 



1835 1697 1698 1912 



1882 1946 



1835 1904 



|iei2 I [l855 I |ie56 I |l89e| I 1957 | 



|t822 I |ie23 I |l924| ||942| 



1863 1897 1933 1933 



I 1932 I 

[1862 I |ie97| 1 1956 I 



1875 1885 1928 



l'"6| 

1 1870 I |l942| 



|I902| ||932 1 




||900| |l950 1 




|iBeo| 




|l86S 1 ||865| 




|l93l 1 




|l925 1 ll925 1 




|ie78| |l892| 




11887 1 ||9I9 1 [l920 | 




|l872| [l96l I 



1905 1955 



1806 1935 1939 



1930 1952 



1612 1814 1854 1878 



1918 1925 



lieiS 1930 



1822 1902 1937 



1897 1910 



1843 1920 



1879 1937 



1869 1910 



1865 1934 



1887 1893 



I1945I 1.945 1 


|,949| 


|l949| |t949| 


|l936 1 |l944| 



[l938 I 



NO DATE : 1810, .826,1837, 1850, 1949, 1950. NO DATE: 1843,1875,1907,1930,1930,1933. 

Fig. 2A. — Meteorite falls by day of month. 



NO. 5 



HEXAHEDRITES — HENDERSON 



13 



OCTOBER 



NOVEMBER 



1868 1923 



1866 1924 1950 



1838 1852 1914 1959 



|l92l I 1 1951 I 



1886 1940 



|l904| |l905| 
I1944I 



l'<*9| Il95r I 



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I1949J |I952| 



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>24[ 



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ll877| 


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1822 


|l842| 


|l850| 


|l90l| 



NO date: 1916, 1930,1951. NO DATE: 1833,1959. 

Fig. 2B. — Meteorite falls by day of month (continued). 



14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I48 

Africa, meteorite fell in the morning hours of either the 22d or 23d 
of November 1907, hence is shovi^n midway between these dates. 
An inspection of figure 2 shows the following : 

1. The falls are not uniformly dispersed through these 122 days. 
Actually, on 32 days no meteorite falls were reported. 

2. The longest gap without falls is the 6th to 10th of November, 
the interval which precedes the reappearance of the Leonid showers. 

3. The greatest number of meteorites to fall on any date is 5, 
and this number fell on each of three days — August 5, October 13, 
and November 12 (see table 3B for detailed listing). 

If the witnessed meteorite falls are grouped into 10-day intervals 
between August 1 and November 30 (table 3A), the maximum 
number of falls, 23, occurs between August 1 and 9 ; the minimum 
number is 8, between November 1 and 9. 

GEOGRAPHICAL ANALYSIS OF HEXAHEDRITES 

The next step is to examine the distribution of the hexahedrites 
listed in table 1 to determine whether their scatter suggests random 
falls or a shower. The hexahedrites from the different continents 
have been plotted on maps, and their groupings will be discussed by 
geographic areas. 

NORTH AMERICA 

The irons from this continent group themselves into two or possibly 
three areas, with two stragglers located outside the main geographic 
concentrations. The stragglers, which occur in western United 
States, are discussed at the end of the section on North America. 

Western North America. — The four hexahedrites from the north- 
western portion of the United States and from part of nearby 
Canada are shown in table 4. These irons can be enclosed within 
an ellipse 875 miles long. Four is an insufficient number of 
specimens from an ellipse of this size to suggest a shower. Yet if the 
groupings of hexahedrites in other areas of the world are significant, 
this may become a promising area for future hexahedrite discoveries. 

Southern United States and northern Mexico. — Table 5 lists the 
specimens recovered in this part of the continent. Six were found 
in an area extending northeast from Coahuila, Mexico, across Texas 
to southern Oklahoma (fig. 3). This area can be enclosed by an 
ellipse with a long axis of about 500 miles. This distance, more 
than half the long axis of the group of four western hexahedrites 



NO. 5 



HEXAHEDRITES — HENDERSON 



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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



Table 4. — Data on hexahedrites from northern and western areas 
of United States and Canada arranged by latitude. 

Meteorite Date found Latitude Longitude 

Bennett County, S. Dak 1934 43° 28' N. 101° 9' W. 

Lombard, Mont ? 46° N. 111° 24' W. 

Bruno, Canada 1931 52° 16' N. 105° 21' W. 

Edmonton, Canada 1939 53° 35' N. 113° 30' W. 

(table 4), exceeds the scatter of stony meteorites from most of the 
witnessed falls by a factor between 50 and 100. The distance over 
which the hexahedrites are dispersed is a most difficult fact to 
account for in accepting the apparent clustering of these irons as 
evidence of a shower of meteorites. 

Only the Chico Mountain, Tex., iron requires further mention 
here. Acquired by the U. S. National Museum in 1915 from E. M. 




105' ioo» 950 

Fig. 3. — Geographic distribution of hexahedrites Hsted in table 5. 



NO. 5 HEXAHEDRITES — HENDERSON \'J 

Flynn of Alpine, Tex., it was described by Merrill in 1922 as the 
Alpine, Brewster County, meteorite. Although it is reported that 
the original body weighed nearly 2 tons, the piece accessioned in 
the national collections weighs only 212 grams. Apparently the 
main mass has vanished. 

Merrill's published picture shows that the specimen probably was 
reheated, but how and where this took place is not known. Actu- 
ally, the entire surface of the small specimen is granulated, but the 
texture of the zone near the surface is finer grained than that of the 
central part. There is no indication of either cleavage or Neumann 
lines. The chemical analysis Merrill reports is consistent with that 
of other hexahedrites, and Merrill suggested the possibility that this 
specimen is related to the Coahuila meteorite. 

Table 5. — Data on hexahedrites from Coahuila, Mexico, and Texas-Oklahoma 

arranged by latitude. 
Meteorite Date found Latitude Longitude 

Coahuila, Mexico 1837 28°40' N. lOZ^SO' W. 

Kendall County, Tex 1887 29°24' N. 98°30' W. 

Chico Mountain, Tex 1915 29° N. 103°15'W. 

Richland, Tex 1951 3r59' N. 96°14'W. 

Iredell, Tex 1898 31°58' N. 97°52' W. 

Soper, Okla 1938 34°5' N. 95°37' W. 

Southeastern United States. — The hexahedrites from this area are 
arranged in table 6 according to the increasing latitudes of their 
points of discovery. Figure 4 shows the arrangement on a map of 
all of these finds with the exception of the Cincinnati iron, the 
omission of which is explained below. The distance from the south- 
ernmost one, Tombigbee River, Ala., to the northernmost, Mt. 
Joy, Pa., is approximately 850 miles. This distance exceeds the 
length of the strewn fields of stony meteorite falls by a factor of 
nearly 100. 

Foote (1899) mentioned that six pieces of the Tombigbee River 
meteorite were found in nearly a straight line some 16 km. long, 
with the heaviest mass to the north. Similarly, the heaviest mete- 
orite in table 6, the Mt. Joy iron, is located in the northeastern end 
of the 850-mile ellipse. It is easier to assume that the 6 irons along 
a line 16 km. long are related as a shower than that all 19 meteorites 
came as a shower. But if the north and south alignment of the 
Tombigbee River iron is important, all the 19 meteorites perhaps 
should be regrouped into smaller clusters, more or less in a north- 
south direction. 



l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Both the Scottsville and Cincinnati irons He to the north and west 
of the oval area enclosing the other hexahedrites found in the zone 
lying- in a northeast-southwest direction. However, if the north- 
south alignment of the six Tombigbee River irons is important, and 
if the other hexahedrites are grouped into north and south clus- 
ters, then the Scottsville and Cincinnati irons fit better into the 
pattern with the other irons. 

Table 6. — Data on the hexahedrites from the southeastern area of the United 
States arranged by latitude. 

Weight, 
Meteorite kilograms Date found Latitude Longitude 

Tombigbee River, Ala 43.8 1858 32°13' N. 88°10'W. 

Auburn, Ala 3.5 1867 32°37' N. 85°32' W. 

Locust Grove, Ga 10.0 1857 33°20' N. 84°8' W. 

Walker County, Ala 75.0 1832 33°50' N. 87°15'W. 

Cedartown, Ga 11.3 1898 34°0' N. 85°16'W. 

Smithonia, Ga 69.8 1940 34°0' N. 83=11' W. 

Aragon, Ga. (Cedartown) 1. .. . (5gm.) 1898 34°1' N. 85°3' W. 

Summit, Ala 1 1890 34°15'N. 86°25' W. 

Holland's Store, Ga 12.5 1887 34°21' N. 85°23' W. 

Chesterville, S. C 16.3 1849 34°43' N. 81°13'W. 

Lick Creek, N. C 7.7 1899 35°5' N. 84°2' W. 

Murphy, N. C 1.2 1879 35°40' N. 80°16' W. 

Forsyth County, N. C 22.5 1891 36°1' N. 80°2' W. 

Mayodan, N. C 15.4 1920 36°23' N. 79°52'W. 

Scottsville, Ky 10.0 1867 36°46' N. 86°10'W. 

Indian Valley, Va 14.2 1887 36°55' N. 80°30' W. 

Keen Mountain, Va 6.6 1950 37°13' N. 82°0' W. 

Cincinnati, Ohio (250 gm.) 1870 39°7' N. 84°30' W. 

Mt. Joy, Pa 385 1887 39°47' N. 77°13'W. 

^ Synonym. 

Little is known about the Scottsville iron except that it was found 
in 1878, identified and described by Whitfield in 1887. There is 
no reason to suspect that it had been transported and abandoned 
by man. 

The Cincinnati iron, which was found near a dwelling house in 
Cincinnati in 1870, was probably carried there by man from where 
it fell. The few specimens of this meteorite that are preserved 
suggest that it was small and easily transportable. Henderson and 
Perry (1958) found it to be a reheated specimen with a composition 
in the range of other hexahedrites. Because of its size and the fact 
that it is unlikely to have fallen in Cincinnati, this specimen is 
unimportant in this study. 



NO. 5 



HEXAHEDRITES HENDERSON 



19 



The Keen Mountain, Va., specimen appears to be much younger 
than the others. Henderson and Perry (1958) assumed that this 
meteorite was a relatively recent fall because it had a fresh-looking 
black fusion crust with flight markings. Sections cut through one 
end showed numerous small open fractures extending into the interior 




82° 



80 



92' 90 8^ 86^ 84" 

Fig. 4. — Geographic distribution of hexahedrites in table 6. The Cincinnati 
iron is omitted for reasons given on page 18. 



only slightly farther than the thermally heated zone around its 
surface. Since these fractures contain little brown iron oxide and 
since this oxide is poorly consolidated, it was estimated by Gordon 
Davis (personal communication) and Henderson and Perry (1958) 
that the meteorite may have fallen between 1940 and 1950. Using 
Ar^® measurements, Vilcsek and Wanke (1962) reported the time 
of fall to be about 900 years ago. 



20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

H. Wanke commented as follows about the Keen Mountain iron 
in private communications: "The terrestrial age of this meteorite 
according to argon-39 and chlorine-36 measurements is 1100 ±200 
years. I had a little problem with my standards, but this definitely 
would not change the value of the terrestrial age more than 200 
years. The argon-39 content of this meteorite is so low that it 
must have been 3 half-lives of argon (T^ = 325 years) on the ground." 
A statement based on a measurement should be superior to an opinion 
about the time needed to alter a fresh flight crust from black to brown. 
However, 900 years seems a long time for fresh flight crust to survive 
in a climate as damp as that of Virginia. This iron may be an example 
of a hexahedrite falling into a cluster of an old hexahedrite fall. 

The Walker County, Ala., iron was found in 1832, which makes 
it the first of this group to be discovered. The data on it came from 
Farrington's (1915) translation of Cohen's discussion in Meteoriten- 
kunde (1903) : "an iron mass of 75 kg. weight was found in 1832 in 
the northeast corner of Walker County, by a hunter living in Morgan 
County who preserved it in his house until 1843, ... It was of 
an irregular oval form, with a smooth exterior covered with a thick 
coating of rust. . , ." 

The alteration (rust) on the Walker County iron might mean a 
long terrestrial exposure. However, rust could have formed during 
the 10 years the specimen was stored in the cabin. Some irons 
exposed to high humidities corrode faster than ones remaining out- 
doors where the rain washes off the iron chlorides. Hence, the rust 
in this instance could represent corrosion products formed within a 
few years. 

The New Baltimore and the Pittsburgh irons should be mentioned 
here even though they are not listed in table 6. These meteorites and 
the Mt. Joy iron were found in a straight line across Pennsylvania, 
and suggested to R, W. Stone (1932) that they were related. A sub- 
sequent investigation by Henderson and Perry (1958) indicates that 
these are unrelated meteorites. 

The unique feature of the New Baltimore iron is the large inclusion, 
about 5x6 cm., with an octahedral pattern enclosed by large kamacite 
grains. The kamacite grains display well-developed, undisturbed 
Neumann lines, indicating that this kamacite was neither heated nor 
deformed since these lines formed. 

It is difficult to explain the mechanism that produces a meteorite 
with two different types of Ni-Fe alloys in contact with each other. 
The possibility of the octahedrite colliding with and penetrating a 



NO. 5 HEXAHEDRITES — HENDERSON 21 

hexahedrite must be considered. However, if a hexahedrite were 
struck in space by an oncoming octahedrite, both the target and the 
impacting object would probably show deformation resulting from 
their collision. In this meteorite, neither part is deformed. Although 
collisions between meteorites must have taken place in space, this 
specimen lacks the most important features one would expect if one 
iron meteorite penetrated another. 

Hexahedrite stragglers in western North America. — Three isolated 
hexahedrites from the western part of the continent remain to be 
considered. 

1. The Wathena, Doniphan County, Kans., iron. This 556-gram 
iron (Henderson and Perry, 1949) was found in 1939 near Wathena, 
Kans., in a locality about 400 miles northeast of the nearest grouping 
of hexahedrites. Since no other hexahedrites have been found in the 
intermediate area, the Wathena iron is assumed not to be associated 
with the foregoing groups. 

2. The Pima County, Ariz., iron. This 210-gram mass is reported 
as having been found before 1947 near Tucson, Ariz. Nothing is 
known of its history except that it was at the University of 
Arizona for many years before it was accessioned into the national 
collections and described by Henderson and Perry (1949). It has 
exceptionally well developed flight surfaces. Although this strange- 
looking specimen is small enough to have been easily carried by man, 
it is thought probable that it fell where it was found, near Tucson. 

3. Chico Mountain, Brewster County, Tex., iron. The 212-gram 
specimen in the National Museum apparently is all that remains of 
what was reported to be a 2-ton meteorite. So little is known about 
the history of this iron, and since it was found west of the area in 
which the meteorites listed in table 5 were found, the Chico Mountain 
iron is grouped with the stragglers. 

SOUTH AMERICA 

Chile 

The hexahedrites from Chile are given in table 7, arranged by their 
increasing latitudes, and plotted on the map in figure 5. Henderson 
(1941) reported that these irons may represent a shower. On the 
other hand, the finding of these irons aligned along a railroad could be 
due to the fact that the exploration in this region followed the course 
of the railroad. Nitrates were hauled to the railroad for shipment, and 
the included irons could have been rejected from the ore before 



22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

shipment. Also, the coordinates of the Chilean hexahedrites may be 
less accurately recorded than those of the American meteorites. 

Thirteen hexahedrites are known from between latitudes 20° and 
24° S., while twelve octahedrites were recovered between approxi- 
mately the same northernmost latitude and 27° S. This is an unusually 
high proportion of hexahedrites to octahedrites. No hexahedrites are 
reported south of latitude 24° S., whereas four octahedrites were 
found there, one of which comes from a point as far south as 33° 30' S. 
No search has been made for meteorites in the area south of latitude 
27°. 

Table 7. — Data on hexahedrites from Chile arranged by latitude. 

Weight, 
Name kilograms Latitude Longitude 

La Primitive (Angela)i 21.5 19°55' S. 69°49' W. 

Negrillos 28.5 20°12' S. 70°10'W. 

Rio Loa 4.0 2r26' S. 70°5' W. 

Quillagua 78.0 2r36' S. 69°32' W. 

San Martin 29.0 22°20' S. 69°45'W. 

Coya Norte 17.0 22°20' S. 69°40'W. 

Union 22.0 22°30' S. 69°30' W. 

Tocopilla 75.0 22°40'S. 69°50'W. 

Sierra Gorda 22.0 22°54' S. 69°21' W. 

Filomena 20.7 23°0' S. 69°24' W. 

Mejillones (1875) (large) 23°7' S. 70°29' W. 

Mejillones (1905) 14.5 23°7' S. 70°29' W. 

Puripica 19.0 23°41' S. 70°15'W. 

1 Synonym. 

Northern Chile is an arid region, while to the south the land is more 
suitable for agriculture. In northern Chile, owing to the extensive 
niter mining, more of the land surface has been scraped and sorted 
than elsewhere. Thus, large, heavy objects, such as iron meteorites, 
have a good chance of being recovered. 

A comparison of statistics on meteorites from two widely separated 
geographic areas may be criticized because climate, topography, 
population density, and the uses made of the land have a bearing on 
the recovery of meteorites. Nevertheless, an area in the United 
States — Georgia and South Carolina — where a noticeable concentra- 
tion of hexahedrites occurs, has been compared to northern Chile in 
table 8. 

Georgia and South Carolina together make an area about 1.5 times 
that of northern Chile, yet more than 3 times as many hexahedrites 
are reported from Chile as from the larger area in the United States. 



NO. 5 



HEXAHEDRITES — HENDERSON 



23 




72» 70" GQ" 66" 

Fig. S. — Geographic distribution of hexahedrites in table 7. 

Ten octahedrites are known from northern Chile, but twelve came 
from Georgia and South Carolina. The conspicuous difference be- 
tween the two areas is in the stony meteorites. All six of the stony 
meteorites from this part of the United States were observed falls, 
while the one stone from northern Chile was a find. This difference 
may be due to the fact that the population density of the Chilean area 
is far lower than in our two states, obviously making it easier for a 



Table 8. — Comparison of areas in which hexahedrites are abundant. 

Area in 
square miles 

Northern Chile.... 60,000 

Georgia 59,000 

South Carolina.... 31,000 



Total 
eteorites 


Hexa- 
hedrites 


Octa- 
hedrites 


Ataxites 


Stones 


26 


13 


10 


2 


1 


17 


3 


9 


1 


4 


6 


1 


3 





2 



24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

meteorite to fall unnoticed in Chile, How these two localities would 
compare if both were as effectively prospected is problematic. 

The arid climate of northern Chile favors preservation of mete- 
orites. Stony meteorites from there should be less contaminated than 
those recovered from more humid areas because, without water, 
contamination is less likely to penetrate a meteorite. However, 
exposed meteorites in arid places can suffer from another type of 
weathering — wind ablation, which, in time, could be an effective way 
of obliterating a meteorite. Some irons from arid regions have 
sculptured surfaces that demonstrate how one constituent is ablated 
faster than another. Wind ablation is relatively rapid compared with 
chemical weathering in arid areas. The products of mechanical 
ablation might be confused with meteoritic dust, because undoubtedly 
some of the metallic iron is removed and accumulates in the wind- 
blown silt. 

Many years ago the author called to C. A. Bauer's attention the 
possible identity of the northern Chilean hexahedrites and later 
furnished him with specimens for study. These specimens apparently 
were later turned over to Signer and Nier (1962), whose measure- 
ments are presented in tables 9 and 10, although in a somewhat 
different order so as to arrange the meteorites in their order of 
increasing latitude. 

Signer and Nier (1962), in discussing the possibility of these 
Chilean irons being a common fall, said : 

Due to the low concentration of cosmogenic rare gases in these samples, the rela- 
tive errors in these measurements may be somewhat higher than the 5% found 
for most other measurements ; unfortunately, the samples available were so small 
that only a single analysis was possible and therefore, no check of reproducibility 
could be made. With this reservation, it seems possible that the Tocopilla, Coya 
Norte and Rio Loa belong to the same fall. Negrillos, however, appears to 
belong to a different fall. It should be mentioned that by nature of the inter- 
pretation two meteorites could by coincidence appear to belong to the same fall. 
The converse does not appear possible. 

The overall scatter of the Chilean hexahedrites extends from about 
20° to 24° S. latitude, while the three irons that Signer and Nier 
suspected of being related He between 21°26' and 22°40' S. latitude. 
Thus, the Rio Loa, Coya Norte, and Tocopilla are confined within 
about 70 miles of the overall spread of about 240 miles for these 
Chilean hexahedrites. 



NO. 5 



HEXAHEDRITES — HENDERSON 



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26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

ARGENTINA 

Only two hexahedrites, the Otumpa and the Tandil, are recorded 
from Argentina. A field investigation recently was made in the area 
of the Otumpa meteorite (Campo del Cielo) by the Lamont Geo- 
logical Observatory under the leadership of Dr. William A. Cassidy. 
Dr. Daniel J. Milton of the U. S. Geological Survey, associated with 
Dr. Cassidy in the meteorite studies in Argentina, reports the follow- 
ing: Seven impact craters have been identified distributed along a 
single line about 18 km. long trending N. 60° E.,S. 60° W. Careful 
search in one area near the middle of this line indicates that a zone of 
abundant meteorites (many thousands per square kilometer) have the 
same ENE-WSW orientation and a width of about 3 kilometers, . . . 
In addition, a hexahedrite of 7 kg. has been found 65 kilometers N. 
60° E. of the northeasternmost crater. The intervening distance has 
not yet been investigated. Locating this on a map, the middle of the 
crater line is about 27°35' S. and 61°40' W. with the westernmost 
crater in the Province of Santiago del Estero. The isolated iron comes 
from approximately 27°23' S., 61° 5' W." 

The Tandil iron is reported as a witnessed fall, although the details 
about this fall and its discovery are not satisfactorily documented. 
If this iron was seen to fall, its geographic relationship with the 
Otumpa specimens is accidental, 

AUSTRALIA 

Four of the five Australian hexahedrites listed in table 11 and 
plotted on the map in figure 6 show a narrow geographic grouping. 
These irons were found along a north and south line about 35 miles 
long — the direction in which the Tombigbee River (Alabama) and 
Chilean irons were aligned. However, in Chile, it would be impossible 
to align that many meteorites in any direction other than north and 
south. 

Table 11. — Data on Australian hexahedrites. 

Weight, 
Meteorite Date found kilograms Coordinates 

Bingara 1 1 1880 (240.7 gms.) 29°53' S. 150°34' E. 

Bingara 2 1924 6.4 9 miles north of No. 1 

Bingara 3 (Barraba) unknown 1.34 30°25' S. 150°37' E. 

Bingara 4 (Warialda) 1919 2.5 29°34' S. 150°3S' E. 

Yarroweyah 1903 9.5 35°59' S. 145°35' E. 

1 The spelling of Bingara varies, in some places appearing as Bingera. 



NO. 5 



HEXAHEDRITES — HENDERSON 



27 



Although the Yarroweyah iron was found a long way from the 
other four Australian hexahedrites, all five can be enclosed within 
an ellipse approximately 450 miles long. There would be no reason 
to associate the Yarroweyah iron with the Bingara group were it not 
for the fact that the hexahedrite grouping in the other parts of the 
world extends a similar distance. Disregarding the Yarroweyah iron, 
the distribution of the four Bingara specimens shows that they must 
be related. However, the ellipse enclosing all the Australian hexa- 





I20» 130" 


140° ISO" 






/I 


p^ 


X 


)\ 




20» 


• 1 


t 


















30° 






f~ 











20» 



30" 



110" 120° 130° 140° 150 

Fig. 6. — Geographic distribution of hexahedrites in table 11. 



hedrites exceeds the area in which fragments are scattered in observed 
falls of meteorites. 

EUROPE 

Since man used iron much earlier in Europe than in the Americas, 
Australia, or Africa, one might suspect that many of the European 
meteorites were transplanted or consumed by the early peoples. If 
this is true, the listing of the specimens in table 12 and the plotting of 
these on the map in figvire 7 may not be reliable. 

Two hexahedrites, Opava and Nenntmannsdorf, were found ap- 
proximately 100 miles apart and close to where the Braunau mete- 
orite fell in 1847. Since these three hexahedrites were found so close 
together, it seems likely that they fell as a shower. 



28 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



Generally speaking, all the hexahedrites found in central Europe, 
Spain, and Russia follow a pattern of alignment which is also 
characteristic of those found from Mexico to Oklahoma and from 
Alabama to Pennsylvania and is also evident in those discoveries in 

Table 12. — Data on European hexahedrites. 



Weight, 
Meteorite Date found kilograms 

Opava, Czechoslovakia 1925 14.3 

Nenntmannsdorf, Saxony. 1872 12.5 

Braunau, Czechoslovakia. 1847 (observed 39. 

fall) 

Hressk, Russia 1 1954 11.9 

Villanueva del Fresno, 

Spain Not given (Not given) 

1 Also spelled Gressk. 



Coordinates 

49°58' N. 17°54' E. 
50°S8' N. 15°57' E. 
50°36'N. 16°18'E. 

53»14'N. 27'20.5'E. 

38°24' N. 3°26' W. 




P'iG. 7. — Geographic distribution of hexahedrites in table 12. 

Argentina and Australia. This agreement — alignment in a north- 
east-southwest direction — would not seem to be merely coincidence. 



AFRICA 



Although only six African hexahedrites are known (table 13; fig. 
8), two pairs occur sufficiently close together to suggest that they fell 
as separate showers. These are the Bellsbank and Hex River irons 
in South Africa and the Chinguetti and Siratik in northwest Africa. 



NO, 



HEXAHEDRITES — HENDERSON 



29 



Table 13. — Data on African hcxahedrites. 



Meteorite Date found 

Aswan, Egypt 1955 

Chinguetti, French West Africa. 1920 
Siratik, French West Africa... 1716 

Uwet, Nigeria 1903 

Bellsbank, South Africa 1955 

Hex River, South Africa 1882 



Weight, 
kilograms 


Coordinates 


12 


23^59' N. 


32°37' E. 


? 


20°15' N. 


12°41'W 


1.7 


14° N. 


11° W. 


54 


5°17' N. 


8°15'E. 


38 


28°18' S. 


24°15'E. 


60 


33°19'S. 


19°37' E. 




10° 0° 10° 20° 30° 40° 

Fig. 8. — Geographic distribution of hcxahedrites in table 13. 



A YET UNEXPLAINED DISTRIBUTION PATTERN 

If a line is drawn on a globe, extending northeasterly from where 
the Tandil, Argentina iron was found through the places listed in 
Table 14, it forms an arc which extends almost one quarter the 



59no' 


W 


60°35' 


W 


46°30' 


W 


11° 


w 


12°41' 


w 


3°26' 


E. 


17°54' 


E. 


lens' 


E. 


15°57' 


E. 


27°20.5 


'E. 



30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

distance of a great circle, and it passes through Braunau, Czechoslo- 
vakia, where a hexahedrite fell in 1847. 

For what significance it may have, attention is called to two other 
pairs of hexahedrites, Uwet, Nigeria and Aswan, Egypt, and the Hex 
River and Bellsbank irons in South Africa, which if connected in 
this order form two lines which are essentially parallel to the one pass- 
ing through the places in Table 14 where the 10 hexahedrites were 
found. 

Table 14. — A Yet Unexplained Distribution Pattern. 

Meteorite Coordinates 

Tandil, Argentina 37°18' S. 

Otumpa, Argentina 27°28' S. 

Corrego de Arede, Brazil 18°35' S. 

Siratik, Mauretania, Africa 14" N, 

Chinguette, Mauretania, Africa 20°15' N, 

Villanueva del Fresne, Spain 38°24' N. 

Opava, Czechoslovakia 49°S8' N. 

Braunau, Czechoslovakia 50°36' N. 

Nenntmannsdorf, Saxony 50°58' N. 

Hressk, U.S.S.R 53°14' N. 

ROLE OF EARLY MAN IN THE DISTRIBUTION OF 
HEXAHEDRITES 

Few iron meteorites other than witnessed falls are known from 
India and Spain. The reason may be that man found and used them. 
As stated previously, man used iron in Asia and Europe long before 
he did in America, Australia, and Africa, yet early North American 
man is known to have fashioned some things from iron meteorites 
and to have transported pieces of others from where they fell to his 
campsites. Previously it was mentioned that the distribution of the 
Coahuila meteorite is attributed to man. If some meteorites were 
scattered in this way, man may have effected the distribution of some 
of the other hexahedrites listed in table 5. 

The fact that the hexahedrites ranging from Texas northeastward 
to Oklahoma are located in an oval provides good reason to believe 
that man had little to do with them. In this region, there are no 
natural barriers to prevent him from moving in a north-south or east- 
west direction any more than in the direction these hexahedrites are 
scattered. Furthermore, archeological studies in Texas (Shum and 
Krieger, 1954) show no relationship between the oval area enclosing 
the places where the hexahedrites were found and the culture pattern 
of early man in Texas. 



NO. 5 HEXAHEDRITES — HENDERSON 3I 

Recent archeological work in northern Mexico has demonstrated 
that the cultural relationships of Chihuahua, Coahuila, eastern Texas, 
New Mexico, and Arizona are directly connected to influences out of 
the high culture area of the \^alley of Mexico, and that relationships 
of Mexico and the southeastern part of the United States are along 
the Gulf Coast and up the Mississippi and its southern tributary, the 
Red River. From an archeological standpoint, the evidence suggests 
that man could not have distributed the hexahedrites in Texas over 
their oval pattern.^ 

American Indians chipped fragments from some large meteorites 
prior to the time modern man discovered the specimens. The Hope- 
well Mound Builders apparently transported small pieces of several 
different types of meteorites considerable distances. At some of the 
Ohio Mounds, several different types of meteorites have been identi- 
fied, and at Havana, 111., meteoritic iron was found fashioned into 
beads. The Casas Grandes, Mexico, iron, which was excavated from 
the ruins of a temple, was incased in wrappings similar to those sur- 
rounding the bodies found in neighboring graves. 

To cite more meteorites which man obviously has transported seems 
unnecessary, as this study is limited to hexahedrites and only a small 
proportion of these irons seems to have been disturbed by man (see 
page 5). Furthermore, since many of the hexahedrites come from 
limited geographic areas, transportation by man would seem to have 
been negligible. If man was a factor, why would he concentrate these 
irons rather than disperse them? To argue that man moved these 
meteorites outward from a central spot strengthens the point that 
hexahedrites have a peculiar worldwide distribution. 

THE PROBABLE GEOGRAPHIC ABUNDANCE OF 
HEXAHEDRITES 

It can be argued that hexahedrites are equally abundant everywhere 
and that chance recovery is responsible for the pattern indicating 
fallout from showers. The best counterargument is the worldwide 
scatter of hexaliedrites, which indicates that they frequently are con- 
centrated into limited areas. 

It can also be argued that possibly in certain localities we are dealing 
with a hexahedrite shower along with one or two single hexahedrite 
falls. Until the terrestrial ages of meteorites are better understood, 
it is impossible to assess the validity of such an assumption. 



3 Personal communications from Dr. Clifford Evans, Jr., curator of the 
division of archeology', U. S. National Museum. 



32 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Six hexahedrites were seen to fall in the last 115 years. Relating 
this figure to an assumption that perhaps the known meteorites are 
those which fell in the past 10,000 years, by extrapolation, between 
500 and 550 hexahedrites should have accumulated in this period. If 
this assumption is valid, less than 20 percent of all the hexahedrites 
have been found. 

Although the area of the surface of the earth is slightly less than 
200,000,000 square miles, only about 57,510,000 square miles of this 
is land. No consideration has been given to the hexahedrites which 
possibly fell into the water nor to the fact that only a small percentage 
of the land surface is effectively observed for meteorite showers. The 
above figures were obtained, assuming just 6 hexahedrites fell in the 
last 115 years, and surely there were more. 

If 550 hexahedrites have fallen, and if these were equally scattered 
over the land surface, there would be one to about every 100,000 
square miles of land surface. When the area of the places shown in 
table 8 is compared with this figure (100,000), or if the areas of the 
localities where hexahedrites seem to be concentrated are compared 
to this figure, the conclusion is that these particular meteorites are far 
from being in random distribution. 

INTERFERENCE OF PHOSPHORUS WITH METEORITE 
STRUCTURES 

Iron meteorites that contain considerable amounts of phosphorus 
often have strange structures. When the schreibersite develops a 
skeleton structure, such as that shown in the Lake Murray and other 
similar meteorites, the kamacite grains enclosing the phosphide body 
become large and equidimensional. Such kamacite grains interfere 
with the normal development of the structure in the meteorite. Four 
meteorites with large phosphide inclusions are shown in plates 1-4. 
Tombigbee River and Bellsbank are hexahedrites, and Santa Luzia, 
Sao Juliao de Moreira, and Lake Murray are coarse octahedrites. 

Apparently no chemical analysis is available for the Lake Murray 
iron, and erratic nickel values will be obtained if the samples selected 
for study come from certain parts of the iron. In an area adjacent 
to the large schreibersite bodies, the nickel will be lower than in the 
kamacite some distance from these phosphide bodies. 

The nickel values in the kamacite around the schreibersite in the 
Tombigbee River iron are lower than the kamacite more remote from 
the phosphide bodies (Henderson and Perry, 1958). Similar results 



NO. 5 IlEXAHEDRITES — HENDERSON 33 

were obtained in some unpublished work on other meteorites at the 
U. S. National Museum. 

The Lake Murray, Okla., iron (pi. 1), shows an octahedral pattern 
with kamacite bands more than 1 cm. wide, but where the large 
skeletal growths of schreibersite form, the octahedral structure in the 
matrix is disrupted. The dark square areas are patches applied to 
protect troilite from being attacked by the etchant. Modern etching 
techniques have found this precaution unnecessary. 

The Bellsbank, South Africa, iron (pi. 2), is a hexahedrite with 
large schreibersite inclusions. The thin lamellae at the left intersect 
each other at a variety of angles and are filled with an alteration 
product. The Neumann lines in the kamacite extend to the breaks, 
then continue on the other side of the lamellae without a change of 
direction. Along these lamellae the kamacite is clear, compared with 
the kamacite more remote from them. 

The kamacite surrounding the schreibersite in the Bellsbank iron 
also is slightly lighter in color than the kamacite remote from the 
phosphide bodies. If iron is rejected from schreibersite as the 
temperature falls, of if nickel from the surrounding kamacite enters 
the phosphide in preference to iron, this may explain the clear 
kamacite. 

The Santa Luzia, Brazil, meteorite (pi. 3), like the Lake Murray, 
Okla., iron, is a coarse octahedrite with wide kamacite bands, some 
about 1 cm. wide. However, when schreibersite forms a skeletal 
habit, the enclosing kamacite becomes equidimensional, and such 
kamacite bodies disrupt the octahedral pattern. Since the slice 
illustrated is 0.5 cm. thick, and this schreibersite body is about 
equally large on both sides of the slice, it probably continued into 
adjoining slices, thus some conception of its size can be made. 

The dark triangular area in the central phosphide body is troilite. 
In places, the troilite makes a direct contact with the schreibersite ; 
elsewhere, it is in direct contact with the kamacite. Schreibersite more 
commonly occurs surrounding the troilite. 

The Central Missouri iron (pi. 4) was found between 1850 and 
1860, but the chemical analysis given by Preston (1900) does not 
appear to be reliable. After Perry (1944) reexamined this iron, he 
considered it to be a granular hexahedrite and placed it in the 
transitional zone between coarse octahedrites and hexahedrites. The 
Central Missouri iron resembles very closely the Ainsworth, Nebr., 
meteorite. Both contain large skeletal schreibersites and some 
alteration products in the fractures separating the coarse kamacite 



34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

grains. Howell (1908) reports that the 10.64-kg. Ainsworth iron was 
found beside a creek in Brown County, Nebr., about 6 miles north- 
west of Ainsworth. His analysis gave 6.49 percent Ni, which, although 
high for a hexahedrite, may be essentially correct because meteorites 
with these phosphide inclusions can give a wide range of nickel values 
depending upon the area selected for study. 

PHYSICAL CHARACTERISTICS RELATIVE TO THE FALLS 
OF HEXAHEDRITES 

CLEAVAGE IN HEXAHEDRITES 

The cubical cleavage in hexahedrites may have an important 
bearing on their geographical distribution. Two pieces of the Bogus- 
slavka, Siberia, iron were found about 1,700 feet apart, yet they 
fitted together, Thus, this hexahedrite was split, near the end of its 
high- velocity flight, comparatively close to the earth while falling 
nearly vertically. 

Any large piece produced by fragmentation of a larger hexahedrite 
mass will be covered with cleavage surfaces. Also, it will have large 
open cleavages and numerous small ones extending inward from its 
surface. While such an irregularly shaped body is in space, the 
poorly bonded pieces remain attached, but upon entry into our 
atmosphere, conditions change. When the mass meets appreciable 
atmospheric resistance, chunks cleave off. Small pieces will decelerate 
quickly and may fall unnoticed, while the large mass may blaze its 
way across the sky for hundreds of miles before falling to earth. 
Hence, many of the cleavages in a hexahedrite approaching the earth 
will part, causing fragments to separate. Because of this, more pieces 
may break off from a hexahedrite than from a stony meteorite or 
from other types of irons. It is said that an iron meteorite is more 
likely to survive its flight in the atmosphere than a stony meteorite, 
and conversely, that a stony meteorite is more likely to break in 
flight than an iron. Because of the cleavages in hexahedrites, there 
is some doubt about the survival of hexahedrites in flight. Thus, 
cleavages in this group of irons may account for their geographic 
distribution. 

SIZE DISTRIBUTION OF HEXAHEDRITES 

Data on the masses of hexahedrites have been summarized in table 
15. Most of the large hexahedrites were never weighed; therefore 
the weight estimates reported may be inaccurate. Ten of these irons 
are said to have exceeded 100 kgs., but none of the 10 is as large as 



NO. 5 



HEXAHEDRITES HENDERSON 



35 



the giants in the octahedrite and ataxite groups. Surely, hexahedrites 
are neither easier nor harder to find than other types of irons. 
Possibly the limited range in their chemical composition restricted 
their number; nevertheless, if chemical composition limited their 
number, it could have no effect on their distribution. 

Table IS. — Hexahedrites arranged according to their weights. 



Weights of more than 1000 kg. : 
Chico 1 Navajo 

Coahuila 2 Otumpa ^ 

Weights between 500 and 100 kg. : 
Boguslavka Mt. Joy 

Weights between 100 and 50 kg. : 

Bennett County Smithonia 

Hex River Tocopilla 

Quillagua Uwet 



Sikhote Alin * 



Walker County 



Weights less than 50 kg. : 






Auburn 


Chesterville 


Iredell 


Aswan 


Cincinnati 


Keen Mountain 


Avce 


Corrego do Areado 


Kendall County 


Barraba 


Coya Norte 


La Primitiva 


Bellsbank 


Edmonton 


Lick Creek 


Bingara 


Filomena 


Locust Grove 


Braunau 


Forsyth County 


Lombard 


Bruno 


Holland's Store 


Mayodan 


Cedartown 


Hressk (Gressk) 


Mejillones (1905) (1875) 


Central Missouri 


Indian Valley 


Murphy 


(Nedagolla?) 


Richland 


Tandil 


Negrillos 


Rio Loa 


Tombigbee River 


Nenntmannsdorf 


San Francisco del 
Mezquital 


Union 


Okano 


San Martin 


Villaneuva del Fresno 


Opava 


Scottsville 


Warialda 


Pima County 


Sierro Gorda 


Wathena 


Pirapora 


Soper 


Yarroweyah 


Puripica 


Summitt 





1 Said to weigh about 2 tons. 

- Several masses larger than 1000 kg. and many smaller pieces in excess of 
100 kg. 
^ Many individuals, total weight in excess of 15 tons. 
■* Many tons. 



ANGLE OF APPROACH 

If a hexahedrite entered our atmosphere at a lov^ angle, the 
fractured material on its surface would separate, and the fragments 



36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

that survive the passage through the atmosphere would fall far short 
of the main mass. The large body would go much farther into our 
atmosphere before further breaking up or would fall to the ground 
intact. The widely scattered geographic groups of hexahedrites must 
be explained by some process that brings one large mass or a cluster 
of separate similar irons along a trajectory that has a low angle of 
approach to the earth. Chance recovery of hexahedrites does not 
explain the distribution of these meteorites. 

INCLUSIONS 

As far as we know, hexahedrites have the same metallic inclusions 
as octahedrites with the exception of cohenite, which is relatively 
abundant in octahedrites but quite rare in hexahedrites. The reason 
being that iron carbide is more soluble in gamma iron (taenite) than 
in alpha iron (kamacite), the chief constituent of hexahedrites. 

The absence of any appreciable silicate inclusions also may be 
significant. Although the Spanish meteorite Colomera was classified 
as a hexahedrite with silicate inclusions, a restudy showed it to have 
an octahedral pattern and a composition in the octahedrite range. 
Since the included silicate is olivine, the Colomera iron may be a 
pallasite, but the 151-gram sample in the U. S. National Museum is 
too small to be useful in typing a meteorite weighing 134 kg. 

RADIATION AGES OF HEXAHEDRITES AND OCTAHEDRITES 
AND TIME OF DAY OF FALLS 

Wanke (1960) noted that by plotting the log N^e against radius, 
all meteorites with the same radiation age lie on a straight line. 
Wanke's plot shows that nearly all the octahedrites lie in a narrow 
band and thus may have the same radiation age, but that the hexa- 
hedrites and ataxites lie definitely lower and thus may have a different 
history. 

Wanke also observed that octahedrites fell between 12 and 24 
hours of the day, whereas hexahedrites fell between 2 and 12 hours, 
or during the morning. 

SUMMARY 

Seventy hexahedrites are considered in this study. Some of those 
listed in the Prior-Hey (1952) catalog were omitted because they 
were incorrectly classified in their original descriptions. When speci- 
mens were unavailable for study, it was necessary to rely either upon 
the author's notes made during visits to other collections, upon 



NO. 5 HEXAHEDRITES — HENDERSON 37 

published analyses, or upon an interpretation of pictures showing the 
metallography of the meteorites. When a seemingly reliable analysis 
reported more than 6 percent nickel, or when a picture showed either 
plessite or taenite in abundance, the meteorite was no longer con- 
sidered to be a hexahedrite. If neither a picture nor an analysis of the 
iron was available, the Prior-Hey classification or the original descrip- 
tion was accepted. 

Obviously the hexahedrites are not scattered at random over the 
world. Unfortunately, at this time we do not know how other types 
of meteorites are distributed. Formerly it was assumed that a shower 
of iron meteorites would scatter like the stony ones. However, the 
evidence here presented suggests that hexahedrites have a different 
fallout pattern from that of stony meteorites, but for reasons not yet 
known. 

Because the four hexahedrites located in Canada and our adjacent 
northern States are so widely separated that they do not make a 
convincing case for a meteorite shower, they were not counted. Table 
16 gives the number of hexahedrites in each of the areas where 
evidence exists that a shower of hexahedrites occurred. The hexa- 
hedrites from Chile, southeastern United States, Europe, two places 
in Africa, and Argentina seem to be geographically grouped in a 
fallout pattern. 

Table 16 shows the numbers of hexahedrites which, by grouping, 

Table 16. — The numbers of hexahedrites from the different geographic areas 

zvhich may be related. 

1 Mexico-Texas, Oklahoma 6 

2 Southeastern U. S 18 

3 Chile 12 

4 Australia 5 

5 Europe 5 

6 Africa 4 

Total 50 

Witnessed falls (excluding the Nedagolla ^) 6 

Number accounted for as possible falls 56, or 80 percent 

Hexahedrites scattered at random 14, or 20 percent 

1 See page 8. 

appear to have fallen in showers. If, to these 50 cases, the 6 which 
were seen to fall are added, we have 56 hexahedrites out of a total of 
70. This means that approximately 80 percent of these irons either 



38 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I48 

fit into fallout patterns or were witnessed falls. Such a percentage 
can hardly be a coincidence. 

The fact that hexahedrites are chemically simple and apparently 
without silicate inclusions raises the possibility that hexahedrites may 
represent fragments from the core of a larger body. Most theorists 
agree that the core should be essentially free from silicates, and from 
a standpoint of quantity, core material should be less abundant than 
material from the surrounding shells. The hexahedrites meet these 
two rather basic requirements of core material. 

Many of these topics have been presented before societies and 
symposia since 1950. Critical comments generally can be divided 
into two types : ( 1 ) Meteoritic statistics are too limited to support 
these groupings; (2) Conditions necessary to accompHsh these 
selected fallout groupings of hexahedrites are difficult to reconcile 
with basic concepts of astrophysics. 

Perhaps some of these criticisms are still valid, but new finds of 
hexahedrites, as well as investigations of other scientists, have pro- 
duced more facts to support these proposals than to disprove them. 
Thus, more investigators seem to agree with the theme here proposed 
than to disagree with it. 

Many assume that meteorites are equally distributed over the earth 
but because they are discovered by accident, their recovery is limited 
to fairly settled regions of the surface of the earth. However, these 
70 hexahedrites are not uniformly scattered over the area from which 
meteorites have been recovered. About 70 percent of them are con- 
centrated into 6 geographic areas, and the points of fall or discovery 
within these areas suggest that they fell as a shower. 

The long axes of these strewn fields exceed those of the observed 
falls of any meteorite, yet are about equal to the paths of several 
observed fireballs and some of the witnessed displays of falling 
meteorites. The long axes of the scatter of the individuals in the 
different geographic areas lie in essentially a northeast-southwest 
direction. 

LITERATURE CITED 

Axon, H. J. 

1962. Dendritic structure in the Nedagolla ataxite. Nature, No. 4854, 
pp. 567-568. 
Brown, H. See Goldberg et al., 1951. 
Cohen, E. W. 

1903. Meteoritenkunde, Heft 3, p. 168. 
Daubree, G. a. 

1875. Compt. Rend., Acad. Sci. Paris, vol. 81, p. 597. 



NO. 5 HEXAHEDRITES — HENDERSON 39 

Ellicot, a. 

1804. Trans. Amer. Philos. Soc, vol. 6, p. 28. 
Farrington, O. C. 

1915. Catalogue of the meteorites of North America. Nat. Acad. Sci., 

vol. 8. 
1915. Meteorites. Privately published. 
FurrcHER, L. 

1890. On the Mexican meteorites, with special regard to the supposed 
occurrence of widespread meteoric showers. Min. Mag., vol. 9, 
pp. 91-178. 
FOOTE, W. M. 

1899. Note on a new meteoric iron found near the Tombigbee River in 
Choctaw and Sumter Counties, Alabama, U.S.A. Amer. Journ. 
Sci., ser. 4, vol. 8, pp. 153-156. 
FxiRCRON, A. S. Sec Henderson, 1957. 
Goldberg, E., Uchiyama, A., and Brown, H. 

1951. The distribution of nickel, cobalt, gallium, palladium and gold in 

iron meteorites. Geoch. et Cosmo. Acta, vol. 2, pp. 1-25. 
Henderson, E. P. 

1941. Chilean hexahedrites and the composition of all hexahedrites. Amer. 

Mineralogist, vol. 26, pp. 546-50. 
Henderson, E. P., and Furcron, A. S. 

1957. Meteorites in Georgia. Georgia Mineral Newsletter, vol. 10, pt. 2, 

No. 4, pp. 113-142. 
Henderson, E. P., and Perry, S. H. 

1948. Re-examination of the Soper, Oklahoma, meteorite. Amer. Min- 

eralogist, vol. 33, pp. 692-94. 

1949. Pima County, Arizona, meteorite. Proc. U. S. Nat. Mus., vol. 99, 

No. 3241, pp. 353-355. 

1949. The Wathena, Doniphan County, Kansas meteorite. Amer. Min- 
eralogist, vol. 34, pp. 102-103. 

1954. A discussion of the densities of iron meteorites. Geoch. et Cosmo. 
Acta, vol. 6, pp. 221-240. 

1958. Studies of seven siderites. Proc. U. S. Nat. Mus., vol. 107, No. 3388, 

pp. 339^03. 
Hey, H. H. 

1953. Catalogue of meteorites. British Museum. 
Howell, E. E. 

1908. The Ainsworth meteorite, witli analysis and notes by Wirt Tassin. 
Amer. Journ. Sci., ser. 4, vol. 25, pp. 105-107. 
Huntington, O. W. 

1889. The crystalline structure of the Coahuila irons. Proc. Amer. Acad. 
Arts and Sci., vol. 24, pp. 30-35. 
Kanda, Sigeru. 

1952. On the meteorites of Japan, Korea and China. Sci. Repts. Yokohama 

Nat. Univ., sec. 2, pp. 97-106. 
Krieger, Alex D. See Shum, 1954. 
La Paz, Lincoln 

1952. Preliminary notes on the Lake Murray, Carter County, Oklahoma, 

siderite. Meteoritics, vol. 1, pp. 109-113. 



40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Marvin, Ursula B. 

1963. Alineralogy of the oxidation products of the Sputnik 4 fragments and 
of iron meteorites. Journ. Geophys. Res., vol. 68, No. 17, pp. 5059- 
5068. 
Merrill, G. P. 

1922. On meteoritic iron from Alpine, Brewster County, Texas, and Signal 
Mountain, Lower California, and a pallasite from Cold Bay, 
Alaska. Proc. U. S. Nat. Mus., vol. 61, art. 4, pp. 1-4. 
1927. Heretofore undescribed meteoric irons from (1) Bolivia, S. America, 
(2) Western Arkansas and (3) Seneca Township, Michigan. 
Proc. U. S. Nat. Mus., vol. 12, art. 4, p. 2. 
NiER, A. O. C. See Signer and Nier, 1962. 

NiNINGER, H. H. 

1931. A unique iron meteorite from Mexico. Amer. Journ. Sci., ser. 5, 

vol. 22, pp. 69-71. 
1934. The great meteor of March 24, 1933. Pop. Astron., vol. 42, pp. 291- 
306. 
NiNiNGER, H. H., and Nininger, Addie D. 

1950. The Nininger Collection of meteorites, a catalog and a history. Amer. 
Meteorite Mus., Winslow, Ariz. 
O'Keefe, John 

1961. Tektites and the Cyrillid showers. Sky and Telescope, vol. 31, pp. 1-6. 
Perry, S. H. 

1944. Metallography of meteoric iron. U. S. Nat. Mus. Bull. 184. See also 
Henderson and Perry, 1948, 1949, 1958. 

POKRZYWNICKI, J. 

1959. Sulechow meteorite. Bull. Acad. Polaise Sci., Ser. Sci. Chem., Geol. 
and Geogr., vol. 7, pp. 57-62. 
Preston, H. L. 

1900. Two new American meteorites. Amer. Journ. Sci., ser. 4, vol. 9, 

pp. 283-286. 
1890. A new meteorite. Science, vol. 15, p. 167. 
Prior, G. T. See Hey, 1953. 
Roy, S. K., and Wyant, R. K. 

1950. The Smithonia meteorite. Field Museum Nat. Hist. Geol. Ser., 
vol. 7, No. 9, pp. 129-134. 
Shum, Dee Ann, and Krieger, A. D. 

1954. An introductory handbook of Texas archaeology. Texas Archeol. 
Soc, vol. 25. 
Signer, P., and Nier, A. O. C. 

1962. The measurement and interpretation of rare gas concentrations in 

iron meteorites. Researches on Meteorites. John Wiley and Sons, 
Inc. 
Smith, J. L. 

1877. A description of the Rochester, Warrenton and Cynthiana meteoric 
stones which fell respectively December 21, 1876, January 3, 1877, 
and January 23, 1877, with some remarks on previous falls of 
meteorites in some regions. Amer. Journ. Sci., vol. 14, pp. 219-229. 



NO. 5 HEXAHEDRITES — HENDERSON 4I 

Stone, R, W. 

1932. Meteorites found in Pennsylvania. Pennsylvania Topogr. Geol. Surv., 
ser. 4, Bull. G2. 
UcHiYAMA, A. See Goldberg et al., 1951. 
Uhlig, H. H. 

1954. Contribution of metallurgy to the origin of meteorites. Pt. I, Struc- 
ture of metallic meteorites, their composition and the effect of pres- 
sure. Geoch. et Cosmo. Acta, vol. 6, pp. 282-301. 
ViLCSEK, E., and Wanke, H. 

1962. Chlorine 06 and argon 39 in meteorites and the exposure and terres- 
trial ages of iron meteorites. Final Report on Contract AF 61 
(052) -334. 
Wanke, H. See Vilcsek and Wanke, 1962. 

1960. Cosmic ray produced isotopes in meteorites. Summer Course on 
Nuclear Geology, Varenna. Comitate Nazionale per L'Energia 
Nucleare, Lab. Geol. Nucleare, Pisa. 
Whitfield, J. E. 

1877. On tlie Johnson County, Arkansas, and Allen County, Kentucky, 
meteorites. Amer. Journ. Sci., ser. 3, vol. Zi, pp. 500-501. 
Zavaritzky, a. N. 

1954. (Specific reference) Aleteoritika, vol. 11, p. 68. Author mentions 
narrow kamacite plates and plessite, illus. 



MITHSONIAN MISCELLAMEOUS COLLECTIONS 



VOL. 148, NO. 5, PLATE 1 




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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



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Central Missouri 
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SMITHSONIAN MISCELLANEOUS COLLECTIONS 

VOLUME 148, NUMBER 6 



CljarlEs; B. anb iMarp "^aux OTalcott 
3^es(earcf) jFunb 



MIDDLE AND LATE TURONIAN OYSTERS 
OF THE LOPHA LUGUBRIS GROUP 

(With Eight Plates) 



By 

ERLE g. kauffman 

U. S. National Museum 
Smithsonian Institution 




(Publication 4602) 



CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

OCTOBER 6, 1965 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 

VOLUME 148, NUMBER 6 



Cftarles; B. anb iMarp IJaux OTalcott 
I^esiearcf) jTunb 



MIDDLE AND LATE TURONIAN OYSTERS 
OF THE LOPHA LUGUBRIS GROUP, 

(With Eight Plates) 



By 
ERLE G. KAUFFMAN 

U. S. National Museum 
Smithsonian Institution 



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(Publication 4602) 



CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

OCTOBER 6, 1965 



PORT CITY PRESS, INC. 
BALTIMORE, MD., U. S. A. 



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Cfjarlesi 3D. anU jHarp "^aux Jlalcott B^csfearcf) Jfunb 

MIDDLE AND LATE TURONIAN OYSTERS OF 
THE LOPHA LUGUBRIS GROUP 

By ERLE G. KAUFFMAN 

U. S. National Museum 
Smithsonian Institution 

(With Eight Plates) 

INTRODUCTION 

Fossil oysters are among the most common and well preserved 
faunal elements in Cretaceous sediments. With few exceptions, how- 
ever, they have been ignored in evolutionary studies and biostra- 
tigraphy. Although countless species have been described, the tax- 
onomy of the group is confusing and inconsistent. It seems ironic, 
therefore, that they are one of the groups most suited to modern 
population systematics. The present investigation attempts to demon- 
strate the feasibility of detailed systematic and evolutionary study, 
faunal zonation, and regional correlation based on oysters. It employs 
simple biometric analysis of large collections, from numerous locali- 
ties, distinct stratigraphic levels, and diverse sediment types. I have 
chosen for this purpose a typical lophid species group centered around 
Lopha lugubfis (Conrad), and including L. bellaplicata hellaplicata 
(Shumard), L. hellaplicata novamexicana n. subsp., and varieties of 
these forms. 

The Lopha lugubris lineage is the predominant ostreid species 
group in Middle and Upper Turonian (Upper Cretaceous) sediments 
of the Western Interior and western Gulf Coast. These plicate 
oysters are abundant and well preserved at various stratigraphic 
levels in the upper Eagle Ford Shale of Texas, the Mancos Shale of 
New Mexico, and the Carlile Shale of Colorado, New Mexico, and, 
rarely, Kansas. They are ideally suited for a modern systematic 
study because the structural complexity of lophid oysters is greater 
than in many other ostreid types. Detailed analysis of this group 
provides a good test for the systematic, taxonomic, and evolutionary 

SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 148; NO. 6 



2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

utility of morphologic features not previously considered by many 
ostreid workers. 

Oysters of the Lopha lugubris group characteristically have a 
rounded, subovate, or subquadrate outline, asymmetrical prosocline 
shells with curved, opisthogyrate beaks and umbones (exogyroid in 
some forms), and coarse, bifurcating, radial plicae originating at the 
imibone on left valves, but variably developed on right valves. The 
shell is lamellate and moderately inequivalve, with the right (upper) 
valve flatter and slightly smaller than the left (lower, attached) 
valve. The valves are denticulate, with small cardinal areas, and a 
subcentral, comma-shaped muscle impression. 

The lineage first appears in Western Interior and Gulf Coast 
sediments during the late Middle Turonian (zone of Collignoniceras 
hyatti Stanton). The youngest known representatives occur in middle 
Upper Turonian sediments (zone of Prionocyclus Wyoming ensis 
elegans Haas). It may range into even younger Carlile strata in the 
Western Interior, as indicated by scattered reports of small plicate 
oysters (indeterminate) in uppermost Turonian beds. 

The Lopha lugubris lineage appears to have had a Gulf Coast 
origin, or center of dispersal, in the United States, and reached its 
maximum development in abundance and size in these southern 
waters. Its immediate ancestor is unknown. Possibly, the lineage 
arose from the European group of L. syphax (Coquand) (Early 
Cenomanian) or from some Early Cretaceous lophid stock, such as 
Lopha marcoui (Bose) . There is a distinct gap, however, in our knowl- 
edge of the evolution of Lopha in sediments of Cenomanian age 
where representatives of this genus are not common. 

ACKNOWLEDGMENTS 

I am greatly indebted to Drs, Norman F. Sohl and William A. 
Cobban of the United States Geological Survey, and to Dr. Richard 
S. Boardman of the United States National Museum, for their excel- 
lent criticism of the manuscript and many suggestions during the 
course of the study. Conversations with Dr. H. B. Stenzel of the 
Shell Development Company were very helpful. Collections were 
kindly donated to the National Museum by Dr. Bob F. Perkins of the 
Shell Development Company and loaned by Dr. Donald E. Hattin 
of the University of Indiana. Specimens that I collected during the 
period 1958 to 1960 are on loan through the courtesy of the 
University of Michigan Museum of Paleontology. The drawings 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 3 

were made by Larry Isham, the photographs by Jack Scott, both of 
the United States National Museum. 

BIOSTRATIGRAPHY 

Members of the Lopha luguhris group have equivalent stratigraphic 
distribution in Turonian sediments of Colorado, New Mexico, and 
Texas (fig. 1). The restricted ranges, broad geographic distribution, 
and abundance of individual species and subspecies render them use- 
ful as stratigraphic tools in regional correlation. In some areas they 
are the best available indices. 

Stratigraphic distribution in Texas. — Lopha bellaplicata novamexi- 
cana n. subsp. has not yet been found in Texas. Lopha bellaplicata 
bellaplicata (Shumard) is the oldest known representative of the 
group on the Gulf Coast, marking a discontinuous faunal zone (zone 
9 of Adkins and Lozo, 1951, p. 155) at the top of the Eagle Ford 
Shale (late Middle and early Late Turonian; Cobban and Reeside, 
1952, chart 10b). It has been reported from the upper Arcadia 
Park Limestone and Shale Member, the upper South Bosque Marl 
Member (questionably), and the upper few feet of the "Condensed 
Zone" of Adkins and Lozo (1951, p. 155). Generally the species 
occurs only in the upper 25 feet of the Eagle Ford, but locally it has 
been reported ranging through as much as 70 feet of section. It 
apparently does not range into the Austin Chalk, although reworked 
fragments of shells have been found in a thin conglomeratic calcarenite 
bed ("reworked Eagle Ford" zone) which locally lies between the 
Austin and Eagle Ford, and which has been assigned by many workers 
to the former. 

Lopha bellaplicata bellaplicata is known to occur only in upper 
Middle Turonian sediments in Texas, above the zone of Collignoni- 
ceras woollgari (Mantell) (early Middle Turonian) and locally below 
a widespread disconformity which, in the Western Interior, forms the 
Middle-Upper Turonian boundary. Faunal associates in the U. S. 
National Museum and U. S. Geological Survey collections from Texas 
include an undescribed species of Inoceramtis closely related to /. 
dimidius White (and ancestral to it), Cardium pauperculum Meek, 
and Cyprimeria? sp. or Tapes sp. cf. T. cyprimeriformis Stanton, all 
characteristic of the middle Carlile Shale (Blue Hill and Codell Mem- 
bers) in the southern Western Interior. Lopha blacki (White) 
morphologically intergrades with L. bellaplicata bellaplicata and 
comes from approximately equivalent upper Eagle Ford strata. It is 
here considered a synonym of L. bellaplicata bellaplicata. 



4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

The zone of Lopha lugubris lies predominantly above that of L. 
hellaplicata hellaplicata, but their ranges overlap slightly (fig. 1), 
At two known localities in Texas, the species are found together in 







SOUTHERN COLORADO 


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Fig. 1. — Stratigraphic range of oysters in the Lopha lugubris group from 
Colorado, New Mexico, and Texas, and proposed correlations. Colorado 
stratigraphy taken along the east flank of the Front Range (Canon City, Pueblo, 
Huerfano Park areas). New Mexico section interpolated from Cerrillos and 
Carthage sections of Rankin (1944) and from stratigraphic data on collections 
made between Cerrillos, N. Mex., and Trinidad, Colo. Texas section generalized 
for central and northeast Texas. 



the upper 2 or 3 feet of the Eagle Ford Shale. They are distinct in 
this zone of overlap, and do not intergrade. L. lugubris does not 
range below this level, as does L. hellaplicata hellaplicata. It 
ranges upward, however, above the range of L. hellaplicata hellapli- 
cata, through the calcarenite bed between typical Eagle Ford Shale 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN 5 

and Austin Chalk (fig. 1). A disconformity of unknown magnitude 
separates the Eagle Ford and the calcarenite at many places. Speci- 
mens of L. luguhris from this calcarenite are complete and do not 
exhibit signs of wear. They appear to have lived during deposition 
of the calcarenite rather than having been reworked from typical upper 
Eagle Ford Shale, as some workers have suggested. A similar situation 
exists in the Juana Lopez Member (Carlile Shale) of the Western 
Interior. The precise age of the "reworked Eagle Ford" calcarenite 
has not yet been established, but it appears to be lithologically and 
faunally the southern equivalent of the Juana Lopez. 

Stratigraphic distribution in the Western Interior. — The strati- 
graphic distribution of the LopJia lugubris group in the Western In- 
terior is the same as that observed in the Texas Cretaceous sequence 
(fig, 1), as are the general progression of ammonites and lithologies. 
The occurrence of lugubris-like oysters in Colorado, particularly in 
Huerfano Park, is of great importance, since it is only here that all 
members of the group have been found together geographically and 
their stratigraphic relationships accurately established. In this area, 
Lopha bellaplicata novamexicana occurs sporadically in septarian lime- 
stone concretions of the upper Blue Hill Shale Member (late Middle 
Turonian, lower part of the range of Collignoniceras hyatti: fig. 1). 
L. bellaplicata bellaplicata and the variety A are common throughout 
the Codell Sandstone Member ("Pugnellus Sandstone" of Stanton, 
1893 [1894] : late Middle Turonian, upper part of the range of C. 
hyatti). L. lugubris questionably occurs in the uppermost Codell 
Sandstone (based on two poorly preserved specimens), and is common 
throughout the Juana Lopez Member (Juana Lopez Sandstone of 
Rankin, 1944; a calcarenite or limestone in Colorado) of the 
Carlile Shale. The upper and lower contacts of the Juana Lopez are 
disconformable throughout much of its geographic range in Colorado 
and northern New Mexico. 

In northeastern and north-central New Mexico, and parts of the 
San Juan Basin, the Coloradoan sequence and distribution of the 
ostreid elements is similar to that in southern Colorado (fig, 1), The 
Juana Lopez Member is thicker in New Mexico, however, and locally 
consists of calcareous sandstone, or of interbedded calcarenites, shales, 
and sandy units. Lopha lugubris occurs throughout this member. 
Those from the base are possibly distinguishable from those occurring 
at the top of the sequence on the basis of relatively longer, coarser and 
less numerous radiating plicae on the older forms. Not enough 
specimens are available, however, to prove this statistically. 



6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Elsewhere in New Mexico, where the Coloradoan sediments are 
more uniform (Mancos Shale of most authors), the distribution of 
members of the L. lugubris group is not as well established. Lopha 
hellaplicata novamexicana occurs in the middle Mancos, in the zone 
of Collignoniceras hyatti (late Middle Turonian). The range and 
position of L. hellaplicata hellaplicata is not precisely known, except 
that it occurs in the middle Mancos below the Juana Lopez calcarenites. 
L. luguhris occurs widely in the middle and basal upper Mancos, in 
calcarenites equivalent to the Juana Lopez Member, Here it is 
associated with Prionocyclus wyomingensis Wyoming ensis Meek, P. 
macombi Meek, and Scaphites warreni Meek and Hayden, a Juana 
Lopez assemblage. It has also been reported from slightly younger 
beds (zone of P. wyomingensis elegans Haas : middle Late Turonian) . 

Stratigraphic conclusions. — Comparison of the Texas, northeastern 
New Mexico, and south-central to southeastern Colorado Turonian 
sediments reveals a marked similarity in the sequence of ostreids, 
ammonites, sediment types (in part), and in the position of the 
Middle-Upper Turonian boundary, in many places marked by a 
disconformity. In these areas dark clay shale, locally sandy, silty, 
and containing lensing siltstones, silty limestones, and sandstones 
(upper Eagle Ford Shale ; Codell Sandstone in many places) underlies 
this boundary. This unit contains L. hellaplicata hellaplicata and 
species of Collignoniceras (C. hyatti, C. sp.) in all areas and is locally 
underlain by sediments carrying L. hellaplicata novamexicana. Brown 
to rusty, sandy calcarenites and calcareous sandstones, locally con- 
taining fish tooth, bone, and phosphate pebble conglomerates overlie 
the boundary, especially where it is marked by a disconformity 
(Juana Lopez Member; "reworked Eagle Ford" zone), at many 
localities. This unit contains L. luguhris and species of Prionocyclus 
(P. wyomingensis wyomingensis, P. macomhi, P. sp.) in the great 
majority of localities where it is found. In both Colorado (question- 
able occurrence) and Texas, L. luguhris is found rarely in the upper- 
most part of the lower unit (upper Eagle Ford equivalents), partially 
overlapping the range of L. hellaplicata hellaplicata. 

I propose that the two sequences are correlative in the manner 
shown on figure 1, and that they may be correlated on the basis of 
lophid oysters as well as ammonites. Based on lithologic and faunal 
relationships, I suggest that the thin calcarenite locally present above 
the Middle-Upper Turonian boundary and disconformity in Texas 
should not be assigned to the Austin but rather to the Eagle Ford, 
forming the highest zone of that formation (zone of Lopha luguhris). 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN 7 

The Austin has been considered totally Coniacian in the past, although 
locally, the lowermost Austin chalks contain a Late Turonian fauna. 
The calcarenite unit is, without doubt, Late Turonian in age and 
faunally allied with pre- Austin sediments. 

HISTORY 

Attempts to treat the Lopha luguhris group in the past have 
encountered the many pitfalls inherent in taxonomic study of the 
Ostreidae. It has been treated as a single variable species (Stanton, 
1893 [1894], pp. 58, 59) and as a series of related species, some of 
which appear valid, others merely environmental variants of described 
forms. The problems which have produced such inconsistency are 
those that have generally affected the taxonomy of ostreids in the 
past: Inability to distinguish environmental control on shell form 
from genetic shift ; failure to define adequately the limits of specific 
variability through the study of small and geographically restricted 
samples rather than analysis of numerous, widely distributed "popula- 
tions" ; application of typologic paleontology ; limited knowledge of 
modern representatives of the family ; insufficient stratigraphic data ; 
and others. It is not surprising that the group has a complex nomen- 
clatural history in previously published studies. 

Conrad's original description (1857, p. 156, pi. 10, figs. 5a, b) 
was based on a few small, densely plicate specimens with large 
attachment areas. These were obtained from calcarenites typical of 
the lower Juana Lopez member (upper Carlile Shale: zone of 
Prionocyclus macombi Meek and P. Wyoming ensis Wyoming ensis) 
in New Mexico and all belong to Lopha luguhris s. 1. Shumard 
(1860, p. 608) later recognized a larger, more coarsely plicate, and 
somewhat older form, Ostrea hellaplicata, in the upper Eagle Ford 
Shale of Texas. White's Ostrea blacki (1880, p. 293, pi. 4, figs. 1, 2) 
appears to be erected on worn, smoother, ecologic variants of L. 
hellaplicata hellaplicata. The two forms occur in approximately time- 
equivalent strata. 

These names were used by a number of authors without much 
change until Stanton (1893 [1894], pp. 58, 59) placed all members 
of the group into synonymy with L. luguhris Conrad, regarding them 
as ecologic variants of a single species. Stanton's concept has been 
generally perpetuated in this country, although the other names are 
used occasionally in fieldwork, on collection labels, and in unpublished 
faunal lists. In Mexico, however, Bose (1913, pp. 47, 48) recognized 
L. luguhris, L. hellaplicata, and L. hlacki as distinct species, but 



8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

overlooked the different stratigraphic ranges of the first two forms. 
Only mention has been made of the group since that time, and it 
has not been widely used in biostratigraphic work. The appearance 
of L. lugubris Conrad on most faunal lists compiled in this century 
has only limited stratigraphic value in that it is probably used in the 
concept of Stanton (1893) and indicates an age no more refined than 
Middle and Late Turonian. 

STUDY OF FOSSIL OSTREIDAE 

The Ostreidae, and in particular Ostrea, Crassostrea, and related 
genera, are among the most variable of shelled animals. The animal 
readily adapts to a number of environmental situations without signifi- 
cant change in morphology of the soft parts. Gross shell form, on 
the other hand, is greatly affected by the surrounding environment 
in many species. Long, narrow, straight shells are produced in 
strong currents ; quiet water favors more rounded, broader shells ; 
crowding produces elongate, irregular, laterally compressed forms ; 
the depth and size of the mature shell is related in some groups to the 
amount of exposure in intertidal areas ; high-energy shallow-water 
environments produce heavier-shelled, more prominently ribbed forms 
than do deep, quiet-water niches ; some ostreids form imbricate frills 
to keep above soft mud and shifting sand bottoms, and so on. Many 
morphologic features of the shell, therefore, are highly variable within 
a single species, and must be analyzed with care. This is particularly 
true in regard to shell outline, convexity, and strength of surface 
ornamentation. Other structures, less affected by environmental 
variation (shell structure, prodissoconch, denticles, position and shape 
of muscle scar, cardinal area), form a more reliable basis for classifi- 
cation. 

Finally, modern types of Ostreidae (Ostrea, Crassostrea, etc.) are 
generalized and successful animals, and have been exceptionally con- 
servative in their evolution. They have undergone little basic change 
in shell form since they became established as an important group 
during the Mesozoic. Variants of living species are in many cases 
indistinguishable from certain Cretaceous forms when only a few 
shells are compared. Closely related species exhibit considerable 
morphologic overlap, and the differences between them are commonly 
subtle. 

In studying the Lopha lugubris group, resolution of the problems 
inherent in biologic interpretation of the Ostreidae required analysis 
of large suites of specimens, including growth series, from many 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 9 

localities and sediment types, representing a broad range of environ- 
ments. Only in this way could normal variation limits, ecologic 
control on shell form, and genetic shift be recognized. During the 
course of this study, I was fortunate to have at my disposal the large 
and well-documented collections of the U. S. National Museum, and 
Denver and Washington collections of the U. S. Geological Survey. 
These were supplemented by my own collections made over a period 
of 5 years in the Western Interior, and by small lots lent or donated 
for this study by various individuals. Several hundred measurable 
specimens, including ontogenetic series, form the basis for species 
descriptions and observations on stratigraphic distribution, variation, 
ecology, and evolution. 

Time equivalency of the various fossil beds from one area to another 
was established on the basis of ammonites, species of Inoceramns, 
and widespread disconformities. The ammonite and inoceramid 
species used are widespread, well-established faunal indices occurring 
in a variety of sediment types (representing various environments) 
and apparently subject to minimal facies control. 

Simple biometric analysis of all available morphologic features, 
using graphs, charts, and simple ratios, indicated structures which 
might be useful in lophid taxonomy, and proved to be sufficient for 
the recognition of specific differences, ontogenetic development, and 
evolutionary trends within the Lopha lugubris group. Features that 
were employed in these aspects of the study are: Maximum adult 
size ; basic ornament pattern ; normal valve outline ; the distribution of 
convexity on both valves ; juvenile ornamentation ; extent of valve 
covered with plicae ; number, size, and bifurcation rates of the plicae 
at given intervals ; plication density in a given area or distance ; gross 
characteristics of the concentric ornamentation ; differences between 
the ornamentation of the auricles and main body of the shell ; relative 
development of the auricles and auricular sulci ; angle of inclination 
of the beaks and umbones, and independently of the valve ; curvature 
and position of the beaks and umbones ; angle of the posterodorsal 
slope; relative size and development of various parts of the cardinal 
area; density and extent of the denticles on the dorsolateral valve 
margins ; relative size and position of the muscle scar ; and in some 
cases, the relative size, position, and inclination of the attachment 
scar. To this list might be added comparison of various ratios, such 
as length to height, length of the auricle to length of the shell, and 
others. 

Although ontogenetic studies have not been attempted to any extent 



lO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 48 

with fossil oysters, distinct and commonly abrupt changes in shell 
morphology with growth are common, especially in the more ornate 
groups, and can probably be tied to developmental phases of the 
animal. In this study the terminology of Hyatt (1894, pp. 349-647) — 
nepionic (babyhood), neanic (youth), ephebic (adult), and gerontic 
(senile) — is used to characterize growth periods between major mor- 
phologic changes in the shell. In oysters, and more specifically in the 
Lopha higubris group, the nepionic stage is represented by the prodis- 
soconch, the neanic (spat) stage by part or all of the umbo. The 
nepionic-neanic transition is marked by development of adult hinge 
characters, change in shell shape (usually from rounded to dorso- 
ventrally elongate) , and development of coarser concentric ornamenta- 
tion. The ephebic stage is characterized by adult ornamentation 
(the plicae in Lopha), change in shell shape including development 
of auricles, folds, etc, well-defined denticles and muscle insertion 
areas, and further differentiation of the cardinal elements. The 
neanic-ephebic boundary is marked in some lophids by the abrupt 
appearance of plicae, development of auricular salients in the 
marginal outline, and differentiation of the resilifer and lateral cardinal 
plates on the hinge line. The gerontic stage is characterized by 
flattening and flaring of the ventral and lateral shell margins, deterio- 
ration of the ornament pattern, decrease in prominence of the radial 
ornament, crowding and increase in prominence of the concentric 
ornament, and decrease in prominence of structures related to sexual 
maturity and reproductive function. 

Graphs and drawings depicting ontogenetic trends in members of 
the Lopha lugubris group are shown in figures 2-4, 6,9, 11-18. 

Geographic variation and environmental control on shell morphology 
were determined by comparing a number of "populations" from time 
equivalent but lithologically distinct sediments in different areas (fig. 
14). Only L. hellaplicata bellaplicata exhibits significant variation 
in both respects. Comparison of related forms from a number of 
different stratigraphic levels, but from similar sediments (roughly 
representing similar environments) is the most satisfactory method 
of demonstrating evolutionary change in the lineage. Unfortunately, 
this method is not wholly applicable to the L. lugubris group, since 
there is little overlap of exact sediment type between faunal zones. 
Evolution of this group, therefore, is necessarily determined by com- 
paring total variation plots of forms from different stratigraphic 
levels, irrespective of lithology (figs. 2-9). Such a system of separating 
evolutionary change from geographic or environmental variation is 



L. BELLAPLICATA 
BELLAPLICATA 




^^o 



L. BELLAPLICATA NOVAMEXICANA 



A 



3000 3200 3400 ' 3600 3800 4000 4200 4400 



000 3200 



all specimens 
ising plication 



<24 



.---■'i^^ L. LUGUBRIS 
; att£> flfi A I 

(A Mi ZAA^ ,' 

A / 

/A /r^MoA r^n, o ' O 




600 800 1000 1200 1400 1600 1800 2000 Z200 2400 

area; INSCRIBING RECTANGLE OF LEFT VALVE OUTLINE (SQ.MM.) 




100 200 



^0 600 800 1000 1200 1400 1600 1800 2000 2200 2400 

AREA; INSCRIBING RECTANGLE OF LEFT VALVE OUTLINE (SQ.MM.) 

lulran of the Ufha haulms group. Increase in the density of the plicae, number per unit ai 
'•niihli IT ^r*""' ''™ ""'"■ ■^""- ^' Scattergram of Colorado sample only. Arrows 
"own by hypothetical regression lines visually filled to plots ot terminal species in group. 



Fk. 2._Evo1, 

masured. from ColoradoT'Ne" 



on left valves of progressively younger species. A. Scattergram for all specimens 
lower left-hand corner of each graph indicate direction of increasing plication 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN II 

admittedly somewhat idealized. Obviously, it is not possible to 
evaluate properly all the environmental factors acting on these 
shells in different areas. The chemical environments of two very 
similar sandstones may have been entirely different and may have 
had a profound effect upon the type of shell produced in each area. 
Analysis of chemical aspects of the paleoenvironment is difficult or 
impossible in most coarse clastic sediments, and is well beyond the 
scope of this study. It should be understood that in dealing with 
environment here, I am dealing in generalities and am cognizant of 
the limitations this places on the accuracy of my interpretations. 

Gross morphologic similarities in form, ornament pattern, develop- 
ment of the auricles, the cardinal area, and the muscle scar, in addition 
to detailed morphologic overlap in marginal variants of consecutive 
species clearly point out the close relationships of members in the 
Lopha lugubris group and suggest that they represent a continuous 
evolutionary sequence, without major break. 

EVOLUTION 

Several of the morphologic characters which are most important in 
the differentiation of species and subspecies of the Lopha lugubris 
group demonstrate significant evolutionary trends (figs. 2-9), most 
of them chronoclinal. These reflect, in part, gradual adaption of the 
lineage to a slowly changing regional environment characterized by 
regression and shallowing of the interior seas, increased wave and 
current action, and increased turbidity. The scope of these changes 
from one level to another is well beyond the normal ecologic variation 
caused by similar shallow water conditions in any member of the 
group during its existence. 

In graphing evolutionary trends in the Lopha lugubris group, 
structures were compared wherever possible at equivalent ontogenetic 
stages on the three principal species and subspecies. Comparison of 
the terminal number of plicae at the margin of adult valves represents 
such a plot and can be analyzed irrespective of the differences in 
size range shown by L. lugubris when compared to subspecies of 
L. bellaplicata. 

In addition to these plots, it seemed desirable to employ another 
type of comparison in which structures of adult valves from the three 
forms of Lopha were contrasted at equivalent sizes (i.e., at 20 mm. 
height) (figs. 6a, 7c). The purpose of this type of plot is twofold: 
(1) It provides a basis for morphologic comparison of the species 
and subspecies at equivalent sizes, and a test of their genetic 



12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 






L. LU6UBRIS 




L. BELLAPLICATA BELLAPLICATA 




L. BELLAPL8CATA NOVAMEXICANA 




L. BELLAPLICATA BELLAPLICATA 



B 



L. BELLAPLICATA NOVAMEXICANA 




L. LUGUBRIS 



L. BELLAPLICATA 
BELLAPLICATA 



L. BELLAPLICATA 
NOVAMEXICANA 



Fig. 3. — For explanation, see opposite page. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN I3 

distinction. (2) At the same time it demonstrates evolutionary 
trends within the group in absolute measurements. These trends are 
not as well shown by this type of plot as they might be by comparing 
structures at the margins of adult shells, where morphologic differences 
are emphasized, but they are validly illustrated and significant be- 
cause even this method essentially compares structures at an approxi- 
mately equivalent stage of development. 

Plots of structures comparing them at a constant height were made 
within the ephebic part of the shell for each species and subspecies ; 
thus, only adult structures were compared. Ephebic development 
starts at about 10 to 15 mm. height on all forms, the difference in 
adult size between L. lugubris and L. bellaplicata (both subspecies) 
representing mainly differences in rate and amount of ephebic growth. 
Since L. bellaplicata bellaplicata and L. bellaplicata novamexicana 
have nearly equivalent size ranges, comparison of any structure at a 
given height on both is essentially a comparison made at equivalent 
ontogenetic stages. Because adult shells of L. lugubris attain a much 
smaller size, they theoretically should not be ontogenetically compa- 
rable with subspecies of L. bellaplicata at a given height. Such a com- 
parison is valid however because the ephebic morphology of this 
species is strikingly constant. The plicae do not normally bifurcate 
(fig. 6b and c) and their number is relatively constant anywhere on the 
adult portion of the shell. In addition, beyond 20 mm. height, the 
width of the plicae and sulcae remains relatively constant. Since 
ephebic structures are so uniform in L. lugubris, and values obtained 



Fig. 3. — Evolutionary trends demonstrated by members of the Lopha lugubris 
group. A, Comparison of cross sections through normal left valves. Beak is to 
the left. Note general decrease in overall convexity, ventral migration of the 
high point of the valve (illustrated by vertical lines through cross sections) 
through time. B, Comparison of cross sections through right valves, beak to the 
right. Note increase in relative convexity and shift in high point of valve 
(illustrated by vertical lines through each cross section). C, Comparison of 
midline traces of typical left valves showing decrease in curvature of beaks, and 
in overall curvature of shell through time. Beaks dorsal in each case. Speci- 
mens: A, Top row, left to right, U.S.N.M. 132157, U.M.M.P. 43472, U.S.N.M. 
132154; middle row, left to right, U.S.N.M. 132307, 132243, 8024b; bottom row, 
left to right, U.S.N.M. 132276, 132288, 132272. B, Top row, left to right, 
U.S.N.M. 132164, 132198, 132168; middle rov/, left to right, U.S.N.M. 132306, 
132305, 132244; bottom row, left to right, U.S.N.M. 132265, 132286, 132287. 
C, L. lugubris, left to right, U.S.N.M. 132157, 132159, 132156; L. bellaplicata 
bellaplicata, left to right, U.S.N.M. 132225, 132224, 132222; L. bellaplicata 
novamexicana, left to right, U.S.N.M. 132275, 132267, 132263. 



14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

in measuring them do not vary significantly from one point to an- 
other, they are comparable at any given height with those of L. 
hellaplicata (either subspecies) regardless of whether or not they 
represent an equivalent stage of ephebic development. 

The absolute height of the smooth stage increases in progressively 
younger species of the L. lugubris group (fig. 8), and its evolution is 
characterized by transgression of its ventral margin from the neanic 
to the ephebic part of the shell. The smooth stage terminates in the 
early to middle neanic stage of L. hellaplicata novamexicana, and in 
the middle to late ephebic stage of L. lugubris. Measurements of the 
height of the smooth stage used in plotting evolution are therefore 
not ontogenetically comparable for the three forms. 

Correspondingly, the number of primary plicae arising at the edge 
of the smooth stage have also been measured at different ontogenetic 
stages. These are more readily comparable than the height of the 
smooth stage, however, because on many specimens of L. hellaplicata 
(both subspecies) and a few L. lugubris the number of primary plicae 
can be directly contrasted at the neanic-ephebic boundary. Although 
the plicae arise early in the ontogeny of the subspecies of L. hellapli- 
cata, they do not undergo extensive bifurcation until the early ephebic 
stage. The number of plicae at the neanic-ephebic boundary 
therefore generally reflects the original number of primary plicae at 
the edge of the smooth stage. In L. lugubris the plicae normally 
arise at a later developmental stage, but on rare specimens with a 
small attachment scar, also arise near the neanic-ephebic boundary. 
In these specimens, the number of primary plicae is equal to the 
number found in specimens where the plicae arise at a later develop- 
mental stage. This indicates that the number of plicae is not onto- 
genetically controlled in L. lugubris, and relatively constant in number 
regardless of where they arise on the shell. Therefore, there is 
some validity in comparing the initial number of primary plicae on 
L. lugubris with subspecies of L. hellaplicata, despite the variation 
in ontogenetic stage at their first appearance. 

Important evolutionary trends noted in progressively younger 
Turonian representatives of the Lopha lugubris lineage are : 

1. Decrease in the maximum size attained by the species (fig. 2). 

2. Slight decrease in the relative convexity of the left (lower, 
attached) valve, and ventral migration of the high point of the valve 
(figs. 3a, 4a, b). 

3. Gradual increase in the relative convexity of the right (upper, 
free) valve, particularly in the umbonal region (fig. 3b). 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 



15 



LEFT VALVE 



L.BELLAPLICATA- 
BELLAPLICATA 




y 






\ 



.i & 






A 






L. LUGUBRIS 



L. BELLAPLICATA 
NOVAMEXICANA 



^0 5'5 go" 



"^ 



30 35 40 45 
HEIGHT (MM) 



10 



30- 
25- 



10 

5^ 



LEFT VALVE 
L. BELLAPLICATA NOVAMEXICANA- 







rA NOVAMEXICANA Z^"*^ ^ . A/ 




L. BELLAPLICATA 

BELLAPLICATA 



15 10 15 20 25 30 35 40 45 50 55 60 65 70 

HEIGHT (MM) 

Fig. 4. — Evolution in the Lopha lugubris group. A, Scattergram showing 
relationship between valve height and the distance between the beak and high 
point of the left valve, measured parallel to height. Note ventral shift of the 
high point in progressively younger forms. Arrow in lower left-hand corner 
denotes direction of ventral migration of high point as illustrated by hypothetical 
regression lines fitted visually to plots of end members of group. B, Scattergram 
showing relationship between height and width of left valves. Note slight 
decrease in relative convexity of left valve in progressively younger forms. 
Arrow in lower left-hand corner denotes direction of decreasing convexity as 
illustrated by hypothetical regression lines fitted visually to plots of end members 
of lineage. 



i6 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 




L.BELLAPLICATA 
NOVAMEXICANA 



L.BELLAPLICATA 
BELLAPLiCATA 



L.LUGUBRIS 




NOVAMEXICANA 



Fig. 5. — Evolution in the Lopha lugubris group. A, B, C, Drawings and cross 
sections of characteristic cardinal areas for species and subspecies within the 
group. Note gradual deepening, and increase in curvature of the resilifer in 
progressively younger forms. Also note increase in convexity of the lateral 
cardinal areas, from slightly arched lateral cardinal plates in the subspecies 
novamexicana, to distinct lateral cardinal folds in L. higubris. D, Outline 
drawings of species and subspecies within the group, with the auricular sulci 
shaded. Note narrowing of the sulci in progressively younger forms, and varia- 
tion in shape of the valves, of the posterior auricle, and in development of the 
anterior auricle. Specimens: A, U.S.N.M. 132263; B, U.S.N.M. 132243; 
C, U.S.N.M. 132167; D. Top row, left to right, U.S.N.M. 13274, 132154, 
U.M.M.P. 43472, 43464, U.S.N.M. 132157; middle row, left to right, U.S.N.M. 
132229, 132225, 132308; bottom row, left to right, U.S.N.M. 132263, 132267, 
132281, 132279. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN \'J 

4. Variation in the development of the auricles ; a general trend 
toward reduction in size of the auricles, and elimination of the 
anterior auricle (fig. 5d). The size of the auricles increases from the 
subspecies novamexicana to subspecies bellaplicata, and decreases 
considerably in L. lugubris. 

5. Reduction in the size (width, depth) of the auricular sulci, 
relative to shell size (figs. 5d, 6a). 

6. Increase in the number of radiating plicae, including an increase 
in the number of primary plicae at the edge of the smooth stage, 
increase in number at any given distance below the beak, increase 
in total number developed at the margin of adult shells, and increase 
in the plication density (number per unit area) (figs. 2, 7). 

7. Decrease in the average width of the radiating plicae, measured 
at a uniform distance below the beak in all species (fig. 7c) . 

8. Variation in the amount of bifurcation of primary plicae, with 
an overall trend toward decrease in bifurcation rate (figs. 6b, c). 
The bifurcation rate increases slightly from subspecies novamexicana 
to subspecies bellaplicata, then sharply decreases with the evolution 
of L. lugubris. 

9. Increase in the absolute height and relative extent of the 
smooth stage on the early shell, particularly in left valves. This is the 
distance between the beak and the first abrupt appearance of plicae 

(fig- 8). 

10. Some posterior migration of the beaks and umbos along the 
dorsal margin, and increase in the amount of curvature of these 
structures (figs. 3c, Sd, 9b). 

11. Changes in the nature of the cardinal area: general, though 
not chronoclinal, increase in the size of the resilifer relative to the 
lateral cardinal areas ; increase in the convexity and prominence of the 
lateral cardinal folds ; development and accentuation of the marginal 
cardinal troughs between the lateral folds and the valve margin 
(figs. 5a-c). 

12. Increase in the density of the denticles on the inner dorso- 
lateral margins (fig. 9a) . 

Many of these trends are interpreted as adaptations to widespread 
environmental changes through Middle and Late Turonian time, 
established in the lineage through natural selection. They are adapta- 
tions shown by many living and fossil, shallow- water, epi fauna! 
pelecypods. In the Lopha lugubris lineage they gradually evolved 
with the steady change from quiet-water, mud-bottom conditions 
(Blue Hill and lower to middle Mancos Shales), through near-shore. 



i8 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 




L. BELLAPLICATA 
BELLAPICATA 



1315 20 25 30 35 'JO 45 50 55 60 65 
LENGTH OF LEFT VALVE (MM.) 



26 

z 
526 

124. 



r 



L. BELLAPLICATA 
BELLAPLICATA 



A A ^ 00 
I O (^<J>0 O 
/i^ G A /^QO <9 

/A zao A O A 





A-d^-A CO 1 



LEFT 
VALVE 



L; BELLAPLICATA 

NOVAMEXICANA 



5 6 e 10 12 14 16 18 20 22 24 
INITIAL NUMBER OF PLICAE 




Fig. 6. — Evolution in the Lopha 
lugubris group. A, Variation plot 
showing relationship between the 
width of the posterior auricular 
sulcus 20 mm. below the beak and 
the length of the left valve, the 
most variable linear measurement. 
Note variation within each form 
and good separation of variation 
plots, lack of correlation between 
width and valve length, and de- 
crease in the relative width of the 
sulcus at this point in progres- 
sively younger species and sub- 
species (the latter defined by differ- 
ences in the vertical range of the 
individual variation plots). B, C, 
Comparison of the bifurcation rates 
of the radiating plicae on various 
members of the group, showing an 
increase in bifurcation of the plicae 
from L. bellaplicata novamexicana 
to the younger L. bellaplicata bella- 
plicata and then an abrupt decrease 
in bifurcation rate with the evolu- 
tion of L. lugubris, in which the 
majority of specimens lack bifurcat- 
ing plicae. Arrows on right central 
portion of B and C denote direction 
of increasing bifurcation rate as 
illustrated by hypothetical regres- 
sion lines visually fitted to plots of 
terminal members of group. 



8 10 12 14 16 IB 20 22 24 
INITIAL NUMBER OF PLICAE 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN 



19 




8 10 12 14 16 18 2022 24 
NUMBER OF PRIMARY PLICAE AT 
FIRST APPEARANCE 



28 



222 
1^20 
?I8 

ol 14- 
</)|2 

felCH 

UJ o 
CD 4 

io 




LUGUBRIS 




L. BELLAPLICATA 
BELLAPLICATA 



L. BELLAPLICATA 
NOVAMEXICANA 



WIDTH OF MEDIAN PLICA 
20MM.BEL0WTHEBEAK 



6 8 K) 12 M 16 18 20 22 24 26 

TOTAL PJfMEER OF PLICAE 

AT MARGIN 

Fig. 7. — Evolution in the Lopha lugubris group. A, Increase in total number of 
radiating plicae developed at the margin of adult shells in progressively 
younger species of the lineage. B, Increase in the total number of primary 
plicae first appearing at the margin of the smooth stage on progressively younger 
species. C, Decrease in the width of the median plica measured 20 mm. below 
the beak on progressively younger species of the group. All measurements made 
on left valves. 



s 

S 2 



LUGUBRIS 




— I — I — 1 — I — I 1 — I — 1 — I — I — 1 1 — I — r— r 

10 12 14 16 18 20 22 24 26 28 
HEIGHT OF SMOOTH STAGE (MM.). RIGHT VALVE 



12-1 
10 
8 
6-1 



L. LUGUBRIS 





L. BELLAPLICATA BELLAPLICATA 



LLAPLICATA NOVAMEXICANA 



B 



6 8 10 12 14 16 18 20 22 

HEIGHT OF SMOOTH STAGE (MM.) , LEFT VALVE 



24 26 28 



Fig. 8. — Evolution in the Lopha lugubris group. Increase in the actual height of 
the smooth umbonal area, dorsal to the abrupt appearance of radiating plicae, 
in successively younger species and subspecies. A, Right valve. B, Left 
(attached) valve, on which the trend is best observed. 



20 




L. LUGUBRIS 



L. BELLAPLICATA BELLAPLICATA 



A 



L. BELLAPLICATA NOVAMEXICANA 



e 8 10 12 14 16 18 20 22 24 26 28 

NUMBER OF DENTICLES IN 5 MM LENGTH 






L. BELLAPLICATA 
NOVAMEXICANA 



^TA ." ^ • . .; i^" •/ 




• .X \l. BELLAPLICATA BELLAPLICATA 



L. LUGUBRIS 



B 



20 25 30 35 40 45 50 
LENGTH OF LEFT VALVE (MM) 



55 60 65 70 



Fig. 9. — Evolution in the Lopha lugnbris group. A, Increase in the density of 
the denticles along the inner lateral and dorsolateral margins in successively 
younger species. B, Ventral shifting of the beaks along the dorsal margin in 
successively younger species and subspecies, and decrease in the length of the 
posterior auricle. Arrow in lower left-hand corner denotes direction of central 
shifting of beak along dorsal margin as shown by hypothetical regression lines 
visually fitted to plots of terminal species in lineage. 

21 



22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 48 

moderate- to shallow- water environments with active currents (upper 
Eagle Ford Shale, Codell Sandstone, parts of the middle Mancos), to 
shallow-water, inner-sublittoral, high-energy conditions, including 
wave action, a great deal of reworking, and periods of nondeposition 
(Juana Lopez Member, "Reworked Eagle Ford zone"). 

Most of the trends thought to be selected for environmental changes 
concern themselves with improving the hydrodynamic stability, 
strength, and anchorage of the shell. Hydrodynamic stability of the 
shell in the face of increased current and wave activity was probably 
improved by the overall decrease in shell convexity, ventral migration 
of the high point, reduction of projecting surfaces such as the auricles, 
increase in relative symmetry of the shell, and evening of the overall 
shell surface by a great reduction in the prominence of the auricular 
sulci, interplical sulci, and plicae. Reduction in shell size may also 
have affected stability of the shell, though it is more likely tied to the 
restricted amount of available feeding time in active shallow-water 
environments as compared to that available in deeper, nonagitated 
waters. 

The development of smaller and more numerous plicae by shallow- 
water ostreids in this lineage appears to be a twofold adaptation to a 
near-shore environment. Most obviously this results in strengthening 
of the shell, necessary for life in the presence of waves, strong 
currents, and continued buffeting, while at the same time eliminating 
coarse projections from the shell surface, producing a more even, less 
resistant surface over which water can flow. Even more important 
may be the role of plications as an adaptation to feeding in a turbid, 
high-energy environment. Development of extensively plicate and 
crenulate commissures in marine bivalves allows the animal to reduce 
considerably the gape of the valves during feeding over that required 
by forms with smooth margins, without greatly altering the total 
amount of open area between the valves for the influx of water. The 
advantages of reducing the gape while maintaining normal water 
intake in a turbid environment are apparent, since there is a 
corresponding reduction in the size and possibly the amount of foreign 
particles able to filter between the valves, and consequently a greater 
degree of protection against clogging of the feeding mechanisms and 
agitation of the mantle. This helps to offset the abundance of mobile 
detritus found in near-shore, high-energy environments, and allows 
the oyster to feed for longer periods of time, and tolerate greater 
turbidity, than nonplicate species subject to the same conditions. 

Progressively younger members of the lineage display a gradual 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN 23 

increase in the relative size of the attachment area, the general size 
and inclination of the area being unusually consistent within species 
and subspecies. Increase in the size of the attachment area, and 
decrease in the angle between the area and the commissure both 
appear to be adaptations to high-energy, near-shore conditions, pro- 
viding a firmer anchor and lower, hydrodynamically more stable shell 
in the face of strong current and wave action. There is evidence in 
the Lopha lugnhris group that these may be genetically controlled 
features of the shell as well as adaptive variations of individual mem- 
bers of the lineage. 

Evidence favoring genetic control of inclination and size of the 
attachment area is found in the end members of the lineage. All 
observed specimens of L. hellaplicata novamexicana have a very 
small attachment area. The size of the area relative to the size of the 
adult shell possibly indicates early detachment of the shell from the 
substrate and a free-living adult stage. Were this purely an adaptive 
feature, one would expect it only in quiet-water environments, since 
a free-living shell of the novamexicana type in normal living position 
(convex left valve downward) would be highly unstable in the face of 
strong currents or wave action, and easily overturned and buried. 
Although sediments containing most L. hellaplicata novamexicana 
indicate quiet or slightly agitated water conditions, a few specimens 
occur in coarse-grained, coarse-bedded sandstones of high-energy 
environments. These maintain the small attachment area. Further, 
no adaptive counterpart of the subspecies having a large attachment 
scar is developed in the near-shore facies. Scar size thus appears to 
be independent of environment in this case. 

Similarly, L. lugubris has an exceptionally large, gently inclined 
attachment area regardless of associated sediment type and inferred 
environment. These features indicate attachment throughout life, 
and are adapted to high-energy conditions. Sediments containing 
most specimens of L. lugubris reflect such an environment. The 
species is most common in cross-bedded, ripple-marked calcarenites 
and calcareous sandstones. A number of examples from thinly 
laminated shales and fine sandstones and siltstones, however, maintain 
the large, gently inclined scar, even though it was probably not neces- 
sary for firm anchorage in the more quiet water environments. 

The change in inferred living habit from partially free to wholly 
attached, and the consistency in the character of the attachment area 
on these two forms, regardless of associated environment, suggest 
genetic control on the size and inclination of the area. 



24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

The middle member of the lineage, L. hellapUcata hellaplicata, 
exhibits more variation in scar size (pi. 3), with individuals that 
probably lived free during part of their adult life, and others that could 
well have been attached throughout life. These two forms coexist in 
the great variety of environments from which the species is known, but 
there is a notable increase in the relative percentage of individuals 
with large attachment areas in shallow-water sediments deposited 
under high-energy wave and current conditions (Codell Sandstone). 
Scar size thus appears to be largely adaptive and environmentally 
controlled in this subspecies. 

Small shell size is considered by some ecologists as an adaptation 
to turbid, near-shore environmental conditions. This may be the 
case in the L. lugiibris lineage where there is a distinct trend toward 
reduction in the average adult dimensions with the onset of shallow- 
water conditions during the Late Turonian. Shallow-water epifaunal 
elements are able to spend less time feeding than their counterparts 
in deeper, quieter waters. Long periods during which little feeding 
takes place are imposed on them by extended times of high turbulence 
and water agitation. This restriction on food intake has been related 
to the below average size of many shallow-water epifaunal pelecypod 
species which develop to normal proportions in quiet, offshore waters. 
This, of course, is purely an ecologic control on shell form. In the 
many cases, however, where the smaller of two closely related species 
or subspecies of epifaunal pelecypods lives closest to the inner sub- 
littoral zones of constant water agitation and turbidity, small size 
seems to be a genetic adaptation to the environment. The smaller 
species, requiring less food, are better able to survive in environments 
presenting shorter and more irregular feeding opportunities. 

The changes of other structures through time are well defined and 
easily recognized, but based on my present knowledge of the zoologi- 
cal characteristics of the group and of the Turonian environment, it is 
difficult to explain them in terms of adaptive features. 

SHELL MORPHOLOGY 

Standard terminology has been used wherever possible in describing 
species and subspecies of the Lopha lugubris group (see Newell 
1937, 1942, Shrock and Twenhofel, 1953, for definitions of standard 
terms). A few new or rarely used terms are employed here for fea- 
tures not generally considered in ostreid description. It is desirable to 
briefly define these. In most cases this is simply accomplished by 
means of an illustration (fig. 10a, b, c, d), especially in regard to 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 25 

spacial divisions of the valve (fig. 10c; see explanation). Discussions 
are presented below for new terms employed, as a key to abbreviated 
ratios (tables 1-5) or where it seems possible that misunderstandings 
may arise in interpretation of a term in the descriptions as it is 
applied to the Ostreidae. The letters arranged alphabetically below 
refer to fig. 12, and tables 1-5. 

A: AATS — The ratio of the approximate area of the left (lower) valve to the 

approximate area of the attachment scar, as determined by their 

inscribing rectangles, oriented with their sides paralleling height 

and length. 
A A — Anterior auricle, or ear (fig. 10a) ; rarely developed and generally poorly 

defined flattening and projection of the dorsoanterior margin, 

generally separated from the main body of the shell by a small 

auricular furrow or sulcus. 
ANS — Anterior slope of the valve (includes lower part of the anterior auricle, 

where developed) ; the portion of the shell between the dorsal and 

anteroventral slopes, and the crest (fig. 10c). 
A : P — The ratio of the area of a rectangle inscribing the valve to the number 

of plications present at the valve margin. 
AS — Auricular sulcus (figs. lOa-c) ; an external furrow or depression which 

separates the anterior and posterior auricles from the main body 

of the shell. In this group it is commonly expressed as a rela- 
tively deep, slightly enlarged interplical sulcus. 
AVS — Anteroventral slope of the shell, between the median plication, crest, 

and anterior slope (fig. lOc). 
CCP — Central cardinal plate. On the right valve, a flat surface developed in 

the central cardinal area, in place of a shallow resilifer. 
CR — Crest of the valve ; the highest area of the valve, either slightly convex or 

nearly flat, situated dorsocentrally (fig. 10c). 
D — Denticles ; small raised nodes, rounded to elongate, on the inner dorsolateral 

margins of the valves (fig. lOd). 
DS — Dorsal slope of the valves (includes the attachment scar where present; 

fig. lOc). 
HA — Hinge axis (cardinal axis), the axis of rotation of the valves (fig. lOd). 

The ligament lies dorsal, the main part of the resilium ventral. 

The only parts of the two shells always in contact. When the 

hinge line is straight, it may parallel this axis. 
H : L — Ratio of valve height to valve length. 
HP — High point of the valve (fig. 10c), marking the point of greatest convexity. 

This is usually within the crest on the median plication, and is a 

good reference point for delineating the various flanks of the 

valves. 
H:DPAS — The ratio of the valve height to the greatest diameter of the 

posterior adductor muscle scar. 
H : HATS — The ratio of the valve height to the height of the attachment scar, 

as measured on the left valve. 
H : HD — The ratio of the valve height to the height of that part of the valve 

bearing denticles along the inner lateral margins. 






D 




Fig. 10. — Morphology of oysters in the Lopha lugubris group, using specimens 
o£ L. bellaplicata bellaplicata for illustration (A, C, U.S.N.M. 132222; B, 
U.S.N.M. 132239; D, U.S.N.M. 8024d). A, External shell morphology of left 
valve. B, External shell morphology of right valve. C, Spatial divisions of valve 
referred to in text, D, Interior morphology of right valve. Symbols explained 
in detail under "Shell Morphology." AA, Anterior auricle. ADM, Anterodorsal 
margin. AM, Anterior margin. ANS, Anterior slope. AS, Auricular sulcus. 
ATS, Attachment scar. AVM, Anteroventral margin. AVS, Anteroventral 
slope. B, Beak. C, Commissure. CR, Crest of valve. D, Denticles. DM, 
Dorsal margin. DS, Dorsal slope. H, Height of valve. HA, Hinge axis. 
HP, High point of valve, i. Angle of inclination. ICL, Imbricating concentric 
lamellae. IPS, Interplical sulcus. L, Length of valve. LCP, Lateral cardinal 
plate. MCT, Marginal cardinal trough. MF, Midcardinal fold. ML, Micro- 
lamellae. MP, Median plica. MSD, Maximum diameter of posterior adductor 
muscle scar. PA, Posterior auricle, paa, Posterior auricular angle. PAS, 
Posterior adductor muscle scar. PDM, Posterodorsal margin. PLS, Postero- 
ventral lip of the muscle scar. PM, Posterior margin. PP, Primary plica. 
PS, Posterior slope. PVM, Posteroventral margin. PVS, Posteroventral slope. 
R, Resilifer. SC, Subcardinal cavity. SP, Secondary plica. SS, Smooth stage 
of umbo. U, Umbo. VM, Ventral margin. All figures y^.. 

26 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 27 

H : HSS — The ratio of the valve height to the height of the smooth stage on 
the early portion of the valve. 

i — The angle of inclination of the valve (fig. 10c) ; the angle between the 
plane of the hinge line (horizontal) and a line connecting the 
beak (or center of the attachment scar) with the most distant 
edge of the shell. This line generally roughly bisects the shell. 

ICL — Imbricating concentric lamellae; the major concentric features of the 
ornamentation (fig. 10b). 

IPS — Interplical sulcus; the trough between any two plicae. The auricular sulci 
are enlarged interplical sulci separating the auricles from the 
main body of the shell (figs. 10a, b). 

LCP — Lateral cardinal plates (fig. lOd, 5a-c) ; triangular flat areas for liga- 
ment attachment on either side of the resilifer and midcardinal 
fold (right valve). These are highly variable in size, and com- 
monly bordered laterally by a shallow groove (marginal cardinal 
trough). 

L :LHL — Ratio of the length of the valve to the length of the hinge line. 

L : LPA — Ratio of the length of the valve to the length of the posterior auricle. 

MCT — Marginal cardinal trough. A shallow, narrow groove or trough on the 
cardinal area between the lateral cardinal plate and upturned 
lateral margin of the valve (fig. lOd). 

MF — Midcardinal fold. The raised convex portion of the central cardinal area 
on the right (upper) valve, below the resilifer (where present). 
It occupies from one-fourth to the whole of the area. 

ML — Microlamellae ; very fine overlapping sheets of lamellar calcite. The 
major ornament on the smooth stage of the shell and between 
imbricating concentric lamellae over the rest of the shell (fig. 
lOb). They appear as simple growth lines in many cases. 

MP — Median plica (figs. 10a, c) ; the major primary plication that runs down 
the approximate center of the valve, passing through its high 
point. It is usually the most prominent plica on the shell, and is 
a useful reference line for defining the various flanks. 

MSD — Maximum scar diameter (fig. lOd) ; the longest diameter of the posterior 
adductor muscle scar, the least variable parameter of the scar 
to measure ; useful in ontogenetic study. 

PA — Posterior auricle (figs. lOa-c), or wing of the shell (in the sense of 
Newell, 1942, p. 22 as applied to the Mytilacea). This is a 
prominent, flattened, projecting salient of the posterior and 
dorsoposterior flanks of the shell, in some cases separated from 
the main body of the shell by an auricular sulcus. 

paa — Posterior auricular angle (fig. 10c) ; the angle between the dorsoposterior 
margin of the posterior auricle and the plane of the hinge line 
(horizontal reference line). 

PD — Plication density. The number of plications per unit approximate shell 
area (HXL). 

PLS — Posteroventral lip of the adductor muscle scar (fig. lOd). A raised ridge 
that bounds the scar posteriorly and ventrally in many species. 

PP — Primary plica ; one of the initial plications of the shell, arising at the edge 
of the smooth stage and extending to the shell margin. It may or 
may not give rise to other plicae by bifurcation (fig. 10a, b). 



28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

PS — Posterior slope of the shell, including the posterior auricle (fig. 10c). 

PVS — Posteroventral slope of the valves, bounded by the median plica, crest, 
and posterior slope of the valve (fig. 10c). 

SC — Subcardinal cavities; shallov^ re-entrants of the valve floor beneath struc- 
tures of the cardinal area, predominantly below the midcardinal 
fold or lateral cardinal plates. 

SP — Secondary plica ; one that arises through bifurcation from a primary plica- 
tion (figs. 10a, b). 

SS — Smooth stage; that portion of the beak, umbo (in many cases the whole 
umbo), and adjacent parts of the valve that lack radiating plica- 
tions (fig. 10b). This probably represents part or all of the 
shell of the spat. 

T — Thickness; valve thickness is employed in this study as the actual thickness 
of the shell material. This is naturally variable in a single valve. 
Valve thickness should not be confused with shell or valve width. 

W — Shell width ; here defined as the broadest diameter of coattached valves when 
viewed along the plane of the commissure. It is the length of a 
diameter joining the high points of each valve and perpendicular 
to the plane of symmetry. The width of a single valve is measured 
similarly — between the high point of the valve and the com- 
missure plane (or if the beak is overhanging, the plane passing 
along its most projecting edge), 

SYSTEMATIC PALEONTOLOGY 
Genus LOPHA Bolten, J. F.: Emended Kauffman, 1964 

1798. Bolten, J. F. (=Roeding, P. F.), Museum Boltenianum sive catalogus 
cimeliorum e tribus regnis naturae, pt. 2, pp. 168, 169. 

1898. Dall, W. H., Contributions to the Tertiary Fauna of Florida. Trans. 
Wagner Free Inst. Sci. Philadelphia, vol. 3, pt. 4, p. 672. 

1936. Maury, C. J., Brazil Servico Geol. e Mineralog., Mon. 11, p. 157. 

1937. Arkell, W. J., A monograph of British Corallian Lamellibranchia. 

Paleont. Soc, p. 180. 
1940. Cox, L. R., The Jurassic Lamellibranch fauna of Kuchh (Cutch). Mem. 
Geol. Surv. India, ser. 9, vol. 3, p. 95. 

Type species. — Ostrea crista-galli Linne, by subsequent designation, 
Dall, 1898, p. 672. 

Diagnosis. — Shell normally small to moderate size, subequilateral 
to moderately inequilateral, slightly to moderately inequivalve, left 
valve slightly larger and more convex than right. Outline ovate, 
subround, or subquadrate; posterior auricle commonly developed. 
Beak opisthogyre to suberect. External ornament subequally devel- 
oped on both valves, consisting of strong radiating plicae originating 
at the umbone and extending to the commissure, increasing by bifurca- 
tion and intercalation. Commissure trace undulating, more rarely zig- 
zag. Shell structure predominantly lamellate (subnacreous layer), 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 2g 

adjacent layers of gently inclined lamellae commonly with opposed 
dips. 

Cardinal area of both valves consisting of central triangular resilifer 
and triangular, subequally developed, lateral cardinal plates. Resilifer 
of right valve commonly bounded ventrally by a low lip or partial 
midcardinal fold. Subcardinal cavities commonly absent. Dorso- 
lateral inner valve margins subequally denticulate ; denticles small, 
simple, ovoid to elliptical, their long axis perpendicular to commissure. 
Posterior adductor muscle attachment area posterocentral ; outline 
comma-shaped ; well defined. 

Remarks. — Many recent workers have included Lopha {= Alec- 
try onia) in synonymy with Ostrea, or considered it a subgenus or 
section of Ostrea. Modern representatives of Lopha lack a promyal 
chamber and are monoecious as are species of Ostrea. Ranson (1942, 
1948) has demonstrated that the prodissoconch features of Ostrea 
and Lopha are similar as well. Paleontologists have continued to 
use the name however, since Lopha is quite distinct from Ostrea 
in shell sculpture, and the two do not intergrade. Ostrea rarely 
develops plications, and in cases where they are present, they do not 
approach those of Lopha in size or development. In addition, species 
of Ostrea are more equivalve, generally lack curved beaks and umbos, 
and have a flat commissure. 

Perhaps the most important distinction between Lopha and Ostrea 
is in the shape of the muscle scar — comma-shaped in Lopha, con- 
sistently laterally elongate, ovate to kidney-shaped, and larger in 
Ostrea. This reflects basic differences in the anatomy of the muscle 
itself. In combination, these distinctions are sufficient to consider 
Lopha and Ostrea separate genera. Their similarities probably reflect 
a common ancestry somewhere in the Mesozoic. 

The name Alectryonia has commonly been applied to oysters with 
the characteristics of Lopha, and the two are objective synonyms, 
having the same type species. The popularity attained by Alec- 
tryonia in recent years stems from Stenzel's acceptance of the name in 
place of Lopha (1947, p. 169, 177) under the rules of the Inter- 
national Commission of Zoological Nomenclature that existed at the 
time of his work. Lopha originally appeared in Bolten's Catalogue 
without description or definition other than "Lopha Der Hahnen- 
kamm" (Lopha the cock's comb : Stenzel, 1947, p. 177). A list of sev- 
eral valid species followed, but with no indication as to which was the 
type. Ostrea crista-galli Linne, now considered the type species of 
Lopha, headed the list. Subsequently, Alectryonia Fischer de Wald- 



30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

heim was validly proposed in 1807 before Lopha was validated with 
formal description. The new rules of the Commission, however, 
published in 1961, do not demand formal description of a new genus 
as long as it is accompanied by listing of a valid species. Thus Lopha 
can be considered validly proposed as of 1798, and Alectryonia, 
proposed later with the same type species, becomes a junior objective 
synonym. 

The restricted usage of Lopha here does not incorporate many 
groups that have previously been assigned to the genus because of 
their plicate shell, but which probably belong to distinct groups. 
Among these are the plicate Pycnodonte, which have vesicular shells, 
Arctostrea, a distinct lineage since the Jurassic, Agerostrea, a modifi- 
cation of the Arctostrea branch, and the narrow elongate "tree 
oysters" with their clasping shelly processes. 

In published descriptions of Lopha or Alectryonia, certain mor- 
phologic features are given as diagnostic of the group which I do not 
consider significant at this taxonomic level. Curvature of the adult 
hinge line is too easily distorted by variation in direction of adult 
growth to be useful, especially for oysters growing in crowded con- 
ditions. The divaricate pattern of radiating ornamentation attributed 
to Alectryonia and Lopha is not characteristic of the genus but rather 
of Arctostrea and some Rastellum. The use of this as a diagnostic 
generic character reflects the time when these groups were all placed 
under Lopha. Clasping shelly processes are rarely developed around 
the attachment area of Lopha and are not diagnostic. They are 
more typical of the so-called tree oysters, which probably constitute 
a distinct group. 

Characters of the shell which appear to be useful in distinguishing 
Lopha from similar forms, and in separating the genera of plicate 
oysters, are: General shell form; basic ornament pattern; relative 
development of component parts of the cardinal area; presence, 
morphology, and distribution of the denticles ; presence or absence of 
subcardinal cavities; depth of the valves (especially the left valve) ; 
position, size, and shape of the posterior adductor muscle scar; shell 
structure ; and in some cases juvenile ornamentation and nature of the 
commissure. 

LOPHA LUGUBRIS Conrad 
Plate 1, figures 1-18; plate 2, figures 1-17; plate 8, figure 12 

Ostrea lugubris Conrad, U. S. Mex. Boundary Rep., vol. 1, p. 156, pi. 10, 
figs. 5a, b, 1857.— CoQUAND, Mon. Genre Ostrea Terr. Cret., p. 66, pi. 36, 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN 3 1 

figs. 22, 23, 1869. — Meek, Macomb's Expl. Exped. from Santa Fe to Junc- 
tion Grand and Green Rivers, p. 123, pi. 1, figs, la-d, 1876. — White, 4th 
Ann. Rep. U. S. Geol. Surv., p. 297, pi. 41, fig. 3, 1884.— Cragin, 4th Ann. 
Rep. Geol. Surv. Texas, p. 204 (in part), 1893. — Stanton, U. S. Geol. 
Surv. Bull. 106, pp. 58, 59 (in part), pi. 4, figs. 1-5, non figs. 6-10, 1893 
[1894]. — Logan, The Univ. Geol. Surv. Kansas, vol. 4, pt. 1, p. 455 (in 
part), pi. 91, figs. 1-5, fton figs. 6-10, 1898. — Herrick and Johnson, Bull. 
Denison Univ. Sci. Lab., vol. 40, p. 202 (in part), 1900. — Johnson, School 
of Mines Quart., vol. 24, No. 2, pp. 186, 187, 1903a ; Columbia Univ. Contr. 
Geol. Dept., vol. 10, No. 90, pp. 114, 115 (in part), 1903b.— Shimer and 
Blodgett, Amer. Journ. Sci. Arts, 4th ser., vol. 25, p. 61 (in part), 1908. 

Ostrea (Alectryoma) lugiibris Conrad, Bose, Bol. Inst. Geol. Mexico, No. 30, 
Algunas faunas del Cret. de Coahuila, pp. 47, 48, pi. 8, figs. 4-6, 1913. — 
Shimer and Shrock, Index foss. N. Amer., p. 395, pi. 154, figs. 4, 5, 1955. 

Alectryonia lugubris (Conrad) Adkins, Handbk. Texas Cret. Foss., p. 104 
(in part), 1928. 

DESCRIPTION 

Material. — Approximately 350 well-preserved specimens (measured) 
and an additional 200 to 300 poorly preserved valves from various 
localities in Texas, New Mexico, and Colorado, including most 
illustrated types of the species. Ontogenetic series and large variation 
suites are available from several New Mexico and Colorado localities. 

General form. — Summary of measurements presented in table 1. 
Shell small, inequivalve, left (lower) valve slightly larger, much more 
convex than right valve. Valves slightly to moderately inequilateral, 
normally prosocline ; beaks, umbos typically opisthogyre (exogyroid) 
(pi. 1, fig. 5). Left valves commonly round, subround, or broadly 
subovate, rarely subelliptical ; right valves subovate to elliptical, slightly 
curved (pi. 1, figs. 1-6; pi. 2, figs. 1-3, 5-12 typical of species). 
Height normally greater than length. Anterior and ventral margins 
slightly to moderately and unevenly rounded, posteroventral corner 
narrowly rounded, posterior margin slightly concave to nearly straight 
on valves with posterior auricle, otherwise moderately curved. Dorsal 
margins short, rounded, moderately inclined anteriorly, gently sloping 
posteriorly over auricle, recessed posteriorly adjacent to beak, umbo. 

Convexity. — Left valve moderately to highly convex, rarely flattened ; 
high point subcentral, on ventral edge of attachment scar. Anterior, 
posterior, ventral, ventrolateral flanks moderately to steeply sloping ; 
dorsal and dorsolateral flanks, including attachment scar, gently 
sloping. Right valve flat to moderately convex, normally slightly 
arched, with umbo more inflated (pi. 2, figs. 2, 6) ; rarely concave. 
Some right valves with upturned margins and submarginal trough. 



32 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



Table 1. — Summary of measurements on specimens of Lopha lugubris (Conrad) 



Character Valve 

Height (H) J^ 

Length (L) j^ 

Width (W) (^ 

( 

Percent valves with H > L LR 

Percent valves with L>H LR 

Percent valves with H = L LR 

Area, inscribing rectangle of valve 

(HXL) L 

Length, beak to posterior margin 

(LBP) L 

Ratio, LBP:L L 

Angle of inclination (i) \ 

Height of attachment scar (HATS). L 
Length of attachment scar (LATS) . L 
Area, inscribing rectangle of attach- 
ment scar (HATS X LATS) L 

Ratio, area of scar (inscribing rec- 
tangle) : area of valve (inscrib- 
ing rectangle) L 

Percentage of valves with plicate 
exterior surface (not including 
those with only the margin plicate 
or crenulate) ) 

Height, smooth young stage (HSS), 
on dorsal part of plicate valves .... 3 

HSS on left valves with HSS > 
HATS L 

Ratio, HHS:H j^ 

Number of primary pHcae at first 

appearance \ 

(^ 
Number of plicae at 10 mm. H (on 

shells where HSS<10 mm.) )^ 

Number of plicae at 20 mm. H ) 

Total number of plicae (marginal 
count) ) 

Number plicae in 20 mm. L at 
20 mm. H (median plica central) . .3 



No, of 
specimens 


Rangf 




Average 


175 


7.6-41.2 


mm. 


17.3 mm. 


161 


7.4-23.9 


mm. 


15.2 mm. 


173 


7.5-23.3 


mm. 


14.9 mm. 


161 


4.6-23.0 


mm. 


12.8 mm. 


169 


1.5-9.6 


mm. 


Z.7 mm. 


160 


1.0-6.2 


mm. 


2.7 mm. 


303 






90.7% 


303 






7.9% 


303 






1.4% 



133 



1 18.8-564.0 mm. 272.5 mm. 



163 


2.5-11.0 mm. 


6.5 mm. 


94 


0.31-0.55 mm. 


0.43:1mm. 


80 


43°-97° 


73.4° 


65 


40°-93° 


72.3° 


157 


4.4-20.0 mm. 


12.3 mm. 


157 


4.0-17.5 mm. 


9.5 mm. 


100 


17.6-285.4 mm.' 


121.9 mm.' 



100 0.13:1-0.78:1 



0.46:1 



175 




81.7% 


161 




23.0% 


40 


9.4-21.1 mm. 


15.0 mm. 


79 


7.1-21.1 mm. 


14.2 mm. 


24 


9.0-20.2 mm. 


13.7 mm. 


80 


0.60:1-1:1 


0.80 : 1 


64 


0.62 : 1-1 : 1 


0.92 : 1 


78 


10-24 


18.1 


38 


13-24 


16.9 


6 


10-18 


14.7 


3 


13-16 


14.7 


47 


15-24 


19.6 


16 


14-24 


18.8 


130 


10-24 


18.8 


38 


13-25 


17.0 


44 


5.75-11.0 


7.32 


19 


5.25-8.5 


6.8 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 



33 



Table 1. — Summary of measurements on specimens of Lopha lugubris 
( Conrad) — continued 



Character Valve 

Width of median plica at 20 mm. H . . ) 

Percentage of plicate valves with 
bifurcating plicae y- 

(R 

Percentage increase in plicae by 
bifurcation (measured only on 
valves with bifurcating plicae) 3 

Percentage of specimens with opis- 

thogyre beaks and umbones 3 

(R 
Percentage of specimens with or- 

thogyre beaks and umbones 3 

(R 
Percentage of specimens with proso- 

gyre beaks and umbones 3 

)R 

Length of hinge line (LHL) 3 

I 
Ratio, LHL:L 3^ 

|r 

Extent of denticles on inner margins 

(in terms of valve height ; HD) 3 

(R 

Ratio, HD:H 3^ 

(R 

Number of denticles in 5 mm. length 
along dorsolateral margins, just 
below cardinal area 3 

(R 

Maximum diameter of muscle scar 
(MDS) jL 



No. of 

specimens 

50 


Range 
1.2-3.5 mm. 


Average 
2.1 mm, 


24 


1.1-3.1 mm. 


2.1 mm. 


130 
32 




23.8% 
18.8% 


13 
2 


4.5-22.2% 
6.7% 


9.22% 
6.7% 


157 
161 




78.9% 
72.7% 


157 
161 




3.3% 
Z.7% 


157 

161 

33 


2.3-8.5 mm. 


17.8% 
23.6% 
5.1 mm. 


26 


2.8-8.1 mm. 


4.4 mm. 


34 


0.15:1-0.55:1 


0.33 : 1 


26 


0.17:1-0.43:1 


0.28:1 


32 


2.2-9.6 mm. 


4.7 mm. 


25 


1.2-10.2 mm. 


4.6 mm. 


32 


0.12:1-0.41:1 


0.26:1 


25 


0.08:1-0.51:1 


0.26:1 


18 


9-17 


13.2 


18 


11-29 


14.3 


32 


3.0-7.8 mm. 


5.1 mm. 


18 


3.3-8.6 mm. 


5.3 mm. 



Auricles. — Anterior auricle rarely developed, most common on 
right valve. Auricle small, rounded, flattened salient of dorsoanterior 
margin (pi. 2, fig. 5), in some cases separated from shell by shallow, 
broad anterior auricular sulcus. Posterior auricle present on 59 per- 
cent of measured specimens ; small to medium size, subtriangular, 
elongate, flattened, margin rounded, position dorsoposterior (pi. 1, 
fig. 4). Auricle rarely separated from main body of shell by shallow, 
broad auricular sulcus. Auricular sulci corresponding to enlarged 
interplical sulci on plicate valves. 

Beaks, umbones. — Typically opisthogyre, rarely erect, more com- 



34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

monly prosogyre, predominantly exogyroid on left valves, attaining 
three-quarters to one and one-half volutions (pi. 1, fig. 5, text fig. 3c) 
on both prosogyre and opisthogyre shells ; strongly curved where not 
exogyroid, Beaks, umbos moderately curved posteriorly on most 
right valves. Beak pointed (right valve) to narrowly rounded (left 
valve), situated centrodorsally or just posterior to midline. Prodis- 
soconch rarely preserved, smooth, flat, separated from umbo by single 
prominent growth line or concentric constriction. Beak, umbo flat 
to concave on left valve, deformed on attachment scar; slightly to 
moderately inflated on right valve, in some cases separated from rest 
of valve by prominent constriction and/or abrupt change in ornament 
(pi. 2, figs. 2, 5, 6). 

Attachment area. — Situated on dorsoposterior flank, large on most 
left valves (pi. 1, figs. 1-14), equal to one-half area of shell, flat to 
concave, gently inclined to plane of commissure (average angle 24°), 
outline rounded to subovate, similar to ultimate shape of valve. 
Ornament of attachment area reflects surface to which attached, nor- 
mally Ostrea and Inoceramus shells; area marked with concentric 
lines and folds. No clasping processes developed. Attachment area 
commonly obscures beak, umbo. 

Ornamentation, left valve. — Beak smooth; early part of umbo 
smooth, central and ventral portions covered with fine growth lines, 
small concentric undulations. Free surfaces of most valves covered 
with coarse, simple (primary), radiating plicae (pi. 1, figs. 1, 2, 4-6), 
originating abruptly at or near margin of attachment area and extend- 
ing to commissure, rarely bifurcating; rare valves smooth, with plicae 
reflected as marginal crenulations, or with plicae greatly reduced in 
prominence (pi. 1, figs. 3, 11-14). All gradations known between 
smooth and fully plicate forms. Primary plicae straight to slightly 
curved, slightly broader than high, crests rounded, flanks steep, more 
prominent centrally than laterally, becoming higher, more angular, 
broader, more prominent with age. Secondary plicae smaller, lower 
than primaries, more rapidly expanding in size (pi. 1, fig. 4). 
Interplical sulci deep, steep-walled, narrower than plicae, angular to 
narrowly rounded at base. Commissure strongly undulating, rarely 
zigzag, at intersection with plicae. 

Concentric ornament between edge of attachment area and plicate 
portion of valve with faint growth lines, microlamellae, more rarely 
with crowded, coarse, flat, major overlapping lamellae. Plicate portion 
of valve characterized by moderately spaced to crowded overlapping 
lamellae separated by very fine growth lines. Lamellae irregularly 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 35 

spaced, normally flat, terminally in contact with succeeding ones ; 
rarely raised. Plicae rugose at intersection with lamellae. 

Ornamentation, right valve. — Ornament of right valve distinct 
from that of left valve. Beak and early umbonal area smooth ; central, 
ventral portions of umbo marked with faint growth lines, less com- 
monly with small, low undulations and microlamellae, rarely with scat- 
tered coarse lamellae or undulations on ventral umbo. Majority of 
specimens lack radiating sculpture over rest of valve, but many of these 
have marginal crenulations near commissure (pi. 2, figs. 1,8). Plicae 
variously developed on minority of specimens (pi. 2, figs. 2-7), never 
covering more than half of valve, commonly confined to marginal 5 
mm. Plicae originate abruptly, on strongly plicate valves at edge of 
inflated umbonal area (pi. 2, fig. 5) ; plicae prominent, rounded, 
with steep flanks, becoming coarser with age, rarely bifurcating; 
secondary plicae smaller, more rapidly expanding than primaries. 
Plicae rugose at intersection with concentric lamellae ; plicae of right 
valve more prominent, sharper, than those of left. Interplical sulci 
deep, narrow, sharp-based, steep-walled. 

Concentric ornament variable, depending on extent of plicae. Low, 
evenly convex valves lacking plicae covered with faint concentric 
growth lines, microlamellae, low, broad undulations (pi. 2, fig. 11) 
except at margin where coarse, crowded lamellae occur. Valves with 
inflated, smooth umbo and flat flanks (pi. 2, fig. 2) exhibit coarse, 
crowded, major lamellae, raised growth lines, small prominent undula- 
tions on flanks ; ornament more prominent near commissure. On 
plicate valves, prominent lamellae and/or concentric constrictions 
occur at inner margin of point of origin for plicae (pi. 2, figs. 5, 6). 
Growth lines and lamellae occur throughout plicate portion of valve. 

Cardinal area. — Composed of subcentral resilifer and/or mid- 
cardinal fold (right valve), bounded laterally by flat to moderately 
arched lateral cardinal plates or folds for ligament attachment. Resili- 
fer of left valve shallow to moderately concave, elongate-triangular 
with twisted apex, higher than long, slightly flared ventrally, equal to 
or larger than lateral cardinal plates or folds (pi. 1, fig. 16). Lateral 
plates, folds subequal, variable in relative size, flat to arched, obscure 
to prominent, triangular with curved dorsal apices, in some valves 
separated from lateral margins by narrow lateral cardinal grooves 
(pi. 2, fig. 17), otherwise merging with margin. Lateral cardinal areas 
of right valve similar, less commonly arched. 

Central part of cardinal area variable in right valves, ranging from 
flat midcardinal plate to shallow concave resilifer with raised ventral 



36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

lip or partial midcardinal fold (pi. 2, fig. 17). Rarely, entire midcar- 
dinal fold developed (pi. 2, fig. 14), slightly to moderately convex. 
Cardinal area of both valves marked by moderately strong, irregularly 
spaced, crowded, raised horizontal lines transected by finer, more 
crowded, more evenly spaced, raised vertical lines, forming reticulate 
pattern. Hinge line short, straight to slightly curved (concave 
ventrally) , situated ventral to hinge axis. 

Denticles. — Denticles present on inner dorsolateral margins of all 
valves, rarely extending below upper one-third of margin; small, 
simple, elongate perpendicular to shell margin, subround to ovate, 
crowded, distributed along commissure and in shallow trough just 
inside it ; color whitish, lighter than surrounding shell. 

Inner valve surface. — Commissure undulating, more rarely zigzag. 
Plicae reflected internally as rounded, low folds and sulci, nearly 
equal in extent to external trace of plicae, more prominent toward 
commissure. Fine, irregularly spaced, sinuous, pallial or vascular 
grooves transgress most of inner shell surface (pi. 1, fig. 17). 

Muscle scar. — Monomyarian, posterior adductor muscle insertion 
area (scar) subcentral, slightly posterior to midline, comma-shaped 
to subcrescentic, moderately curved, slightly to moderately concave, 
prominent. Surface of area marked with faint concentric lines and 
microlamellae, crowded near ventral and posterior margins, their 
trace conforming to growth lines. Posterior and ventral part of 
area bordered by low, raised, lip ; dorsal and dorsoanterior margins 
overlapped by inner shell layers. 

Shell structure. — ^Valves of medium thickness, variation in thickness 
moderate. Shell thickest at cardinal area, moderately thick over 
attachment area, thinning laterally, posteriorly. Thickness of average 
left valve : at cardinal area 0.9 mm. ; middle of attachment area 0.6 
mm. ; high point 0.5 mm. ; 2 mm. from ventral margin, 0.5 mm. 
Periostracum, prismatic layer, hypostracum not observed on sectioned 
valves. Subnacreous layer forms greatest part of shell, consisting of 
flat to gently curved calcite lamellae, parallel to one another on free 
flanks of valve, and curved, slightly inclined plates in distinct sets or 
layers over attachment scar. Inclination of plates in one layer com- 
monly opposed to those of adjacent layers (pi. 8, fig. 12). Cardinal 
area composed of slightly curved, subparallel, thin lamellae of calcite. 

ONTOGENY 

Lopha luguhris is the species least suited for ontogenetic study in 
this group owing to the size of the attachment scar, which obscures 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN yj 

the nepionic and neanic development of many left valves, the lack of 
immature shells in the collections, and the limited size range of the 
species. Ontogenetic trends can be studied in the following structures, 
which are graphed or illustrated in figures 2-4, 6b, c, 9, 11-13. 

Concentric ornament. — Nepionic shell smooth, transition to neanic 
marked by single growth line or small constriction. Neanic stage with 
fine growth lines, becoming coarser, more crowded, mixed with micro- 
lamellae ventrally. Neanic-ephebic boundary poorly defined. Ephe- 
hic stage with coarse growth lines, microlamellae and scattered macro- 
lamellae, faint undulations, on left valve. Right valve with faint 
growth lines during early ephebic stage (ventral umbo), abrupt con- 
striction of shell at midephebic stage, marking cessation of major 
growth in body size, prominent lamellae, growth lines in late ephebic. 
Gerontic stage characterized by crowded, coarse major lamellae, small 
undulations near margin, marking great reduction in rate of shell 
growth, sharp change in concentric ornament marks ephebic — gerontic 
boundary. 

Radiating ornament. — Plicae appear abruptly in middle to late 
ephebic (most left, some right valves), rarely earlier, marking point 
where shell begins to grow free of substrate ; plicae becoming higher, 
broader, sharper, and rarely bifurcating through late ephebic, gerontic 
stages. 

Marginal outline. — (See fig. 11.) Nepionic: Prodissoconch sub- 
round. Neanic: Ventral growth exceeds lateral, outline vertically 
ovate, slight expansion of posterior flank. Ephebic: Ventral and 
posterior growth exceed that anteriorly and are nearly equal. Auricles 
form in early ephebic stage, expand with age. Relationship between 
expansion rate of auricle and overall lateral ephebic growth constant 
(fig. 12a). Gerontic: Outline remains essentially the same, slight 
flaring of ventral, ventrolateral margins. 

Curvature of midline axis. — Nepionic: Slight, poorly known. 
Neanic: Moderate to great (fig. 3c), gradually decreasing in late 
neanic stage and through ephebic and gerontic stages, becoming slight. 

Convexity. — On right valve (fig. 3b), gradual increase in degree of 
outward curvature from nepionic through early neanic, greatest in 
late neanic, early ephebic, gradually to abruptly decreasing through 
late ephebic. Gerontic stage marked by abrupt flattening, upturning 
of margin. 

Internal structures. — Rate of expansion of muscle scar, hinge line, 
constant, and less than rate of shell growth during neanic and early 
ephebic stages, tapered off gradually during late ephebic, and gerontic 



38 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



stages (figs. 13b, c). Elements of cardinal area poorly differentiated 
in neanic stage, becoming well defined at later stages. Extent of 
denticles relative to height of shell, and density of denticles, greatest 
during neanic, early ephebic stages, gradually decreasing in later 
growth stages (fig. 13a). 

Attachment scar. — Rate of size increase relative to total size of 
shell constant throughout neanic, ephebic stages, demonstrating con- 
tinued growth of attachment area throughout life. 




Fig. 11. — Ontogeny of Lopha lugnbris (Conrad). Growth line traces at 
approximately 1.25 mm. intervals on representative left (A) and right (B) 
valves of the species, showing developmental history of the marginal outline. 
Drawings X2. A, U.S.N.M. 132156; B, U.S.N.M. 132164. 



REMARKS 

Lopha luguhris (Conrad) is the most distinct member of the group 
and easily differentiated from related older species. In the Western 
Interior, it is the terminal member of the lineage known. On the 
Gulf Coast, however, Lopha panda (Morton) (Campanian, Lower 
Maestrichtian) possibly represents a stratigraphic extension of the 
lineage. Forms definitely connecting the two are presently unknown 
in this country. 

Lopha lugubris may be distinguished from L. bellaplicata bella- 
plicata (Shumard) and L. bellaplicata novamexicana n. subsp. by its 
smaller size, greater relative height, much-reduced posterior auricle, 
general absence of an anterior auricle, subovate to subelliptical mar- 
ginal outline, shorter, more inclined dorsolateral margins, subcentral 
and strongly curved to exogyroid beak and umbo, much larger and 
more gently inclined attachment scar, less convex left valves and 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 



39 



relatively more convex right valves, relatively larger muscle scar, a 
less inflated midcardinal fold (where present), and in having the 
resilifer relatively larger than either lateral cardinal plate or fold. 
It may be further distinguished from older species by the external 
ornamentation of the valves. In L. luguhris, the majority of right 
valves lack plicae, and smooth left valves are common. Plicate 
valves may be distinguished from those of older species in the follow- 



30 



25 



2 
S20 



il5 
u 



^lO 

< 
> 




5 10 15 

LENGTH: BEAK TO 

POSTERIOR EDGE 

(MM) 



N 




E 


1 
1 


G 






. 


• i*. ^ 


* * 


• 


•! 


B 








LEFT VALVE 




5 


10 


15 


20 


2£ 



iO- 




N 


— 1 

1 
1 


£ 1 G 


25- 






1 
1 
1 




2 

S20- 






1 
i 


•1 


X 

J- 
il5- 

Ul 

-1 






V . 
1 ■ • 


SP*.' 


^10- 

i 




". 


■ 




5- 








c 








RIGHT VALVE 


°4 


^5 




10 


15 20 25 



VALVE HEIGHT (MM) 



VALVE HEIGHT (MM) 



Fig. 12. — Ontogeny in Lopha lugtibris (Conrad). A, Relationship between 
length of the left valve and the distance between the beak and posterior edge, 
measured parallel to the length. B, C, Relationship between height and length 
of the left and right valves, respectively. Approximate boundaries between 
ontogenetic stages marked by dashed lines. N = Neanic ; E := Ephebic ; 
G =: Gerontic. 



ing manner : The plicae appear at a later stage of development, rarely 
bifurcate, and then only in the ephebic stage, and are smaller, nar- 
rower, and more numerous than those of other species. The auricular 
plicae are similar to those of the main body of the shell. L. lugubris is 
further distinct in generally lacking coarse concentric sculpture, and 
in having the plicae well defined on part of the valve interior. 

No species of oysters known to me are closely comparable to L. 
luguhris, although marginal variants of some North American and 
foreign species resemble it. Notable among these are "Ostrea" semi- 
plana Sowerby, L. bellaplicata hellaplicata, and L. panda Morton. 

No consistent ecologic control on any morphologic feature was 




A 



10 15 20 

SHELL HEIGHT (MM) 




10 15 20 25 

SHELL HEIGHT (MM) 




B 



10 15 20 25 

LENGTH OF VALVE(MM) 




5 
z 10 

UJ 



15 20 25 

LENGTH OF VALVE (MM) 




X 

< 



16 18 20 

VALVE HEIGHT (MM) 




X 

< 
2 



14 



16 18 20 

VALVE HEIGHT (MM) 



22 



24 



Fig. 13. — Ontogeny in Lopha lugubris (Conrad). A, Relationship between 
valve height and the amount of dorsal and lateral margin covered with denticles, 
measured parallel to valve height. B, Relationship between the length of the 
hinge line and the length of the valve. C, Relationship between the maximum 
diameter of the muscle scar and the height of the valve. All lines fitted visually. 
Approximate boundaries between ontogenetic stages marked by dashed lines. 
E = Ephebic ; G =: Gerontic ; R = Right valve ; L = Left valve. 



40 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 4I 

noted in comparing- suites of specimens from calcarenite, calcareous 
sandstone, dark shale, and conglomeratic calcarenite facies. The 
species is amazingly consistent in form for an ostreid. Similarly, 
there appears to be no recognizable geographic variation between 
Texas and northern Colorado. There is, however, some suggestion 
of stratigraphic variation which, when studied with large suites of 
specimens, may prove to be of subspecific importance. In Colorado 
and New Mexico, the species ranges through the Juana Lopez 
Member and its equivalents. In New Mexico, where the Juana Lopez 
includes a relatively thick series of calcarenites, shales, and calcarous 
sandstones, specimens of L. lugubris (particularly left valves) from 
the base of the section appear to be covered to a greater extent with 
radiating plicae than those from the top, which typically have the 
plicae limited to the valve margins. The younger specimens also have 
denser plication. Similar trends were noted at scattered localities in 
southern Colorado. The proper interpretation of these apparent trends 
must await larger collections, with better stratigraphic data, than are 
now available. 

Specimens of Lopha lugubris commonly occur in great numbers in 
basal Upper Turonian calcarenites of the Juana Lopez Member and 
its equivalents. The valves are typically unbroken, separated, and 
oriented with the convex surface upward. They do not occur in beds 
or "colonies," and very few show any evidence of deformation due to 
crowding. In many cases, they are the only well-preserved, complete 
shells in the sediment. 

Of particular interest is the commonly developed reverse curvature 
of the valves, and the development of exogyroid beaks in either direc- 
tion. In most species of oysters that develop tightly coiled or exogy- 
roid beaks and umbones, the direction of coiling is relatively constant 
and appears to be genetically controlled. Exceptions to the rule are 
deformed specimens growing in crowded living conditions. There are 
examples of reverse curvature in many of these species, but it is rare 
in almost all of them. The unusual coiling behavior of L. lugubris 
therefore provoked an investigation to see whether it was due to a 
breakdown in normal genetic control over coiling direction, or whether 
the species was capable of attachment by either valve. 

Well-developed reverse beak curvature is found in 17.8 percent 
of all left valves and 23.6 percent of all right valves of L. lugubris. 
In most of these, the coiling is exogyroid. In all cases of reverse cur- 
vature the muscle scar retains its position just posterior to the midline 
and there is no alteration in the structure of the cardinal areas on 



42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

either valve. I conclude from this that the direction of curvature is 
variable and not rigidly controlled genetically in this species (although 
posterior curvature dominates). Consistency in the position of the 
muscle scar and cardinal characters on both valves, irrespective of 
coiling direction, indicates attachment is always by the left valve, as in 
other ostreids. 

Stratigraphic and geographic occurrence. — Lopha lugubris ranges 
through the Juana Lopez Member and its equivalents (zones of 
Prionocyclus wyomingensis wyomingensis: early Late Turonian, and 
P. wyomingensis elegans: middle Late Turonian) in central, south- 
central, and eastern Colorado, western Kansas, and northern New 
Mexico. The primary types were reported to have come from beds 
containing P. macombi {P. wyomingensis wyomingensis zone). It 
has been found at an equivalent level in the Mancos Shale of western 
Colorado and New Mexico. In Huerfano Park, Colo., fragments 
questionably referable to this species were collected in the upper part 
of the "Pugnellus Sandstone" (Codell Sandstone Member, CarHle 
Shale; upper part of zone of Collignoniceras hyatti) associated with 
L. hellaplicata bellaplicata. The ranges of these species overlap 
slightly in Texas also, where L. lugubris is found in the upper 3 feet 
of the Eagle Ford Shale (late Middle Turonian, upper part of L. bella- 
plicata bellaplicata zone) and in the overlying conglomeratic calcaren- 
ite bed between typical Eagle Ford Shale and Austin Chalk. Hattin's 
report of this species from the Blue Hill Shale Member in Kansas 
(lower part of zone of Collignoniceras hyatti; 1962, p. 84) is based on 
a typical specimen of L. lugubris collected by J. B. Reeside, Jr. 
Pieces of matrix adhering to the specimen are rusty-brown calcarenite 
characteristic of the Juana Lopez Member in Colorado and at scattered 
Kansas localities, and the specimen probably came from a higher level 
than Reeside assumed. I have also examined specimens from the 
Fairport Chalk Member which Hattin assigned to this species (1962, 
p. 54). These belong to a distinct lineage and appear most closely 
related to the younger "Ostrea" tecticosta Gabb. 

Specimens of Lopha lugubris used in this study were obtained from 
localities 1 through 39 and 48, described in detail at the end of this 
report. 

Illustrated and measured specimens. — Lectotype, selected by 
Stanton (1894), U.S.N.M. 9822, the original of Conrad's plate 10, 
figure 5b (1857); Stanton's hypotypes, reillustrated (1893, pi. 4), 
U.S.N.M. 22859a (Stanton's fig. 5) 22859b (Stanton's fig. 3), 
22860a (Stanton's fig. 2) ; Meek's hypotype (1876, pi. 1, fig. la). 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN 43 

U.S.N.M. 20255 ; new hypotypes, U.S.N.M. 8354, 22008a, b, 22210a, 
b, 22211, 132154-132168 inclusive, 132174, 132198, 132258, 
132285; U.M.M.P. 43463-43465 inclusive, 43470-43472, inclusive. 
43476, 43484, 43486, 43487. Measured specimens, unfigured, 
U.S.N.M. 22210c, 132169-132173 inclusive, 132175-132197 inclusive, 
132199-132210 inclusive: U.M.M.P. 43460-43462 inclusive, 43467- 
43469 inclusive, 43473-43475 inclusive, 43477, 43488, 43489, 43491. 
Specimens from the upper Codell Sandstone questionably referred 
to this species, U.S.N.M. 132211, 132212. 

LOPHA BELLAPLICATA BELLAPLICATA (Shumard) 

Plate 3, figures 1-18 ; plate 4, figures 1-8 ; plate 5, figures 1-15 ; 
plate 6, figures 7-24; plate 8, figures 10, 11 

Ostrea bellaplicata Shumard, Trans. St. Louis Acad. Sci., vol. 1, p. 608, 1860. — 
White, 4th Ann. Rep. U. S. Geol. Surv., p. 292, pi. 47, figs. 1, 2, 3, 1884.— 
Cragin, 4th Ann. Rep. Geol. Surv. Texas, p. 199, 1893. — Bose, Algunas 
faunas del Cret. Sup. Coahuila, p. 48, 1913. — Winton, Univ. Texas Bull. 
2544, p. 62, pi. 8, fig. 5, 1925. 

Ostrea (Alectryonia) bellaplicata White, 11th Ann. Rep. U. S. Geol. Geogr. 
Surv. Terr. Idaho and Wyoming, pp. 276, 277, pi. 4, figs. 3a, b; pi. 8, 
figs. 2a, b, 1879. 

Ostrea (Alectryonia) blackii White, Proc. U. S. Nat. Mus., vol. 2, p. 293, pi. 4, 
figs. 1, 2, 1880; 12th Ann. Rep. U. S. Geol. Geogr. Surv. Terr. Wyoming 
and Idaho, pt. 1, pp. 11, 12, pi. 14, figs, la, b; pi. 17, fig. 5a, 1883. 

Ostrea blackii White, 4th Ann. Rep. U. S. Geol. Surv., p. 292, pi. 45, fig. 1 ; 
pi. 46, fig. 2, 1884. 

Ostrea lugubris Conrad, Stanton, U. S. Geol. Surv. Bull. 106, pp. 58, 59, pi. 4, 
figs. 6-10, non figs. 1-5, 1893 [1894].— Logan, The Univ. Geol. Surv. 
Kansas, vol. 4, pt. 1, pp. 445, 446, pi. 91, figs. 6-10, 1898.— Hill, 21st Ann. 
Rep. U. S. Geol. Surv., pi. 40, fig. 9, 1901. — Herrick and Johnson, Bull. 
Denison Univ. Sci. Lab., vol. 40, p. 202 (in part), 1900. — Johnson, School 
of Mines Quart., vol. 24, No. 2, pp. 186, 187 (in part), 1903a; Columbia 
Univ. Contr. Geol. Dept., vol. 10, No. 90, Geol. of the Cerrillos Hills, New 
Mexico, p. 114 (in part), 1903b. — Shimer and Blodgett, Amer. Journ. 
Sci. Arts, 4th sen, vol. 25, p. 61 (in part), 1908. — Hopkins, Powers, 
Robinson, U. S. Geol. Surv. Bull. 736, pi. 3, figs. 1, 2, 1923.— Adkins 
and Lozo, Stratigraphy of the Woodbine and Eagle Ford, Waco Area, 
Texas, pi. 5, fig. 1, 1951. 

Alectryonia lugubris, Adkins, Handbk. Texas Cret. Foss., p. 104 (in part), 
pi. 16, fig. 5; pi. 24, figs. 8, 9, 1928. Listed on pis. 16, 24, as A. lugubris 
(bellaplicata) . 

Description 

Material. — Approximately 400 well-preserved specimens (measured) 
from localities in Texas, New Mexico, and Colorado, including large 



44 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



variation and ontogenetic series, fossil "populations," and most North 
American types of the species. Numerous additional fragments. 

General form. — Summary of measurements presented in table 2. 
Shell attaining moderate size, average size decreasing from south 
(Texas) to north (Colorado) (fig. 14a, c) ; inequivalve, left valve 
slightly larger, much more convex than right ; slightly to moderately 
inequilateral, prosocline to acline. Outline commonly round to ovate, 
subquadrate, rarely triangular (pis. 3-6; pi. 3, figs. 1, 3, 5, 9-15 
typical) ; height slightly greater than length on majority of specimens. 
Anterior, ventral margins straight to slightly curved; ventrolateral 
margins moderately curved ; posterior margin with moderately convex 
curvature in absence of auricle, moderately concave beneath auricle 
when developed. Dorsolateral margins normally straight to slightly 
curved, gently inclined (pi. 3, fig. 3), posterodorsal margin longest, 
equaling two-thirds to slightly over one-half total length of shell. 



Table 2. — Summary of measurements for Lopha bellapHcata bellaplicata (Shumard) 



Character Valve 
Height (H) J^ 

Length (L) \^ 

Width (W) 1^ 

Percent valves with H > L LR 

Percent valves with H=:L LR 

Percent valves with H < L LR 

Area, inscribing rectangle of valve...) 

Length, beak to posterior margin 
(LBP) ^ 

Ratio, LBP : L L 

Angle between dorsal and dorso- 

posterior margins L 

Angle of inclination (i) LR 

Percent of specimens with observable 

attachment scar L 

Height of attachment scar (HATS) . . L 
Length of attachment scar (LATS) . . L 
Area, inscribing rectangle of attach- 
ment scar (HATS X LATS) L 

Height of smooth portion of shell 
dorsad to plicate ornamentation. . . . ) 



No. of 
specimens 


Range 


Average 


171 


12.2-69.0 mm. 


38.7 mm. 


112 


4.4-63.8 mm. 


37.3 mm. 


173 


6.3-66.1 mm. 


37.5 mm. 


112 


4.0-58.9 mm. 


34.6 mm. 


162 


3.0-28.5 mm. 


13.4 mm. 


109 


1.0-17.2 mm. 


7.4 mm. 


186/265 

13/265 

66/265 

171 


153-4416 mm.= 


70% 

5% 

25% 

1670.5 mm.'' 


51 


235-3637 mm.^ 


1782.1 mm.'' 


172 


5.2-40.4 mm. 


22.1 mm. 


109 


1.5-37.8 mm. 


19.2 mm. 


150 


0.33:1-0.76:1 


0.58 : 1 


56 


5-47° 


23.1° 


249 


62-95° 


79° 


138/173 
123 


1.0-42.6 mm. 


80% 
7.8 mm. 


137 


1.1-36.0 mm. 


10.1 mm. 


124 


2-1367.5 mm.-" 


llLPmrn."* 


50 


1.5-17.4 mm. 


5.9 mm. 


36 


0-36.8 mm. 


24.7 mm. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 



45 



Table 2. — Summary of measurements for Lopha bellaplicata bellaplicata 
( Shumard) — continued 



Character Valve 

Number of primary plicae at first 

appearance 3 

Total number of plicae (plicate ( 
valves only) — 

At 10 mm. height 1^ 

( 

At 20 mm. height \^ 

At 30 mm. height J^ 

/ R 

At 40 mm. height 1^ 

/ R 

At 50 mm. height \^ 

j R 

Total number of plicae at margin 3 

Number of plicae in 20 mm. length ] L 
at 20 mm. height ) R 

Percentage increase in plicae by 
bifurcation J 

Width of posterior auricular sulcus, 
20 mm. below beak L 

Width of median plica 20 mm. below 

beak L 

Inclination of beak, umbo : 

f T 
Percent opisthogyre ) 

Percent orthogyre ) 

|r 

Percent prosogyre ) 

( 

Length of hinge line (LHL) J ^ 

/ R 

Ratio, LHL:L jL 

Height of denticulate portion of 
margins (HD) 3^ 

Number of denticles in 5 mm. distance 
along margin 3 

Ratio, HD:H J^ 

Maximum diameter of muscle scar 
(MDS) P- 

m 

Ratio, MDS:H )^ 

R 



No. of 




specimens 


Range 


50 


6-17 


36 


4-22 


44 


8-19 


13 


6-16 


48 


10-21 


28 


7-22 


37 


12-27 


26 


8-22 


18 


13-22 


21 


8-23 


6 


14-23 


13 


11-22 


173 


9-27 


104 


1-26 


78 


3-8.5 


28 


4-7 


50 


12-263% 


34 


0-400% 



53 



.4-9.4 



Average 

10.6 
13.4 

14 

11.6 

15.8 

14.8 

17.9 

19 

18.4 

15.8 

18 

17.9 

16.4 

15.9 

5.6 

5.9 

79.6% 
72.1% 

4.9 mm. 



78 


2.0-7.3 mm. 


3.7 mm 


115/173 




66.5% 


68/112 




60.7% 


44/173 




25.4% 


27/112 




24.1% 


14/173 




8.1% 


17/112 




15.2% 


50 


4.2-29.0 mm. 


14.5 mm. 


43 


5.1-28.5 mm. 


15.0 mm. 


50 


0.21 : 1-0.75 : 1 


0.37 : 1 


43 


0.16:1-0.60:1 


0.37:1 


32 


5.1-30.0 mm. 


10 mm. 


41 


1.8-33.0 mm. 


12.8 mm. 


28 


5-13 


9 


34 


6-20 


9.7 


32 


0.15:1-0.69:1 


0.30:1 


40 


0.09:1-0.79:1 


0.28 : 1 


63 


5.2-20.3 mm. 


14.0 mm. 


45 


7.2-20.1 mm. 


14.2 mm. 


63 


0.23:1-0.42:1 


0.31:1 


45 


0.24:1-0.41:1 


0.32 : 1 



46 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Rarely, dorsolateral margins moderately rounded or steeply inclined 
(pi. 5, figs. 7, 10). Left valve typically moderately to highly convex, 
rarely flattened (pi. 5, figs. 1, 2 typical). High point dorsocentral, 
commonly on crest of median plica. Slope of anterior, ventral flanks 
moderate, dorsal slope steep, posterior slope gentle, flattened on 
auricle. Right valves slightly concave, flat, or gently arched, in rare 
cases gently and irregularly undulating. High point of right valve on 
umbone. 

Auricles. — Anterior auricle a flattened dorsoanterior expansion of 
margin and first few plicae ; auricle small, rounded, semicircular, com- 
monly absent, in most cases separated from body of shell by an 
enlarged interplical sulcus, the anterior auricular sulcus (pi. 3, fig. 15). 
Posterior auricle variable, normally well developed, ranging from 
indistinct, small, flattened area on dorsoposterior flank (pi. 3, fig. 13) 
to prominent, flattened, projecting dorsoposterior salient (pi. 4, fig. 2), 
straight dorsally, narrowly rounded posteriorly, slightly curved to con- 
cave ventrally, delineated by concave midposterior notch in valve 
outline. All gradations noted between the two forms. Auricle sepa- 
rated from body of shell by faint and shallow, to deep and prominent 
auricular sulcus, an enlarged interplical sulcus (pi. 3, figs. 11, 15), 
connecting umbo and midposterior notch. 

Beaks, umbos. — Opisthogyre, rarely exogyroid (one volution). 
Beak of left valve flat, small, bluntly pointed to moderately rounded, 
commonly obscured by attachment scar. On right valve, posterior 
curvature of beak, umbo, greater than on left, rarely orthogyre or 
exogyroid, moderately convex, smooth or with faint growth lines 
(pi. 5, fig. 7). Left and right umbones typically moderately to highly 
inflated, rarely flat, right valve with greatest umbonal convexity. 
Umbonal axes moderately curved, opisthocline medially, acline ven- 
trally on umbo. Beaks situated anterior to midline, about one-third 
the length from the anterior margin, slightly elevated above dorsal 
margin but not projecting. 

Attachment scar. — Predominantly small, commonly minute or 
apparently missing, rarely large (pi. 3, fig. 17), position middorsal 
on early part of umbone ; highly variable in shape, normally round to 
subovate, slightly concave, steeply inclined to plane of commissure. 
Attachment commonly to small, smooth oyster shells, other Lopha, 
elongate objects (sticks, etc., but without clasping processes) gastro- 
pods, and large pelecypods. Shell thin in area of scar, apparently 
reinforced with secondary calcite layers in some specimens. Shape, 
size of scar unrelated to that of adult valve, or to plication density. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 47 

Ornamentation, left valve. — Beak smooth or with fine growth Hnes ; 
first 3-8 mm. of umbo with fine growth Hnes, flat microlamellae, faint 
concentric undulations, rarely faint radiating undulations (pi. 3, fig. 
3). Majority of shell marked with coarse radiating plicae transected 
by prominent concentric lamellae (pi. 3, fig. 15). Plicae arise abruptly 
on early part of umbo, extend to commissure, increasing in number 
irregularly through bifurcation, especially on early plicate portion of 
valve, posterior auricle, and on ventral and lateral margins of large 
shells. Plicae high, rounded, steep-flanked, broader than angular 
interplical sulci between them, becoming coarser but lower, more 
rounded with age, faint or absent near margins of largest valves. 
Secondary plicae smaller, lower, narrower than primaries but more 
rapidly expanding, commonly equal to primary plicae in size at valve 
margin. Posterior auricular plicae smaller, narrower, more divergent, 
more extensively bifurcating, more curved than those of main body 
of shell (pi. 3, fig. 11). Plicae most prominent centrally and ventrally 
on valve; spinose, subnodose, fluted on rare left valves where inter- 
sected by coarse, raised concentric lamellae (pi. 3, fig, 6; pi. 4, 
fig. 4). Rare adult shells smooth, or with plicae faintly developed 
throughout (L. blacki types), expressed mainly as marginal crenula- 
tions. 

Development of plicae preceded by formation of a few coarse, 
crowded lamellae on umbone. Concentric sculpture on plicate portion 
of valve consisting of prominent, moderately to widely spaced, con- 
centric lamellae separated by numerous, very fine, crowded, irregu- 
larly spaced, growth lines and microlamellae (pi. 3, fig. 15). Major 
lamellae terminally in contact with succeeding ones, or raised above 
valve surface, forming flutes over plicae. 

Ornamentation, right valve. — Right valve distinct from left in 
detail of ornament. Beak smooth or with faint growth lines. Umbo 
almost totally devoid of plicae; smooth stage higher than that of left 
valve (pi. 5, fig. 7). Umbo smooth or with very fine, crowded, growth 
lines and microlamellae ; commonly with narrow zone of crowded, 
coarse lamellae ventrally, near point of origin of plicae. Plicate 
portion of valve marked by numerous, raised, closely spaced, major 
concentric lamellae (pi. 5, fig. 8), becoming crowded near margin of 
adult valves, much coarser than on left valve. 

Plicae originate abruptly on ventral portion of umbo or below it ; 
plicae very prominent, high, steep-sided, with sharp to narrowly 
rounded crests, fluted and spinose at intersection with major concentric 
lamellae. Interplical sulci narrower than plicae, deep, angular at 



48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

base, more prominent than those of left valve. Radial elements most 
prominent at valve margin, becoming coarser with age. 

Cardinal area. — Composed of central resilifer bounded laterally by 
flat to slightly arched, striated, triangular lateral cardinal plates. 
Resilifer of left valve shallow (most common) to moderately concave, 
triangular to subtriangular with bent dorsal apex, slightly flared base ; 
moderately narrow (common) to broad (rare). Lateral cardinal 
plates subequal to moderately unequal (on shells with prominent 
posterior auricle), posterior plate largest; each plate larger than 
resilifer in most valves. Narrow marginal cardinal troughs commonly 
developed between lateral cardinal plates and margin of valve, most 
common on left valves. Cardinal area of right valve similar to left 
except for resilifer, which is commonly shallow (concave), flat, or 
rarely raised into a low midcardinal fold. Majority of right valves 
with shallow resilifer bounded ventrally by a raised lip (partial mid- 
cardinal fold). 

Cardinal area marked with moderately strong, crowded, irregularly 
spaced, horizontal striae, raised lines, and narrow ridges of various 
sizes. Horizontal elements transected by faint, crowded, vertical lines. 
Ornament most strongly developed in adult shells, on lateral cardinal 
plates. Cardinal area color-banded on some specimens, with narrow, 
dark horizontal lines on lighter background. Hinge line short to 
moderately long (in presence of well-developed posterior auricle), 
straight to slightly curved (common), concave toward center of valve 
except below resilifer, where slightly convex (pi. 5, fig. 13). 

Denticles. — Present on inner dorsolateral margins of both valves ; 
small, simple, subround to elongate perpendicular to margin, in some 
valves their trace visible on lateral margin of shell, crossing lamellae. 
Interspaces equal to or slightly wider than denticles. Denticles 
situated on commissure and in narrow trough just inside it, generally 
restricted to dorsolateral margins, rarely extending well down margin, 
generally faint on young shells, best developed on adults, becoming 
indistinct on large old valves. 

Commissure, interior surface. — Commissure situated at margin of 
left valve, just inside margin of right valve ; normally undulating, 
rarely zigzag or flattened (old specimens). Plicae faintly expressed on 
interior of left valves near margins, more prominent on interiors of 
right valve, extending to center as rounded folds, sulci. Scattered, 
sinuous, pallial grooves faintly developed on a few valves. 

Muscle scar. — Monomyarian, insertion area of moderate size, well 
defined, subcrescentic to comma-shaped if not worn (pi. 5, fig. 13), 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 49 

slightly concave, bordered ventrally, posteroventrally by low raised 
lip, overlapped dorsally and anteriorly by inner shell layers ; position 
subcentral, in posteroventral quadrant of valve on corner nearest 
center. Surface of area coarsely striated with flat, crowded micro- 
lamellae, scattered raised ridges, their trace conforming to the growth 
lines ; rare muscle scars exhibit faint radiating lines. 

Shell structure. — Thickness moderately variable in single valve; 
greatest in cardinal area and vicinity of beak and umbone, thinning 
ventrally and laterally. Crest of left valve commonly thinner than 
shell immediately around it. Shell thickness of average left valve: 
cardinal area, 4.1 mm. ; crest, 2.9 mm. ; 10 mm. above ventral margin, 
1.8 mm. Right valve: Cardinal area, 6 mm., center of valve 2.3 
mm. ; 10 mm. above ventral margin, 1.4 mm. Only subnacreous layer 
preserved, forming bulk of shell, consisting of subhorizontal to gently 
curved and inclined plates of calcite arranged en echelon in distinct 
to roughly defined layers. Inclination of plates in each layer opposed 
to that in every other, or every third layer adjacent to it (pi. 8, fig. 11). 
Individual calcite plates thin, moderately short, of irregular thickness, 
with irregular terminations. Layered arrangement of plates, and 
opposed inclination of units well defined over most of shell, less 
distinct in cardinal-umbonal area, where orientation of plates more 
uniform, not commonly with opposed inclination. 

ONTOGENY 

Numerous well-preserved specimens of Lopha hellaplicata hella- 
plicata in the collections used for this study retain the morphologic 
detail of the early ontogenetic stages. The small size, or apparent 
absence, of the attachment scar on many left valves is of additional 
help in ontogenetic study since it allows observation of even the 
earliest stages of the attached valve, an opportunity not afforded by 
many species of oysters. Graphs and figures depicting the ontogenetic 
development of L. hellaplicata hellaplicata are presented in figures 
2-4, 6b, c, 9b, 14-17. Ontogenetic changes were observed in the 
following structures. 

Concentric sculpture. — Nepionic shell smooth or with faint growth 
lines; nepionic-neanic houndary marked by a prominent growth 
line. Fine growth lines characterize early neanic development ; middle 
and late neanic marked with more crowded growth lines, micro- 
lamellae, small folds and undulations, becoming progressively coarser. 
Abrupt appearance of plicae during neanic preceded by a few, closely 
spaced, moderately coarse lamellae or growth lines, Ephehic stage 



50 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



characterized by scattered coarse lamellae on left valve, some raised 
above shell surface, and by numerous, closely spaced, very prominent 
raised lamellae on right valve. Growth lines, microlamellae crowded 
between major lamellae. Neanic-ephebic boundary marked on many 



/ - ••• ;o / 







V/t- COLORADO (S.S.) 



VALVE LENGTH (MM) 



LEFT VALVE 




-^COLORADO (S.S.) 
\ 



B 3 4 5 6 7 8 

WIDTH OF MEDIAN PLICA AT 20 MM. HEIGHT (MM) 



LEFT VALVE 




i 5- 



^-^-^ COLORADO (VAR. A) 



lOO" 



4O0JI 



1000 1500 2(300 2500 3000 ' 

area; inscribing rectangle of valve OUTLINE (SQ.MMj 



Fig. 14. — Geographic variation in Lopha bellaplicata bellaplicata; comparison of 
Texas and Colorado specimens of the typical form of the subspecies, and 
Colorado representatives of L. bellaplicata bellaplicata variety A. A, Variation 
in height to length relationship and size range. B, Variation in width of the 
median plica 20 mm. below the beak. C, Variation in size range, and in number 
of plicae relative to area of an inscribing rectangle of valve. 



shells by first common occurrence of major lamellae. Lamellae be- 
come gradually coarser, more elevated, more crowded through 
ephebic development, probably recording a decrease in growth rate 
and increase in the length of resting periods with increasing age. 
Gerontic stage characterized by numerous, coarse, crowded lamellae 
and coarse growth lines near margin of old shells. 

Radiating sculpture. — Neanic stage marks first abrupt appearance 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 5 1 

of plicae, anywhere from earliest to late neanic in left valves, at or 
near beginning of ephehic development in right valves. Plicae be- 
come gradually coarser with age to late ephehic stage on left valves 
(about 40 mm. height) ; beyond this they become fainter, broad, low 
folds, many of which disappear with continued deterioration of 
ornamentation during gerontic development. Plicae of right valve 
become coarser with age through at least early gerontic stage. Plicae 
bifurcate throughout development; bifurcation greatest in late neanic 
or early ephebic stage, again at late ephehic development, the former 
possibly marking a period of accelerated growth. 




Fig. 15. — Ontogeny of Lopha bellaplicata bellaplicata (Shumard). Growth line 
traces at approximately 2.5 mm. intervals on representative left (A) and right 
(B) valves of the species. Traces show developmental history of the valve 
outline and the auricles. Drawings XL A, U.S.N.M. 132225; B, U.S.N.M. 
132239. 

Convexity. — Outward curvature of valves (convexity) slight in 
nepionic shell, on the left valve (fig. 3a) becoming moderate to great 
during neanic and early ephehic development, decreasing through 
late ephehic stage. Relatively abrupt flattening, flaring of flanks 
characterizes gerontic development. On right valves (fig. 3b), 
moderate outward curvature characterizes neanic, earliest ephehic 
stages ; gradual to abrupt flattening occurs during most of ephehic 
stage. Upturning of valve margin and flaring are common gerontic 
characters. 

Valve outline and auricles. — (Based on fig. 15.) Nepionic shell 
subround. Neanic shell ovate, with ventral growth exceeding lateral 
growth. Auricles appear as faint salients of dorsolateral margins in 



lii 10- 



o s 5 



RIGHT VALVE 




"20 25 30 35 3o Ji 15 55 io 65 ?0 
VALVE HEIGHT (MM.) 



|20i LEFT VALVE 



S < IS- 




IS 20 25 30 35 40 45 50 55 60 65 TO 
VALVE HEIGHT (MM.) 



L.blQCki 




CONVEXITY OF LEFT VALVE (MM.). 



Fig. 16. — A, Ontogeny of the muscle scar in Lopha hellaplicata bellaplicata 
(Shumard), showing relationship between maximum diameter of the posterior 
adductor muscle scar and the height of the valve. Note the decline and virtual 
cessation of scar growth with increased size and age. Approximate boundaries 
between ontogenetic stages marked by dashed lines. E = Ephebic ; T = Ephebic- 
Gerontic transition ; G = Gerontic. B, Comparison of the plication density of 
Lopha bellaplicata bellaplicata with that of L. blacki (White), showing total 
overlap of the two forms. C, Comparison of the relative convexity of L. bella- 
plicata bellaplicata and L. blacki, showing nearly total overlap between the two 
forms. 

52 



No. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 53 

late neanic or early ephebic stage, corresponding to development of 
plicae. During ephebic and gerontic development ventral and pos- 
terior growth exceeded that anteriorly and the auricles continued to 
expand at a constant, but greater, rate than normal lateral expansion. 

Curvature of growth axis {midline). — (See fig. 3c.) Axis slightly 
curved in nepionic shell, more moderately curved during neanic 
and early ephebic development, slightly curved, becoming nearly 
straight through ephebic and gerontic stages. Inclination of neanic 
shell possibly opisthocline. Ephebic, gerontic shells prosocline. 

Mtiscle scar. — Scar growth constant through neanic, ephebic stages, 
at a rate less than overall growth of shell ; growth rate tapers off dur- 
ing latest ephebic stage (40 to 45 mm.), corresponding to decrease in 
rate of shell growth, and ceases altogether in gerontic stage (fig. 16a), 
after animal reaches maximum size. Muscle scar migrates ventrally 
through neanic, ephebic stages, with increase in shell size. 

Cardinal area. — Elements of cardinal area distinct in early ephebic 
stage, becoming thicker, broader, better defined at a diminishing rate 
through life of animal. Length of hinge line gradually increasing 
through middle ephebic stage at a rate slightly less than overall lateral 
expansion of valve ; during late ephebic and gerontic stages growth of 
hinge line continues, but at a rate greater than that of lateral expan- 
sion of valve (fig. 17c). 

Denticles. — Present in all observed stages, forming throughout life 
and gradually extending farther down commissure with age. Rate of 
transgression of denticles down margin (denticle height vs. valve height 
at various growth stages) uniform and less than rate of ventral shell 
expansion during neanic through mid-ephebic stages (20-43 mm. 
height), accelerating and eventually exceeding rate of ventral shell 
growth in late ephebic and gerontic stages (fig. 19b). Density of 
denticles decreased at a variable rate throughout growth of shell to 
gerontic stage (fig. 17a), where it remained stable. 

REMARKS 

Lopha bellaplicata bellaplicata is the best-known species in the 
L. lugubris group. It is represented by a greater number of individuals, 
from more localities, and from a broader geographic range than any 
other member of the group. This is primarily due to its extensive 
occurrence in the upper Eagle Ford Shale of Texas, and the numerous 
collections available from that area. 

L. bellaplicata bellaplicata may be distinguished from the mor- 
phologically similar subspecies novamexicana by its more rounded or 



54 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 




i'20 25 30 35 40 45 50 55 
2 VALVE HEIGHT (MM) 



60 655 20 25 



30 35 40 45 50 55 . 60 65 
VALVE HEIGHT (MM) 




20 



25 30 35 40 45 50 55 60 65 
VALVE HEIGHT(MM) 



20 25 30 35 40 45 50 55 60 65 
VALVE HEIGHT(MM) 




301 












5 


RIGHT 


VALVE 




c ••/ 


2 25 










• / • 


bJ 










* x^ • 


520 






• 


• 


>* 


bJ 












(9 










/^"^ 1 • 


515- 

X 








y 


• • 1 1 






• • 


Y 


• 1 • • 


ll. 






• • V/* 




•■ 1 1 


^'0 






^y^ 


• 


1 I 
1 1 


H 



• • 


• j^ 


^^« • 




1 1 


!55- 




"S • 


• 




1 1 


_j 










E I T 1 G 

t 1 


^ 


5 20 


25 


30 35 


40 


45 50 55 



30 35 40 45 50 
VALVE LENGTH (MM) 

Fig. 17. — Ontogenetic development of Lopha bellaplicata bellaplicata (Shumard). 
A, Relationship between number of denticles in 5 mm. length (measured along 
margin) and valve height, showing decrease in density with age, and with 
increase in size. B, Relationship between the height of the valve and the extent 
of the denticulate portion of the margin, measured in terms of height, showing 
increase in extent of denticles with age and size. C, Relationship between length 
of hinge line and valve length, showing increase in size of hinge line relative to 
lateral expansion with age and size. All lines fitted visually. Approximate 
boundaries between ontogenetic stages marked by dashed lines. E = Ephebic ; 
T = Ephebic-Gerontic transition ; G = Gerontic. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 55 

subquadrate outline, less oblique shell, gently sloping- posterodorsal 
margin, more projecting dorsoanterior margin and auricle, larger and 
better-defined posterior auricle, which is dorsoposterior rather than 
centroposterior in position, and by its less convex left valve, especially 
in the umbonal area. In the subspecies hellaplicata, the plicae 
originate at a later developmental stage, especially on the right valve, 
and are smaller, narrower, more numerous, more extensively bifur- 
cating, and differentially developed on the auricles and main body of 
the valve. The posterior auricular sulcus is narrow and composed of 
a single, accentuated interplical sulcus. 

The differences between L. hellaplicata hellaplicata and L. luguhris 
have previously been discussed under "Remarks" for the latter species. 
L. hellaplicata hellaplicata is easily distinguished from its variety A 
by being broader, rounder, less erect, auriculate, and in having better 
defined, much more numerous plicae. 

Among foreign species of Lopha, L. hellaplicata hellaplicata is 
most closely comparable to Lopha syphax (Coquand), a Lower 
Cenomanian species which is larger, more coarsely and irregularly 
ribbed, and has a more pronounced anterior auricle. It further 
differs from the North American species in being proportionately 
higher, having a larger posterior auricle, and a more twisted umbone. 
This form may well be ancestral to the North American group of 
L. luguhris. 

White (1880, p. 293; 1883, p. 12) gave the name Ostrea 
(Alectryonia) hlacki (a Lopha) to a variant of L. hellaplicata hella- 
plicata which he considered distinct on the basis of its greater size, 
flatter valve, coarser and less numerous plicae, proportionately broader 
ventral dimension of the valves, and longer, more oblique dorsal 
margin. He evidently did not recognize the apparent age equivalency 
of the two forms. Cragin (1893, p. 199) and later writers have 
established that the two species both came from the upper Eagle Ford 
Shale of Texas. The present study validates this observation. 

White's syntype lot of L. hlacki consists of 26 specimens, most of 
them large, displaying late ephebic or gerontic ornament, and obviously 
worn. Among these latter specimens are the ones White illustrated 
(1880, pi. 4, figs. 1, 2; 1883, pi. 14, figs, la, b, pi. 17, fig. 5a; 1884, 
pi. 45, fig. 1, pi. 46, fig. 2), His collection also includes, however, 
specimens identical to Lopha hellaplicata hellaplicata, and a complete 
morphologic gradation exists between the two forms in this and other 
collections from the upper Eagle Ford Shale. 

Differences between the species cited by White break down under 



56 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

simple biometric comparison. The syntype lot of L. hlacki contains 
predominantly large individuals, but all fall within the size limits of 
L. hellaplicata bellaplicata populations (fig. 16b). The plicae are 
not less numerous than those of L. bellaplicata bellaplicata (fig. 16c). 
They appear broader owing to the great amount of wear on certain 
valves. The valves are neither flatter (fig. 16b), nor broader ventrally 
than typical examples of L. bellaplicata bellaplicata, and there is total 
overlap in the inclination of the dorsal margin. Slight differences 
existing between these forms are probably the product of environ- 
mental control. Examples of L. blacki are from a relatively coarse 
argillaceous sandstone, while forms typical of L. bellaplicata bella- 
plicata occur in finer clastic and mud facies. 

Lopha bellaplicata bellaplicata occurs in a number of different 
sediments over a broad area and provides a good basis for the study 
of environmental control on shell form. This opportunity is not 
presented by other members of the group, which occur in more uni- 
form lithologies. Large collections of L. bellaplicata bellaplicata were 
obtained from buff calcarenitic chalk, gray carbonaceous and calcare- 
ous shale with numerous shell fragments, shaly calcarenite, sandy 
shale, and in argillaceous to calcareous quartz sandstone (Colorado). 
A single specimen from New Mexico was found in dark clay shale. 

In collections from Texas, oysters from the calcarenitic marl units 
are thinner shelled, less convex, less inclined, and have less prominent 
posterior auricles than those from calcarenitic, sandy, or clay shale, 
and from thin calcarenites. Specimens from the latter lithology have 
the largest, thickest shells. These differences are probably related to 
differences in the energy conditions of the environment. Current and 
wave action was probably much stronger in the shallow-water environ- 
ment where the calcarenites were formed than it was in the quieter, 
presumably deeper marl-forming areas. Thickening of the shell 
appears to be an adaption to this more active environment, its chief 
function being to strengthen the valves. 

Specimens from New Mexico, found as gypsum replacements in 
dark clay shale, are typical of the species. The Colorado sample, 
however, shows significant environmental, and possibly geographic 
variation. Specimens from the Codell Sandstone Member ("Pugnellus 
Sandstone") of south-central Colorado attain a much smaller size than 
those from Texas and show a somewhat greater variation in marginal 
outline. The majority of specimens from Colorado, though smaller, 
are typical of the species and closely comparable morphologically to 
the Texas forms (compare pi. 3, figs. 1-15, with pi. 6, figs. 7-15). 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 57 

Marginal variants of the Colorado sample, however, show structural 
features that are not within the range of variation observed for the 
Texas specimens. The most notable variant, here termed variety A, 
is a narrow, high form with relatively few plicae and no auricles 
(pi. 6, figs. 1-6, 19), possibly but not definitely a product of crowded 
growth conditions. This form is treated separately on subsequent 
pages. 

A second unusual variant of Colorado L. bellaplicata hellaplicata 
assemblages is exceptionally long, with abnormally produced anterior 
and posterior auricles and, in some cases, very broad, rounded, plicae 
(pi. 6, figs. 11, 15). This form is also represented by a single 
specimen in the upper Blue Hill Shale, where it is probably a marginal 
variant of L. bellaplicata novamexicana, gradational into the younger 
L. hellaplicata bellaplicata. 

Finally, rare specimens of L. bellaplicata bellaplicata from Colorado 
are nearly smooth, and lack well-developed plicae (pi. 6, figs. 17, 18, 
21, 24), a condition not attained by Texas representatives of the 
species. This is most commonly expressed on right valves. 

Analysis of these differences between Texas and Colorado repre- 
sentatives of L. bellaplicata bellaplicata is difficult, since it is not 
possible here to separate geographic variance from environmental 
variance. The shallow-water, high-energy environment indicated by 
the Codell Sandstone lithology and sedimentary structures is not 
duplicated in Texas, so there is no basis for comparison of environ- 
mental influences. I would not consider any of the unique variation 
in morphology shown by the Colorado sample as being particularly 
adaptive to the shallower, more turbid, active Codell environment. 
Modern oysters do not show such structural adaptations in similar 
niches. This is the only argument that can be presented in favor of the 
differences being geographic, and thus genetically controlled. Even if 
this were the case, I would not consider the differences between the 
Texas and Colorado samples to be of subspecific magnitude, especially 
since they are shown by a very small percentage of the specimens 
examined. 

Stratigraphic and geographic occurrence. — In Texas, L. bellaplicata 
bellaplicata occurs in the upper 50 to 70 feet of the Eagle Ford Shale, 
being most common in the upper 15 to 25 feet, and forming prominent 
beds in the upper 2 to 5 feet at various localities. The species has 
been found in New Mexico at only one locality, in the dark shale of 
the Benton Subgroup (Mancos), on the Zuni Indian Reservation. 
In Colorado, the species is restricted to the "Pugnellus Sandstone" 



58 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

(Codell Sandstone Member) of the Carlile Shale, where it is found in 
limestone and calcareous sandstone lenses throughout the unit. 

In Colorado, the species has been found at localities 40-43, 55, and 
58-61 ; in New Mexico, at locality 45 ; in Texas, at localities 15, 44, 
46-54, 56, and 57, described in detail at the end of this report. 

Illustrated and measured specimens. — The holotype is presumed to 
have been lost in the fire at the St. Louis Academy of Science. Neo- 
type, here selected, a mature left valve (pi. 3, fig. 11), U.S.N.M. 
132222. White's hypotypes, paired valves (1879; 1884), illustrated 
on plate 3, figure 13, U.S.N.M. 12383; White's "paratype" of O. 
(A.) hlacki (1884, pi. 46, fig. 2), U.S.N.M. 8024b. Stanton's 
hypotypes (1893 [1894], pi. 4), U.S.N.M. 11822a (Stanton's fig. 8), 
U.S.N.M. 22860b, c, d (Stanton's figs. 9, 6, 4, respectively), 22861 
(Stanton's fig. 7). New hypotypes, U.S.N.M. 8024a, c. d; 
U.S.N.M. 11882b; U.S.N.M. 22009a, b; U.S.N.M. 2201 lb; U.S.N.M. 
132213-132221, inclusive, U.S.N.M. 132223-132244, inclusive; 
U.S.N.M. 132250, 132251, 132283, 132284, 132305-132308; 
U.M.M.P. (University of Michigan Museum of Paleontology) 38038, 
38039, 38041, 43466, 43478, 43482, 43483. Measured specimens, 
unfigured: U.S.N.M. 8024e, U.S.N.M. 11882c, U.S.N.M. 22009; 
U.S.N.M 22011c; U.S.N.M. 22860e, U.S.N.M. 132245-132249, 
inclusive; U.S.N.M. 132291-132300, inclusive, 132304. 

LOPHA BELLAPLICATA BELLAPLICATA var. A 

Plate 6, figures 1-6, 19 

DESCRIPTION 

Material. — 36 left and right valves, moderately well preserved, 
from the Codell Sandstone Member. ("Pugnellus Sandstone"), Car- 
lile Shale, at a number of localities in Huerfano Park, Colorado. The 
collection includes mostly small individuals, forming a partial growth 
series. 

General form. — Summary of measurements presented in tables 
3, 4. Shell small, inequivalve, left (lower, attached) valve much 
more convex, slightly larger, less curved dorsally than right ; most 
valves slightly inequilateral, prosocline to erect. Highly variable in 
outline: typically elongate-ovate along midline axis (pi. 6, figs. 1, 
2, 5) less commonly broadly subovate due to lateral flaring of pos- 
terior or posteroventral margins (pi. 6, figs. 6, 19), or irregularly 
elongate due to crowded growing conditions. Height greater than 
length. Anterior margin steeply inclined, straight to slightly and 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 



59 



irregularly curved, without anterior auricle. Ventral margin moder- 
ately to narrowly rounded, regular to irregular. Posterior margin with 
irregular outline, slightly concave (outward) dorsally, moderately to 

Table 3. — Summary of measurements on left valves of Lopha bellaplicata 
bellaplicata var. A 

No. of 

Character specimens Range Average 

Height (H) 21 15.4-38.4 mm. 23.4 mm. 

Length (L) 22 10.1-29 mm. 17.0 mm. 

Ratio, L:H 17 0.56:1-1.20:1 0.73:1 

Width (W) 23 3.0-12.9 mm. 7.7 mm. 

Area, inscribing rectangle of valve 

(A) 20 179.6-1128.1 mm.== 432.9 mm." 

Length ; beak to posterior margin 

(LBP) 22 3.9-14.4 mm. 9.4 mm. 

Ratio, LBPrL 21 0.39:1-0.71:1 0.53:1 

Angle of incHnation (i) 20 67-101° 82.3° 

Height of attachment scar (HATS) : 

Maximum vertical diameter 20 2.6-21.9 mm. 9.8 mm. 

In plane of commissure 20 1.4-21.9 mm. 8.4 mm. 

Length of attachment scar (LATS). 20 2.3-17.2 mm. 9.5 mm. 
Area, inscribing rectangle of attach- 
ment scar (HATS X LATS) .... 20 6-354.8 mm." 110.6 mm." 
Height, smooth young stage (HSS), 

dorsal part of valve 22 2.3-23.4 mm. 9.98 mm. 

Height, plicate portion of valve 20 4.9-26.5 mm. 13.6 mm. 

Ratio, H : HSS 20 0.108 : 1-0.777 : 1 0.432 : 1 

Number of plicae at first appearance. 22 4-12 8 

Number of plicae at 10 mm. height. . 14 4-12 8.5 

Number of plicae at 20 mm. height. . . 16 5-12 9.6 

Total number of plicae 22 4-14 9.3 

Number of plicae in 10 mm. distance 

(length) 10 mm. below beak 13 3-6.75 4.8 

Width of median plica at 10 mm. 

height 21 0.8-2.6 mm. 1.7 mm. 

Percentage of plicate valves with 

bifurcating plicae 23 78.3% 

Percentage increase in number of 

plicae by bifurcation 18 9.1-41.7% 17.9% 

Curvature of beaks and umbones : . . . 21 

Opisthogyre 81% 

Orthogyre 9.5% 

Prosogyre 9.5% 



slightly convex ventrally (pi. 6, figs. 2, 6, 19) . Dorsal margin short, 
straight to moderately curved, generally equal to width of attachment 
scar. On rare specimens, ventroposterior margin flared outward, 
considerably flattened, forming small, rounded, semicircular, pos- 



6o SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

terior auricle separated from main body of shell by a broad, shallow, 
indistinct auricular sulcus, generally a broadened interplical sulcus or 
2 sulci with the intermediate plication greatly reduced. 

Right valve flat to slightly arched ; convexity greatest in umbonal 
region; flanks flat, rarely concave near margin when ventral edge 
upturned. Left valve moderately to highly convex, convexity greatest 
at upper edge of attachment scar where prominent ; otherwise crest 
and high point situated medially on lower third of valves. Anterior 
slope typically steep, ventral slope shallow, posterior slope steep 
dorsally, moderate to gentle or irregular ventrally, depending on devel- 
opment of posterior auricle. 

Table 4. — Representative measurements of right valves associated with Lopha 
bellaplicata bellaplicata var. A and possibly belonging to this form. 

U.M.M.P. U.M.M.P. 

Character 43406 43413 

Height (H) 19.1 mm. 16.7 mm. 

Length (L) 9.6 mm. 15.8 mm. 

Width (W) 3.5 mm. 4.8 mm. 

Height, cardinal area 2.2 mm. 

Length, hinge line 3.9 mm. 

Width, midcardinal fold 1.9 mm. 

Height, denticulate margin 7.1 mm. 

Number of denticles in 5 mm. distance 11 

Maximum diameter of muscle scar 6.9 mm. 

Minimum diameter of muscle scar 3.6 mm. 

Distance (height), dorsal edge of muscle scar 

to beak 8.1 mm. 

Angle of inclination (i) 82° 61° 

Number of major lamellae in 5 mm. height 

(midvalve) 3 

Beaks and umbos. — Beak, umbo unknown on left valve, obscured 
by attachment scar, apparently slightly recurved, orthogyre to slightly 
opisthogyre. Beak of right valve known from numerous, nearly smooth, 
associated upper valves; pointed to narrowly rounded, smooth, nor- 
mally opisthogyre, moderately recurved. Umbone gently arched, in 
some valves separated from main body of shell by a constriction or 
large lamella. 

Attachment scar. — Area of attachment terminal, small to medium 
size, round to subovate, flat to slightly concave, steeply inclined or 
vertical relative to plane of commissure, rarely moderately inclined. 
Scar surface smooth or with faint concentric markings of shell to 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 6l 

which oyster attached; attachment to other Ostrea and Inoceramus 
shells. In some specimens scar area appears secondarily thickened 
by additional layers of lamellar calcite. 

Ornamentation, left valve. — Variable: Beak and early umbo 
smooth, or with fine concentric ornamentation. Lower umbo and 
portion of valve between attachment scar and plicate flanks marked 
by numerous fine, crowded, overlapping lamellae, fine growth lines, 
and scattered concentric undulations or moderate size lamellae. All 
lamellae terminally in contact with succeeding ones. 

Plicae commonly arise abruptly at or slightly below ventral edge of 
attachment scar (pi. 6, fig. 2). Plicae large, coarse, rounded, broader 
than interspaces between them, their width greater than their height, 
subequally developed to irregular (compare pi. 6, fig. 1, with fig, 2), 
bifurcating irregularly over entire valve; rate of bifurcation greatest 
dorsally. Secondary plicae rapidly expanding, rarely attaining size 
of primaries near commissure. Plicae become broader, lower, more 
rounded, indistinct near ventral and ventrolateral margins of a few 
valves, rarely disappearing altogether (pi. 6, figs. 2, 4), InterpHcal 
sulci narrow, sharp to narrowly rounded at base. 

Concentric ornamentation on plicate portion of valve consisting of 
numerous crowded, subequally to irregularly spaced, fine to medium 
size, overlapping lamellae, most terminally in contact with succeeding 
lamellae, and scattered coarse, raised lamellae; latter particularly 
common near margin. Plicae finely fluted at intersection with major 
lamellae. Radial and concentric ornamentation of posterior auricle, 
where developed, more irregular than that of main body of shell ; 
plicae smaller, more curved and sinuous, more extensively bifur- 
cating. Concentric elements coarser on auricle. 

Ornamentation, right valve. — Beak smooth ; umbone with scattered 
fine growth lines and faint concentric undulations. Remainder of 
valve covered with numerous fine growth lines, scattered flat lamellae 
of several sizes, and low concentric undulations, irregularly spaced 
and unequally developed, becoming coarser toward valve margins. 
Some valves with several coarse lamellae crowded near margins. 

Majority of specimens lack radiating ornamentation. A few right 
valves have traces of plicae near and on margins. Rare valves 
exhibit well-developed plicae similar to those of left valve ; plicae 
arise abruptly near ventral and ventrolateral margins and extend to 
the edge. Variants of these associated right valves illustrated on 
plate 6, figures 3, 4, 



62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

REMARKS 

The collections contain no valves with the interior preserved, and 
the thin, fragile nature of the shell makes it difficult to excavate one 
successfully. Presumably, the internal structures are the same as 
those on L. hellaplicata hellaplicata forma typica. Right valves 
were not found coattached with left valves. Their description is based 
on numerous smooth valves occurring in the same sediment and con- 
forming in shape and size to typical left valves. 

It seems advisable to describe separately this marginal variant of 
L. hellaplicata hellaplicata for two reasons. First, a continuous mor- 
phologic series cannot be established between the typical form of the 
species and variety A. The specimens illustrated on plate 6, figures 6 
and 19, are the only ones that approach the typical form, and these 
show significant differences. Graphs and charts comparing structures 
of the two forms invariably show a bimodal distribution with little 
overlap (figs. 14a-c). There is a possibility, therefore, that the 
differences between the two forms are not totally environmental, but 
genetic, and that they were related and coexisting subspecies or 
species. 

This possibility is further evident considering the apparent environ- 
ment of deposition of the Codell Sandstone Member. The Codell 
contains a diverse normal marine, shallow-water invertebrate 
fauna. The deposit has all the characteristics of a shallow-water, 
inner sublittoral sand sheet formed under moderate- to high-energy 
conditions of current and wave action. Variety A and the typical 
form of the species occur together, represented by numerous well- 
preserved shells, in the same lenses of fossils. They appear to have 
lived together and were probably subject to the same environmental 
influences. L. hellaplicata hellaplicata var. A occurs characteristically 
in clusters, where the elongate form of the shell appears to be, in part, 
a product of crowding. But free-growing examples are also known, 
and these are equally elongate. The form, convexity, and ornamenta- 
tion are more regular on the free-growing specimens. The differ- 
ences between the two forms therefore do not appear to be ecologic, 
or wholly a product of growth habit, indicating that L. hellaplicata 
hellaplicata var. A may be genetically distinct from the typical form 
of the species. The small number of specimens available for study, 
their limited size range, and lack of knowledge concerning the shell 
interior do not permit verification of these differences, or formal 
description of a new species or subspecies. Based on modern obser- 
vations, it seems more likely that a single variable ostreid species 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 63 

would occupy such a well-defined ecologic niche than that two closely 
related species or subspecies would be living together and competing 
for the same niche. 

Recognition of the variety is of additional importance since it may 
be the source from which contemporary and younger species of 
Lopha, having generally similar features, originated. Such ostreids, 
mostly undescribed, occur at various localities and stratigraphic 
levels in the Western Interior and will be the object of future study. 
They are not found in older sediments. 

The morphologic distinctions between L. bellaplicata hellaplicata 
and variety A have been previously discussed under "Remarks" for 
the former subspecies. 

Stratigraphic and geographic occurrence. — ^The variety occurs 
throughout the Middle Turonian "Pugnellus Sandstone" (Codell 
Sandstone member) of the Carlile Shale at localities 41, 58, 59, 60, and 
61 in Huerfano Park, Colo. Rare marginal variants of the Texas and 
Colorado collections of L. hellaplicata hellaplicata approach this 
form, but none attain it. 

Illustrated specimens.— Leit valves: U.S.N.M. 22011a, d; 132249; 
U.M.M.P. 38051, 38052; associated right valves, illustrated; 
U.S.N.M. 132259, U.M.M.P. 43413; hypotypes. Measured speci- 
mens, not illustrated : U.S.N.M. 132301-132303 ; U.M.M.P. 43406. 

LOPHA BELLAPLICATA NOVAMEXICANA new subspecies 

Plate 7, figures 1-19; plate 8, figures 1-9 

DESCRIPTION 

Material. — About 100 well-preserved specimens (measured), pre- 
dominantly left valves, from 4 localities in New Mexico and 8 localities 
in Colorado, including ontogenetic series and 2 large suites of speci- 
mens from single localities. 

General form. — Summary of measurements presented in table 5. 
Shell attaining moderate size ; inequivalve, left (lower, attached) valve 
slightly larger, much more convex than right valve ; slightly to moder- 
ately inequilateral, prosocline. Valves close-fitting, outline moder- 
ately variable ; typically subovate, commonly subquadrate or elongate- 
ovate parallel to axis of inclination, rarely rounded (pi. 7, figs. 1-5, 
10-12, 14-19; pi. 8, figs. 7-9 typical of subspecies). Height greater 
than length in most specimens. Anterior margin slightly curved dor- 
sally and ventrally, moderately rounded medially. Ventral margin 
moderately and evenly rounded ; ventroposterior corner more narrowly 



64 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



Table 5. — Summary of measurements for Lopha bellaplicata novamexicana 



Character Valve 

Height (H) J^ 

Length (L) i^ 

/ K 

Width (W) j^ 

Percent valves with H > L LR 

Percent valves with H<L LR 

Percent valves with H = L LR 

Area, inscribing rectangle of valve 
(A = HXL) |L 

Length, beak to posterior margin 
(LBP) JL 

Ratio, LBP : L |^ 

Angle of inclination (i) LR 

Percent of specimens with observa- 
ble attachment scar L 

Height of attachment scar (HATS). L 
Length of attachment scar (LATS) . . L 
Area, inscribing rectangle of attach- 
ment scar (HATS X LATS) L 

Ratio, area, inscribing rectangle of 
scar : area, inscribing rectangle of 

valve L 

Height of smooth portion of valves 

dorsad to plicae (HSS) ) 

I 

Ratio, HSS:H 3^ 

(R 

Number of plicae (total) : , 

Primary plicae at first appearance.. ) 

1 

Number of plicae at 10 mm. height. . ) 

Number of plicae at 20 mm. height . . ) 

Number of plicae at 30 mm, height. . ) 

/ R 

Number of plicae at 40 mm. height. . ) 

I 

Number of plicae at 50 mm. height • • ) 

I 

Total number of plicae at margin ) 

/R 



No. of 






specimens 


1 Range 


Average 


67 


14.2-90 mm. 


39.5 mm. 


8 


18.3-53.6 mm. 


36.3 mm. 


67 


13.4-61 mm. 


35.9 mm. 


8 


20.7-51.5 mm. 


32.5 mm. 


67 


5.0-28.9 mm. 


15.7 mm. 


6 


3-18.3 mm. 


8.7 mm. 


59/75 




78.6% 


16/75 




21.4% 










66 


201-4050.4 mm.'' 


1550 mm.2 


8 


379-2760 mm.'' 


1125 mm.2 


67 


5.4-41.0 mm. 


22.5 mm. 


8 


11.2-34.0 mm. 


19.2 mm. 


50 


0.40:1-0.83:1 


0.63 : 1 


8 


0.53:1-0.66:1 


0.58:1 


64 


59°-89'' 


76.5' 


84 




20.2% 


13 


1.0-12.1 mm. 


4.7 mm. 


17 


2.1-22.3 mm. 


7.3 mm. 


24 


2.1-265.0 mm.^ 


39.3 mm." 


24 


0.002:1-0.24:1 


0.04:1 


26 


1.0-7.3 mm. 


2.7 mm. 


11 


4.0-11.1 mm. 


6.3 mm. 


26 


0.03:1-0.18:1 


0.08 : 1 


11 


0.15:1-0.35:1 


0.25:1 


44 


5-15 


8.1 


11 


7-15 


10.4 


50 


7-19 


11.5 


11 


8-15 


12.0 


48 


9-18 


15.0 


10 


10-17 


13.4 


40 


9-20 


13.8 


4 


10-15 


12 


22 


9-21 


14.8 











3 


13-19 


16.0 











52 


9-21 


14.4 


11 


10-17 


13.9 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 



65 



Table 5. — Summary of measurements for Lopha bellaplicata 
novamexicana — continued 



Character Valve 
Number of plicae in 20 mm. length 
at 20 mm. height 3 

Width of median plica 20 mm. below 
beak L 

Percent increase in plicae by bifurca- ^ j 

^°" |r 

Width of posterior auricular sulcus 

20 mm. below beak L 

Inclination of beak, umbo (67 left 

valves, 8 right valves) : ^^ 

Percent opisthogyre \^ 

I is. 

Percent orthogyre ) 

Percent prosogyre ) 

/ 

Length of hinge line (LHL) ) 

/ 

Ratio, LHL:L \^ 

I 
Number of denticles in 5 mm. length . ) 

I 
Maximum diameter of muscle scar 

(MDS) L 

Ratio, MDS : H L 

Ratio, area of scar : area of valve. . . L 



No. of 
specimens 


Range 


Average 


64 


3-8 


4.75 


15 


4-6 


4.43 


63 


2.2-8.3 mm. 


4.9 mm 


44 
11 


7-200% 
6-77% 


84% 

37% 


43 


3.9-12.4 mm. 


6.6 mm. 


41 
3 

14 
5 

12 





61.2% 

37.5% 
20.9% 
62.5% 
17.9% 



1 




14.6 mm. 


1 




10.7 mm. 


1 




0.43 : 1 


1 




0.33 : 1 


1 




8 


1 




9 


1 




12.9 mm. 


1 




12.8 mm. 


1 




0.37:1 


1 




0.08 : 1 



rounded. Posterior margin straight to gently curved except in valves 
with prominent posterior auricle, where concave notch developed in 
outline at intersection with posterior auricular sulcus. Dorsolateral 
margins straight to slightly curved; dorsolateral comers narrowly 
rounded over auricles. Anterodorsal margin steeply to moderately 
inclined ; inclination least in presence of auricle. Posterodorsal mar- 
gin longest, moderately inclined with or without auricle. 

Left valve moderately to highly convex (pi. 8, figs. 1-3) ; high point 
dorsocentral, just anterior to midline, on median plica. Anterior and 
dorsal flanks steeply sloping; ventral, posteroventral, posterodorsal 
flanks moderately sloping ; posterior flank slopes steeply into auricular 
sulcus, becomes flat beyond this. Right valve flat to slightly concave 
dorsally and centrally, slightly convex ventrally, ventrolaterally, rarely 



66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I48 

with margins upturned, forming shallow submarginal trough. High 
point central to posterocentral. 

Auricles. — Anterior auricle not commonly developed (20 percent 
of left valves, 5 percent of right valves), dorsoanterior in position, 
small, flat, subtriangular, terminally rounded, bearing 1 or 2 flattened 
primary plicae. Anterior auricular sulcus prominent, deeper, broader 
than adjacent interplical sulci (pi. 7, figs. 10, 11). Posterior auricle 
small to large, typically of moderate size, flat to slightly convex ; out- 
line subtriangular, with posterior apex situated centrally on posterior 
margin (pi. 7, figs. 3, 4, 10, 11). Auricular sulcus very prominent, 
composed of single broad interplical sulcus, or 2 adjacent interplical 
sulci with intermediate plica greatly reduced or absent (pi. 7, figs. 10, 
11). Auricle smaller, less distinct on right valves than on left valves ; 
rarely absent. 

Beaks and umbos. — Normally slightly opisthogy re, rarely prosogyre, 
orthogyre, or with strong posterior curvature; slightly projecting, 
incurved, commonly extending inward beyond plane of commissure 
on left valve. Beaks small, narrowly to broadly rounded, flat to 
slightly convex, smooth, situated one-third to slightly less than one- 
half the length from the anterior margin, commonly obscured on 
attachment scar. Umbo of left valve highly arched, prominent, 
plicate. Umbone of right valve flat, smooth to partially plicate. 
Curvature of umbonal axis gentle, dorsally orthocline to slightly 
opisthocline, ventrally prosocline. 

Attachment scar. — Small, indistinct, commonly not visible or absent; 
round to subovate, flat to slightly concave, steeply inclined to plane of 
commissure ; terminal and central in position, or on posterior slope 
of early umbo. Attachment to smooth, slightly convex surfaces, pre- 
dominantly other oysters, smooth clams. Shell moderately thick over 
attachment area. 

Ornamentation, left valve. — Beak smooth, earliest umbo bearing 
growth lines, fine concentric lamellae. Plicae originate abruptly on 
early umbo, at edge of attachment scar (where present), or rarely 
on middle umbo. Primary plicae typically large, narrow in early 
stages, broader than high on adult part of shell, becoming broader, 
more rounded, lower with age, extending to margin on largest valves. 
Crests of plicae moderately to narrowly rounded, flanks moderately 
inclined. Plicae bifurcate over entire valve ; bifurcation rate high on 
umbonal and subumbonal areas, low and irregular over rest of valve. 
Secondary plicae smaller, narrower, more rapidly expanding than 
primaries, some attaining size equal to primaries near margin. Rare 



NO. 6 OYSTERS OF TflE LOPHA LUGUBRIS GROUP — KAUFFMAN 67 

valves with sharp, narrow plicae over entire valve (pi. 7, fig. 11), 
Plicae of posterior auricle smaller, more curved, more irregular, and 
more extensively bifurcating than those of main body of shell. 

Concentric sculpture over plicate portion of valve consisting of 
fine, crowded, irregularly spaced growth lines and flat microlamellae 
dorsally, becoming gradually coarser ventrally. Coarse, raised, major 
lamellae appear at midvalve (pi. 7, figs. 10, 18), and are scattered 
singly, or in groups of 2 or 3, over ventral half of valve, intercalated 
with growth lines and microlamellae. Major lamellae coarsest, most 
crowded near commissure. Plicae fluted at intersections with major 
raised lamellae. 

Ornamentation, right valve. — Right valve distinct from left in detail 
of ornamentation. Beak smooth ; umbo with fine growth lines, micro- 
lamellae, faint undulations, becoming coarser ventrally. Plicae arise 
abruptly at edge of umbo, preceded by a few coarse, crowded major 
lamellae and/or concentric ridges. 75 to 80 percent of valve pli- 
cate. Plicae coarse, higher than wide initially, becoming broader with 
age but remaining prominent; crests narrowly rounded to angular, 
flanks steep ; plicae sparsely bifurcating throughout, generally near 
margins, much less than on left valve. Interplical sulci narrow, with 
angular to narrowly rounded bases. Concentric ornament of plicate 
flanks consisting of numerous, prominent, raised lamellae, moderately 
and unevenly spaced centrally, crowded ventrally, commonly marking 
major constrictions or change in slope of shell surface, more promi- 
nent on right than on left valve. Major lamellae intercalated with nu- 
merous crowded, growth lines and microlamellae. Plicae spinose, fluted 
at intersection with major lamellae. Typical right valves illustrated on 
plate 7, figures 8, 9. 

Cardinal area. — Known from single right and single left valves ; on 
left valve consisting of subcentral, broad, shallow, triangular resilifer, 
and equally large, flat, subequal (posterior largest), subtriangular, 
lateral cardinal plates. Surface of cardinal area marked with closely 
spaced, moderately strong horizontal lines of various sizes and by 
fine, crowded, subequally spaced, raised vertical lines. Cardinal area 
of right valve similar, but with ventral half of resilifer convexly 
folded, forming a low lip. 

Denticles. — Denticles present on inner dorsolateral margins of 
both valves ; small, simple, rounded to ovate, crowded, moderately 
convex, situated on commissure, rarely reflected on thick lateral edges 
of auricles. 

Commissure. — Commissure at edge of right valve, just within edge 



68 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

of left valve ; flat dorsolaterally, undulating at intersection with major 
plicae elsewhere. Internal expression of plicae variable, typically 
developed as low, rounded folds and sulci confined to valve margins, 
less commonly extending to center of shell, becoming more subtle 
inward. Thick-shelled specimens commonly with lamellate lateral 
edges of shell flattened in plane of commissure (pi. 7, fig. 5) . 

Muscle scar. — Monomyarian ; posterior adductor scar large, situated 
centroposteriorly, or in upper part of posteroventral quadrant of valve 
(pi. 7, fig. 5) ; comma-shaped, arcuate, slightly concave, well defined, 
overlapped dorsally, anteriorly by inner shell layers, bordered ventrally 
by a low, raised lip. Surface striated, covered with fine, crowded, 
microlamellae and raised lines, irregularly spaced, conforming to 
trace of growth lines. 

Shell structure. — Periostracum, prismatic layer, and hypostracum 
not observed. Subnacreous layer forms bulk of shell, consisting of 
several layers of slightly curved, inclined calcite plates arranged en 
echelon within each layer. Inclination of plates in each layer may be 
opposed to that of adjacent layers. Individual plates and layers 
flatter, more conformable around cardinal area and at ventral edge. 
Nacreous layer thin, composed of flat calcite lamellae. Shell thick; 
thickness of a typical left valve (height 38 mm., length 34 mm.) 
through the hinge area, 4.5 mm. ; thickness at crest, 3.4 mm. ; thickness 
5 mm. above ventral margin, 2.3 mm. 

ONTOGENY 

A few significant ontogenetic trends regarding the external features 
of the shell are worthy of note. Internal structures of the valves are 
virtually unknown in this respect. 

Concentric sculpture. — Nepionic stage smooth. Neanic stage with 
fine growth lines, microlamellae initially, becoming coarser toward 
late neanic. Early to middle neanic in left valve marked by a few, 
coarse, crowded growth lines, lamellae, and ridges just before abrupt 
development of plicae. Ephebic stage marked by development of 
scattered (left valve) to moderately spaced (right valve) major con- 
centric lamellae in addition to fine ornament, possibly marking growth 
rests, and becoming somewhat more crowded in late ephebic as 
growth slowed. Gerontic stage marked by crowded, coarse lamellae 
and growth lines near margin. 

Radiating sculpture. — Plicae abruptly appear in early, rarely middle 
neanic stage on left valves, at the beginning of ephebic development 
on right valves, becoming coarser, more prominent, broader, more 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN 69 

rounded with age through the middle ephehic stage ; becoming lower, 
more subtle during late ephehic and gerontic stages, especially on 
left valves. Bifurcation rate highest during neanic, low and irregular 
at later stages. 

Convexity. — Outward curvature of shell growth moderate to great 
through neanic and early ephebic development, gradually decreasing 
in later growth (fig. 3a), becoming moderate to slight. No flattening 
and flaring noted in late growth stages. 

Marginal outline; auricles. — (Based on fig. 18.) Nepionic shell sub- 
round, Neanic shell ovate, longer than high ; lateral growth exceeded 





B 



Fig. 18. — Ontogeny of Lopha bellaplicata novamexicana new subspecies. Growth 
line traces at approximately 2.5 mm. intervals on representative left (A) and 
right (B) valves of the subspecies, showing developmental history of the 
marginal outline and the auricles. Drawings Xl- A, U.S.N.M. 132267, 
B, U.S.N.M. 132265. 

ventral growth during neanic and early ephehic stages. Ephehic stage 
marked by ventral growth exceeding lateral expansion and the latter 
becoming irregular. Auricles appear in early ephehic as more rapidly 
expanding salients of lateral margins, continue to grow at a more 
accelerated rate throughout life. Gerontic growth similar to that of 
ephehic stage. 

Curvature of growth axis {midline). — Curvature slight during 
nepionic, neanic, early ephehic stages, decreasing uniformly through 
ephehic and gerontic stages, becoming nearly straight (fig. 3c). 

REMARKS 

The distinction between L. hellapliata novamexicana and its most 
closely comparable relative, L. hellaplicata hellaplicata has been 
discussed in detail under the "Remarks" section of the latter sub- 



70 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 48 

species. Basically, L. hellaplicata novamexicana is distinguished by 
its more oblique marginal outline, greater convexity of the umbonal 
region, larger, broader, less numerous plicae, reduced and more 
centrally situated auricles, much larger posterior auricular sulcus, and 
more inclined posterodorsal margin. The plicae arise at an earlier 
developmental stage than in L. hellaplicata hellaplicata. No other 
Cretaceous species of Lopha are closely comparable. Young shells of 
these two subspecies are nearly identical (compare pi. 3, figs. 1-9, 
with pi. 7, figs. 1-3), but average adult shells are readily distinguished. 
Marginal variants of the subspecies show overlap of many structures. 

Shells of this subspecies are typically found complete, with both 
valves intact and well preserved. Although they are common at 
some localities, they have not been observed living gregariously in 
beds or "oyster reefs," and show no evidence of crowding. The 
small size of the attachment scar (in some cases too small to be 
observed, or preserved, on the beak) possibly indicates early detach- 
ment from the substrate and predominantly a free life. 

Lopha hellaplicata novamexicana is known from three lithofacies: 
Fine- to medium-grained, well-sorted, cross-bedded marly sandstone ; 
similar sandstone with an argillaceous cement and abundant carbo- 
naceous debris; and sandy, argillaceous, limestone concretions or 
lenses (septarian) in a sandy shale matrix. The first two types are 
from New Mexico, and the concretions mark its occurrence in 
Colorado. The only observable morphologic differences between 
forms from the two States which may be environmentally controlled 
are (1) the sharper plicae on many Colorado examples (pi. 7, fig. 11), 
and (2) the tendency for some Colorado specimens to have a ventral 
"hump," or sharp break in slope about one-third the height from the 
ventral margin. On the steep slope below this break, the plicae on 
certain specimens show greater bifurcation than is normal for the sub- 
species. No such structure was noted on New Mexico specimens. 
These differences are difficult to evaluate in light of the sparse knowl- 
edge concerning the paleoenvironment to which this form was sub- 
jected. Similar irregularities in growth form are produced in some 
oysters exposed to abrupt changes in rate of sedimentation, in others 
periodically exposed in intertidal zones. This structure is genetically 
produced in certain species of Inoceramus, irrespective of environ- 
ment. It is a gerontic feature of other pelecypods. 

Stratigraphic and geographic distribution. — Lopha hellaplicata nova- 
mexicana is the oldest known member of the L. luguhris group. It 
is commonly found in the middle Mancos Shale of New Mexico, in the 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN Jl 

zone of CoUignoniceras hyatti (Stanton) (late Middle Ttironian), 
well below the occurrence of L. lugubris. Its position relative to 
L. bellaplicata hellaplicata in New Mexico is uncertain, however, since 
the latter is rare in this area, and the two have not yet been found 
associated. 

The stratigraphic relationship between L. hellaplicata hellaplicata 
and the subspecies novamexicana can be established in Huerfano 
Park, Colo. Here, typical examples of L. hellaplicata hellaplicata 
are found throughout the Codell Sandstone Member ("Pugnellus 
Sandstone") (pi. 6, figs. 7-9, 12). Below this unit, in the upper part 
of the Blue Hill Shale Member, septarian limestone concretions con- 
tain scattered but characteristic examples of the subspecies nova- 
mexicana (pi. 7, fig. 11). The two forms do not have overlapping 
ranges in this area, although rare individuals transitional between 
them occur as marginal variants of each form. This occurrence sug- 
gests, therefore, that L. hellaplicata novamexicana is characteristic of 
the lower part of the CoUignoniceras hyatti zone (Blue Hill Shale 
Member equivalents) and L. hellaplicata hellaplicata marks the upper 
part of the C. hyatti zone (Codell Sandstone Member: "Pugnellus 
Sandstone" of older authors). If future collections prove this to be 
true over a broad area in the Western Interior, these ostreids will have 
particular importance as stratigraphic markers, since the faunas of 
these two units overlap in almost every other respect. The subspecies 
novamexicana occurs at localities 62 through 73, described in detail at 
the end of this report. 

Illustrated and measured specimens. — Holotype, a typical left valve 
with the interior excavated, U.S.N.M. 132267 (pi. 7, fig. 10). 
Figured paratypes, left and right valves, U.S.N.M. 22012 ; U.S.N.M. 
132260-132266 inclusive; U.S.N.M. 132268-132282 inclusive; 
U.S.N.M. 132286-132288 inclusive. Measured, unfigured paratypes, 
U.S.N.M. 132252-132257 inclusive, 132290. University of Michigan 
Museum of Paleontology (U.M.M.P.) 43480, 43481. Sectioned 
specimen, discussed, U.S.N.M. 132289. 

COLLECTING LOCALITIES 

Collecting localities and stratigraphic information are cited as they 
appear in the Mesozoic catalogs of the U. S. Geological Survey and 
U. S. National Museum. In many cases, data available for older 
collections are brief and generalized. Many such collections have 
been omitted from this study for this reason. Others have been 
incorporated because it is obvious from the locality data and from 



72 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

associated matrix at what stratigraphic level they were obtained. 
Localities cited for the latter collections contain, in parentheses, 
Stratigraphic data which is not listed in our catalogs and which 
represents my own interpretation, based on experience in the areas in 
question. For localities that I have not actually visited, this infor- 
mation is followed, in parentheses, by a question mark. I have 
collected from all other areas in the past 6 years, and feel certain of 
the stratigraphic assignments. 

Lopha lugubris (Conrad) 

1. U.S.G.S. 513 — "Colorado Formation" (Juana Lopez equivalent ?), hills 

6 miles each of Mexican settlements on road from Jemez to Copper 
City, N. Mex. 100 feet above massive gray sandstone standing on edge. 
Collected by J. W. Powell, 1887. 

2. U.S.G.S. 747 — "Colorado Formation" (Juana Lopez Member of the 

Carlile Shale), Rattlesnake Buttes, 18 miles east of Walsenburg Post 
Office, Colo. Collected by T. W. Stanton, 1890. 

3. U.S.G.S. 827 — "Colorado Formation" (Juana Lopez Member, Carlile 

Shale), near Malachite, Huerfano County, Colo. Collected by T. W. 
Stanton, 1891. 

4. U.S.G.S. 833 — 100 to 600 feet above base of Colorado Shale (Juana Lopez 

equivalent ?), near Mancos, Colo. Collected by T. W. Stanton, 1891. 

5. U.S.G.S. 1306 — Benton (Subgroup: Juana Lopez Member, Carlile Shale), 

12 miles northwest of Pueblo, Colo., lat. 38°25', long. 104°47'. Collected 
by G. K. Gilbert, 1893. 

6. U.S.G.S. 1380 — Upper Benton (Subgroup: Juana Lopez equivalent ?), 

mesa 5 miles west of Drip Springs, lat. 37 "38^ long. 104°30', Colo. 
Collected by G. K. Gilbert, 1894. 

7. U.S.G.S. 2005 — Colorado (Group: Juana Lopez equivalent ?), about 

150 feet above top of Dakota Sandstone, railroad cut north of Thompson 
Park, Colo. Collected by A. C. Spencer, 1897. 

8. U.S.G.S. 2009 — Colorado (Group), Mancos Shale (Juana Lopez equivalent 

?), near F — down corral on middle Mancos (River ?), La Plata Quad., 
Colo. Collected by W. T. Lee. 

9. U.S.G.S. 2015 — Colorado (Group: Juana Lopez equivalent ?), west fork 

of Mancos (River ?), 10,700 feet elevation, Colo. Collected by W. 
Cross. 

10. U.S.G.S. 2019 — Colorado (Group: Juana Lopez equivalent in Mancos 

Shale), second fossil layer exposed northwest of Mancos, Colo. Col- 
lected by Mr. Cane, 1895. 

11. U.S.G.S. 3673 — (Colorado Group, Juana Lopez equivalent), "Ostrea" 

lugubris zone, Rio Puerco, about 5 miles above San Ygnacio, Albuquer- 
que Quad., N. Mex. Collected by T. W. Stanton, 1906. 

12. U.S.G.S. 4358 — Benton (Subgroup), fine brown sandstone ledges 400 feet 

above Dakota Sandstone (Juana Lopez equivalent). Willow Creek at 
the old wagon road south of Blue Mountain, sec. 12, T. 3 N., R. 102 W., 
coal fields of northwest Colorado and adjacent territory. Collected by 
H. S. Gale, 1907. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 73 

13. U.S.G.S. 4456 — Benton (Subgroup: Juana Lopez equivalent ?), horizon 

No. 2 (J. H. Gardner: unpublished), about 60 feet below main massive 
sandstone of Coloradoan age, 5 miles below Arnold's store, 10 miles 
northeast of Gallup, N. Mex. Collected by J. H. Gardner, 1907. 

14. U.S.G.S. 6516 — Upper part of the Benton (Subgroup: Juana Lopez 

equivalent), 150 to 200 feet above the Greenhorn Limestone, branch of 
Vermejo Creek, about 12 miles northwest of Vermejo Park Post Office, 
N. Mex. Collected by T. W. Stanton, 1910. 

15. U.S.G.S. 7539 — Eagle Ford Shale, layer No. 1, quarry of the Texas 

Portland Cement Co., 2.5 miles due east of Eagle Ford, Dallas County, 
and 3 miles west of Trinity River at Dallas, Tex. Collected by L. W. 
Stephenson, 1911. 

16. U.S.G.S. 7579 — Basal bed of the Austin Chalk, on Walnut Creek, about 

1 mile east of Waiters' Station, Travis County, Tex. Collected by 
L. W. Stephenson, 1911. 

17. U.S.G.S. 7993 — Colorado (Group: Juana Lopez equivalent), in 50 feet of 

yellow calcareous shaly sandstone, zone of Prionocyclus Wyoming ensis 
and Scaphites warreni, about 3.5 miles south of Casa Salazar, Mt. 
Taylor Quad., N. Mex, Collected by W. T. Lee and T. W. Stanton, 
1912. 

18. U.S.G.S. 9250— Mancos Shale, 300 to 400 feet above the base, near Delta, 

Colo. Collected by G. H. Stone, 1915. 

19. U.S.G.S. 10368 — Colorado (Group: Juana Lopez equivalent ?), 14 miles 

S. 20° W. from Shiprock Mt. (Wilson Peak), sec. 5 or 8, T. 9 N., 
R. 4 W., Navajo Meridian, near the base of Beautiful Mt., San Juan 
Basin, N. Mex. Collected by W. E. Bryant, Dobbin, and J. B. Reeside, 
Jr., 1920. 

20. U.S.G.S. 10506 — Mancos Shale, 300 feet above Dakota Sandstone, 

Scaphites zone (Juana Lopez equivalent), 1.5 miles west of Durango, 
NWl/4 SEl/4 sec. 18, T. 35 N., R. 9 W., Ignacio Quad,, Colo, Col- 
lected by J. B. Reeside, Jr., 1920. 

21. U,S.G.S. 12883 — Reworked Eagle Ford Shale zone in the base of the 

Austin Chalk, exposures in bank of creek east of railroad, south of 
Colorado River, south of Austin, Travis County, Tex. Collected by 
L. W. Stephenson, 1924. 

22. U.S.G.S. 13663 — (Juana Lopez equivalent), 2 miles north of Whitewater, 

Grand Junction region, Colo. Collected by J. B. Reeside, Jr., 1926. 

23. U.S.G.S. 14691— "Blue Hills Shale" (Carlile Shale, questionably from 

pockets of Juana Lopez Limestone at top of so-called Blue Hill Shale of 
older authors), Lopha lugtibris zone, near Beloit, Kans. Collected by 
by J. B. Reeside, Jr., 1929. 

24. U.S.G.S, 15923 — Mancos Shale, 348 feet below Gallup Sandstone (Juana 

Lopez equivalent ?), triangulation point, Gallup, approximately center 
of sec. 12, T. 14 N., R. 2 W., southern San Juan Basin, N. Mex. 
Collected by C. B. Hunt and party, 1931. 

25. U.S.G.S, 18876 — "Codell ? Sandstone" (Juana Lopez Member at top of 

Codell), thin beds 30 feet below highly fossiliferous zone (of Mancos 
Shale), on Biltabito Road, 15 miles west of junction with highway to 
Gallup, 15 miles west of Shiprock bridge, San Juan County, N. Mex. 
Collected by N. W. Bass, 1943, 



74 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

26. U.S.G.S. 20562 — Upper Cretaceous (Juana Lopez equivalent ?), approxi- 

mately 2 miles west-southwest of Hagan, sec. 6, T. 12 N., R. 6 E., Tejon 
Grant, N. Mex. Collected by C. E. Stearns, 1946. 

27. U.S.G.S. 24443 — Frontier Sandstone (Juana Lopez equivalent ?), 1.75 

miles northwest of Newcastle, SEl/4 sec. 23, T. 5 S., R. 91 W., Glen- 
wood Springs Quad., Colo. Collected by N. W. Bass, 1952. 

28. U.S.G.S. 25592 — Mancos Shale (Juana Lopez equivalent), 525 feet above 

base, section No. 2, southeast Gypsum Valley-Disappointment Valley 
area, aerial photo D.R.N. 2-10, San Miguel County, Colo. Collected by 
O. T. Marsh, 1955. 

29. U.S.N.M. Cat. No. 8354 — Colorado (Group: Juana Lopez equivalent), 

Colorado. Type specimen with no other locality data. 

30. U.S.N.M. Cat. No. 9822 — Upper Cretaceous (Juana Lopez equivalent), 

zone of Prionocyclns macombi ?, rocks east of Red River (Canadian), 
Santa Fe road, N. Mex. T. A. Conrad. 

31. U.S.N.M. Cat. No. 20255 — Middle Cretaceous, Colorado (Group: Juana 

Lopez equivalent), Vada del Chama, N. Mex. 

32. Jtiana Lopez Member (top), Carlile Shale, Colorado Group, low cliff along 

the northwest side of Oak Creek, NEl/4 SWl/4 sec. 5, T. 27 S., 
R. 68 W., Huerfano Park, Huerfano County, Colo. Collected by 
E. G. Kauffman, 1958. 
iZ. Juana Lopez Member, Carlile Shale, Colorado Group, in a stream gully 
1.3 to 1.5 miles north-northwest of Red Wing, on the Jones' Cattle 
Company Ranch, SWl/4 SEl/4 sec. 26, T. 26 S., R. 71 W. Huerfano 
Park, Huerfano County, Colo. Collected by E. G. Kauffman, 1959. 

34. Juana Lopez Member, Carlile Shale, Colorado Group, i mile east of 

Maes' School, north of an unimproved dirt road, along the Fort Hays 
limestone hogback, SEl/4 sec. 11, T. 26 S., R. 69 W., Huerfano Park, 
Huerfano County, Colo. Collected by E. G. Kauffman, 1958. 

35. Juana Lopez Member, Carlile Shale, Colorado Group, along the Fort Hays 

Limestone hogback south of unimproved dirt road, 0.8 mile southeast of 
Maes' School, NWl/4 NEl/4 sec. 14, T. 26 S., R. 69 W., Huerfano 
Park, Huerfano County, Colo. Collected by E. G. Kauffman, 1958. 

Z6. Juana Lopez Member, Carlile Shale, Colorado Group, on the southeast side 
of Oak Creek, 0.2 mile southwest of Badito, NWl/4 NEl/4 sec. 8, 
T. 27 S., R. 68 W., Huerfano County, Colo. Collected by E. G. Kauff- 
man, 1958. 

Z7. Juana Lopez Member, Carlile Shale, Colorado Group, in a subsidiary 
stream valley of Pantleon Creek, north of an unimproved road crossing 
sec. 28, on the Jones' Cattle Company Ranch, Sl/2 NWl/4 sec. 28, 
T. 26 S., R. 71 W., Huerfano Park, Huerfano County, Colo. Collected 
by E. G. Kauffman, 1959. 

38. Juana Lopez Member, Carlile Shale, Colorado Group, 2-3 miles north of 

Thatcher, Colo., in Juana Lopez-Fort Hays limestone hogback, on 
east side of dirt road leading north from general store and Thatcher 
School, 50 to 100 yards east of road. Collected by E. G. Kauffman, 
1961. 

39. Juana Lopez Member, Carlile Shale, Colorado Group, 2-3 miles north of 

Thatcher, Colo., on west side of dirt road leading north from Thatcher 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 75 

School, in two fault or slump blocks, 0.5 and 0.7 mile west of road. 
Collected by E. G. Kaufifman, 1961. 

Lopha bellaplicata bellapUcata (Shumard) 

IS. U.S.G.S. 7539 (same as listed for Lopha lugubris) — Eagle Ford Shale, 
layer No. 1, quarry of Texas Portland Cement Company, 2.5 miles due 
east of Eagle Ford, Dallas County, and 3 miles west of Trinity River at 
Dallas, Tex. Collected by L. W. Stephenson, 1911. 

40. U.S.G.S. 741 — Colorado Group (Codell Sandstone Member, Carlile Shale), 

near Charles Smith's Ranch, on Muddy Creek, 10 miles above Gardner 
Post Office, Huerfano Park, Huerfano County, Colo. Collected by 
T. W. Stanton, 1890. 

41. U.S.G.S. 743 — Colorado Group (Codell Sandstone Member, Carlile 

Shale), 1 mile east of Quillian's Ranch on Williams Creek, Huerfano 
Park, Huerfano County, Colo. Collected by T. W. Stanton, 1890. 

42. U.S.G.S. 1310 — Benton (Subgroup: Codell Sandstone Member, Carlile 

Shale), near 3-R Ranch, lat. 38°2', long. 104°57', Colo. Collected by 
G. K. Gilbert, 1893. 

43. U.S.G.S. 1318 — Benton (Subgroup: Codell Sandstone Member, Carlile 

Shale), near Turkey Creek, lat. 38° 30', long. 104° 49', Colo. Collected by 
G. K. Gilbert, 1893. 

44. U.S.G.S. 439b — (Eagle Ford Shale), 2 miles east and 3 miles south of 

Denison, Tex. Collected by R. T. Hill, 1886. 

45. U.S.G.S. 8081 — Benton ? (Subgroup: Mancos Shale), on surface of steep 

slope at B-34, sec. 18, T. 10 N., R. 17 W., Zuni Indian Reservation, 
N. Mex. Collected by D. E. Winchester, 1912. 

46. U.S.G.S. 10046 — Eagle Ford Shale, 7 miles west of Palestine at the salt 

works, on ridge g mile northeast of plant, Texas. Collected by O. B. 
Hopkins, 1915. 

47. U.S.G.S. 11096— Eagle Ford Sandstone, in pebble bed IS to 25 feet below 

Ector Chalk, in big gully 1 mile southeast of Bells, Tex. Collected by 
O. B. Hopkins, 1918. 

48. U.S.G.S. 11732 — Upper 3 feet of the Eagle Ford Shale, in quarry of the 

Texas Portland Cement Company plant west of Dallas, Tex. Collected 
by T. W. Stanton, 1923. 

49. U.S.G.S. 12942 — Eagle Ford Formation, Palestine salt dome, east of salt 

works, at an old cabin, Anderson County, Tex. Collected by L. W. 
Stephenson, 1924. 

50. U.S.G.S. 14SS3 — Sand of upper Eagle Ford age, Whitesboro road, 1.75 

miles west of Sherman, Grayson County, Tex. Collected by L. W. 
Stephenson, T. W. Stanton, and J. B. Reeside, Jr., 1929. 

51. U.S.G.S. 19017— Upper part of the Eagle Ford Shale, North- South Road, 

1.7 miles W. by S. of Ellsworth, 5.4 miles southwest of Denison, 
Grayson County, Tex. Collected by R. T. Hazzard, 1941 ( ?). 

52. U.S.G.S. 22608 — Eagle Ford Shale, 3 miles southeast of Mountain Creek 

Power Plant, Dallas County, Tex. Collected by Mrs. Renfro. 

53. U.S.N.M. Cat. No. 8024— Eagle Ford Shale, Collin County, Tex. 

54. U.S.N.M. Cat. No. 11882— Eagle Ford Shale, near Sherman, Tex. 



76 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

55. U.S.N.M. Cat. No. 22861— Colorado Group (Codell Sandstone Member), 

at Carlile Springs, 18 miles west of Pueblo, Colo. 

56. U.S.N.M. Cat. No. 12383— Eagle Ford Shale, Denison, Tex. 

57. B. F. Perkins collection No. 55-206 — Upper Eagle Ford Shale, Turonian, 

Jefferson Blvd., roadcut, Dallas County, Tex. Collected by B. F. 
Perkins, 1955. U.S.N.M. accession 241760. 

58. Codell Sandstone Member ("Pugnellus Sandstone" of Stanton, 1894), 

Carlile Shale, Colorado Group, 50 to 100 yards southwest of Lower 
Pass Creek School, along Colorado State Highway 305, SEl/4 sec. 7, 
T. 27 S., R. 70 W., Huerfano Park, Huerfano County, Colo. Collected 
by E. G. Kauflfman, 1959, 1961. 

59. Codell Sandstone Member ("Pugnellus Sandstone" of Stanton, 1894), 

Carlile Shale, Colorado Group, in a stream gully 1.3 to 1.5 miles north- 
northwest of Red Wing, on the Jones' Cattle Company Ranch, 
SWl/4 SEl/4 sec. 26, T. 26 S., R. 71 W., Huerfano Park, Huerfano 
County, Colo. Collected by E. G. Kauffman, 1959. 

60. Codell Sandstone Member ("Pugnellus Sandstone" of Stanton, 1894), 

Carlile Shale, Colorado Group, in a subsidiary stream valley of Pantleon 
Creek, north of an unimproved dirt road crossing sec. 28 on the Jones' 
Cattle Company Ranch, Sl/2 NWl/4 sec. 28, T. 26 S., R. 71 W., 
Huerfano Park, Huerfano County, Colo. Collected by E. G. Kauffman, 
1959. 

61. Codell Sandstone Member ("Pugnellus Sandstone" of Stanton, 1894), 

Carlile Shale, Colorado Group, in a wooded area 0.4 mile east of 
Turkey Creek, NEl/4 NWl/4 sec. 22, T. 25 S., R. 69 W., Huerfano 
Park, Huerfano County, Colo. Collected by E. G. Kauffman, 1959. 

Lopha hellaplicata novamexicana new subspecies 

62. U.S.G.S. 738 — Colorado Group (septarian limestone concretion zone, 

upper Blue Hill Shale Member, Carlile Shale), near Badito, Huerfano 
County, Colo. Colected by T. W. Stanton, 1890. 

63. U.S.G.S. 3295— Colorado Group (Mancos Shale ?), Carthage, N. Mex. 

Collected by W. T. Lee, 1905. 

64. U.S.G.S. 3297— Colorado Group (Mancos Shale ?), i mile south of 3295, 

Carthage, N. Mex. Collected by W. T. Lee, 1905. 

65. U.S.G.S. 5303 — Colorado Group, Benton (Subgroup: Mancos Shale), 

710 feet above the Dakota Sandstone, SWl/4 NEl/4 sec. 9, T. S S., 
R. 2 E., New Mexico, P. M., 0.5 mile N. 30° from Manilla Mine, 
Carthage, N. Mex. Collected by J. H. Gardner, 1908. 

66. U.S.G.S. D2042 — Massive sandstone in the Mancos Shale, zone of 

Collignoniceras hyatti, just north of U. S. Highway 380, 7.75 miles east 
of San Antonio, Socorro County, N. Mex. Collected by W. A. Cobban. 

67. Blue Hill Shale Member, Carlile Shale, Colorado Group, in septarian lime- 

stone concretions 10 to 15 feet below the top of the member, and in 
lenticular limestone beds at the Blue Hill-Codell Sandstone contact, 
lower part of the zone of Collignoniceras hyatti, 100 yards southwest of 
Lower Pass Creek School, just west of Colorado State Highway 305, 
SEl/4 sec. 7, T. 27 S., R. 70 W., Huerfano Park, Huerfano County, 
Colo. Collected by E. G. Kauffman, 1959, 1961. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN J^ 

68. Upper Blue Hill Shale Member, Carlile Shale, Colorado Group, in a 2- 

inch limestone overlying cone-in-cone beds, septarian limestone concre- 
tion zone, zone of Collignoniceras hyatti, stream gully 1.3 to 1.5 miles 
north-northwest of Red Wing, on the Jones' Cattle Company Ranch, 
SWl/4 SEl/4 sec. 26, T. 26 S., R. 71 W., Huerfano Park, Huerfano 
County, Colo. Collected by E. G. Kauffman, 1959. 

69. Blue Hill Shale Member, Carlile Shale, Colorado Group, zone of septarian 

limestone concretions in upper 10 feet of member, 1 mile east of 
Williams Creek, ^ mile south of unimproved dirt road, Wl/2 NEl/4. 
sec. 12, T. 25 S., R. 70 W., Huerfano Park, Huerfano County, Colo. 
Collected by E. G. Kauffman, 1959, 1961. 

70. Blue Hill Shale Member, Carlile Shale, Colorado Group, zone of septarian 

limestone concretions in upper 20 feet of member, along the Fort Hays 
Limestone hogback south of an unimproved dirt road, 0.8 mile southeast 
of Maes' School, NWl/4 NEl/4 sec. 14, T. 26 S., R. 69 W., 
Huerfano Park, Huerfano County, Colo. Collected by E. G. Kauffman, 
1958. 

71. Blue Hill Shale Member, Carlile Shale, Colorado Group, zone of septarian 

limestone concretions in upper 25 feet of member, below? Codell Sand- 
stone-Juana Lopez limestone hogback 0.5 mile north of Colorado State 
Highway 69, near center of sec. 31, T. 26 S., R. 68 W., 1.4 miles east of 
Farisita, Huerfano Park, Huerfano County, Colo. Collected by E. G. 
Kauffman, 1959. 

72. Blue Hill Shale Member, Carlile Shale, Colorado Group, septarian lime- 

stone concretion zone in upper 15 feet of member, just below Juana 
Lopez-Fort Hays Limestone hogback, 2-3 miles north of Thatcher, Colo., 
50 to 100 yards east of an improved dirt road leading north from gen- 
eral store and Thatcher School. Collected by E. G. Kauffman, 1961. 
73. Blue Hill Shale Member, Carlile Shale, Colorado Group, septarian lime- 
stone concretions in upper part of member, 1 mile north of the 
Arkansas River, on slopes surrounding a dry tributary, SEl/4 NEl/4 
sec. 25, T. 20 S., R. 66 W., Pueblo County, Colo. Collected by E. G. 
Kauffman and F. Collier, 1962. 

Lopha hellaplicata bellaplicata var. A. 

Collected in the Codell Sandstone Member, Carlile Shale, Colorado Group, at 
localities 41, 58, 59, 60, and 61, previously cited under Lopha bellaplicata. 

LITERATURE CITED 

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1954. American seashells, p. 2i7Z. D, Van Nostrand Co., Inc., New York. 
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Adkins, W. S., and Lozo, F. E. 

1951. Stratigraphy of the Woodbine and Eagle Ford, Waco area, Texas. 
Fondren Sci. Ser., No. 4, p. 155, pi. 5, fig. 1. Southern Methodist 
Univ. 



78 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Arkell, W. J. 

1937. A monograph of British Corallian Lamellibranchiata. Paleonto- 
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BOLTEN, J. F. (or ROEDING, P. F.) 

1798. Museum Boltentanum sive catalogus cimeliorum e tribus regnis 
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BosE, Emil. 

1913. Algunas faunas del Cretacico Superior de Coahuila y regiones 
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1952. Correlation of the Cretaceous formations of the Western Interior 
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Conrad, T. A. 

1857. Descriptions of Cretaceous and Tertiary fossils. Rep. U. S. and 
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COQUAND, H. 

1869. Monographic genre du Ostrea terrain Cretace, p. 66, pi. 36, figs. 22, 
23. J. B. Bailliere and Fils, Paris. 
Cox, L. R. 

1940. The Jurassic lamellibranch fauna of Kuchh (Cutch). Mem. Geol. 
Soc. India, ser. 9, vol. 3, pt. 3, p. 95. 
Cragin, F. W. 

1893. A contribution to the invertebrate paleontology of the Texas Creta- 
ceous. 4th Ann. Rep. Geol. Surv. Texas, pp. 199, 204. 
Dall, W. H. 

1898. Contributions to the Tertiary faiuia of Florida, with special reference 
to the Silex beds of Tampa and the Pliocene beds of the Caloosa- 
hatchee River, including in many cases a complete revision of the 
generic groups treated of and their American Tertiary species. 
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675, 676. 
Fischer, G. de Wau)heim. 

1807. Museum Demidoff, ou. Catalogue systematique et raisonne des 
curiosites de la nature et de I'art, donnees a I'Universite Imperiale 
de Moscou, par Son Excellence, Monsieur Paul de Demidoff, vol. 3, 
pp. 269, 270. Moscow. 
Gunter, Gordon. 

1950. The generic status of living oysters and the scientific name of the 
common American species. Amer. Midi. Nat., vol. 43, No. 2, 
pp. 438-449. 
Hattin, D. E. 

1962. Stratigraphy of the Carlile Shale (Upper Cretaceous) in Kansas. 
State Geol. Surv. Kansas, Bull. 156, p. 84. 
Herrick, C. L., and Johnson, D. W. 

1900. The geology of the Albuquerque sheet (New Mexico). Bull. Denison 
Univ. Sci. Lab., vol. 11, p. 202. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN 79 

Hill, R. T. 

1901. Geography and geology of the Black and Grand Prairies, Texas : 
Part III, Geology of the Black and Grand Prairies. 21st Ann. 
Rep. U. S. Geol. Surv., pi. 40, fig. 9. 
Hopkins, O. B., Powers, Sidney, and Robinson, H. M. 

1922 (1923). The structure of the Madill-Denison area, Oklahoma and 
Texas, with notes on oil and gas development. U. S. Geol. Surv. 
Bull. 736a, pi. 3, figs. 1, 2. 
Hyatt, Alpheus. 

1894. Phylogeny of an acquired characteristic. Proc. Amer. Philos. Soc, 
vol. 32, No. 143, pp. 349-647. 
Johnson, D. W. 

1903a. The geology of the Cerrillos Hills, New Mexico. School of Mines 

Quart., vol. 24, No. 2, pp. 186, 187. 
1903b. The geology of the Cerrillos Hills, New Mexico. Columbia Univ. 
Contr. Geol. Dept., vol. 10, No. 90, pp. 114, 115. 
Lamarck, J. B. 

1799. Prodrome d'une nouvelle classification des coquilles. Mem. Soc. Hist. 
Nat. Paris, p. 81. 
Linne, Carl. 

1758. Systema naturae, etc., 10th ed., vol. 1, p. 704. Stockholm. 
Logan, W. N. 

1898. The invertebrates of the Benton, Niobrara, and Fort Pierre Groups. 
Univ. Geol. Surv. Kansas, vol. 4, pt. 1, pp. 455, 456, pi. 91, figs. 1-10. 
Maury, C. J. 

1936. O Cretaceo de Sergipe. Brazil Servico Geol. e Mineralog., Mon. 11, 

p. 157. 
McLean, R. A. 

1941. The oysters of the Western Atlantic. Notulae Naturae of Acad. 

Nat. Sci. Philadelphia, No. 67, p. 5. 
Meek, F. B. 

1876. Descriptions of the Cretaceous fossils collected on the San Juan 

exploring expedition under Capt. J. N. Macomb, U. S. Engineers. 

in Rep. Expl. Exped. Santa Fe, New Mexico, to June. Grand and 

Green Rivers, in 1859 by Capt. J. N. Macomb, p. 123, pi. 1, 

figs. la-d. 
Newell, N. D. 

1937. Late Paleozoic pelecypods: Pectinacea. Univ. Kansas, State Geol. 

Surv. Kansas, vol. 10, text, p. 30. 

1942. Late Paleozoic pelecypods : Mytilacea. Univ. Kansas Publ., State 

Geol. Surv. Kansas, vol. 10, pt. 2, p. 22. 
Rankin, C. H. 

1944. Stratigraphy of the Colorado Group, Upper Cretaceous, in northern 
New Mexico. New Mexico School of Mines Bull. 20, pp. 12, 19-22, 
figs. 4, 5. 
Ranson, Gilbert. 

1942. Note sur la classification des Ostreides : Bull. Geol. Soc. France, 

vol. 5, No. 12, pp. 161-164. 
1948. Prodissoconchs et classification des Ostreides vivants. Bull. Mus. 
Roy. d'Hist. Nat. Belgique, tome 24, No. 42, pp. 1-12. 



80 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Schmidt, F. C. 

1818. Versuch iiber die beste Einrichtung zur Aufstellung, etc., p. 69. 
Shimer, H. W., and Blodgett, M. E. 

1908. The stratigraphy of the Mt. Taylor region, New Mexico. Amer. 
Journ. Sci., 4th ser., vol. 25, pp. 60, 61. 
Shimer, H. W., and Shrock, R. R. 

1955. Index fossils of North America, p. 395, pi. 154, figs. 4, 5. John Wiley 
and Sons, Inc., New York. 
Shrock, R. R., and Twenhofel, W. H. 

1953. Principles of invertebrate paleontology, 2d ed., pp. 363-402, New 

York, McGraw-Hill Book Co., Inc. 
Shumard, B. F. 

1860. Descriptions of new Cretaceous fossils from Texas. Trans. St. Louis 
Acad. Sci., vol. 1, p. 608. 
Sowerby, G. B., Jr. 

1839, A conchological manual. 1st ed., p. 75, table opposite p. 6, London. 
Stanton, T. W. 

1893 (1894). The Colorado Formation and its invertebrate fauna. U. S, 
Geol. Surv, Bull. 106, pp. 58, 59, pi. 4, figs. 1-10. 
Stenzel, H. B. 

1947. Nomenclatural synopsis of supraspecific groups of the family 
Ostreidae (Pelecypoda, Mollusca). Journ. Paleontol., vol. 21, 
No, 2, pp. 165-185. 
Stoliczka, F. 

1871. Cretaceous fauna of southern India. Geol. Surv. India, Pal. Indica, 
ser. 6, vol. 3, pp. 454, xxii. 
Stoll, N. R., et al. 

1961. International code of zoological nomenclature adopted by the XV 
International Congress of Zoology, 176 pp. London, International 
Trust for Zoological Nomenclature. 
Thomson, J. M. 

1954. The genera of oysters and the Australian species. Australian Journ. 

Marine and Freshwater Res., vol. 5, No. 1, pp. 132-168. 
VlALOV, O. S. 

1936, Sur la classification des huitres. Acad. Sci, U.R.S.S., Comptes 

Rendus (Doklady), n. s., vol. 4 (13), No. 1 (105), pp. 17-20. 
White, C, A, 

1879. Contributions to invertebrate paleontology, No. 1. Cretaceous fossils 

of the western states and territories. 11th Ann. Rep. U. S. Geol. 
Geogr. Surv. Terr. Idaho and Wyoming, pp. 276, 277, pi, 4, 
figs, 3a, b ; pi. 8, figs. 2a, b. 

1880. Descriptions of new Cretaceous invertebrate fossils from Kansas and 

Texas. Proc. U. S. Nat. Mus., vol. 2 (for 1879), p. 293, pi. 4, 
figs. 1, 2. 
1883. Contributions to invertebrate paleontology, No. 2. Cretaceous fossils 
of the western states and territories. 12th Ann, Rep. U. S. Geol. 
Geogr. Surv, Terr. Wyoming and Idaho, pt. 1, pp. 11, 12, pi. 14, 
figs, la, b ; pi. 17, fig. 5a. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP KAUFFMAN 8l 

1884. A review of the fossil Ostreidae of North America, and a comparison 
of the fossil with the living forms. 4th Ann. Rep. U. S. Geol. Surv., 
pp. 272-430, pi. 41, fig. 3 ; pi. 45, fig. 1 ; pi. 46, fig. 2 ; pi. 48, figs. 1-3. 

WiNTON, W. M. 

1925. The geology of Denton County. Univ. Texas Bull. 2544, p. 62, pi. 8, 
fig. 5. 



EXPLANATION OF PLATES 

U.S.N.M. = United States National Museum 

U.M.M.P. = University of Michigan Museum of Paleontology 

U.S.G.S. = United States Geological Survey 

Plate 1 

Lopha luguhris (Conrad) 

Fig. \. Lateral view (Xl) of a left valve with reverse curvature; a hypotype 

from a calcarenite bed between typical Austin Chalk and Eagle Ford Shale 

(locality 16, U.S.G.S. loc. 7579) ; U.S.N.M. 132154. 
Fig. 2. Lateral view of a typical left valve (Xl) ; Stanton's hypotype from 

Mancos, Colo, (locality 4, U.S.G.S. 833), the original of his plate 4, 

figure 3 (1893) ; U.S.N.M. 22859b. 
Fig. 3. Lateral view (X2) of a left valve with abnormally small attachment 

area; a hypotype (locality 38) ; U.S.N.M. 132155. 
Fig. 4. Lateral view (Xl) of a typical left valve, the lectotsnpe; the original 

of Conrad's (1857) plate 10, figure 5b, (locality 30, east of Red River, 

Santa Fe Road, N. Mex.) ; U.S.N.M. 9822. 
Fig. 5. Lateral view (X2) of a typical left valve; a hypotype from the 

upper Eagle Ford Shale of Texas (locality 15, U.S.G.S. 7539) ; U.S.N.M. 

132156. 
Fig. 6. Lateral view (X2) of a left valve with well-developed reverse curva- 
ture of the exogyroid beaks and umbo; a hypotype from Huerfano Park, 

Colo, (locality 34) in the Juana Lopez Member (Carlile Shale) ; 

U.M.M.P. 43472. 
Fig. 7. Lateral view (X2) of a typical left valve; a hypotype from the zone 

of Prionocyclus wyomingensis wyomingensis, near Casa Salazar, N. Mex. 

(locality 17, U.S.G.S. 7993) ; U.S.N.M. 132157. 
Fig. 8. Lateral view (X2) of an unusually erect left valve; a hypotype from 

the upper 3 feet of the Eagle Ford Shale, Texas (locality 48, U.S.G.S. 

11732) ; U.S.N.M. 132158. 
Fig. 9. Lateral view (X2) of a left valve with a large, flat attachment scar 

and somewhat restricted plicae ; a hypotype from the Juana Lopez Member, 

Huerfano Park, Colo, (locality 34) ; U.M.M.P. 43464. 
Fig. 10. Lateral view of a left valve (X2) ; a hypotype from the Juana 

Lopez Member, Huerfano Park, Colo. (locality 34) ; U.M.M.P. 43472. 
Fig. 11. Lateral view (X2) of a distorted left valve with plicae limited to the 

margins; a hypotype from Mancos, Colo, (locality 4, U.S.G.S. 833); 

U.S.N.M. 22210a. 
Fig. 12. Lateral view (X2) of a nearly smooth left valve with only faint 

marginal plicae; a hypotype from the Juana Lopez Member, Huerfano 

Park, Colo, (locality 34) ; U.M.M.P. 43465. 
Fig. 13. Lateral view (X2) of an erect left valve with a large scar and 

relatively few, restricted, marginal plicae; a hypotype from the Juana 

Lopez Member, Huerfano Park, Colo, (locality 36) ; U.M.M.P. 43476. 

82 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 83 

Fig. 14. Lateral view (X2) of a left valve with radiating ornament restricted 

to marginal crenulations ; a hypotype from the upper Eagle Ford Shale of 

Texas (locality 15, U.S.G.S. 7539) ; U.S.N.M. 132159. 
Fig. 15. Interior view (X2) of a large left valve showing internal reflection 

of ornamentation, marks of the attachment area, and the normal position 

of the muscle scar; a hypotype, the original of Stanton's plate 4, figure 5 

(1893) (locality 4, U.S.G.S. 833) ; U.S.N.M. 22859a. 
Fig. 16. Interior view (X2) of a left valve showing nature of cardinal area, 

denticles, muscle scar, and internal reflection of the ornamentation; a 

hypotype from Colorado (locality 29) ; U.S.N.M. 8354. 
Fig. 17. Interior view (X2) of a left valve showing fine interior lines on 

inner surface, denticles, cardinal area, and muscle scar ; a hypotype from 

the zone of Prionocyclus Wyoming ensis wyomingensis (Juana Lopez 

equivalent), near Casa Salazar, N. Mex. (locality 17; U.S.G.S. 7993); 

U.S.N.M. 132160. 
Fig. 18. Interior view (X2) of a left valve; hypotype illustrated by Meek 

on plate 1, figure la (1876), from Vada del Chama, N. Mex. (locality 

31) ; U.S.N.M. 20255. 

Plate 2 
Lopha lugubris (Conrad) 

Fig. 1. Lateral view (X2) of an unusually elongate right valve showing 
strong lamellae developed at beginning of plicate stage of valve, and 
weak plicae; a hypotype from the upper Eagle Ford Shale of Texas 
(locality 15, U.S.G.S. 7539) ; U.S.N.M. 132161. 

Fig. 2. Lateral view (X2) of a typical plicate right valve, showing abrupt 
formation of plicae at margin of smooth stage; hypotype illustrated by 
Stanton (1893, pi. 4, fig. 2), from Huerfano Park, Colo, (locality 3, 
U.S.G.S. 827) ; U.S.N.M. 22860a. 

Fig. 3. Lateral view of a right valve (X2) ; a hypotype from Rattlesnake 
Buttes, Colo, (locality 2, U.S.G.S. 747) ; U.S.N.M. 22008a. 

Fig. 4. Lateral view (X2) of an unusually elongate, curved, plicate right 
valve ; a hypotype from the zone of Prionocyclus wyomingensis wyoming- 
ensis (Juana Lopez equivalent) near Casa Salazar, N. Mex. (locality 17, 
U.S.G.S. 7993) ; U.S.N.M. 132162. 

Fig. 5. Lateral view (X2) of a coarsely plicate right valve showing sharp 
demarcation between smooth stage and plicate portion of valve; a hypo- 
type from near Mancos, Colo., in the Juana Lopez equivalent (locality 10, 
U.S.G.S. 2019) ; U.S.N.M. 132163. 

Fig. 6. Lateral view (X2) of a plicate right valve characteristic of the 
species, showing abrupt origin of plicae, and reflection of attachment sur- 
face on smooth stage of valve; a hypotype from the upper Eagle Ford 
Shale of Texas (locality 15, U.S.G.S. 7539) ; U.S.N.M. 132164. 

Fig. 7. Lateral view (X2) of a right valve showing reflection of attachment 
surface on smooth stage, and restriction of plicae to marginal area. This 
form is intermediate between plicate and nonplicate types. A hypotype 
from near Mancos, Colo, (locality 4, U.S.G.S. 833) ; U.S.N.M. 22210b. 



84 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 48 

Fig. 8. Lateral view (X2) of a right valve with radiating ornament limited 
to crenulations in marginal lamellae ; a hypotype from Huerfano Park, 
Colo, (locality 34) ; U.M.M.P. 43470. 

Fig. 9. Lateral view (X2) of an elongate, nonplicate right valve; a hypotype 
from Huerfano Park, Colo, (locality 32) ; U.M.M.P. 43487. 

Fig. 10. Lateral view (X2) of a smooth right valve showing reflection of 
attachment surface (probably an Inoceramus shell) on exterior of upper 
valve; a hypotype from near Mancos, Colo, (locality 4, U.S.G.S. 833); 
U.S.N.M. 22211. 

Fig. 11. Lateral view (X2) of a smooth right valve showing nature of 
growth lines and fine lamellae; a hypotype from Huerfano Park, Colo, 
(locality 58) in the Juana Lopez Member; U.M.M.P. 43484. 

Fig. 12. Lateral view (X2) of a small right valve with well-developed 
marginal lamellae, and faint crenulations on the anterior and ventral 
borders; a hypotype from Huerfano Park, Colo, (locality 33) in the 
Juana Lopez Member ; U.M.M.P. 43471. 

Fig. 13. Interior view (X2) of a thick right valve showing unusually deep 
but typically shaped posterior adductor muscle scar, traces of fine 
radiating incised lines on inner surface of valve ; a hypotype from Rattle- 
snake Buttes, Colo, (locality 2, U.S.G.S. 747) in the Juana Lopez Mem- 
ber; U.S.N.M. 22008b. 

Fig. 14. Interior view (X2) of a small right valve with unusually large 
cardinal area, typical muscle scar, and well-developed denticles (repre- 
sented by notches) ; a hypotype from Rattlesnake Buttes, Colo, (locality 2, 
U.S.G.S. 747), in the Juana Lopez Member; U.S.N.M. 22008b. 

Fig. 15. Lateral view (X2) of a typical right valve, nonplicate, and with 
reverse curvature; a hypotype from Huerfano Park, Colo, (locality 34), 
in the Juana Lopez Member ; U.M.M.P. 43486. 

Fig, 16. Interior view (X2) of a typical right valve showing nature of 
cardinal area, well-developed denticles, a typical muscle scar, and fine, 
sinuous, incised lines on the inner valve surface; a hypotype from the 
Mancos Shale, San Miguel County, Colo, (locality 28, U.S.G.S. 22592) ; 
U.S.N.M. 132258. 

Fig. 17. Interior view (X2) of a right valve with unusually large resilifer 
and muscle scar, well-developed denticles ; a hypotype from near White- 
water, Colo., from the Juana Lopez Member equivalent in the Mancos 
Shale (locality 22, U.S.G.S. 13663) ; U.S.N.M. 132165. 

Plate 3 

(All figures Xl) 

Lopha hellaplicata hellapUcata (Shumard) 

Figs. 1, 3, 9, 11, IS, 18. Lateral views of typical left valves of the species, 
placed in a growth series ; note characteristic outline, nature and extent 
of auricles and auricular sulci, small attachment scars, nature of plicae and 
height of smooth stage ; all specimens hypotypes from the upper Eagle 
Ford Shale, 2.5 miles east of Eagle Ford, Dallas County, Tex. (locality 
15, U.S.G.S. 7539). Catalog Nos. : 1 (U.S.N.M. 132213), 3 (U.S.N.M. 
132215), 9 (U.S.N.M. 132220), 11 (U.S.N.M. 132222, the neotype), 
15 (U.S.N.M. 132225), and 18 (U.S.N.M. 132228). 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 85 

Fig. 2. Lateral view of a left valve, abnormally short owing to reduced 
posterior auricle ; a hypotype from the upper Eagle Ford Shale, 2.5 miles 
east of Eagle Ford, Dallas County, Tex. (locality 15, U.S.G.S. 7539) ; 
U.S.N.M. 132214. 

Fig. 4. Lateral view of a left valve with reduced posterior auricle, unusually 
large attachment scar and prominent umbo; a hypotype from the upper 
Eagle Ford Shale of Texas (locality 15, U.S.G.S. 7539, cited above) ; 
U.S.N.M. 132216. 

Fig. 5. Lateral view of a worn left valve with unusually large smooth stage ; 
a hypotype from the Eagle Ford Shale at Sherman, Tex. (locality 54), 
the original of Stanton's plate 4, figure 8 (1893) ; U.S.N.M. 11882a. 

Fig. 6. Lateral view of a left valve with unusually large attachment scar; 
posterior auricle broken; a hypotype from the upper Eagle Ford Shale, 
Dallas County, Tex. (locality 15, U.S.G.S. 7539, cited above) ; U.S.N.M. 
132217. 

Fig. 7. Lateral view of an abnormal left valve ; note unusual height, reduction 
of auricles, broad plicae, a hypotype from the upper Eagle Ford Shale, 
Dallas County, Tex. (locality 57) ; U.S.N.M. 132218. 

Fig. 8. Lateral view of an unusual left valve with broad plicae, fluted at 
their intersection with coarse concentric lamellae, and abnormally large 
smooth umbonal area. This form is possibly transitional to Lopha panda 
(Morton). A hypotype from the upper Eagle Ford Shale, Dallas County, 
Tex. (locality 15, U.S.G.S. 7539, cited above) ; U.S.N.M. 132219. 

Fig. 10. Lateral view of a typical left valve with abnormally projecting beak 
and early umbo; a hypotype from the upper Eagle Ford sands, 1.75 miles 
west of Sherman, Tex. (locality 50, U.S.G.S. 14553) ; U.S.N.M. 132221. 

Fig. 12. Lateral view of a left valve, unusual in having a nearly centrally 
situated beak and broad plicae; a hypotype from the upper Eagle Ford 
Shale, Dallas County, Tex. (locality 15, U.S.G.S. 7539, cited above) ; 
U.S.N.M. 132223. 

Fig. 13. Lateral view of White's hjpotype (1879, pi. 4, figs. 3a, b) from the 
Eagle Ford Shale at Denison, Tex. (locality 56) ; U.S.N.M. 12383. 

Fig. 14. Lateral view of a typical adult left valve; a hypotype from upper 
Eagle Ford sands, 1.75 miles west of Sherman, Tex. (locality 50, U.S.G.S. 
14553) ; U.S.N.M. 132224. 

Fig. 16. Lateral view of an unusually elongate, high left valve, more inclined 
than normal, and with a large attachment scar; a hypotype from Dallas 
County, Tex. (locality 57) ; U.S.N.M. 132226. 

Fig. 17. Lateral view of a typical left valve with an unusually large attach- 
ment scar, a hypotype from the upper Eagle Ford Shale, 2.5 miles east of 
Eagle Ford, Dallas County, Tex. (locality 15, U.S.G.S. 7539, cited 
above) ; U.S.N.M. 132227. 

Plate 4 

(All figures XI) 

Lopha bellaplicata hellaplicata (Shumard) 

Fig. 1. Lateral view of a left valve from White's syntype lot of Lopha blacki. 
Note that other than the projecting beak and umbo, deformed by the 



86 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

attachment scar, and the rounded nature of the plicae (worn), the nature 
of the valve is identical with those of L. bellaplicata bellaplicata illustrated 
on plates 3 and 4; hypotype (of L. bellaplicata bellaplicata) from the 
upper Eagle Ford Shale, Collin Coimty, Tex. (locality 53) ; U.S.N.M. 
8024a. 

Fig. 2. Lateral view of a large left valve with unusually well developed 
posterior auricle and faint, worn plicae ; hypotype from upper Eagle Ford 
sands, 1.75 miles west of Sherman, Tex. (locality 50, U.S.G.S. 14553) ; 
U.S.N.M. 132229. 

Fig. 3. Lateral view of a typical left valve. Note change in prominence of 
plicae at midshell, giving rise to faint plicae similar to those on L. blacki 
(White). A hypotype from the upper Eagle Ford Shale, 2.5 miles east of 
Eagle Ford, Dallas County, Tex. (locality 15, U.S.G.S. 7539) ; U.S.N.M. 
132230. 

Fig. 4. Lateral view of an unusually flat left valve with abnormal prosocline 
inclination, a hypotype from the upper Eagle Ford Shale, Dallas County, 
Tex. (locality 57) ; U.S.N.M. 132231. 

Fig. 5. Lateral view of an adult left valve showing extensive bifurcation of 
plicae, and unusually reduced posterior auricle ; a hypotype from the upper 
Eagle Ford Shale, 2.5 miles east of Eagle Ford, Dallas County, Tex. 
(locality 15, U.S.G.S. 7539) ; U.S.N.M. 132232. 

Fig. 6. Lateral view of the smoothest specimen from White's syntype lot of 
L. blacki, considered here a smooth variant of L. bellaplicata bellaplicata 
(Shumard). The original of White's plate 46, figure 2 (1884). Hypotype 
from the upper Eagle Ford Shale, Collin County, Tex. (locality 53) ; 
U.S.N.M. 8024b. 

Fig. 7. Lateral view of a large left valve showing large attachment scar but 
otherwise typical of the species ; hypotype from the upper Eagle Ford 
Shale, Dallas County, Tex. (locality 15, U.S.G.S. 7539, cited above) ; 
U.S.N.M. 132233. 

Fig. 8. Interior view of a left valve showing nature and position of muscle 
scar, flattened lateral lamellae forming part of commissure, and unusually 
massive cardinal area with characteristic structures ; a hypotype from 
the upper Eagle Ford Shale, Dallas County, Tex. (locality 57) ; U.S.N.M. 
132234. 

Plate 5 
(All figures Xl) 
Lopha bellaplicata bellaplicata (Shumard) 

Figs. 1-4. Anterior (side) views of representative left valves, illustrating the 
range of variation in convexity. No. 1 is typical of the species. 1-3, 
Neotype and hypotypes from the upper Eagle Ford Shale, Dallas County, 
Tex. (locality 15, U.S.G.S. 7539) ; U.S.N.M. 132222 (fig. 1) ; U.S.N.M. 
132228 (fig. 2) ; U.S.N.M. 132235 (fig. 3). 4, Hypotype from the upper 
Eagle Ford Shale, Dallas County, Tex. (locality 57) ; U.S.N.M. 132231. 

Figs. 5-8. Lateral views of typical right valves, arranged in growth series. 
Note development of auricles (fig. 7 is atypical in this respect, having 
rounded auricles), anterior position of beaks, posterior curvature of beaks. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 87 

nearly straight dorsal margin, height of smooth stage (greater than on 
average left valves), the abrupt appearance, prominence, and bifurcation 
of the plicae, and the well-developed concentric lamellae. Hypotypes 
from the upper Eagle Ford Shale, 1.5 miles east of Eagle Ford, Dallas 
County, Tex. (locality 15, U.S.G.S. 7539) ; U.S.N.M. 132236 (fig. 5) ; 
U.S.N.M. 132237 (fig. 6) ; U.S.N.M. 132238 (fig. 7) ; U.S.N.M. 132239 
(fig. 8). 

Fig. 9. Lateral view of a right valve from the syntype lot of "Ostrea^' blacki 
White. Note the only difference between this specimen and typical right 
valves of L. bellaplicata bellaplicata is the height of the smooth stage. 
A hypotype of L. bellaplicata bellaplicata from the upper Eagle Ford 
Shale in Collin County, Tex. (locality 53) ; U.S.N.M. 8024c. 

Figs. 10, 13. Lateral and interior views of an abnormal right valve lacking 
auricles and prominent plicae. Note nature of cardinal area and muscle 
scar, both characteristic for the species. A hypotype from the upper 
Eagle Ford Shale of Texas (locality 57, previously cited) ; U.S.N.M. 
132240. 

Fig. 11. Lateral view of a nearly smooth right valve of a mature shell, a 
marginal variant occurring with specimens illustrated in figures 5-8. 
Compare with figure 12, a syntype of L. blacki (White). Hypotype from 
the upper Eagle Ford Shale of Texas (locality 15, U.S.G.S. 7539, 
previously cited) ; U.S.N.M. 132241. 

Figs. 12, IS. Lateral and interior views of a smooth right valve with faint 
plicae and well-developed interior features. Hypotype of Lopha bella- 
plicata bellaplicata from the upper Eagle Ford Shale of Collin County, 
Tex. (locality 53) ; U.S.N.M. 11882b. 

Fig. 14. Lateral view of an unusually elongate right valve with characteristic 
ornamentation, somewhat worn ; hypotype from the upper Eagle Ford 
Shale of Dallas County, Tex. (locality IS, U.S.G.S. 7539, previously 
cited) ; U.S.N.M. 132242. 

Plate 6 
Lopha bellaplicata bellaplicata (Shumard), variety A 

Fig. 1. Lateral view (Xl) of a typical left valve, showing shape, plicae, 
narrow beak and umbo, and small attachment scar. A hypotype from the 
Codell Sandstone Member, Carlile Shale, Huerfano Park, Colo, (locality 
41, U.S.G.S. 743) ; U.S.N.M. 22011a. 

Fig. 2. Lateral view (X2) of a left valve with an unusually large attachment 
scar; a hypotype from the Codell Sandstone Member, Huerfano Park, 
Colo, (locality 59; U.M.M.P. 38052. 

Fig. 3. Lateral view (Xl) of a small plicate upper valve associated with 
L. bellaplicata bellaplicata var. A ; a hypotype from the Codell Sandstone 
Member of Huerfano Park, Colo, (locality 58) ; U.S.N.M. 132259. 

Fig. 4. Lateral view (Xl) of a smooth, elongate right valve associated with 
specimens of L. bellaplicata bellaplicata var. A; a hypotype from the 
Codell Sandstone Member, Huerfano Park, Colo, (locality 61); 
U.M.M.P. 43413. 



88 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Fig. 5. Lateral view (X2) of a left valve with unusually broad plicae; a 

hypotype from the Codell Sandstone Member, Huerfano Park, Colo. 

(locality 59) ; U.M.M.P. 38051. 
Fig. 6. Lateral view of a left valve (Xl) with a prominent attachment scar; 

hypotype from the Codell Sandstone Member, Huerfano Park, Colo. 

(locality 41, U.S.G.S. 743) ; U.S.N.M. 22011d. 
Fig. 19. Lateral view (Xl) of a small left valve showing ventral flaring of 

the lateral margins; a hypotype from the Codell Sandstone Member, 

Huerfano Park, Colo, (locality 61) ; U.S.N.M. 132249. 

Lopha bcllaplicata bclIapHcata (Shumard) : forma typica 

Fig. 7. Lateral view (Xl) of a small left valve typical of the species, a 
hypotype from the Codell Sandstone Member, Huerfano Park, Colo, 
(locality 40, U.S.G.S. 741) ; U.S.N.M. 22009a. 

Fig. 8. Lateral view (Xl) of a left valve with moderately large attachment 
scar: a hypotype figured bj' Stanton (1893, pi. 4, fig. 4) from the Codell 
Sandstone Member, Huerfano Park, Colo, (locality 41, U.S.G.S. 743) ; 
U.S.N.M. 22860d. 

Fig. 9. Lateral view (Xl) of a left valve, characteristic of the species; hypo- 
type from the Codell Sandstone Member, Huerfano Park, Colo, (locality 
61); U.M.M.P. 38038. 

Fig. 10. Lateral view of an unusual left valve (Xl) with abnormally elongate 
posterior auricle, broad, faint plicae; a hypotype from the Codell Sand- 
stone Member, Carlile Shale, Huerfano Park, Colo. (locaHty 61) ; 
U.M.M.P. 43482. 

Fig. 11. Lateral view (Xl) of a mature left valve, slightly longer than 
average, similar to Texas specimen illustrated on plate 3, figure 12; 
hypotype from the Codell Sandstone Member, Huerfano Park, Colo, 
(locality 40, U.S.G.S. 741) ; U.S.N.M. 22009b. 

Fig. 12. Lateral view (Xl) of a typical left valve, a hypotype from the 
Codell Sandstone Member, Huerfano Park, Colo, (locality 59) ; 
U.M.M.P. 38039. 

Fig. 13. Lateral view (Xl) of a nearly symmetrical left valve with a large 
attachment scar and unusually inflated umbone, a hypotype from the 
Codell Sandstone Member, Huerfano Park, Colo, (locality 41, U.S.G.S. 
743); U.S.N.M. 22011b. 

Fig. 14. Lateral view (Xl) of a mature left valve with unusually deep 
attachment scar, abnormally situated dorsoposteriorly ; a hypotype from 
the Codell Sandstone Member, Huerfano Park, Colo, (locality 59) ; 
U.M.M.P. 38041. 

Fig. 15. Lateral view (Xl) of a large left valve vvith extended auricles, 
abnormally broad plicae, and subcentral beak ; a Colorado variant of the 
species not yet found elsewhere; a hypotype from the Codell Sandstone 
Member, CarHle Springs, Colo, (locality 55) ; the original of Stanton's 
plate 4, figure 7 (1893) ; U.S.N.M. 22861. 

Fig. 16. Interior view of a left valve (Xl) showing normal cardinal area, 
denticles, internal reflection of ornamentation, and posterior adductor 
muscle scar, the hypotype figured by Stanton (1893, pi. 4, fig. 9), from the 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 89 

Codell Sandstone Member, Huerfano Park, Colo (locality 41, U.S.G.S. 
743); U.S.N.M. 22860b. 

Fig. 17. Lateral view of a typical right valve from Colorado (X2) showing 
limited extent of plicae, concentric ornamentation, shape; a hypotype 
from the Codell Sandstone Member, Huerfano Park, Colo, (locality 61) ; 
U.M.M.P. 43466. 

Fig. 18. Lateral view (X2) of a totally nonplicate right valve, otherwise 
typical of the species; a hypotype from the Codell Sandstone Member, 
Huerfano Park, Colo, (locality 59) ; U.M.M.P. 43483. 

Fig. 20. Lateral view (Xl) of a large, unusually high right valve, showing- 
typical development of the concentric lamellae; a hypotype from the 
upper Eagle Ford Shale, Dallas County, Tex. (locality 15, U.S.G.S. 
7539) ; U.S.N.M. 132250. 

Fig. 21. Lateral view (Xl) of a nearly smooth right valve showing a few, 
sinuous, irregular plicae near margin ; a hypotype from the Codell Sand- 
stone Member, Huerfano Park, Colo, (locality 59) ; U.M.M.P. 43478. 

Figs. 22, 23. Dorsal and posterior views (Xl) of a small left valve with 
plicae less extensive than average, and an unusually large attachment 
scar; the hj'potype illustrated by Stanton (1893, pi. 4, fig. 6), from the 
Codell Sandstone Member, Huerfano Park, Colo, (locality 41, U.S.G.S. 
743) ; U.S.N.M. 22860c. 

Fig. 24. Lateral view of a large, old right valve showing degeneration of 
radial ornamentation near margin, and increase in number and prominence 
of the concentric lamellae with age; a hypotype from the upper Eagle 
Ford Shale, Dallas County, Tex. (locality 15, U.S.G.S. 7539) ; U.S.N.M. 
132251. 

Plate 7 
(All figures Xl) 
Lopha bellaplicata novamexicana Kauffman, new subspecies 

Figs. 1, 2. Lateral views of immature left valves, typical of the subspecies. 
Note general similarity to immature left valves of L. bellaplicata 
bellaplicata (pi. 3) but the smaller auricles and more inclined postero- 
dorsal margin in the subspecies novamexicana at this and later growth 
stages. Paratypes from the zone of Colligiwniceras hyatti (Stanton), 
Mancos Shale, Socorro County, N. Mex. (locality 66, U.S.G.S. D2042) ; 
U.S.N.M. 132260 (fig. 1), and 132261 (fig. 2). 

Fig. 3. Lateral view of a young adult left valve, typical of the subspecies 
except for narrow auricular sulci. Note broad plicae. A paratype from 
the Colorado Group (Mancos?), Carthage, N. Mex. (locality 64, U.S.G.S. 
3297) ; U.S.N.M. 132262. 

Figs. 4, 5. Lateral and interior views of a typical adult valve showing broad, 
widely spaced plicae, few in number, inclined posterodorsal margin, 
broad posterior auricular sulcus, and the nature of the cardinal area and 
muscle scar. A paratype from the Mancos Shale, Socorro County, N. Mex. 
(locality 66, U.S.G.S. D2042) ; U.S.N.M. 132263. 



90 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Fig. 6. Lateral view of a small, incomplete, right valve showing broad plicae 
and short smooth stage. A paratype from the Mancos Shale, Socorro 
County, N. Mex. (locality 66, U.S.G.S. D2042) ; U.S.N.M. 132264. 

Fig. 7. Lateral view of a small, unusually curved right valve with recurved 
beak and umbo, short smooth stage limited to umbo, and typical plicae. 
A paratype from the Colorado Group (Mancos Shale?), Carthage, 
N. Mex. (locality 64, U.S.G.S. 3297) ; U.S.N.M. 132262. 

Fig. 8. Lateral view of an adult right valve similar in shape to those of 
L. bellaplicata bellaplicata, but with a much shorter smooth umbonal area. 
Note coarse lamellae, characteristic plicae. A paratype from the Colorado 
Group (Mancos) at Carthage, N. Mex. (locality 63, U.S.G.S. 3295) ; 
U.S.N.M. 132265. 

Fig. 9. Lateral view of a right valve with reverse inclination (opisthocline) 
and enlarged anterior auricle. Note broad plicae, short smooth stage 
limited to umbo. A paratype from the Mancos Shale, zone of 
Collignoniceras hyatti, Socorro County, N. Mex. (locality 66, U.S.G.S. 
D2042) ; U.S.N.M. 132266. 

Fig. 10. Lateral view of a left valve, characteristic of the subspecies. Note 
broad plicae, few in number, broad posterior auricular sulcus, inclination 
of posterodorsal margin. The holotype, from a massive sandstone in the 
Mancos Shale, zone of Collignoniceras hyatti, Socorro County, N. Mex. 
(locality 66, U.S.G.S. D2042) ; U.S.N.M. 132267. 

Fig. 11. Lateral view of a left valve with narrow plicae, otherwise typical 
of the subspecies ; a paratype from the septarian limestone concretion 
zone, upper Blue Hill Shale Member, Huerfano Park, Colo, (locality 62, 
U.S.G.S. 738) ; U.S.N.M. 22012. 

Fig. 12. Lateral view of a left valve with narrow ribs, or plicae, occurring 
along with normal individuals of the subspecies in the Mancos Shale near 
Carthage, N. Mex. (locality 63, U.S.G.S. 3295). Compare this with 
figure 11, from the Blue Hill Shale Member, Huerfano Park, Colo. A 
paratype, U.S.N.M. 132268. 

Fig. 13. Lateral view of an unusually broad variant of the subspecies from 
the Blue Hill Shale Member, Huerfano Park, Colo, (locality 69), closely 
comparable to marginal variants of L. bellaplicata bellaplicata from the 
Codell Sandstone in the same area (see pi. 6, fig. 15). A paratype; 
U.S.N.M. 132269. 

Fig. 14. Lateral view of a high left valve with reduced posterior auricle; 
paratype from the Mancos Shale at Carthage, N. Mex. (locality 65, 
U.S.G.S. 5303) ; U.S.N.M. 132270. 

Fig. 15. Lateral view of an exfoliated left valve, showing characteristic 
outline and radial ornamentation; a paratype from the Mancos Shale at 
Carthage, N. Mex. (locality 64, U.S.G.S. 3297) ; U.S.N.M. 132271. 

Fig. 16. Lateral view of a robust left valve, characteristic of the subspecies ; a 
paratype from the Mancos Shale, zone of Collignoniceras hyatti, Socorro 
County, N. Mex. (locality 66, U.S.G.S. D2042) ; U.S.N.M. 132272. 

Fig. 17. Lateral view of a left valve with posterior auricle larger than normal 
and density of plicae approaching that of L. bellaplicata bellaplicata; a 
paratype from the Mancos Shale, Carthage, N. Mex. (locality 65, 
U.S.G.S. 5303) ; U.S.N.M. 132273. 



NO. 6 OYSTERS OF THE LOPHA LUGUBRIS GROUP — KAUFFMAN 9I 

Fig. 18. Lateral view of a large left valve, characteristic of the subspecies ; 

a paratype from the Mancos Shale at Carthage, N. Mex. (locality 64, 

U.S.G.S. 3297) ; U.S.N.M. 132274. 
Fig. 19. Lateral view of an unusually high left valve, otherwise characteristic 

of the subspecies; a paratype from the Mancos Shale at Carthage, N. 

Mex. (locality 65, U.S.G.S. 5303) ; U.S.N.M. 132275. 

Plate 8 
Lopha hellaplicata novamexicana Kauff man, new subspecies 

Fig. 1-3. Anterior views of left valves illustrating the range in convexity, the 
great convexity of the umbonal region, and the dorsal position of the high 
point of the valve. All specimens from the Mancos Shale of New Mexico, 
zone of Collignoniceras hyatti. 1, U.S.N.M. 132282, from locality 66. 
2, U.S.N.M. 132271, from locality 64. 3, U.S.N.M. 132276, from locality 
66. All figures Xl- 

Fig. 4, Lateral view (Xl) of a left valve, characteristic of the subspecies 
except for fainter plicae; paratype from locality 66, U.S.G.S. D2042, 
Mancos Shale, zone of Collignoniceras hyatti, Socorro County, N. Mex. 
U.S.N.M. 132277. 

Fig. 5. Lateral view (Xl) of a left valve with large vertical attachment 
scar and unusually fine plicae; paratype from the Mancos Shale, zone of 
Collignoniceras hyatti, Socorro County, N. Mex. (locality 66, U.S.G.S. 
D2042) ; U.S.N.M. 132278. 

Fig. 6. Lateral view (Xl) of a large left valve transitional with L. hella- 
plicata hellaplicata in development of plicae and auricular sulci, but retain- 
ing characteristic shell form of the subspecies; a paratype from the 
Mancos Shale, zone of C. hyatti, Socorro County, N. Mex. (locality 66, 
U.S.G.S. D2042) ; U.S.N.M. 132279. 

Fig. 7. Lateral view of a large left valve (Xl) characteristic of the sub- 
species; a paratype from the zone of C. hyatti, Mancos Shale, Socorro 
County, N. Mex. (locality 66, U.S.G.S. D2042) ; U.S.N.M. 132280. 

Fig. 8. Lateral view (Xl) of a typical left valve with worn plicae; a paratype 
from the zone of C. hyatti, Mancos Shale, Socorro County, N. Mex. 
(locality 66, U.S.G.S. D2042) ; U.S.N.M. 132281. 

Fig. 9. Lateral view (Xl) of a typical large, adult left valve; a paratype 
from the zone of C hyatti, Mancos Shale, Socorro County, N. Mex. 
(locality 66, U.S.G.S. D2042) ; U.S.N.M. 132282. 

Lopha hellaplicata hellaplicata (Shumard) 

Fig. 10. Thin section (X4) through the umbo and cardinal area of a large 
left valve; section parallel to the hinge line. Note major layers in sub- 
nacreous layer, and fine crystalline calcite sheets within them. Fine layers 
inclined to plane of major layers over umbo, parallel to this plane 
laterally; a hypotype from the upper Eagle Ford Shale, Dallas County, 
Tex. (locality 15, U.S.G.S. 7539) ; U.S.N.M. 132283. 

Fig. 11. Thin section (X4) taken along the median plica, showing the struc- 
ture of the subnacreous shell layer, the "hingement" of the valves, position 



92 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

of the ligament, and the position of the cardinal axis on the cardinal plate. 
Note that subnacreous layer is composed of distinct major calcite layers 
(lamellae) parallel to the surface of the shell; each layer is composed of 
fine fibrous-appearing calcite crystals or plates inclined to the plane of the 
major layers, and in many cases, with opposed inclination within or 
between major layers. A hypotype from sands of upper Eagle Ford age, 
Grayson County, Tex. (locality 50, U.S.G.S. 14553) ; U.S.N.M. 132284. 

Lopha liigubris (Conrad) 

Fig. 12. Thin section (X8) through part of the left valve, showing major 
calcite lamellae in subnacreous layer and minor inclined fibrous calcite 
crystals or plates within them, as described for figure 11. A hypotype 
from New Mexico (locality 1, U.S.G.S. 513) in the zone of Prionocychis 
wyomingensis. U.S.N.M. 132285. 



PLATES 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 6. PLATE 1 




LOPHA LUGUBRIS (CONRAD): UEFT VAUVE 
(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 6. PLATE 2 




LOPHA LUGUBRIS (CONRAD) : RIGHT VALVE 

(SEE EXPLANATION OF PLATES AT END OF TEXT. 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 6. PLATE 3 




LOPHA BELUAPLICATA BELLAPLICATA (SHUMARD): LEFT VAUVE. TEXAS 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 6, PLATE 4 




LOPHA BELLAPUICATA BEULAPLICATA (SHUMARD): LEFT VAUVE. TEXAS 
(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



HITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO 6. PLATE 5 




LOPHA BELLAPLICATA BELLAPLICATA (SHUMARD): LEFT AND RIGHT VALVES. TEXAS 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



1 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 6. PLATE 6 




LOPHA BELLAPLICATA BELLAPLICATA (SHUMARD): VAR. A AND FORMA TYPICA: 

Left and Right Valves. Texas and Colorado 
(see explanation of plates at end of text.) 



1ITHS0NIAN MISCELLANEOUS COLLECTIONS 




LOPHA BELLAPLICATA NOVAMEXICANA KAUFFMAN. N. SUBSP. 

Left and Right Valves. Colorado and New Mexico 

(see explanation of plates at end of text.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148. NO. 6. PLATES 




LOPHA BELLAPLICATA NOVAMEXICANA KAUFFMAN. N. SUBSP.: 
L. BELUAPLICATA BELLAPLICATA (SHUMARD): L. LUGUBRIS (CONRAD) 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



_SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 7 




ISloebling: jf unb " ^PR2 



AN ACCOUNT OF THE ASTROPHYSICAL 

OBSERVATORY OF THE SMITHSONIAN 

INSTITUTION, 1904-1953 



By 

C G. ABBOT 

Research Associate, Smithsonian Institution 




CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

FEBRUARY 24, 1966 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 7 



Eoelilmg Jf unb 



AN ACCOUNT OF THE ASTROPHYSICAL 

OBSERVATORY OF THE SMITHSONIAN 

INSTITUTION, 1904-1953 



By 
C. G. ABBOT 

Research Associate, Smithsonian Institution 




(Publication 4656) 



CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

FEBRUARY 24, 1966 



PORT CITY PRESS, INC. 
BALTIMORE, IVID., U. S. A. 



AN ACCOUNT OF THE ASTROPHYSICAL 

OBSERVATORY OF THE SMITHSONIAN 

INSTITUTION, 1904-1953 

By Charles G. Abbot, D.Sc. 
Research Associate, Smithsonian Institution 

The Smithsonian's Astrophysical Observatory was founded by 
Secretary Samuel P. Langley in 1890. Until 1900 the Observatory's 
original research activities included developing and improving appa- 
ratus, and mapping the then little-known infrared spectrimi of the 
sun. The bolometer, which Langley had invented about 1878, was 
given photographic registration, tamed to be as quiet and reliable as 
a mercury thermometer, and used to record small depressions where 
absorption lines occurred in the solar spectrum. The Observatory's 
highly exact determinations of the dispersion of rock-salt and fluorite 
prisms fixed the wavelengths of these absorption lines. Volume 1 of 
the Annals, describing all of this work, was published in 1900. Expe- 
ditions to North Carolina and to Sumatra observed the total solar 
eclipses of 1900 and 1901, and a small eclipse volume was published 
in 1903. 

The Observatory then took up measurement of the intensity of the 
sun's radiation, the variability of it, and the transmission of radiation 
by the earth's atmosphere in the visible and infrared spectrum. The 
average intensity of solar radiation received by the earth, called the 
"solar constant," was then unknown between the limits 1.76 and 
4.0 calories per square centimeter per minute. Solar constant research 
and the dependence of weather on solar variation principally occupied 
the Observatory from 1904 through 1953. 

ADMINISTRATION OF THE OBSERVATORY, 1904-1953 

FINANaAL SXH'PORT 

A breakdown of the Observatory's financial support from 1904 
through 1953 shows that the average yearly support for this period 
was $37,000. 

SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 148, NO. 7 



2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Congressional appropriations $1,148,000 

Gifts by John A. Roebling 617,000 

Grants by National Geographic Society 65,000 

From Smithsonian funds 10,000 

Other gifts 10,000 

Total $1,850,000 

The finances were managed by the Smithsonian Disbursing Office. 

STAFF 

The number of persons employed for all purposes varied from 2 
to 14. 

BUILDINGS 

With headquarters in Washington, instruments were designed and 
constructed there, and early observations were made there. However, 
most of the observing later was done on several high mountains in 
distant arid lands. In all, 16 structures were built in these far-off 
lonely places to house observers and instruments. A valuable sug- 
gestion by E. B. Moore led us to construct underground laboratories 
in sloping ground for the spectrobolometric apparatus. Thus we 
obtained constant temperature. We fed the sun-rays into these 
tunnels horizontally with coelostats. 

ACTIVITIES OF THE OBSERVATORY, 1904-1953 

INSTRUMENTS 

Five kinds of pyrheliometers for measuring the intensity of sun- 
rays were designed. These included the silver-disk, the water-flow, the 
water-stir, the improved Angstrom, and the automatic-balloon pyrheli- 
ometers. For measuring sky-radiation the pyranometer was designed. 
Other instruments designed included the vacuum bolometer, special 
extrapolator for spectral atmospheric transmission measures, appa- 
ratus for observing stars by day for guiding airplanes, a compact 
spectrobolometer for expeditions, eclipse apparatus, high intensity 
lamps for Fowle's infrared investigation, numerous supports for 
mirrors, and many other observing devices. All of these instruments 
were constructed by Andrew Kramer, instrument maker for the 
Observatory, 1891-1950, and after 1950 by Darnel Talbert. 



NO. 7 ASTROPHYSICAL OBSERVATORY, I904-I953 — ABBOT 



PUBLICATIONS 

Quarto volumes 2-6 of the Annals, prepared by C. G. Abbot, F. E. 
Fowle, and L. B. Aldrich, and volume 7, prepared by L. B. Aldrich 
and W. H. Hoover, were published 1908-1953. About 150 papers, 
mostly published in Smithsonian Miscellaneous Collections, were 
written by members of the staff.^ 

THEORETICAL FINDINGS 

Langley showed about 1880 that, to determine the solar constant, 
the spectral transmission of the atmosphere must be measured. This 
was always done by us with a clock-operated recording spectro- 
bolometer in Langley's Method (now often called the "long method"). 
Langley did not publish a complete theory of this method, and he 
used it erroneously in publishing his Mount Whitney Expedition of 
1881. This error gave his preferred solar constant value 3.07 instead 
of 2.0 calories. The full theoretical demonstration, and examples of 
the correct application of Langley's method are published in Annals, 
volume 2. 

Although Langley's method is fundamental, it requires several 
hours of observing while the sun's air mass or atmospheric path 
changes from (say) 3.5 to 1.5 times that for vertical sun. During this 
considerable time the transparency of the atmosphere always changes. 
If it grows clearer for small air masses the resulting solar constant 
is too large, and vice versa. Hence only large groups of solar constant 
measures by Langley's method can be trusted ; these give mean values 
nearly correctly. 

A brief method for measuring spectral transparency was required, 
so that several values of the solar constant could be obtained daily, 
with little atmospheric variation affecting any one of them. Then 
the day's mean value would be good. 

From 1920 to 1924 the A.P.O. developed the "short method." This 
is empirical, depending on the fact that the brightness of the sky near 
the sun is greater as the sky becomes more hazy. It is found pos- 
sible to draw curves suited at all times to yield transmission coefficients 
suited to each station occupied for all of the 40 wavelengths used in 
Langley's method. A "short method" measurement requires only 
one reading of the pyranometer of sky-brightness near the sun. So 
in the 10 minutes employed for making a spectrobolometric graph of 

1 1 will use the abbreviations "A.P.O." for Astrophysical Observatory, and 
"Pub." for publication. 



4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

the solar spectrum, with a reading of the pyranometer on a limited 
sky area surrounding the sun, a reading of the pyrheliometer on the 
sun itself, and a theodolite measurement of the sun's zenith distance, 
the observations are complete. 

We made three or sometimes five determinations of the solar con- 
stant a day by the short method, and used their mean value for the 
day's result. From 1924 to 1952 over 9,000 mean daily values of the 
solar constant were obtained. Many of them were observed from 
three independent stations on the same day. It is shown by table 1, 
page 13 of Smithsonian Publication 4545,^ that by comparing 1992 
pairs of solar constant observations of the same day, made individu- 
ally at stations separated by thousands of miles, some in the Northern, 
others in the Southern Hemisphere, and at all times of the year, the 
probable error of a single day's observation of the solar constant at 
one station is ^ of 1 percent. All of the approximately 9,000 daily 
determinations, published in volumes 6 and 7 of Annals, were scru- 
tinized at Washington, and unanimously approved for publication by 
a committee comprising L. B. Aldrich, W. H. Hoover, and Mrs. 
A. M. Bond. 

TOWER TELESCOPE 

Langley hoped that these 9,000 daily determinations would prove 
that a strong correlation could be found between daily solar constant 
values and simultaneous observations of the distribution of the 
intensity of solar radiation along the east-west diameter of the sun's 
disk. Some preliminary observations of that distribution were made 
in Washington in 1908. Later a tower telescope to form an 8-inch 
image of the sun was erected on our observatory on Mount Wilson, 
about 1913. From 1913 to 1920, on all observing days, the telescope 
also was adjusted between observations to form a solar image on the 
slit of the spectrobolometer. The telescope clock was then stopped, 
and the solar image was allowed to drift centrally over the slit. Thus 
was recorded D -shaped distribution curves in five wavelengths on 
each day that a solar constant value was obtained. See figure 52, 
Pub. 4545.2 

Owing to inexactness of solar constant values due to the fluctuation 
of atmospheric transmission during the several hours required for 
solar constant measures by Langley's method (used exclusively on 

^ Solar variation and weather, by C. G. Abbot. Smithsonian Miscellaneous 
Collections, vol. 146, No. 3. 1963. 



NO. 7 ASTROPHYSICAL OBSERVATORY, I904-I953 — ABBOT 5 

Mount Wilson, 1905-1920) it was not then possible to be assured of 
the correlation between solar constant and diametral distribution. But 
when the family of harmonic variations in the solar constant values 
became known about 1940, the solar constant value was back-casted 
from 1920 to 1913, and such correlation seemed indicated. See fig- 
ures 50 and 51, Pub. 4545.^ Solar contrast observations were dis- 
continued in 1920, and solar constant determinations have never been 
made anywhere in the world since 1955. So this correlation cannot 
now be fully proved. 

PRINCIPAL RESEARCHES 

Leading Operations of the Smithsonian Astrophysical Observatory, 
1895 to 1955^ (Smithsonian Pub. 4222) gives brief summaries of 
82 researches, with bibliographic references to the original publica- 
tions of them. I select here for notice a few of the most important 
researches which occupied the years 1904 to 1953. 

1. Inventions of pyrheliometers, vacuum bolometer, pyranometer, 

honeycomb pyranometer, two-mirror coelostat, highly sensi- 
tive radiometer, and solar heat collector. 

2. Absolute measurement in heat units to 1 percent of the solar 

constant, with probable error of a day's measurement at one 
station ^ of 1 percent relative to other day's measures. 

3. Fixing the limits of sun's radiating temperature as between 

5800° and 7000° C. Abs. Four methods used. 

4. Measurement of atmospheric spectral transmission in 40 wave- 

lengths at 10 stations located between sea level and 14,500 
feet elevation. 

5. Determining the distribution and intensity of radiation in the 

solar spectrum at 10 stations, and outside the earth's atmos- 
phere. 

6. Short method for the solar constant, and also automatic balloon 

determination. 

7. Discovery of solar variation between limits of 2.0 percent in 

amplitude. 

8. Discovery of a 27-day period in "solar constant" variation. 

9. Discovery of a numerous harmonic family of exact periods in 

solar variation with a master period of exactly 273 months. 



3 Leading operations of the Smithsonian Astrophysical Observatory, 1895 to 
1955, by C. G. Abbot. Smithsonian Miscellaneous Collections, vol. 131, No. 1. 
1955. 



6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I48 

10. Discovery of these identical harmonic periods in terrestrial 

temperature, and in precipitation, and a method of long- 
range forecasts based thereon. 

11. Discovery of opposing trends in terrestrial temperature, at- 

tending for 16 days after rising and falling trends in solar 
radiation. 

12. Fowle's work on terrestrial radiation and its absorption. 

13. Aldrich's measure of the earth's albedo. 

14. Aldrich's work with the honeycomb pyranometer, 

15. Aldrich and Hoover's work, in volume 7 of Annals, on the 

solar constant, and on solar and sky radiation at military 
camp sites. 

16. Work of the Division of Radiation and Organisms, a subsidi- 

ary branch of the A.P.O., founded by Secretary Abbot in 
1929. 

CRITICISM OF CERTAIN METEOROLOGICAL FINDINGS 

While many of the pieces of work are everywhere praised and 
accepted,* professional meteorologists have disparaged the alleged 
results indicated by numbers 2, 7, 8, 9, 10, and 11, listed above. I had 
hoped to overcome their doubts by my publication 4545.^ However, 
recent private advices from responsible officers of the U.S. Weather 
Bureau, the American Meteorological Society, and the High Level 
Atmospheric Observatory at Boulder, Colorado, convince me that 
their doubts still remain. As I feel quite certain of the soundness of 
these A. P.O. results, I feel a duty to dispel these official objections. 
In the remainder of this paper new evidence will be presented. 

A DEFENSE OF CERTAIN METEOROLOGICAL FINDINGS 

SOtAR RADIATION AND ITS VARIABILITY 

Numbers 2 and 7 — The accuracy of A. P.O. measures of the solar 
constant, and the limits of its variation. 

Referring to table 1, page 13 of Pub. 4545,^ the probable error of 
one day's solar constant measure at one station (usually the mean of 
three independent observations) is -^ of 1 percent. It is certified by 
1992 pairs of solar constant measures on identical days made at four 
observing stations at all times of the year. One station is in the 
Southern, three in the Northern Hemisphere, and they are separated 
by thousands of miles. Table 1, just cited, is composed of four sec- 



* See expert opinions given in volume V of Annals, A. P.O., pp. 32-35. 



NO. 7 ASTROPHYSICAL OBSERVATORY, I904-I953 — ABBOT 7 

tions whose individual mean values differ only through the small range 
from 76.0 to 77.9 parts in 10,000 of the solar constant. 

As for the extreme limits of solar variation, I sent Dr. Roberts 
of High Level Observatory a rough plot of all Montezuma solar 
constant daily mean values, 1923 to 1952. He retains a copy of it. 
From numerous of these values, some as low as 1.910, some as high 
as 1.970, I believe it fair to set solar variation limits as above 2 per- 
cent. Dr. Franz Baur of the University of Frankfurt, A.M., Germany, 
has published 2.2 percent as his conclusion.^ 

On one occasion the solar constant appears to have gone as low as 
1.870 calories in 1922 and 1923, for a considerable time. This unique 
depression may be associated with a long-range period in solar varia- 
tion that would require scores or centuries of years of observation to 
verify. 

PERIODIC SOLAR VARIATION 

Number 8 — The 27-day period in solar variation. 

It has long been known that the sun's surface shows rotation vary- 
ing in velocity from the sun's equator to its poles. At the equator the 
sun rotates in about 25 days, and in about 35 days at 80° latitude. 
A weighted value of the sun's rotation period, considering areas and 
latitude, may be taken at 27 days. In Pub. 2499,* I showed strong 
correlation in solar constant measures ranging continuously from 
+ 25 to —30 percent, with a period of 27 days. See figure 15, Pub. 
4545.2 jj^jg ^i(je range was observed in Mount Wilson values in 1915, 
but not in other years, 1912-1920. 

Having discovered the master period, 22 years, 9 months (273 
months) in solar variation about 1940, it seemed to me probable that 
the highly accurate solar constant measures made at Montezuma would 
show a 27-day period strongly in the year 1937 (1915 + 22 years), 
perhaps repeated several times. I have computed from records in 
volume 6 of the Observatory's Annals for four recurrences of the 
27-day period in daily solar constant values observed at Montezuma 
from early April to late September of 1937. Table 1 and accompany- 
ing Figure 1 show the detailed and mean results. A 27-day periodic 

^Met. Rundschau, 17 January, Jahrb. 1, Heft 1964, pp. 19-25. 

273 273 

^ Solar rotation and solar variation. Periods 27 days and ■j-.r^ and 



1250 2500 

months shown by correlation in 1915 and 1916, by C. G. Abbot. Smithsonian 
Miscellaneous Collections, vol. 66, No. 6. 1918. 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



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NO. 7 ASTROPHYSICAL OBSERVATORY, I904-I953 — ABBOT 9 

variation, with an amplitude of about ^ percent of the solar constant, 
appears as the mean result of four well-observed repetitions. 

This new evidence and that of 1915 (Pub. 4545, fig. 15) seems to 
me to show decisively the 27-day rotation period in solar variation. 

I have referred to the apparent 27-day effect on Washington pre- 
cipitation at pages 45 and 46, and table 8 of Pub. 4545.^ Using 27.0074 
days as the exact period, I found good success in predicting the 



1955 



1.935 




Fig. 1. — The 27.006-day period in solar variation. 



175 days more apt to have rain in Washington than the other 190 or 
191 days of the years 1942-1954. (See table 8, Pub. 4545.^) The 
formula failed only in 1952 and 1953 (possibly because of bomb 
explosions and fallout). Continuing to use the same formula in pre- 
diction for the year 1963, the whole group of preferred days proved 
displaced, recurring one day too early. But if the period is slightly 
changed to 27.0056 days it would have made no difference in fore- 
casts prior to 1954, but in 1963 the preferred days (one day earlier) 
would have had 1.30 times the average precipitation falling in all 
others. 



10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

OPPOSING SOLAR TRENDS 

Number 11 — Important opposed trends in solar variation^ 

The A. P.O. at Washington devoted much effort after 1942 to 
studying such upward and downward trends in solar variation as are 
shown in figure 46, Pub. 4545,^ not here reproduced. It was 
found that the temperature in Washington and several other United 
States and European cities responded to these solar trends by long- 
lasting marches, opposed like right and left hands. So many papers 
have been published on this observation that it seems superfluous 
to bring more evidence here. Figures 46, 47, and 49, and pages 52 to 
57 of the text of Pub. 4545 ^ show that large opposed temperature 
changes occurred simultaneously in Europe as well as in the United 
States in response to over 300 cases of such opposite solar trends. (See 
fig. 45, Pub. 4545^.) Pub. 3771 ^ presents a long investigation of the 
subject. It ends with a summary containing 18 sections. Not only 
solar constant measures, but solar faculae, calcium flocculi, and iono- 
spheric phenomena act as triggers to set off these opposed long- 
continued large temperature variations. 

In Pub. 4462 ^ of 1961 it is suggested that much better solar con- 
stant measures could be made from earth satellites than from moun- 
tains, because the atmosphere would be eliminated. If that were done, 
forecasts of detailed world temperature, depending on trends of solar 
variation, could be obtained covering 16 to 20 days in advance con- 
tinuously. (The above cited fig. 49 of Pub. 4545 ^ is given originally 
in Pub. 4462.^) 

TERRESTRIAL WEATHER 

Number 10 — Harmonic periods and long-range forecasts. 

We now come to the important claim of a harmonic family in 
weather changes identical in periods with such a family in solar varia- 
tion, but showing far more percentage change in weather than in 
solar variation. Even more obnoxious to meteorologists has been the 
claim that useful weather predictions can be made from knowledge 

'' I insert Ntimber 11 before Number 10, because Number 10 is potentially our 
most important discovery, requiring extensive comment and deserving the most 
emphatic place of all our discoveries. 

8 Weather predetermined by solar variation, by C. G. Abbot. Smithsonian 
Miscellaneous Collections, vol. 104, No. 5. 1944. 

^ 16-day weather forecasts from satellite observations, by C. G. Abbot. Smith- 
sonian Miscellaneous Collections, vol. 143, No. 2. 1961. 



NO. 7 ASTROPHYSICAL OBSERVATORY, I9O4-I953 — ABBOT II 

of it, 10 or even 50 years in advance, or backwards. Recently, how- 
ever, some meteorologists seem to be more favorably impressed. 

Some confusion has been caused by over-riding periods. 

It must be clear to all that if there actually is such a large harmonic 

family in weather periods, ranging in lengths from 4 months to the 

master period of 273 months, then a tabulation at individual stations 

273 
of weather periods, e.g., of — j-=68:|: months must be overlaid by 

273 273 
shorter periods, such as ~"o~'"^o~' ^t cetera. So the primary tabulation 

for a 68:|^-month period must necessarily look very rough. It may not 
even suggest a "hidden" period of 6S^ months unless those overlying 
shorter harmonics can first be removed. 

I now refer the reader to the accompanying figures 2, 3, and 4, pre- 
pared from Jon Wexler's electronic tabulations of monthly "World 
Weather Records," 1870 to 1940. He obtained monthly normals of 
precipitation at Rome, Italy, Kief, U.S.S.R., Capetown, South Africa, 
and other stations, separately for years when Wolf sunspot numbers 
^ 20. From these he obtained the departures in percentage of normal 
for all months, 1870-1949. These are divided into four groups which 
we call Category 1, Divisions 1 and 2; Category 2, Divisions 1 and 2. 
"Division" refers to first and second half of the interval 1870-1949, 
"Category" refers to Wolf numbers ^ 20 sunspot numbers. 

Figure 2, for the 68^-month period in Category 2, combines Divi- 
sions 1 and 2 at Rome, Italy. It shows five starting dates : June 1902, 
February 1908, October 1913, June 1919, and March 1925. A lack 
of recorded observations in later years before 1949 prevented using 
a sixth column. The mean of these 5 columns is plotted in the bottom 
full curve. No one seeing this curve could suppose it would easily 
be resolved, and would disclose a smooth sine curve of 68^ months. 

^ ,^ .J. . J 273 273 273 273 273 273 

But when the over-ndmg periods —^, -ry, -^, -j^-' -^f -jj; are 

successively computed and removed, as shown in figure 2, there re- 
sults the beautiful smooth sine curve shown at the top of figure 3, 

273 
representing only -r-or 68-^ months. Its amplitude is over 30 percent 

of normal precipitation. 

I am sure it will not be necessary to so particularly describe figures 3 

and 4 relating to Kiev, U.S.S.R. and Cape Town, South Africa, which 

each include one group of Jon Wexler's electronic tabulations, being 

273 273 
for the periods -^— and -5— months, respectively. They display over- 



12 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



273 273 273 , ^^. , 273 273 273 273 , ^ rr, ^ 

riders,^,-24 ,-40", for Kiev, and — ,— ,^,-^, for Cape Town. 

These two stations, cleared, show smooth sine curves, respectively, of 
amplitudes 25 and 16 percent of normal precipitation. I call attention 




Fig. 2.— Rome, Italy. 68i Month Period Cleared. 

to the far geographical separation of the three cities concerned in 
figures 2, 3, and 4. Similar results, not so fully exposed in the pub- 
lishing of them as figures 2, 3, and 4, are shown for several U.S cities 
in figures 18, 19, 20, 23, 24, and 25 of Pub. 4545 ^ and for other sta- 
tions not here cited. Altogether the figures just cited would display, 



NO. 7 ASTROPHYSICAL OBSERVATORY, I9O4-I953 — ABBOT 



13 



necessarily as super-riders, the existence of nearly all of the 27 periods, 
harmonics of 273 months, which we use in forecasting weather. 
Similar clearing gives similar sine-curve results for long periods at all 
54 stations so far forecasted. 
Referring now to figure 21 of Pub. 4545,^ it shows the actual plus 




Fig. 3.— Kiev, U.S.S.R., Precipitation. 34i Month Period Cleared. 



and minus quantities which resulted from tabulations I made for 
St. Louis, working on them alone without electronic assistance. These 
23 columns of figures, being added, gave a 20-year back-cast from 
the mean date 1897 of the precipitation at St. Louis, 1875-1879. It is 
nearly identical with the actual precipitation observed. As stated in 
Pub. 4211,^° all that work was done on 5-month consecutive means 



1° 60-year weather forecasts, by C. G. Abbot. Smithsonian Miscellaneous 
Collections, vol. 128, No. 3. 1955. 



14 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



of the monthly records of St. Louis, 1854-1940. Such 5-month con- 
secutive smoothing is also used in Jon Wexler's electronic tabulations 
for foreign stations, mentioned above. But that does not prejudice 
at all our discovery that very successful long-range forecasts can be 
made. See also figure 22 of Pub. 4545.^ 




Fig. 4. — Cape Town, South Africa Precipitation. 30;^ Months Cleared. 



Landsberg, Mitchell, and Crutcher, in their paper on climatological 
data for Woodstock, Md., describe that station "as a member of the 
Weather Bureau's Climatological Benchmark Network." I feel very 
grateful to Dr. Landsberg that he has sent me two sheets of the 
monthly records of precipitation at Woodstock covering 1870 to 
1963. Mr. Jon Wexler has prepared these records for my use to 
make an analysis with forecast through 1969. I have made such a 
forecast 1950 through 1969 for Woodstock, which shows correlation 



NO. 7 ASTROPHYSICAL OBSERVATORY, I904-I953 — ABBOT 1 5 

with observation from 1950 to 1963 of about +42 percent. Unfor- 
tunately displacements of obviously similar features made this cor- 
relation coefficient fully 10 percent lower than those for most U.S. 
stations. Rectifying these obvious displacements, I found a correla- 
tion coefficient of +72 percent for Woodstock. 

Figures 2, 3, and 4 of the present paper, and figures 18, 19, 20, 
21, 22, 23, 24, and 25 of Pub. 4545,^ and many examples I have en- 
countered in forecasts of precipitation for 54 cities show how over 
30 regular periods, harmonics of 273 months, are "hidden" if one 
regards meteorological time as if it were a river running serenely 
forever in a smooth uniformly inclined channel. All researchers do 
so who neglect time of the year, sunspot activity, and march of popu- 
lation, all affecting atmospheric transparency, and neglect the super- 
position of short-period harmonics confusing longer ones. 

CLASSIFIED REFERENCES FROM SMITHSONIAN PUBLICATIONS 

A. Accuracy of the solar constant as measured. 

(1) Annals, A.P.O., vol. 6, p. 163. Published 1942. 

(2) Smith. Misc. Coll., vol. 134, No. 1, Pub. 4265, p. 2. Published 1956. 

(3) Smith. Misc. Coll., vol. 146, No. 3, Pub. 4545, table 1, pp. 10-15. Pub- 
lished 1963. 

B. "Hidden" periodicities. 

In solar constant measures: 

(1) Smith. Misc. Coll., vol. 117, No. 10, Pub. 4088. Published in 1952. 

(2) Smith. Misc. Coll., vol. 128, No. 4, Pub. 4213, pp. 4 and 6, table 1, fig. 1, 
and pp. 9 and 10, fig. 2. Published 1955. 

In weather: 

(2) Smith. Misc. Coll., vol. 117, No. 16, pp. 11-18, 5 tables, 8 figs., Pub. 4095. 
Published 1952. 

(3) Smith. Misc. Coll., vol. 121, No. 5, pp. 2-5, table 1, fig. 1, Pub. 4103. Pub- 
lished 1953. 

(4) Smith. Misc. Coll., vol. 128, No. 3, pp. 1, 2, Pub. 4211. Published 1955. 

(5) Present paper. Number 10 "Harmonic periods and long-range forecasts." 

C. Weather forecasts do not require solar observations. 

Their independence from all solar measures except Wolf niunbers. ^ 20. 
(1) Smith. Misc. Coll., vol. 121, No. 5, line 22, p. 2; line 15, p. 11, Pub. 4103. 
Published 1953. 

D. High positive correlation with events. 

(1) Smith. Misc. Coll. vol. 128, No. 3, pp. +5, Pub. 4211. Published 1955. 

(2) Smith. Misc. Coll., vol. 139, No. 9, p. 1, Pub. 4390. Published 1960. 

(3) Smith. Misc. Coll., vol. 146, No. 3, pp. 60, 63, 64, Pub. 4545. Published 
1963. 

(4) Smith. Misc. Coll., vol. 143, No. 5, p. 5, fig. 4, Pub. 4471. Published 1961. 
I have (unpublished) the correlation coefficient between back-cast and obser- 



l6 SMITHSONKAN MISCELLANEOUS COLLECTIONS VOL. I48 

vation for St. Louis monthly precipitation, 24 months, 1878 and 1879. It is 
based on all records 1854 to 1939, centering at 1897. It is + 87.5 ± 6.5 percent 
E. Average deviations of forecasts from events are no greater at wide depar- 
tures from normal, or after long lapse of time. 

(1) Smith. Misc. Coll., vol. 143, No. 5, pp. 1, 6, table 1. Pub. 4471. Published 
1961. 

(2) Smith. Misc. Coll., vol. 128, No. 3, Pub. 4211. Published 1955. 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 8 



S^oeblins jFunb 



FORECASTING FROM HARMONIC 
PERIODS IN PRECIPITATION 



By 
C G. ABBOT 

Research Associate, Smithsonian Institution 




(Publication 4659) 



CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

MARCH 23, 1966 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 8 



Eoebling Jfunb 



FORECASTING FROM HARMONIC 
PERIODS IN PRECIPITATION 



By 
C. G. ABBOT 

Research Associate, Smithsonian Institution 






PBR\ 



(Publication 4659) 

ABl*i 

Gift-V 

Publislx«8 
Copy ( 

CITY OF WASHINGTON 

PUBLISHED BY THE SMITHSONIAN INSTITUTION 

MARCH 23, 1966 



PORT CITY PRESS, INC. 
BALTIMORE, MD., U. S. A. 



FORECASTING FROM HARMONIC PERIODS 
IN PRECIPITATION 

By C. G. Abbot 
Research Associate, Smithsonian Institution 

This paper presents evidence showing that the identical family of 
harmonic periods found in solar variation is also present strongly in 
terrestrial precipitation, and may be used for long-range forecasting. 
I wish to direct attention of those interested in water supply to fig- 
ures 7 and 8, and to the Conclusion of this article. Figures 7 and 8 
show in A the march of yearly precipitation at two stations for 36 
years. The curves A in figures 7 and 8 are made from recorded 
observations after it happened. The curves B, which are for practical 
purposes nearly identical with curves A, could be predicted and were 
actually predicted from records of observations made long ago before 
the events happened. 

1. PERIODS IN SOLAR VARIATION 

Volumes 5, 6, and 7 of the Annals, Smithsonian Astrophysical 
Observatory, tabulate over 9,000 days' measures of the solar constant 
of radiation. At page 13 and figure 1, Smithsonian Publication 4545, 
it is computed that the daily accidental error of a measure of the solar 
constant from one solar station is 0.007 calorie. Considering the num- 
ber of stations responding, and the loss of days by clouds or other 
causes, the accidental probable error of mean monthly values is esti- 
mated at 0.05 percent of the solar constant. 

Mr. Jon. Wexler has electronically smoothed the monthly solar 
constant values, 1921 through 1952, by the formula c^ = l/10(a + 2& + 
4c + 2d + e) which gives the central month, c, | as much weight as 
the total weight of the other four. His results are given by table 1 and 
figure 1. 

In the year 1922 an exceptional depression of about 8 percent in 
figure 1 is seen. This may possibly indicate the existence of a solar 
period of long duration. The results from 1923 to 1955 display many 
cases of long trends with amplitudes of solar variation up to 3 per- 
cent. Figure 8a of Publication 4545 shows that the monthly values of 
the solar constant repeated themselves, approximately, in great detail 
with an interval of 273 months. 

SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 148, NO. 8 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



Table 1. — Smooth Solar Constant 

Solar Solar Solar Solar Solar Solar 

Date constant Date constant Date constant Date constant Date constant Date constant 

1921 J +39 1927 J -43 1933 J +18 1939 J +3 1945 J +1 1951 J +22 
F +31 F -40 F +15 F -12 F +4 F +26 
M +20 M -33 M +2 M —17 M -2 M +23 
A +8 A —20 A -7 A —21 A +1 A +1 
M +6 M —14 M -8 M —22 MO M —10 
J -5 J -8 J -3 J -25 JO J -10 
J +7 J -7 J +6 J -23 JO JO 
A +14 A —6 A +10 A —21 A —5 A +6 
S +35 S -4 S +23 S -9 S -8 S +1 
O +51 O —10 O +29 0—4 O —10 O — S 
N +53 N -9 N +33 N +3 N -3 N -8 
D +38 D —15 D +31 D +3 D —10 D —6 

1922 J +13 1928 J -17 1934 J +25 1940 J -1 1946 J —14 1952 J -8 
F -5 F —16 F +17 F -6 F -24 F -19 
M —30 M — 8 M +14 M — 8 M —24 M —24 
A —58 A —3 A +10 A —2 A —9 A —13 
M —86 M +3 M +13 M +6 M +2 M — S 
J -117 J +2 J +17 J +9 1+8 i -4 
J _134 J -9 J +16 J +11 J +3 J -14 
A —126 A —17 A +16 A +9 A —2 A —16 
S —118 S —19 S +24 S +9 S — 2 S —20 
O —106 O —12 O +33 0+6 0+2 O —16 
N —94 N — 3 N +36 N +5 N +14 
D —87 D — 1 D +32 D +9 D +20 



J +24 J +14 1+8 I +J6 J 

J +27 J +18 J +9 J +18 J 



1923 J -69 1929 J -3 1935 J +23 1941 J +10 1947 J +15 
F -74 F -14 F +12 F +10 F -2 
M -63 M -18 M +6 M +10 M —17 
A —63 A —22 A +2 A +6 A —18 
M —S3 M -24 M +3 M +9 M -13 
J -52 J -31 J +3 J +15 J -8 
J -34 J -31 J +2 J +22 J -8 
A —14 A —33 A +4 A +22 A —7 
S +6 S —31 S +3 S +20 S —4 
O +5 O —27 0+8 O +21 O +4 
N — 2 N —18 N +13 N +21 N +13 
D -10 D —11 D +15 D +23 D +19 

1924 J —9 1930 J —10 1936 J +7 1942 J +17 1948 J +23 
F — 7 F — 11 F — 1 F +8 F +26 
M -1 M -13 M -6 M -3 M +25 
A +2 A —8 A —2 A —1 A +28 
M +16 M +3 M +3 M +7 M +30 

' +37 

, , -_ , , - - . - +40 

A +25 A +13 A +9 A +13 A +35 

S +26 S +6 S +12 S +8 S +32 

O +35 0+7 O +16 0+7 O +29 

N +41 N +12 N +22 N +8 N +34 

D +47 D +17 D +22 D +2 D +37 

1925 J +48 1931 J +12 1937 J +15 1943 J -2 1949 J +32 
F +48 p +7 F +3 F F +25 
M +38 M +6 M — 11 M +3 M +9 
A +21 A +9 A -18 A +8 A +1 
M +12 M +19 M —17 M +15 M +1 
J +10 j +21 J -8 J +24 J -2 
J +12 J +23 J -4 J +24 JO 
A +13 A +22 A +1 A +23 A —1 
S +11 S +21 S +4 S +18 S -2 
O +5 O +17 0+7 O +15 O +4 
N +3 N +13 N +10 N +13 N +14 
D — 2 D +10 D +13 D +17 D +22 

1926 J -11 1932 J +3 1938 J +8 1944 J +18 1950 J +21 
F -26 F -8 F +6 F +20 F +5 
M —30 M -15 M +2 M +12 M —8 
A —35 A —16 A —6 A +7 A —14 
M -31 M -14 M —10 M +7 M -10 
J -26 J -8 J -12 1+7 1-4 
J -19 J -4 J -9 J +6 J -4 
A —14 F — 7 A — S AG A 
S -21 S —10 S +4 S -6 S +1 
O —34 O —16 O +14 0—3 0+9 
N —42 N — 9 N +21 N +S N +9 
D —46 D +7 D +16 D +9 D +12 



NO. 8 HARMONIC PERIODS IN PRECIPITATION — ^ABBOT 




(9ZI 



Fig. 1. — Smoothed solar constant. 
Scale : 2 = iV solar constant 



4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

I have now analyzed Wexler's smoothed values to see if 27 exact 
submultiples of 27Z months, which I have long believed in, are verified. 
The number of repetitions decreases from 17 , for 4^ months, to 5 




to 
63 28 



Section 2. ±i± to ^ii« Section 3. 

27 18 

Monthly solar constants, smoothed, 1923 to 1952. Formula: C'= 



1 

100 



273 

15 

1 

100 

Solar constant = 2. 



■^—5. Sub-periods removed. 

4 

(.A+2B+AC+2D+E). 



Ordinates scale 

Fig. 2. — Solar periodic variation, 



273 



to^" —r~ = 68^ months. With only 3 repetitions for 91 months, I 

273 
omitted -ir-. All periods longer that 1 5^ months had one or more 

over-riders, exactly their submultiples in length, whose amplitudes I 



NO. 8 



HARMONIC PERIODS IN PRECIPITATION ABBOT 



computed and subtracted, in a method illustrated below in figure 3 
for 54| months. My results, all closely approximating to sine curves, 
are shown in figure 2. 



Me an oJ 8 ^^v^fAufm oi Ffe rloi 
\o +!« -10 



273 M o-ntKs CUa-n^ of ^ and ^^ Not R^"^^*".!? • 

' w 4-3 M ^ t4 Ma 




Fig. 3. — A solar constant period cleared of submultiples. 
Amplitude : 0.20 percent. 



The harmonics of 273 months are shown in figure 2 to range in 
amplitude from 0.10 to 1.05 of 1 percent of the solar constant. All 
are far greater than the accidental error of monthly solar constant 



6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

measures as given above. And as each harmonic period is the mean of 
many determinations, their amplitudes have probable errors far too 
small to be due to chance. 

2. PERIODIC TERRESTRIAL PRECIPITATION 

Convinced 20 years ago of existing solar periodic variation, I 
noticed in the long monthly records of Peoria, 111., an indication of a 
period of about 23 years in precipitation. I then tried during several 
years to find other periods there. They appeared to exist, but to suffer 
variable displacements associated with changes in atmospheric trans- 
parency. Persevering, ways avoiding these difficulties were found, 
leading at length to a method of long-range forecasting which I used 
with surprising success on the records of St. Louis. See Smithsonian 
Publication 4545, figures 21, 22, and 25, and explanatory text. 

Prof. Wexler, of State University of Arizona, interested his son, 
Jonathan Wexler, in my forecasting. Jon. Wexler, a student in 
electronic programming, saw how the computing might be greatly 
aided. Since 1955, he has prepared for my forecasts the long rec- 
ords of precipitation of 55 stations in all parts of the world. I have 
described in the publication "Solar Energy," volume 1, No. 1, 1956, 
and volume 2, No. 1, 1957, the tedious process used for my forecasts. 
Smithsonian Publication 4390 gives forecasts, 1950 to 1967, for 
32 stations in the United States. But while over 5,000 copies of 
it were sold, besides 1,500 copies freely distributed by the Institu- 
tion, professional meteorologists are still skeptical, notwithstanding 
evidences of useful value given in pages 1 to 6 of Smithsonian Publi- 
cation 4471. Hence it seems good to present now, in detail, evidence 
that the identical family of harmonic periods found in solar variation 
is also present strongly in terrestrial precipitation, and may be used 
for long-range forecasting. 

Figure 4 plots the forms and amplitudes of 26 periods in the precipi- 
tation of Rochester, N.Y., 1884-1955, as computed by Jon. Wexler in 

273 
222 separate tabulations. Period —:r- months is omitted from figure 4 

273 
because repetitions are too few for good evidence. Period —r- is 

found in evidence at Rochester only as represented by the shorter 

273 273 273 

over-riding periods —^ and -y^- Yet —r— is strong itself in St. Louis 

precipitation. See Publication 4545, page 32, and at other stations. 



NO. 8 



HARMONIC PERIODS IN PRECIPITATION — ^ABBOT 



I give in figure 4 only the periods in Category 2. These, about 
60 percent of the whole record, relate to intervals when Wolf sunspot 
numbers exceed 20. The other 40 percent (in Category 1) were also 
computed and used in the forecast below. But as their forms and 
amplitudes are similar to those of Category 2, I omit printing them 




Fig. 4. — Rochester harmonic periods, 1884-1956. 
Ordinates percent normal precipitation. 

here. I give in table 2 details of interest regarding the periods plotted 
in figure 4. 

In Section 3 of figure 4 (18^ to 68| months) all periods had over- 
riding subperiods, such as ^, ^, \. These were removed and not shown. 
Figure 3 illustrates by numbers and forms the method of clearing 



I 



8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

long periods from over-riders, applicable both in radiation and in 
precipitation. 

3. LONG-RANGE PREDICTION OF PRECIPITATION 

It is urged by experts in meteorology that exact measurements of 
precipitation are so difficult, its local distribution so extraordinarily 

Table 2. — Harmonic Periods in Rochester, N.Y., Precipitation 
Exact Fractions of 273 Months, Category 2 Only 









Amplitude 


Number of 






Period 


percent of normal 


repetitions 


Number 


Fraction 


in months 


precipitation 


per period 


1 


yes 


4y3 


3 


127 


2 


y54 


syis 


8 


111 


3 


y45 


6% 


9 


91 


4 


ysa 


7 


9 


90 


5 


yae 


7%2 


8 


7i 


6 


%3 


8%i 


13 


66 


7 


yso 


9yio 


21 


60 


8 


y28 


9% 


17 


58 


9 


¥11 


10% 


10 


56 


10 


%6 


loya 


15 


53 


11 


Vzi 


11% 


18 


48 


12 


V12 


12%2 


10 


47 


13 


Y21 


13 


14 


41 


14 


y2o 


1313/20 


19 


41 


IS 


yi8 


isye 


15 


36 


16 


yi5 


i8y5 


8 


29 


17 


yi4 


i9y2 


12 


26 


18 


yi2 


223/4 


11 


23 


19 


yii 


24%i 


7 


22 


20 


yio 


27%o 


10 


20 


21 


y9 


3oy3 


9 


19 


22 


ys 


34y8 


9 


14 


23 


y7 


39 


7 


14 


24 


ye 


45y2 


9 


11 


25 


y5 


54% 


10 


8 


26 


y* 


68y4 


— 


5 


27 


ys 


91 


— 


3 



irregular, its jumps between zero and super-normal amplitude so 
erratic that 50 years of observation are hardly enough to give satis- 
factory monthly normals. Hence they prefer to do research with 
temperature and pressure, hoping through atmospheric circulation to 
find a path to advance in the forecasting of precipitation. My former 
chief, the late Dr. S. P. Langley, encouraged me to hope that knowl- 
edge of solar radiation and of its atmospheric transmission might 



NO, 8 HARMONIC PERIODS IN PRECIPITATION ABBOT 9 

open a direct path to foreknowledge of precipitation, that highly- 
important variable in agriculture and water supply. 

This hope has now been realized by a combination of five discoveries 
of the twentieth century. For more than 10 years now it has been 
possible, with these five helps, to make useful forecasts longer than 
one generation in advance. The discoveries referred to are as follows : 

1. Nearly a century of patiently continued weather records are 
now available. They embrace many stations in all continents, and are 
published in World Weather Records. 

2. Both the sun's radiation and the long-continued weather records 
contain as many as 27 harmonic periods, exact submultiples of 273 
months, of equal lengths in solar radiation and in weather. 

3. While solar variation varies in amplitude, its phases appear 
constant. Weather phases, on the other hand, vary considerably as 
conditions alter in the atmosphere. These phase shifts, which may be 
as great as several months, differ with length of period, locality, time 
of the year, sunspot frequency, and growth of population. These diffi- 
culties require a large number of divisions to be made of the long 
weather records. Indeed, 222 tables for each station are required, 
as I have explained in previous publications. 

4. The invention and development of the electronic computer 
makes it possible to handle the multiplication of phase diflFerences, and 
any desirable smoothing of arrays of numbers in a few moments, 
instead of years, as when I computed alone for St. Louis forecasts, 
1854 through 1957. 

5. The introduction of the smoothing formula YQ{a + 2b+Ac + 

2d + e) is highly valuable. In it the value c has y^ as great weight as 

the four neighboring values combined. With an irregular variable, 

like precipitation, smoothing is necessary. But to avoid displacing 

phases by smoothing, it must avoid giving preponderant weight to 

values outside the central value. 

Before demonstrating more, it may not be superfluous to point out 

that with nearly 100 years of records available, they may fairly be 

used, not only for prediction but to test the validity of predictions 

when made. For if all records of A^ years be employed in a prediction, 

the monthly records of a single year cannot affect the prediction for 

12 
that year by more than r^. That quantity diminishes proportionally 

with the increase of N and reaches the negligible value of 1 percent 
when AT =100, 



lO 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 







« 



o 



(IH 



o o o _ 

i>» so »^ ^r 



NO. 8 HARMONIC PERIODS IN PRECIPITATION — ^ABBOT II 

Figures 5 and 6 give 6-year samples, graphically, of forecasts at 
Rochester, N.Y., and Nashville, Tenn,, within the interval 1921 
through 1956. That entire interval has been forecasted. Its forecast 
has been compared to observed departures from normal, and smoothed 
by the formula Yo{a + 2b + 4c + 2d + e). I give here only 6-year por- 
tions of the comparison for I wish to keep this paper as brief as 
possible. I fear that Smithsonian Publication 4545, on which I placed 
high hopes, is too long, so that no one but myself ever reads it. The 
forecasts given in figures 5 and 6 employ all the "World Weather" 
records. These comprise for Rochester, 1884 through 1956, 72 years, 
and for Nashville, 1870 through 1956, 86 years. 

Readers may notice that due to the new smoothing formula, this 
comparison mostly avoids the distressing shifts of prominent features 
which sometimes amounted to 3 or 4 months in Publication 4390. 
Both stations are included in the tables given in Publication 4390, 
and Nashville is illustrated there in figure 29. 

I have preferred to use Nashville forecast, 1950-1956, because it 
was given 1950-1957 in Publication 4390, plate 3. Now employing 
the new smoothing formula the new illustration is better. Besides, it 
shows in 1950 to 1952 shifts and differences in amplitude of features 
that may have resulted from hydrogen bombing by the U.S.A. and 
the U.S.S.R. about 1950. I have found similar indications in nearly 
all of 23 foreign stations I have forecasted. 

Now I proceed to considerations which seem to me to clinch the 
case for the validity and usefulness of long-range forecasts of pre- 
cipitation. Figures 7 and 8 give for both Rochester and Nashville: 
(A) percentage-yearly departures from the mean, 1921 through 
1956, and 1921 through 1956, respectively, of the total rainfall 
observed. (B) Departures from the smoothed means (of 72 and 86 
years respectively) of forecasts, 1921 through 1956. These are com- 
puted from all monthly records oi 72 and 86 years respectively. 
(C) Values of (A) smoothed by ^(a + 2b + 4c + 2d + e), and (D) 
values of (B) smoothed similarly. 

First consider Rochester, figure 7, only. It will be seen from (A) 
and (B) that the mean of all yearly departures, 1921 through 1956, 
of (B), involving my forecast, is smaller than that of (A) observed. 
These results are 9.3 and 11.5 percent. But it is also quite obvious 
that if one confines attention to large departures, (B) has a much 
larger advantage over (A). These results support long-range predic- 
tions somewhat. 

But what really clinches the case for the validity of my forecasting, 
and all it comprises, is the second pair of curves (C) and (D). For 



12 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 




NO. 8 HARMONIC PERIODS IN PRECIPITATION — 'ABBOT 1 3 

both curves show four major episodes. They are 1922 to 1928; 1928 
to 1940; 1940 to 1949; and 1949 to 1954. Curve (C) is rigidly con- 
ditioned by observation. But curve (D), on the other hand, depends 
on forecasting, based on all the monthly observations, 1884 through 
1956. 

It shows in D, however, the same four great trends in precipitation 

Table 3. — Harmonic Periods in Solar Constant Exact Fractions of 
273 Months, Category 2 Only 



Number 


Fraction 


Period 
in months 


Amplitude 

percent of solar 

constant 


Number of 
repetitions 
per period 


1 


%3 


4% 


0.10 


127 


2 


%4 


SMs 


0.08 


111 


3 


%5 


6M5 


0.22 


91 


4 


%9 


7 


0.25 


90 


5 


%6 


7%2 


0.11 


73 


6 


^ 


8%i 


0.05 


66 


7 


%0 


9Mo 


0.11 


60 


8 


%8 


9% 


0.15 


58 


9 


^ 


10% 


0.20 


56 


10 


%e 


10^ 


0.18 


53 


11 


%4 


11% 


0.32 


48 


12 


%2 


12%2 


0.25 


47 


13 


%1 


13 


0.27 


41 


14 


%0 


13i%o 


0.10 


41 


15 


Ms 


15% 


0.20 


36 


16 


Ms 


18% 


0.17 


29 


17 


M4 


19% 


0.10 


26 


18 


M2 


22% 


0.10 


23 


19 


Ml 


24%i 


0.11 


22 


20 


Mo 


27%o 


0.15 


20 


21 


H 


30% 


0.13 


19 


22 


% 


34% 


0.24 


14 


23 


M 


39 


0.75 


14 


24 


% 


45% 


0.20 


11 


25 


% 


54% 


0.35 


8 


26 


M 


68y4 


0.65 




27 


M 


91 







as those actually observed to be real in (C). If the forecasts making 
up curve (D) were not sound, there is not one chance in a thousand 
that the two curves would be so similar. Moreover, the curve (D) 
has a smaller average departure from curve (B) than curve (C) has 
from curve (A), and curve (D) is far smoother than curve (C). 

Now we turn to Nashville in figure 8, with its four curves of the 
same letters as Rochester. Obviously the same remarks hold almost 
in toto. 



14 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 




NO. 8 HARMONIC PERIODS IN PRECIPITATION — JABBOT 



15 



I 




l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

CONCLUSION 

I feel that I may now justly claim to have made with my associates 
three discoveries of merit: 

1. The sun's radiation varies far beyond accidental errors of 
observation, in numerous harmonic periods exactly related to 273 
months. 

2. Harmonic periods of these identical lengths exist, and with 
much greater percentage amplitude, in long records of the precipita- 
tion at scores of stations in all parts of the world. 

3. Useful forecasts for many future years may be made when 
amplitudes and forms of these harmonic periods are determined from 
official records of precipitation for many past years. 

It is shown that such forecasts are as close to observation at inter- 
vals when wide departures from the normal occur, as when the 
precipitation is nearly normal. (See Smithsonian Publication 4471, 
page 6, 1961.) 

It would be interesting if some expert in mathematics should dis- 
cover why terrestrial precipitation reacts so strongly to small per- 
centage changes in the solar constant. I suggest a possible explana- 
tion in Smithsonian Publication 4135, page 3. 

Mathematics may even be necessary in order to trace effects of cer- 
tain human actions which may make records of the past inaccurate for 
future forecasts. Such may be super-powerful nuclear bombs, com- 
bustion of long train-loads of oil to propel spacecraft, and means 
used to effect changes in weather to improve it, as now proposed. All 
these may change atmospheric circulation and make past records use- 
less for forecasting in the future. 

LITERATURE CITED 

Solar variation, a leading weather element, by C. G. Abbot. Smithsonian 
Miscellaneous Collections, vol. 122, No. 4. 1953. (Smithsonian Publica- 
tion 4135.) 

A long-range forecast of United States precipitation, by C. G. Abbot. Smith- 
sonian Miscellaneous Collections, vol. 139, No. 9. 1960. (Smithsonian 
Publication 4390.) 

A long-range temperature forecast, by C. G. Abbot. Smithsonian Miscellaneous 
Collections, vol. 143, No. 5. 1961. (Smithsonian Publication 4471.) 

Solar variation and weather, by C. G. Abbot. Smithsonian Miscellaneous Col- 
lections, vol. 146, No. 3, 1963. (Smithsonian Publication 4545.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 9 



Cl)arles( ©. anb iWarp Yra«xJ[aialcott__^ 
J^esiearcf) Jf unb I 

/ 4 - JUN - 9 

NEW LOWER CAMBRIAN TMSBtTE-' 

FAUNULE FROM THE TACONIC 

SEQUENCE OF NEW YORK 

(With 12 Plates) 



By 
FRANCO RASETTI 

Johns Hopkins University, Baltimore, Md. 
Honorary Research Associate, Smithsonian Institution 



6 




(Publication 4662) 



CITY OF WASHINGTON 
PUBLISHED BY THE SMITHSONIAN INSTITUTION 
MAY 23. 1966 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 
VOLUME 148, NUMBER 9 



Cfjarles; ©. anb JWarp "^aux OTalcott 
IResiearcf) Jf unb 



NEW LOWER CAMBRIAN TRILOBITE 

FAUNULE FROM THE TACONIC 

SEQUENCE OF NEW YORK 

(With 12 Plates) 

By 

FRANCO RASETTI 

Johns Hopkins University, Baltimore, Md. 
Honorary Research Associate, Smithsonian Institution 






t^S 






(PUBIICATION 4662) 



CITY OF WASHINGTON 
PUBLISHED BY THE SMITHSONIAN INSTITUTION 
MAY 23. 1966 



PORT CITY PRESS, INC. 
BALTIMORE, MD., U. S. A. 



CONTENTS 

Page 

Introduction and Acknowledgments 1 

Occurrence and Preservation of the Fossils 2 

Age and Character of the Faunule 4 

Systematic Descriptions : 

General Statement 7 

Family EODISCIDAE 7 

Family OLENELLIDAE 39 

Family DORYPYGIDAE 42 

Family Undetermined 46 

References 47 

Explanation of Plates 48 



Cliarlejf B. anb iHarp ^aux Mahott 3^tieattff jfunb 

NEW LOWER CAMBRIAN TRILOBITE FAUNULE 

FROM THE TACONIC SEQUENCE OF 

NEW YORK 

By 

FRANCO RASETTI 

Johns Hopkins University, Baltimore, Md. 

Honorary Research Associate, Smithsonian Institution 

(With 12 Plates) 

INTRODUCTION AND ACKNOWLEDGMENTS 

The Lower Cambrian formations of the Taconic sequence in New 
York are among the most thoroughly investigated deposits of this age 
in eastern North America. After the classic faunal studies of Ford 
and Walcott in the second half of the last century, no essentially 
new faunules were discovered. Lochman (1956) described several 
new species and gave a general review of the known Lower Cambrian 
fossils of the sequence, occurring in what was formerly known as the 
Schodack Formation, now subdivided (Zen, 1964) into several units. 
All the species may be considered members of a single assemblage, 
named from the characteristic olenellid trilobite Elliptocephala asa- 
phoides. 

The discovery of an essentially new Lower Cambrian trilobite 
faunule was therefore unexpected. In 1956 Mr. Thomas W. Tal- 
madge noticed the presence of fossiliferous limestone outcrops on a 
hill south of North Chatham, Columbia County. In 1963 Dr. John 
M. Bird collected small samples from two of these outcrops and 
submitted them to the U.S. Geological Survey for identification of 
the fossils. Dr. A. R. Palmer prepared and examined the specimens 
and recognized in one of the collections the presence of trilobites 
unlike any of those previously known from the Lower Cambrian of 
the Taconic sequence or any other region. He suggested to the 
writer a study of the new faunule. Collections much larger than the 
original ones were made by Dr. Bird and the writer, until most of the 
accessible, fossiliferous portions of the limestone outcrop had been 
recovered and examined. Hundreds of trilobite specimens, represent- 

SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 148, NO. 9 



2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

ing about 30 species, largely new and belonging to new genera, 
form the object of the present study. 

The writer is indebted to the American Philosophical Society for 
grant No. 3454-P which defrayed field and laboratory expenses. He 
thankfully acknowledges the enthusiastic cooperation of Dr. John M. 
Bird in quarrying the limestone and searching for other fossiliferous 
localities. Thanks are also due to Dr. A. R. Palmer for suggesting 
this study and for valuable discussions on Cambrian faunas ; to Mr. 
Thomas W. Talmadge for information on the results of his strati- 
graphic studies in the East Chatham quadrangle and for accompany- 
ing the writer on a field excursion; to Dr. George Theokritoff for 
information on an undescribed Lower Cambrian faunule from Wash- 
ington County, New York; to Dr. E-an Zen for discussions on the 
Taconic sequence ; and to Mr. A. W. A. Rushton of the British 
Geological Survey for communicating specimens and photographs of 
an undescribed faunule from England which shows interesting affini- 
ties with the one described herein. 

OCCURRENCE AND PRESERVATION OF THE FOSSILS 

The Cambrian strata in the northwestern quarter of the East Chat- 
ham 7^-minute quadrangle are notable for the development of regu- 
larly bedded limestone units, an unusual feature in the Cambrian 
of the Taconic sequence in Columbia and Rensselaer Counties, New 
York, where fossiliferous limestone generally occurs only in con- 
glomerates. Among the localities where such limestone beds form 
outcrops is a hill (Griswold farm) about 1 mile southeast of North 
Chatham, Columbia County. The summit of the hill is a plateau 
where limestone beds interstratified with black shale form scattered 
outcrops. The beds strike north-south and dip steeply (50°-60°) 
east. All the fossils described herein (with the exception of one 
species from Quebec, Canada) were recovered from a limestone bed 
traceable through intermittent outcrops over a distance of several 
hundred feet. Even though fossils of the same faunule were observed 
at several places along this bed, only one block of limestone, about 
1 foot thick, 5 feet long, excavated to a depth of 3 feet, supplied 
all the described fossils, the remainder of the limestone usually being 
too fine-grained to yield fossils. About 400 pounds of rock were 
removed and examined. The limestone is dark-gray, finely granular 
to aphanitic, in some portions the bedding being clearly marked by 
layers of more abundant insoluble material or fossil fragments, else- 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 3 

where indistinct. Most of the fossils were concentrated in small 
pockets. 

The fossiliferous outcrop is located 27 mm from the west edge 
and 164 mm from the north edge of the East Chatham 7;|-minute 
USGS quadrangle, scale 1 : 24,000 (USGS collections 3810, 4216; 
writer's collection cs-4). The faunule from this bed is referred to 
hereafter as the Acimetopus hilohatus faunule from one of the most 
common and characteristic trilobites. 

The most common fossils are small inarticulate brachiopods, espe- 
cially an acrotretid and less abundant linguloid forms. Trilobites are 
also copious in some portions of the rock, but most of the specimens 
are too fragmentary for identification. Evidently the tests were trans- 
ported by currents for considerable time and distance before being 
covered by the sediment. All the trilobites are dismembered, except 
one cephalon with two thoracic segments attached. Nevertheless, 
many of the compact eodiscid cephala and pygidia did not suflfer 
excessive damage. In exposing the fossils, the matrix invariably sepa- 
rates at the boundary of the outer surface of the test, hence orna- 
mentation is well preserved. Some of the specimens suffered slight 
flattening or fracturing in the slumping or compaction of the sedi- 
ment. Distortion due to tectonic deformation of the rock is present 
to a slight degree in some of the material. 

The size of the trilobites presents an unusual situation. The Eodis- 
cids are, on the average, large for the family. Examples of Litometo- 
pus longispinus indicate that the species attained a length of 50 mm, 
almost gigantic for an Eodiscid. Most of the examples are much 
smaller, but very small, immature specimens seem to be lacking, 
cephala or pygidia below 3 or 4 mm in length being rare. All the 
Olenellids on the contrary are of small size, fairly complete cephala 
not exceeding 4-5 mm in length. It seems difficult to attribute this 
fact to the delicate nature of the olenellid tests and their consequent 
fragmentation, since no fragments indicating individuals of medium 
or large sizes were observed. In the well-known conglomeratic lime- 
stones at Schodack Landing and Troy, even though the trilobite 
tests are excessively fragmentary and no large cephala have been 
recovered, the presence of adult examples of Elliptocephala asa- 
phoides is proved by the frequent occurrence of fragments of their 
large pleurae. Nor can the lack of very small Eodiscids and large 
Olenellids be attributed entirely to sorting by current action, since 
very small brachiopods and relatively large Eodiscids are rather 
common. 



4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

AGE AND CHARACTER OF THE FAUNULE 

The present information is insufficient to determine the precise 
relative age of the new faunule with respect to other known Lower 
Cambrian faunules of North America, and in particular of the Taconic 
sequence. The scanty stratigraphic evidence that might supply such 
information is summarized below. 

Other fossiliferous strata form outcrops east of the bed yielding 
the Acimetopus faunule, and a greater variety of Cambrian fossils 
was obtained from limestone blocks in the surrounding stone walls, 
partly derived from beds not presently exposed. The next bed to the 
east, 45 feet higher stratigraphically than the Acimetopus stratum 
(under the unconfirmed assumptions that the intervening beds form 
an orderly stratigraphic succession and that the strata are not in- 
verted), yielded a Pagetides faunule, also collected at several other lo- 
calities in the northeastern quarter of the East Chatham quadrangle. 
Pagetides elegans and another species of the genus are by far the most 
common identifiable fossils in this faunule ; Olenellid fragments, Bon- 
nia and Prozacanthoides have been observed. The third fossiliferous 
limestone bed, which under the above assumptions would be about 450 
feet higher stratigraphically than the Acimetopus bed, yielded Pagetia 
and Peronopsis, almost certainly indicative of the Middle Cambrian. 
Trilobites of the typical Elliptocephala asaphoides assemblage, such as 
Elliptocephala itself, Calodiscus lobatus, or Serrodiscus speciosiis, have 
never been seen at the locality, either in outcrops or loose blocks; 
they are known in the East Chatham quadrangle only from the 
exposures of the Ashley Hill Conglomerate (Dale, 1904; Zen, 1964) 
whose type locality lies in the northeastern quarter of the quadrangle. 

The structure of the area is exceedingly complicated, as may be 
observed, for example, in a deep cut on the road from North Chat- 
ham to Maiden Bridge, which exposes a considerable thickness of 
limestone beds interstratified with black shale. The strata appear 
closely folded, causing some intervals to be repeated in reverse order, 
even though the dip seems to remain fairly constant. It would be 
difficult to discern such structures from scattered outcrops as observed 
at the Acimetopus locality, where one might readily be misled to 
infer an orderly succession. Limestone beds in the road cut yielded 
a Pagetides faunule, hence they may be equivalent to a portion of 
the section on the Griswold farm. For these reasons, the succession 
of faunules outlined above, i.e., in ascending order the Acimetopus, 
Pagetides, and Pagetia-Peronopsis faunules, is only suggested as 
tentative. Talmadge (private communication) from purely strati- 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 5 

graphic and structural evidence had previously reached the conclusion 
that by and large the strata on the Griswold farm become progres- 
sively younger toward the east, which would confirm the suggested 
order. He also considers all these strata higher than the Ashley Hill 
Conglomerate. Since the latter holds the Elliptocephala fauna not 
only in boulders, but also in a regularly bedded limestone interval 
at the base of the conglomerate, one might conclude that the latter 
fauna is older than the Acimetopus and Pagetides faunules. 

The Elliptocephala asaphoides assemblage extends through a con- 
siderable thickness of strata in Washington County (Lochman, 1956; 
Theokritoff, 1964), It is possible that the difference between the 
Acimetopus bilobatus faunule and that assemblage is one of environ- 
ment rather than age. A faunule reported by Theokritoff (1964) 
from Washington County, believed to be somewhat younger than the 
typical Elliptocephala asaphoides assemblage, shows no particular 
resemblance to the one described herein. 

The Acimetopus bilobatus faunule is notable for the number and 
variety of trilobites of the family Eodiscidae, of which 9 new genera, 
20 new named species, and an unnamed one are described herein, 
all based on cephala. A few unassigned pygidia, in part possibly 
representing additional species, are also described. None of the 
Eodiscidae can be referred to previously known species, even though 
several are referable to the well-known genera Calodiscus and Ser- 
rodiscus. 

The Olenellidae are represented by numerous fragments of small 
individuals, referable to three species, none of which is the common 
Elliptocephala asaphoides known from numerous localities in the 
Taconic sequence of Washington, Rensselaer, and Columbia Coun- 
ties. Immature Olenellid cephala cannot be specifically identified by 
comparison with adult individuals, and even the generic reference 
may remain doubtful, since several of the genera were based on the 
features of the entire exoskeleton. Two of the species are tentatively 
referred to Paedeumias and one to Olenellus; none shows close 
resemblance to named species. 

The opisthoparian trilobites are represented by four undetermined 
species of Bonnia, a pygidium referred to Kootenia, and a peculiar 
pygidium belonging to an undescribed genus of uncertain affinities. 

Conspicuously absent from the Acimetopus bilobatus faunule are 
Eodiscids with eyes and facial sutures, which constitute the family 
Pagetiidae, even though species of Pagetides are the most common 
trilobites in the nearest fossiliferous outcrop. Also totally absent are 



6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

the ptychoparioid trilobites, so common in the late Lower Cambrian 
deposits of the Appalachian and Cordilleran provinces. No fragments 
referable to the Agnostids were observed. 

Even though the Acimetopus bilobatus faunule has few, if any, 
species in common with the Elliptocephala asaphoides assemblage, 
the latter is still the Lower Cambrian fauna of North America which 
it resembles most closely. Possibly all the species, and many of the 
genera, are different, but the same families are represented, approxi- 
mately in the same relative abundance : the Eodiscidae and Olenel- 
lidae are common, Bonnia and Kootenia are rare in both cases. 
The Acimetopus bilobatus faunule shows far less affinity with the 
late Lower Cambrian fauna of the Pacific province (era tonic facies 
of Lochman and Wilson, 1958), which is characterized by the abun- 
dance of Ptychoparioids and Bonnia, frequently includes Kootenia, 
Protypus, and Prozacanthoides, and also Pagetia and Pagetides. The 
resemblance is not very close either with the typical late Lower 
Cambrian fauna of the Acado-Baltic province (eugeosynclinal facies 
of Lochman and Wilson), chiefly characterized by the Protolenidae, 
where the Eodiscids are represented both by oculate (Hebediscus), 
and blind genera {Calodiscus, Cobboldites, Serrodiscus). In North 
America faunules of this type are known from Massachusetts and 
eastern Newfoundland (Hutchinson, 1962). The evidence favors the 
reference of the new faunule, like the Elliptocephala asaphoides 
assemblage, to an "intermediate realm" (Lochman and Wilson, 
1958) between the cratonic and eugeosynclinal sedimentary prov- 
inces. 

Through the courtesy of Mr. A. W, A. Rush ton, the writer was 
able to examine specimens and photographs of a remarkable new 
faunule discovered in the Purley Shales of Warwickshire, England. 
The faunule includes several new species of Eodiscidae, of which two 
belong to new genera, one is a Serrodiscus remarkably similar to 
Serrodiscus subclavatus described herein, and another is definitely 
referable to Acidiscus, closely resembling Acidiscus hexacanthus in 
possessing two pairs of marginal cephalic spines. The Eodiscidae 
in the Purley Shales are associated with Ellipsostrenua and Condy- 
lopyge. Even though all the previously described species of this 
agnostid genus occur in the Middle Cambrian, the remainder of the 
faunule is suggestive of a late Lower Cambrian age. A fairly close 
time equivalence of the two faunules may be indicated by the 
presence of closely related Eodiscidae. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 7 

SYSTEMATIC DESCRIPTIONS 
GENERAL STATEMENT 

All the fossils described herein were deposited in the U.S. National 
Museum collections, excepting one specimen from Quebec which is 
in the collections of the Geological Survey of Canada. 

All the illustrations show the outer surface of the test. 

The abbreviations (tr.) for transverse, (sag.) for sagittal, and 
(exsag.) for exsagittal qualify such terms as "wide," "short," etc., 
whenever the direction of the measurement might otherwise be mis- 
interpreted. 

Family EODISCIDAE Raymond, 1913 

The Eodiscidae are the most numerous and interesting of the tri- 
lobites described herein, as they show a greater variety of forms 
than the genera previously known. Hence the characters observed 
in the different parts of the exoskeleton are briefly discussed. 

All the species described herein are represented by separate cephala 
and pygidia; hence the number of thoracic segments is unknown. 

Owing to the large number of species occurring in the same bed, 
matching of cephala and pygidia presented a problem. In several 
cases assignments with varying degree of probability could be made. 
Criteria for associating cephala and pygidia that were used are 
general shape, size, surface ornamentation, and frequency of occur- 
rence. It is unlikely that the collection contains a pygidium for every 
cephalon or vice versa. To avoid the risk of nomenclatural confusion, 
no taxa were based on pygidia ; those pygidia that could not be 
assigned to cephala are described and illustrated but not named. 

Features of the various parts of the exoskeleton are discussed 
below. 

Glabella. — ^The glabella shows considerable variety of form. It may 
be tapered as in Bolboparia, where it is short in proportion to the 
length of the cephalon ; more or less parallel-sided as in most of the 
species ; or even somewhat expanded toward the front as in Serrodis- 
cus subclavatus and Bathydiscus dolichometopus. Lateral furrows 
are usually short and shallow or absent. However, in Acimetopus, 
Analox, and some species of Calodiscus, the glabella is divided by 
a deep transverse furrow into an anterior and a posterior lobe. A 
tendency in this direction had been observed, for example, in Calo- 
discus lohatus and its form agnostoides (Lochman, 1956), in C. 
helena, C. meeki, and even in Serrodiscus speciosus (Rasetti, 1952). 



8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

In these cases there may even be two shallow furrows across the 
glabella. The sharp and deep transglabellar furrow of Acimetopus 
hilohatus and Calodiscus reticulatus, and the somewhat shallower one 
of Analox bipunctata, seem to represent more advanced stages of 
this type of glabellar lobation. A sharp transverse furrow was pre- 
viously known in Opsidiscus bilobatus (Westergard, 1946) and Tan- 
nudiscus tannuolaicus (Pokrovskaya, 1959). It is not clear whether 
the transglabellar furrow in these Eodiscids, and the possibly homol- 
ogous furrow in the Agnostids, result from modification of one of 
the pairs of glabellar furrows, or are independent of them, represent- 
ing a secondary segmentation. The doubt is suggested by the prob- 
able secondary nature of the segmentation of the pygidial axis in the 
Agnostids (Palmer, 1955). 

In Acimetopus the glabellar lobation is the most specialized of 
any described Eodiscid, the broad transglabellar furrow possessing a 
pair of small, rounded lobes at the sides. 

In Stigmadiscus, and to a lesser extent in Acidiscus, the two pairs 
of lateral glabellar furrows assume the form of short, fairly deep pits, 
a feature unusual in the family even though it occurs in other groups 
of trilobites. 

Another unusual character for the Eodiscids is the extension of 
the posterior portion of the glabella into an upright spine, observed 
in Acidiscus, Acimetopus, and Bolboparia. In Acidiscus there is, in 
addition, an occipital spine, whereas in Acimetopus and Bolboparia 
the occipital ring is short and simple. 

Cephalic border. — A definite border furrow and border around the 
cephalon are present in all genera excepting Analox where the lateral 
border is missing, although an anterior border of triangular shape 
and the posterior border are well developed. One of the striking 
features of the border in several of the new genera is the develop- 
ment of marginal spines at various positions. 

One pair of short, lateral marginal spines is observed in Acimeto- 
pus, Bolboparia, Litcnnetopus, and Acidiscus birdi. Two pairs are 
present in Acidiscus hexacanthus and Oodiscus subgranulatus. As 
the spines vary in position, it is questionable whether they can be 
homologized among the different species. 

The posterior cephalic border shows variable features that can 
not be readily homologized among the different genera. In many of 
the species it bears a pair of spines, which may vary in position from 
less than halfway from the axial furrow to the genal angle (in Oodis- 
cus, Bathydiscus, and Stigmadiscus stenometopus) to the proximity 
of the genal angle as in Serrodiscus subclavatus, Acimetopus bilobct- 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 9 

tus, Bolhoparia superba, Acidiscus hirdi, Litometopus longispinus, 
and Stigmadiscus gihhosus. Presumably the spine should be con- 
sidered homologous in all these genera, but there are no decisive 
arguments in favor of this assumption. In Oodiscus and B at hy discus 
the base of the spine coincides vi^ith the position of a sharp genicula- 
tion, the portion of the posterior border distal to this point being 
sharply bent downward and somewhat forward. In Litometopus 
longispinus and, to a lesser extent, in Serrodiscus suhclavatus, the 
posterior border presents an unusual feature consisting of a narrow 
ridge separated from the main part of the border by a short, trans- 
verse furrow. The distal end of this ridge produces a slight rearward 
projection of the posterior margin. In one specimen of Serrodiscus 
suhclavatus preserving two thoracic segments attached to the cepha- 
lon, the ridge on the cephalic margin is seen to correspond to the 
fulcrum on the anterior margin of the first thoracic segment. A simi- 
lar feature is present at the articulation between the first and second 
thoracic segments. In Litometopus longispinus the tooth on the pos- 
terior cephalic border is more conspicuous. In both species the 
"genal" spine is located more distally than these features. 

Pygidium. — The pygidia present less variety than the cephala. The 
axis is always well defined except in one unassigned pygidium where 
the axial furrow is barely indicated. In Acimetopus and Bolhoparia 
there is a large, upright spine on the second axial ring. In Serrodiscus 
suhclavatus there is a long spine on the posterior part of the unseg- 
mented axis. In Acidiscus there are spines on several of the axial 
rings. Border furrow and border are well differentiated in all pygidia. 
A well-developed articulating facet is present in all genera; this is 
the most obvious feature for distinguishing pygidia from cephala 
in doubtful cases. Marginal spines, sometimes visible from above, 
more often appearing as extensions of the doublure and hence ventral 
in position, may be present. In most species the doublure is reflexed 
as usual in trilobite pygidia. However, in Analox bipunctata and the 
pygidium attributed to Bathy discus dolichometopus, the pygidial 
doublure forms an almost vertical face rather than being reflexed 
inward to parallel the dorsal exoskeleton. In neither species this 
feature is present in the cephalon, where the doublure appears to 
be narrow and not sharply defined, the dorsal test being gradually 
downrolled. 

Ornamentation. — The outer surface of the test may be smooth, 
punctate, finely granulate, coarsely granulate with granules of one 
size (Acimetopus) or different sizes (Bolhoparia). The larger of 
these granules seem broken at the tip and may represent the bases 



lO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

of short spines. Calodiscus reticulatus has a strong reticulate orna- 
mentation. 

Classification. — The Eodiscidae of North America have so far 
been referred to five genera (Rasetti, 1952) : Calodisctis Howell, 
1935 (type species, Agnostus lobatus Hall) ; Dawsonia Hartt in 
Dawson, 1868 (type species, Microdiscus dawsoni Hartt in Dawson) ; 
Eodiscus Hartt in Walcott, 1884 (type species, Eodiscus pulchellns 
Hartt in Walcott^ Microdiscus scanicus Linnarsson) ; Serrodiscus R. 
and E. Richter (type species, Eodiscus {Serrodiscus) serratus R. 
and E. Richter) ; and Weymouthia Raymond, 1913 (type species, 
Agnostus f nobilis Ford). Of these five North American Eodiscid 
genera, Dawsonia and Eodiscus occur exclusively in the Middle Cam- 
brian Paradoxides beds ; the other genera are Lower Cambrian. 

Genera that have been proposed for Eodiscidae from Europe 
and Asia are Cobboldites Kobayashi, 1943 (type species, Microdis- 
cus comleyensis Cobbold) ; Metadiscus Kobayashi, 1943 (type spe- 
cies, Microdiscus sculptus Hicks) ; Ladadiscus Pokrovskaya, 1959 
(type species, Ladadiscus limbatus Pokrovskaya). To these genera 
the writer would add Tannudiscus Pokrovskaya, 1959 (type spe- 
cies, Tannudiscus tannuolaicus Pokrovskaya), originally assigned to 
the family Opsidiscidae (Pokrovskaya, 1959), which seems of 
questionable validity since Opsidiscus, which has vestigial eyes but 
no facial sutures, could be referred either to the Pagetiidae or the 
Eodiscidae, the presence of a transglabellar furrow having little sig- 
nificance. Tannudiscus has no trace of eyes and should be placed in 
the Eodiscidae even if a separate family Opsidiscidae were recog- 
nized. 

The nine new genera described herein approximately double the 
size of the family and it was considered whether the additional 
knowledge suggested some grouping of the genera that would indicate 
evolutionary trends. On the basis of present knowledge there seems 
to be no basis for a meaningful arrangement of the genera. The glabel- 
lar lobation, which in general is one of the important taxonomic 
features in trilobites, seems of little significance, as shown by the 
gradual transition from generalized lobation to the specialized loba- 
tion where all furrows have disappeared but for a deep, straight 
transglabellar furrow (Calodiscus reticulatus) . Other characters, such 
as shape and relative length of the glabella, cephalic border furrow 
and border, glabellar, occipital and marginal cephalic spines, orna- 
mentation, etc., seem even less significant, as also are believed to 
be the pygidial features. Even an arrangement of the genera based 
on characters of little evolutionary and taxonomic significance would 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI II 

be difficult to carry out because genera that are alike in one feature 
are apt to be strikingly different in one or several others. For this 
reason the genera are described herein in alphabetical order. 

ACIDISCUS Rasetti, new genus 

Description. — Cephalon of moderate convexity, semielliptical. 
Glabella not reaching the anterior border, subcylindrical, with two 
short, somewhat pit-like pairs of lateral furrows, in the two known 
species possessing a small upright spine on its posterior portion. 
Occipital furrow wide; occipital ring well defined, bearing a spine. 
Posterior border straight from the axial furrow to the base of the 
genal spine. Lateral cephalic border with one or two pairs of mar- 
ginal spines. 

Pygidium with long, multisegmented axis. Geniculation situated 
rather distally; facet well developed. Pleural regions unfurrowed; 
border and border furrow well developed, of average width. Surface 
smooth or with weak ornamentation. The narrow doublure may 
be extended into short spines. 

Type species. — Acidiscus birdi Rasetti, new species. 

Occurrence. — Late Lower Cambrian of New York. Also in the 
Purley Shales of Warwickshire, England (Rushton, private com- 
munication). 

Discussion. — This genus is obviously a close relative of Serrodis- 
cus. The pygidium is much the same as in that genus. The cephalon, 
however, has important distinctive features, the most significant being 
the development of glabellar and occipital furrows. Another distinc- 
tive character is the tendency to develop spines on the glabella, 
occipital ring, at the genal angle, and on the cephalic border. The 
glabellar furrows also indicate relationship to Stigmadisc%s; in sev- 
eral features Acidiscus may be considered transitional between the 
latter genus and Serrodiscus. 

ACIDISCUS BIRDI Rasetti, new species 
Plate 1, figure 2 ; plate 6, figures 11-19 

Available material. — Numerous cephala and pygidia, of which a few 
are fairly complete. 

Description.— Co^h^Xon semielliptical. Glabella rising well above 
the cheeks, very convex transversely, tapered in anteriormost por- 
tion, narrowly rounded in front, occupying with occipital ring more 
than two-thirds of cephalic length. Two pairs of distinct, short, 



12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I48 

somewhat pit-like lateral furrows ; the posterior pair longer, directed 
backward almost to meet occipital furrow, hence defining small, 
elongate-triangular basal lobes. The glabella reaches maximum ele- 
vation near the posterior end, at the level of the posterior pair of 
lateral furrows, where it possesses a small upright spine. Occipital 
furrow deepened into a pair of small pits laterally, wide medially; 
occipital ring of moderate length (sag.), extended into a spine incom- 
plete in all specimens. Cheeks convex, not separated medially by a 
preglabellar depression, sloping steeply to border furrow in posterior 
portion. Border lying in a plane, slightly convex, widest medially, 
narrowing toward the genal angles, possessing a pair of small lateral 
spines anterior to the level of the front end of the glabella. A series 
of five or six pairs of low tubercles, as usual in species of Serrodiscus, 
is visible on the lateral border. The posterior border furrow is 
directed outward and slightly forward from the axial furrow, thus 
forming an angle with the posterior cephalic margin and giving the 
posterior border an elongate-triangular shape. Posterior cephalic mar- 
gin straight from axial furrow to base of short, outward-directed 
genal spine. 

Pygidium similar to cephalon in general shape, somewhat more 
distinctly subtriangular. Axis narrow and long, barely failing to 
reach the posterior border furrow, fully segmented for the entire 
length, composed of 12 rings including the terminal one. There is a 
short, upright spine on each of the first seven axial rings. Pleural 
regions convex, totally un furrowed. Border furrow deep, border rela- 
tively narrow, of almost even width. Articulating facet well devel- 
oped. Border extended downward and inward into narrow doublure 
forming a series of blunt spines not visible except by removing the 
matrix under the border ; terrace lines on doublure following the 
serrated outline. 

Surface of test mostly smooth, except for granules visible in some 
specimens on the last few axial rings and sometimes on the posterior- 
most portion of the pleural regions. Length of largest (incomplete) 
cephalon 18 mm, width 20 mm. Length of largest pygidium 12 mm, 
width 16 mm. 

The species is named for Dr. John M. Bird who collected the 
holotype. 

Occurrence. — Collection cs-4. North Chatham. 

Ty/>^j.— Holotype : U.S.N.M. 145987. Paratypes: U.S.N.M. 
145988. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI I3 

ACIDISCUS HEXACANTHUS Rasetti, new species 
Plate 7, figures 1-6 

Available material. — Two cephala and one pygidium. 

Description. — It is sufficient to point out the differences from the 
type species. Shape and convexity of cephalon and pygidium the 
same as in ^. birdi. Glabella and occipital ring, including the spines, 
almost identical. Cephalic border bearing, in addition to an anterior 
pair of spines as in A. birdi, a second pair halfway between the first 
pair and the genal angle. Posterior cephalic border and genal spine 
as in preceding species. Lateral border lacking tubercles. 

Pygidium (referred to the species on account of the ornamentation) 
with entirely segmented axis, also showing 12 rings including the 
terminal section. Axial spines developed on the first six instead of 
seven rings. The character of the pygidial doublure has not been 
ascertained. 

Surface of cheeks and pleural regions of pygidium covered with 
small, sparse, but sharply elevated granules. The ornamentation is 
less marked in the holotype cephalon than in the paratype cephalon 
and pygidium. Similar individual variations in the identical type of 
ornamentation were observed in Oodiscus subgranulatus. 

Occurrence. — Collection cs-4, North Chatham. 

7y^^^._Holotype : U.S.N.M. 145989. Paratypes: U.S.N.M. 
145990. 

ACIMETOPUS Rasetti, new genus 

Description. — Cephalon and pygidium strongly convex. Glabella 
divided by a deep, wide transglabellar depression into anterior and 
posterior lobes. Anterior lobe bulbous, not reaching the anterior 
border. Transglabellar depression subdivided laterally into two pairs 
of furrows, isolating a pair of small lobes ; these furrows are confluent 
medially into one broad furrow. Posterior glabellar lobe strongly 
elevated and extended into a long, uptilted spine. Occipital ring short 
(sag.), well defined by occipital furrow, not spinose, partly concealed 
in dorsal view by the rearward extension of the glabella. Cheeks 
strongly convex, confluent anteriorly without any trace of a pre- 
glabellar depression, in their posterior portion overhanging the bor- 
der furrow. Border well developed, defined by a deep border furrow, 
approximately lying in a plane, wide anteriorly, tapering toward the 
genal angle, extended into a pair of small lateral spines. Near the 
genal angle the lateral border furrow is confluent with the deep 
posterior border furrow ; the border at this point is greatly reduced. 



14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

The posterior cephalic margin is straight, lacking geniculation, and 
extends into a short, outward-directed genal spine. 

Pygidium with strongly elevated axis, furrowed for entire length 
and showing in type species nine segments ; axis almost reaching the 
border, possessing a strong upright spine on the second ring. Pleural 
regions strongly convex and steeply downsloping ; border furrow deep, 
border of even width, lacking spines. Surface strongly granulate. 

Type species. — Acimetopus hilohatus Rasetti, new species. 

Occurrence. — Late Lower Cambrian of New York. 

Discussion. — The genus is characterized by the glabella deeply 
divided into anterior and posterior lobes, a feature present in some 
forms of Calodiscus, and also well developed in Analox. However, 
Acimetopus is unique in the development of the extra pair of small 
lateral lobes in the transglabellar depression. 

ACIMETOPUS BILOBATUS Rasetti, new species 
Plate 2, figure 3 ; plate 4, figures 1-14 

Available material. — Numerous, well-preserved cephala and py- 
gidia. The assignment of the two shields to one species is unquestion- 
able because of the unique ornamentation among the members of 
the faunule. 

Description. — Features indicated in the generic description are not 
mentioned. The anterior glabellar lobe is exceedingly convex, falling 
vertically to the preglabellar field, moderately rounded anteriorly 
and slightly wider than the posterior lobe; the latter is more nearly 
straight-sided. The glabellar spine varies somewhat in size and atti- 
tude among the specimens; on the average it is directed upward at 
an angle about 30° and is sharply pointed. The border spines are 
situated somewhat in advance of the midpoint of the anterior glabellar 
lobe and are short and rapidly tapered. 

The pygidial axis is deeply furrowed for the entire length, the 
furrows being deeper laterally. The second segment has a strong, 
long upright spine whose base somewhat encroaches on the adjacent 
ring furrows; it was not possible in any case to extract the entire 
spine from the matrix. The pleural regions are so convex that they 
somewhat overhang the border furrow, which is deep and wide. 
Border convex, relatively narrow. 

Entire surface covered with large, elevated granules of one size. 
Length of largest cephalon, exclusive of glabellar spine, 9.5 mm, 
width 10 mm. Length of largest pygidium 7.5 mm, width 7 mm. 

Occurrence. — Collection cs-4. North Chatham. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 15 

Types.— Rolotype: U.S.N.M. 145991. Paratypes: U.S.N.M 
145992. 

ANALOX Rasetti, new genus 

Description. — Cephalon of moderate overall convexity, well rounded, 
somewhat narrowing toward the front. Glabella terminating in the 
merged axial and border furrows, divided into posterior and anterior 
lobes by a wide, moderately deep transglabellar furrow; no other 
furrows present. Posterior glabellar lobe strongly elevated and 
extended backward into a broad spine. Occipital ring short, barely 
differentiated under the rearward extension of the glabella. Anterior 
border swollen medially, defined by a pair of furrows directed out- 
ward and forward from the anterior angles of the glabella, not reach- 
ing the cephalic margin but ending abruptly in a pair of pits. Lateral 
border absent ; cephalic margin in this portion downrolled into the 
doublure. Posterior border furrow and border well developed ; genic- 
ulation distally located ; genal spine absent. Border furrow extended 
for a short distance forward from the genal angle and then fading 
out. 

Pygidium about equally wide and long, rather strongly convex; 
posterior outline regularly rounded. Axis relatively narrow, defined 
by a narrow but deep axial furrow, not greatly raised above the 
general convexity, in type species showing seven rings plus a terminal 
section, lacking nodes or spines. Border present but exceedingly 
narrow, defined by an equally narrow border furrow. Doublure form- 
ing a vertical face, not extended into spines. 

Type species. — Analox bipunctata Rasetti, new species. 

Occurrence. — Late Lower Cambrian of New York. 

Discussion. — The glabella with its transglabellar furrow is like 
certain forms herein attributed to Calodiscus. The unique feature 
of the genus is the lack of a lateral cephalic border. The pygidium 
in dorsal view resembles the pygidia of Pagetides, but has the unusual 
vertical doublure. 

ANALOX BIPUNCTATA Rasetti, new species 
Plate 2, figure 2 ; plate 6, figures 1-10 

Available material. — Numerous, well-preserved cephala and py- 
gidia. This is one of the more common species of the Acimetopus 
hilobatus faunule. 

Description.— Most of the features were indicated in the generic 
diagnosis. Glabella defined by a broad, fairly deep axial furrow; 



l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

anterior glabellar lobe barely rising above the cheeks ; posterior lobe 
extended into a broad spine tilted at about 30° ; the spine appears to 
be bluntly terminated, although this portion is not well preserved in 
any of the cephala. The cephalic margin lies approximately in a 
plane. The pygidial axis has rings well defined by straight ring fur- 
rows becoming gradually shallower toward the rear, deeper 
medially, and shallower near the axial furrows. The axis does not 
reach the posterior border, although it appears almost to do so in 
dorsal view on account of the strongly downsloping marginal por- 
tions of the pleural regions. The excessively narrow lateral border 
furrow and border maintain an almost even width throughout. The 
anterior border furrow instead is relatively wide; the anterior py- 
gidial margin has a straight transverse course from the axial furrow 
to the geniculation, which is closer to the lateral margin than to the 
axial furrow. The facet is well developed. 

The surface of the test is finely punctate, this ornamentation both 
in the cephalon and pygidium being more marked on the pleural 
than the axial parts. Length of the larger cephala, exclusive of 
glabellar spine, 4 mm, width 5 mm. Length of largest pygidium 
3.5 mm, width 4 mm. 

Occurrence. — Collection cs-4. North Chatham. 

Types.— Uolotype: U.S.N.M. 145093. Paratypes: U.S.N.M. 
145094. 

BATHYDISCTTS Rasetti, ne-w genus 

Description. — Cephalon with considerable relief. Glabella with 
almost undifferentiated occipital ring prominent, slightly expanded 
forward, reaching the anterior border, unfurrowed. Cheeks convex 
and downsloping. Border convex, wide, well defined by a border 
furrow inbent on either side of the anterior portion of the glabella 
to merge with the axial furrow. In anterior view, the medial por- 
tion of the border is seen to be slightly arched, instead of lying in a 
plane as in most Eodiscids. Posterior cephalic border with sharp 
geniculation and short, erect spine located close to axial furrow as 
in Oodiscus. Surface of test smooth. 

Pygidium tentatively assigned to the type species with long, well- 
defined, unfurrowed axis not reaching the border furrow. Border 
furrow narrow laterally, widened posteriorly ; border narrow, slightly 
elevated. Doublure not reflexed to parallel the dorsal exoskeleton as 
in most Eodiscids, but almost vertical, with a slight inward slope, 
wide everywhere except in the posteriormost portion. This attitude 
of the doublure gives the pygidium as a whole an unusual depth. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 17 

Type species. — Bathydiscus dolichometopus Rasetti, new species. 

Occurrence. — Late Lower Cambrian of New York. 

Discxission. — The cephalon indicates close relationship to Oodis- 
cus as evidenced by the same general shape, characters of glabella 
and occipital ring, position of the geniculation and spine on the 
posterior border. The chief difference is the extension of the glabella 
encroaching upon the anterior border furrow and the peculiar inbend 
of the latter at the sides. Another important feature is the arched 
anterior border, which does not occur in Oodiscus. If the pygidium 
is correctly assigned, its peculiar doublure represents one of the most 
characteristic features of the genus. 

BATHYDISCUS DOLICHOMETOPUS Raaetti, new species 
Plate 1, figure 3 ; plate 9, figures 1-16 

Available material. — Several cephala and about an equal nimiber 
of pygidia. 

Description. — Cephalon highly convex, semielliptical, well 
rounded in front. Glabella strongly elevated, slightly pear-shaped, 
well rounded in front, totally unfurrowed. Occipital furrow very 
shallow at the sides, obsolete medially ; occipital ring very short, con- 
tinuing the longitudinal profile of the glabella, extended farther back- 
ward than the cheeks. Cheeks very convex, laterally sloping down 
vertically to the border furrow. Border furrow well impressed, later- 
ally paralleling the cephalic margin, anteriorly inbent at each side 
to merge with the axial furrow that separates the front of the glabella 
from the border. Border convex, wide, lacking tubercles. Cephalic 
doublure very narrow, normally reflexed. Border in anterior view 
arched medially, paralleled by the border furrow which rises on each 
side to meet the axial furrow. The pygidium is referred to the species 
chiefly on account of the position of the geniculation and the fit of 
the up-arched anterior border of the cephalon and down-arched 
posterior border of the pygidium, an arrangement that must have 
ensured a close fit of the two shields in enrollment. Pygidium widest 
at anterior end, semielliptical, with strong relief. Axis elevated, well 
defined by the axial furrow, tapered, occupying about three- fourths 
of the pygidial length, unfurrowed. Articulating half-ring short (sag.), 
defined by a deep articulating furrow. Pleural regions convex and 
downsloping. Anterior border with sharp geniculation at one-third the 
distance from the axial furrow to the lateral margin ; articulating facet 
well developed. Border narrow and but slightly elevated laterally, 
defined by a very shallow border furrow, but elevated at the level 



l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

of the posterior end of the axis. Beyond this elevation the border 
appears concave upward in posterior view, while the border furrow 
widens and the border becomes almost flat medially. Doublure wide, 
sloping but slightly inward and forming an almost vertical face. The 
edge of the doublure does not partake of the downward curve of the 
posterior border, hence the doublure is much narrower in its poste- 
riormost portion. Doublure with irregular terrace lines and smooth 
margin. Upper surface of cephalon and pygidium perfectly smooth. 
Length of largest pygidium 1 1 mm. 

Occurrence. — Collections cs-4 and USGS 4216, North Chatham. 

Ty/>^.f.— Holotype : U.S.N.M. 145995. Paratypes: U.S.N.M. 
145996-7. 

BOLBOPARIA Rasetti, new genus 

Description. — Cephalon with strong relief. Glabella well tapered, 
pointed in front, highest posteriorly where it extends into an upright 
spine. Lateral furrows short, of generalized pattern. Occipital fur- 
row distinct, occipital ring short (sag.) and simple. Cheeks as a 
whole forming a subquadrate area in dorsal view, rising from a low 
posterior part to their highest point near the anterolateral angles, 
here bulging and overhanging the lateral border. The relatively long 
(sag.) preglabellar field is a broad depression separating the bulging 
cheeks. Anterior portion of border expanded ; border narrowest later- 
ally under the bulge of the cheeks, widening again toward the 
genal angle, extended into a pair of small, lateral spines and near the 
genal angle carrying one or more pairs of tubercles. In front of the 
genal angle the lateral border furrow merges with the posterior bor- 
der furrow, at considerable distance from cephalic margin. Posterior 
border furrow directed obliquely outward and forward from the 
axial furrow, sharply turning outward after merging with the lateral 
border furrow, and reaching the lateral cephalic margin well in 
advance of the genal angle which bears a small spine. 

Pygidium semielliptical, strongly convex transversely. Axis well 
defined, long, with numerous rings, the second bearing a large spine. 
Pleural regions un furrowed ; border narrow, extended into minute, 
downward-directed spines. Surface of test densely granulate in the 
three known species. 

Type species. — Bolboparia superba Rasetti, new species. 

Occurrence. — Later Lower Cambrian of New York and Quebec. 

Discussion. — This is probably the most distinctive of all the new 
genera of Eodiscidae described herein. The short, downsloping 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI I9 

glabella and the bulging cheeks give it a very peculiar aspect. Among 
previously known forms it might perhaps be compared with Calo- 
discus walcotti Rasetti (1952), unfortunately known from a single, 
somewhat incomplete cephalon. This form also has a pointed, but 
much longer, glabella, whose posterior portion is extended into a 
spine. The cheeks, however, have a normal shape. 

BOLBOPARIA SUPERBA Rasetti, new species 
Plate 3, figure 1 ; plate 5, figures 1-6 

Available material. — A few cephala, small and more or less frag- 
mentary excepting the holotype which is a large, almost perfect exam- 
ple. Also a thoracic segment attributed to the species. 

Description. — Cephalon somewhat wider than long, widest at the 
posterior third, slightly narrowed toward the genal angle, pointed 
in front. Glabella occupying about two-thirds of the cephalic length, 
defined by a very deep axial furrow, well tapered, pointed in front, 
extended into a slender almost vertical spine just in front of the 
occipital furrow. Lateral furrows short, merging with the axial 
furrow ; two pairs relatively deep, one additional pair barely visible. 
Occipital furrow straight, deeper at the sides, but not quite connect- 
ing with the axial furrows ; occipital ring wider medially, with rounded 
outline. Cheeks bounded by an irregular line, consisting of strongly 
oblique posterior border furrow, followed by an almost longitudinal 
section of the lateral border furrow; at this point the cheeks are 
widest, then narrow again for a considerable, fairly straight portion; 
then the outline curves sharply inward in correspondence with the 
highest part of the bulge and becomes fairly straight, transverse in 
the anterior portion. The border furrow is well marked all around 
the cheeks and attains its maximum depth anterolaterally. The bor- 
der extends into a pair of small, slender spines located somewhat 
back of the level of the anterior end of the glabella. Two rounded 
tubercles are located in the wider portion of the lateral border just 
in front of the posterior border ; as mentioned in the generic diagno- 
sis, a deep furrow separates here the lateral border, elevated into 
the posterior tubercle, and the posterior border, carrying the short 
genal spine. 

Entire surface very densely covered with granules of various sizes ; 
the largest appear broken at the tip and may represent the bases 
of short spines. Length of largest (holotype) cephalon 9.0 mm, 
width 11 .0 mm. 

A peculiar thoracic segment is attributed to the species because 



20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

the ornamentation of the pleura is similar to that of the cephalon. 
On each side of the axis there is an oblique furrow, directed outward 
and forward, reaching the axial furrow at the anterior corner of the 
ring. The pleura is flat and horizontal for most of its length, with a 
furrow paralleling and close to the posterior margin. The anterior 
margin has a very sharp geniculation, where it bends backward and 
downward, forming a marked facet. At the fulcrum a very narrow 
ridge is set off near the anterior margin by a shallow furrow, a feature 
also observed in Serrodiscus subclavatus. The distal end forms a 
short, sharp spine directed outward and backward. 

Occurrence. — Collection cs-4. North Chatham. 

Types.— Holotype: U.S.N.M. 145998. Paratypes: U.S.N.M. 
145999. 

BOLBOPARIA ELONGATA Rasetti, new species 
Plate 3, figure 2 ; plate 5, figures 7-12 

Available material. — A few cephala, of which two reasonably 
complete, and three tentatively assigned, incomplete pygidia. 

Description. — The cephalon is so similar to the type species 
that it is sufficient to point out the differences. Cephalon somewhat 
longer than wide. Glabella proportionately narrower and longer 
than in B. superba, bearing the same kind of lateral furrow and 
posterior spine. Anterior cephalic outline somewhat more sharply 
pointed; cheeks bulging anteriorly but not as much as in the type 
species ; outline at the anterolateral corners turning even more abruptly 
than in that species. Posterior portion of border furrow even more 
oblique than in B. superba, forming an angle of 45° with the axis 
of the body. Widened posterior portion of lateral border bearing two 
pairs of tubercles as in preceding species. Genal angle not well pre- 
served. Length of largest cephalon 8 mm. Ornamentation as in pre- 
ceding species. 

Three incomplete examples of a pygidium undoubtedly belong to 
Bolboparia as they match the unique ornamentation of the cephala. 
However, the reference to B. elongata rather than B. superba, sug- 
gested by the relatively narrow shape, is tentative. Axis moderately 
wide, slightly tapered, defined by deep axial furrows, almost reaching 
the posterior border, furrowed for entire length, showing approxi- 
mately 12 rings ; end portion not well preserved. A broad-based 
spine on the second ring encroaches on the adjacent ring furrows. 
Pleural regions attaining a vertical slope, almost concealing the bor- 
der in dorsal view. Border furrow well impressed ; border vertical, 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 21 

extended into about 12 pairs of minute spines. Length of largest 
pygidium 8 mm. 

Occurrence. — Collection cs-4, North Chatham. 

ry/)^^.— Holotype : U.S.N.M. 146001. Paratypes: U.S N M 
146002. 

BOLBOPARIA CANADENSIS Rasetti, new species 
Plate 5, figures 13, 14 

Available material. — A single, well-preserved cephalon. 

Description. — Cephalon relatively broad and short as in B. superba. 
Glabella somewhat longer in proportion to the cranidium, long and 
narrow, subcorneal, pointed in front. Three pairs of lateral furrows 
impressed, the posteriormost pair deep, short, pit-like, the other two 
similar but increasingly shallow. The glabellar spine is broken off, 
but its base shows that it was large and equally located as in B. 
superba. Occipital furrow straight, of even width throughout ; occip- 
ital ring short and simple. Outline of the cheeks of the same general 
type as in 5. superba, but differing in several details. The posterior 
portion, from the axial furrow to the widest point of the cheeks, is 
almost straight, since there is hardly any change of direction between 
the posterior border furrow and the posterior portion of the lateral 
furrow. Where these furrows meet, there is the usual deep furrow 
directed toward the cephalic margin ; but in the present species this 
furrow extends also inward and forward, forming a broad, shallow 
depression across the cheek reaching the axial furrow at the level 
of the middle pair of glabellar furrows. At the widest point, the 
cheek outline forms a narrowly rounded angle, continues straight 
forward and somewhat inward to the anterolateral corners where 
the cheek attains its highest elevation, and then curves to a transverse 
inward course as in B. superba. As a whole the cheeks acquire thereby 
a peculiar subhexagonal outline. The border furrow and border are 
much like the other species, except that there is only one, large 
tubercle at the posterior end of the lateral border. The small lateral 
border spines are in the same position as in B. superba. Ornamenta- 
tion identical with the other two species of the genus. Length of 
cephalon 4.5 mm, width 4.8 mm. 

Occurrence. — The single known specimen was collected by Mr. 
Claude Hubert when mapping an area near the south shore of the St. 
Lawrence River in Quebec. The collection, designated as 63-F24, is 
stated to be made from a calcarenite bed a half mile north of Elgin 
Station, LTslet County. The locality is about 60 miles northeast of 



22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Levis. Unfortunately no other identifiable fossils were recovered from 
this bed, although trilobite fragments presumably representing Ole- 
nellids were observed. Lower Cambrian strata are known from this 
general area, and were designated by the writer (Rasetti, 1964) the 
Charny formation, to avoid the confusion associated with names pre- 
viously in use. The easternmost occurrence of identified Lower Cam- 
brian beds in place (the Botsfordia pretiosa shale) previously reported 
was about 20 miles northeast of Levis ; hence Mr. Hubert's finding 
extends the known presence of Lower Cambrian strata 40 miles north- 
east. Lower Cambrian fossils at many other localities farther east are 
only found in boulders in Lower Ordovician conglomerates. 

It should be pointed out that the only Lower Cambrian Eodiscid 
trilobites previously known from the Charny formation (Rasetti, 
1945) belong to the family Pagetiidae. The same applies to the forms 
described (Rasetti, 1948) from conglomerate boulders. However, 
Raymond (1913) mentioned the presence of a blind Eodiscid, 
Serrodiscus speciosus, in the boulders at Bic. The writer, who col- 
lected thousands of Lower Cambrian trilobite specimens from that 
and nearby localities, was unable to find this species or any other 
blind Eodiscid. Search in the collections of the Geological Survey of 
Canada and the U.S. National Museum failed to yield any such 
material from the Bic locality. Hence the writer (1948) did not 
include Serrodiscus speciosus in the list of species from the Lower 
Cambrian of the Quebec conglomerates. 

Recently two good specimens of Serrodiscus speciosus, one cepha- 
lon and one pygidium, bearing labels of the Bic locality and pre- 
served in the characteristic, light-gray limestone prevailing in those 
conglomerates, were discovered in the collections of the New York 
State Museum. The writer was able to examine these through the 
courtesy of Dr. Donald W. Fisher. It is thus now ascertained that 
there are at least two blind Eodiscids in the Lower Cambrian of 
Quebec. 

Type. — Holotype: Geological Survey of Canada No. 19887. 

Genus CALODISCUS Howell, 1935 
T)rpe species. — Agnostus lohatus Hall. 

CALODISCUS FISSIFRONS Rasetti, new species 

Plate 9, figures 17-21 

Available material. — A few cephala, mostly fragmentary, and 
two tentatively assigned pygidia. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 23 

Description. — Glabella divided by a broad transverse furrow into 
anterior and posterior lobe ; lobation more marked in larger individ- 
uals. Anterior lobe rounded, slightly narrower than posterior lobe; 
the latter rising steeply and extended upward and backward beyond 
the occipital ring ; whether this extension is rounded or pointed at the 
extremity could not be determined, as this portion is incompletely 
preserved. One pair of short lateral furrows is visible on the posterior 
lobe. Occipital ring short (sag.), mostly masked in dorsal view by 
the glabellar extension, directed inward and backward at the sides. 
Cheeks strongly convex, in their posterolateral part overhanging the 
border furrow. Border expanded medially and causing a slight median 
inbend of the border furrow which here forms a depression by merg- 
ing with the axial furrow ; border narrowing gradually toward the 
genal angle. Posterior cephalic border poorly preserved. Surface of 
test faintly reticulate ; lateral border with four or five pairs of low 
tubercles. 

Pygidium tentatively referred to the species on account of similar 
ornamentation with axis well defined by deep axial furrows, showing 
about seven rings plus a terminal unsegmented section, almost 
reaching border. The first three rings may have had a node. Anterior 
border furrow deep and wide, with well-developed geniculation and 
facet. Lateral and posterior border furrow and border narrow through- 
out. Pleural regions unsegmented, very convex like the cheeks. 

Width of largest cephalon 9.5 mm; length of holotype cephalon 
4.6 mm, width 5.6 mm. Length of largest pygidium 5.0 mm, width 
6.0 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — This species differs considerably from C. lobatus 
in the shape of the glabella, divided by a broad transverse furrow 
and with the rear lobe extended backward above the occipital ring. 
However, the presence of one or more, shallow transglabellar fur- 
rows is a feature present in species obviously congeneric with C. 
lobatus, and even in the form agnostoides of this species which 
Lochman (1956) showed to intergrade with the typical form. Calo- 
discus Helena (Walcott) has a broad, very shallow transglabellar 
furrow and a rearward extension of the glabella, although not as 
pronounced as in the present species, and on the whole the cephala 
of C. Helena and C. fissifrons are very similar. The pygidium of C. 
Helena, however, differs considerably in the broad, paucisegmented 
axis from any pygidium observed at the North Chatham locality. 

T.v/'^^.— Holotype: U.S.N.M. 146004. Paratypes: U.S.N.M. 
146005. 



24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

CALODISCUS RETICULATUS Rasetti, new species 
Plate 1, fig. 1 ; plate 7, figures 12-18 

Available material. — A few cephala, mostly fragmentary. 

Description. — Glabella divided by a deep, wide transverse fur- 
row into two lobes. Anterior lobe subovate, very convex, anteriorly 
sloping down almost vertically to the broad depression formed by 
the coalescence of the axial and border furrows. Glabella constricted 
at the transverse furrow. Posterior lobe widening backward from the 
transverse furrow, rising steeply, extended well beyond the general 
outline of the cephalon; seemingly rounded at the posterior end, 
although this portion is not completely preserved in any of the speci- 
mens. Occipital ring differentiated under the rearward glabellar exten- 
sion, at least at the sides where it is directed rather backward than 
inward. Cheeks very convex, at least posteriorly where they over- 
hang the lateral border furrow. Border expanded medially as in 
preceding species, slightly convex, narrowing toward the genal angle, 
lacking tubercles. Posterior border set off by a wide, deep furrow, 
rather wide in distal portion ; genal angle narrowly rounded, lacking 
spine. 

Surface of test covered with raised lines forming a reticulate pat- 
tern. The largest cephalon has a width of 10.5 mm and a length of 
approximately 10 mm. 

Occurrence. — Collections cs-4 and U.S.G.S. 4216, North Chatham. 

Discussion. — This species is closely related to the preceding, dif- 
fering in the deeper division of the glabella by a transverse furrow, 
greater elevation of the two glabellar lobes, reticulate ornamentation, 
and lack of tubercles on the border. Clearly the present species is 
so strikingly different from Calodiscus lobatus that, were intermediate 
forms unknown, reference to the genus would hardly be suggested. 
However, when one considers the series Calodiscus lobatus, C. loba- 
tus agnostoides, C. helena, C. fissifrons, and C. reticulatus, it appears 
difficult to decide where to place a possible generic boundary. 

Types.— RoXoty^t: U.S.N.M. 146006. Paratypes: U.S.N.M. 
146007 and 146008. 

CALODISCUS OCCIPITALIS Rasetti, new species 
Plate 9, figures 22, 23 

Available material. — One cephalon. 

Description. — Cephalon semielliptical, of low convexity. Glabella 
elevated above the cheeks, higher posteriorly, with little longitudinal 
convexity, parallel-sided in the posterior two-thirds, anteriorly taper- 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 2$ 

ing to a fairly sharp point, occupying about two-thirds of the 
cephalic length, unfurrowed. Occipital furrow deeper laterally, 
impressed throughout ; occipital ring extended into a robust, horizon- 
tal spine longer than all the rest of the cephalon. Cheeks lowest 
medially, slightly convex, their outline forming a sharp angle at the 
posterolateral corner. Border furrow well impressed ; border convex, 
fairly wide, of about even width but for a slight narrowing toward 
the genal angle, bearing a few, indistinct tubercles. Posterior border 
furrow deep and wide ; posterior border with geniculation about half- 
way between axial furrow and genal angle, the latter lacking a spine. 
Surface of test smooth. Length of cephalon (exclusive of occipital 
spine) 3.4 mm, width 3.8 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — This form seems referable to Calodiscus even 
though it differs in several features from all previously described 
species. Its chief distinguishing characteristics are the relatively 
short glabella, well-impressed occipital furrow, excessively long occip- 
ital spine, narrowness of the border furrow, and even width of the 
border. 

Types.— RoXotypo,: U.S.N.M. 146003. 

LEPTOCHILODISCUS Rasetti, new genus 

Description. — Cephalon of moderate convexity. Glabella defined 
by deep axial furrow but not rising much above the cheeks, narrow 
and long, tapered, pointed in front, not reaching the anterior border, 
unfurrowed. Occipital furrow deep; occipital ring extended into 
spine. Cheeks everywhere convex, not separated in front by a pre- 
glabellar depression. Border very narrow, wire-like, well defined by 
narrow border furrow, narrowest in frontal portion, somewhat wid- 
ened laterally. Posterior border furrow deep ; posterior border widen- 
ing distally, with geniculation near genal angle. Surface of test in 
type species punctate. 

Type species. — Leptochilodiscus punctulatus Rasetti, new species. 

Occurrence. — Late Lower Cambrian of New York. 

Discussion. — This simple eodiscid cephalon does not seem refer- 
able to described genera. Compared with Calodiscus, it shows impor- 
tant differences that are sufficient to doubt a close relationship. In 
Calodiscus the anterior border is much wider, usually widest medially, 
and the cheeks are separated in front of the glabella by a more or 
less extended preglabellar depression. The glabella of Leptochilodis- 
cus is unusually long and pointed. The deep occipital furrow and 
spinose occipital ring also are not suggestive of Calodiscus. 



26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

LEPTOCHILODISCUS PUNCTULATIS Rasetti, new species 
Plate 1, figure S ; plate 11, figures 1-7 

Available material. — Four cephala in fair state of preservation. 

Description. — Cephalon of about equal length and width, well 
rounded anteriorly. Glabella rising steeply above the occipital fur- 
row, then sloping down toward a low anterior end without much 
longitudinal convexity, tapered at low, almost uniform rate but for a 
barely perceptible constriction at one-third the distance from the an- 
terior end, reaching not far from the anterior border furrow. Occipital 
furrow deep and wide ; occipital ring at lower level than glabella, 
extended into a slender, moderately long spine. Axial furrow deep 
except in its anteriormost portion. Cheeks rising above the axial 
furrow, convex transversely, in posterior portion sloping down steeply 
to border furrow. Border defined by narrow but fairly deep border 
furrow, convex, wire-like, very narrow in frontal portion. A unique, 
though inconspicuous, feature of the border is a slight widening 
that occurs at the point where the margin forms an angle of 45° 
with the sagittal line; here a small pit, distinguishable in all speci- 
mens, occurs on the upper surface. The portion of the border pos- 
terior to the pit remains wider than the frontal border. Another 
characteristic feature of the border is its sinuous outline in frontal 
view; the border curves slightly downward medially, upward at the 
sides of the median downbend, then again downward to assume a 
smooth course laterally. The slight crushing of the test in some 
specimens has made these features visible in dorsal view also. Pos- 
terior cephalic border with straight margin from axial furrow almost 
to genal angle, at this point reaching maximum elevation and sharply 
turned downward and forward to join the lateral border, possibly 
extended into a genal spine. Posterior border furrow deep and wide. 
Surface of cheeks definitely pitted in all specimens ; similar but shal- 
lower ornamentation on glabella. Length and width of largest cepha- 
lon 4.4 mm. 

Occurrence. — Collections cs-4 and U.S.G.S. 4216, North Chat- 
ham. 

Ty/'^.y.— Holotype : U.S.N.M. 146009. Paratypes: U.S.N.M. 
146010 and 146011. 

LITOMETOPUS Rasetti, new genus 

Description. — Cephalon relatively wide, almost semicircular, with 
considerable relief. Glabella long and narrow, slightly tapered, 
reaching the anterior border furrow which therefore merges medially 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 27 

with the axial furrow. Glabellar and occipital furrows entirely obso- 
lete. Cheeks convex ; border wide, convex, downrolled into the dou- 
blure. Posterior cephalic border with a blunt tooth, extended at the 
genal angle into strong spine. 

Pygidium similar in shape to cephalon, more tapered posteriorly. 
Axis reaching posterior border, un furrowed, well defined by axial 
furrow. Border furrow well impressed ; border flat, fairly wide ; dou- 
blure sloping inward at about 45° to vertical, with serrated margin. 
Size large for an Eodiscid. 

Type species. — Litometopus lotigispinus Rasetti, new species. 

Occurrence. — Late Lower Cambrian of New York. 

Discussion. — This form is a close relative of Serrodiscus, sharing 
with that genus the shape of the glabella, the general structure of the 
pygidium, and a slightly serrated doublure. Chief dijfferences are 
the width and convexity of the cephalic border, the entire lack of 
preglabellar field, the unusual tooth at the posterior cephalic border, 
and the strong genal spine. The last two features also distinguish 
the genus from Cobboldites comleyensis, which has an equally long 
glabella and a similar pygidium. The very large size of Litometopus 
contrasts with the small size of the known examples of Cobboldites. 

LITOMETOPUS LONGISPINUS Rasetti, new species 
Plate 3, figure 3 ; plate 8, figures 1-9 

Available material. — A few cephala and a larger number of pygidia. 

Description. — Cephalon 1.3 times wider than long, with uniformly 
rounded anterior and lateral outline. Glabella widest at the undif- 
ferentiated occipital ring, with slightly concave lateral outline, 
rounded in front, well defined by the axial furrow, convex in both 
directions. Cheeks very convex, sloping down steeply to the deep 
border furrow. Border wide anteriorly, narrowing toward the genal 
angle, convex, downrolled into doublure, showing a pair of small 
lateral spines somewhat anterior to the cephalic midlength. Border 
furrow becoming very shallow at the genal angle ; genal spine strong, 
curving inward, not greatly tapered, when complete probably equal- 
ing the cephalon in length. Posterior border furrow well impressed ; 
posterior border straight from axial furrow to near base of genal 
spine, where it forms an obtuse tooth set off by a narrow, short 
furrow. Surface of test sparsely punctate, more distinctly in larger 
individuals. The largest (holotype) complete cephalon has a length 
of 8.3 mm and a width of 10.7 mm. However, a large cephalon in 
the collection, crushed by the slumping of the sediment in such 



28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

manner that the anterior portion was bent under the posterior part, 
but nevertheless recognizable, has a width of 30 mm excluding the 
genal spines. 

Pygidium 1.4 times wider than long. Axis well defined by the 
axial furrow, just touching the border furrow, not showing segmen- 
tation except for the articulating half -ring. Pleural regions convex. 
Anterior border with sharp geniculation at two-fifths the distance 
from axial furrow to lateral angle ; facet well developed. Lateral bor- 
der flat, defined by sharp change in slope, widening from anterior 
angle to midlength, then narrowing again, narrowest medially. Dou- 
blure somewhat wider than border, marked with terrace lines that fol- 
low the blunt serrations of the margin. Surface pitted like the cepha- 
lon. Length of largest pygidium 16 mm, width 22 mm. 

From the proportions of the various parts and the size of the 
largest cephalon, the presence of individuals about 50 mm long may 
be inferred. This may be the largest size for an Eodiscid ever 
reported. 

Occurrence. — Collection cs-4. North Chatham. 

Types.— Uoloty^: U.S.N.M. 146012. Paratypes; U.S.N.M. 
146013. 

OODISCUS Rasetti, new genus 

Description. — Cephalon tending to a subquadrate shape. Gla- 
bella with undifferentiated occipital ring ovate, occupying more than 
one-third of the cephalic width, strongly elevated, totally unfurrowed. 
Preglabellar field short (sag.) . Cheeks convex and downsloping. Bor- 
der furrow and border well defined all around the cephalon; lateral 
border may show one or two pairs of short spines ; in one species 
the frontal border bears a pair of tubercles. Posterior border with 
sharp geniculation and short spine at one-third the distance from axial 
furrow to rounded genal angle. 

Pygidium with tapered, unfurrowed axis not reaching posterior 
border. Border furrow and border as in cephalon; border lacking 
marginal spines. 

Type species. — Oodiscus subgranulatus Rasetti, new species. 

Occurrence. — Late Lower Cambrian of New York. 

Discussion. — The type species and others included in the genus 
have a rather simple structure which, nevertheless, distinguishes them 
clearly from previously known Eodiscidae such as Serrodiscus and 
Calodiscus. The glabella is wider relative to the entire cephalon than 
in these genera, and has an oval shape ; the undifferentiated occipital 
ring extends farther back than usual relative to the cheeks. The 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 



29 



geniculation of the posterior cephalic border, marked by a short 
spine, is much closer to the axial furrow than in previously known 
Eodiscidae. The pygidium, compared with Serrodiscus, has a shorter 
axis and lacks marginal spines. 

OODISCUS SUBGRANULATUS Rasetti, new species 

Plate 1, figure 4; plate 10, figures 1-10 

Available material. — Several cephala and pygidia more or less 
completely preserved. 

Description. — Cephalon somewhat widening forward from the 
genal angle, widest slightly in front of the midlength, well rounded 
anterolaterally, with almost straight portion of frontal outline. Gla- 
bella ovate, somewhat pointed in front, not reaching anterior border 
furrow, strongly elevated above the cheeks, sloping down from pos- 
terior to anterior end. Occipital furrow barely indicated by a pair 
of exceedingly shallow lateral depressions, very short (sag.), rounded. 
Cheeks strongly downsloping posteriorly, gradually flatter toward 
the anterior part ; no preglabellar depression. Border somewhat con- 
vex, well defined by border furrow, of even width around the anterior 
half of the cephalon, narrowing toward the genal angle, bearing two 
pairs of small, short marginal spines, one pair at the level of the 
cephalic midlength, a second pair halfway between the first and the 
genal angle. Lateral border furrow continued into posterior border 
furrow ; the latter directed outward and forward from axial furrow, 
curving outward distally, hence as a whole convex forward. Posterior 
border horizontal in inner third, then sharply downturned to reach 
the much lower level of the genal angle ; a small, upright spine at the 
geniculation, usually broken in extracting the specimen from the 
matrix. Genal angle narrowly rounded. 

Pygidium assigned to the species on the basis of similar shape 
and identical ornamentation, less convex than cephalon, about paral- 
lel-sided in anterior half, well rounded posteriorly. Axis widest at 
the base, not greatly elevated, tapered, un furrowed, occupying two- 
thirds of pygidial length. Anterior border straight, transverse from 
axial furrow to geniculation which is relatively close to axial furrow, 
distally slanted backward and with marked facet, paralleled by well- 
impressed anterior border furrow; remainder of border furrow and 
border as in cephalon; border lacking spines. Doublure reflexed in 
usual manner. 

Cheeks and pleural regions of the pygidium covered with small, 
sparse granules, of density variable in different individuals. The py- 



30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

gidia usually show one or two small median nodes on the anterior 
portion of the axis when the preservation is perfect. Length of largest 
cephalon 8.0 mm, width 8.8 mm. Length of largest pygidium 8.0 mm, 
width 8.0 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Types.— UolotyT^e: U.S.N.M. 146014. Paratypes: U.S.N.M. 
146015. 

OODISCUS BINODOSUS Rasetti, new species 

Plate 10, figures 16-18 

Available material. — Three cephala, of which only the holotype 
well preserved. Pygidia may be present, but cannot be identified 
among similar species of the genus. 

Description. — The cephalon is so similar to the type species that 
only the differences are listed. Glabella narrower and of more 
uniform elevation throughout its length, slightly longer, almost reach- 
ing the anterior border furrow. Border furrow and border some- 
what wider; anterior border bearing a pair of low, closely spaced 
tubercles that somewhat encroach upon the border furrow. Lateral 
border spines seemingly absent. Posterior border furrow straighter 
than in type species ; geniculation with small, upright spine. Surface 
of test smooth. Length of largest cephalon 6.5 mm. 

Occurrence. — Collection cs-4. North Chatham. 

Types.— Holotype: U.S.N.M. 146016. Paratypes: U.S.N.M. 
146017. 

OODISCUS LONGIFRONS Rasetti, new species 
Plate 10, figures 20, 21 

Available material. — A few cephala, none of which well preserved. 

Description. — Glabella of the same shape as in the type species, 
but longer, just reaching the anterior border furrow. Border furrow 
and border somewhat wider than in 0. subgranulatus; anterior border 
furrow showing a slight median inbend where it merges with the axial 
furrow; anterior border lacking nodes. Lateral border seemingly 
lacking spines, but none of the specimens are well preserved enough 
for this feature to be established with certainty. Geniculation of 
posterior border as in the two preceding species. In the holotype a 
pair of low, inconspicuous nodes is present on the downsloping 
portion of the posterior border between the geniculation and the 
genal angle, but this feature is indistinct in the paratypes. 

Occurrence. — Collection cs-4, North Chatham. 



NO. 9 NEW CAMBRIAN TRILOBITE PAUNULE — RASETTI 3I 

Types.— Uolotype: U.S.N.M. 146018. Paratypes: U.S.N.M. 
146019. 

OODISCUS, species undetermined No. 1 
Plate 11, figures 8-11 

Available material. — A few pygidia, of which two well preserved. 

Description. — Axis very prominent, un furrowed, slightly tapered, 
rounded posteriorly, not reaching the posterior border furrow. Pleu- 
ral regions convex and downsloping. Anterior border with genicu- 
lation relatively close to axial furrow and well-developed facet. Bor- 
der furrow wide, relatively shallow. Border flat, rather wide. Anterior 
angles of pygidium sharp. Doublure sharply reflexed, apparently 
with smooth margin. Length of largest specimen 8.2 mm, width 8.0 
mm. Surface of test smooth. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — This pygidium seems definitely to belong to Oodiscus, 
but it cannot be determined to which, if any, of the species based 
on the cephala it should be referred. Compared with the pygidium 
assigned to O. subgranulatus, it has a more prominent and longer 
axis. 

Disposition of material. — Figured specimens: U.S.N.M. 146020. 

OODISCUS, species undetermined No. 2 
Plate 11, figures 12, 13 

Available material. — A few pygidia. 

Description. — The pygidia in question do not appreciably differ 
in shape from those referred to O. subgranulatus, but lack the 
ornamentation of the cephala and pygidia of that species. Hence they 
may belong to a similar species, possibly 0. binodosus, that has a 
smooth cephalon. The assignment cannot be decided on the basis 
of the available evidence. 

Occurrence. — Collection cs-4, North Chatham. 

Disposition of material. — Figured specimens: U.S.N.M. 146021. 

Genus SERRODISCUS R. and E. Richter, 1941 
Type s^toits.—Eodiscus (Serrodiscu^) serratus R. and E. Richter. 

SERRODISCUS SUBCLAVATUS Rasetti, new species 
Plate 2, figure 1 ; plate 8, figures 10-19 
Available material— 'Numerous cephala and pygidia, including one 
cephalon with two thoracic segments attached. 



32 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Description. — Glabella with totally undifferentiated occipital ring 
defined by an exceptionally deep axial furrow, strongly convex trans- 
versely, unfurrowed, slightly narrowed from the occipital ring to the 
level of the posterior third, then slightly expanded forward, sharply 
narrowed and somewhat pointed in front, reaching the border fur- 
row. Cheeks very convex, posteriorly overhanging the border furrow, 
anteriorly separated by a narrow (tr.) preglabellar depression formed 
by the merging of the axial and border furrows. Border strongly 
convex, fairly wide, defined by a deep border furrow, contributing 
to the great relief of the cephalon. Tubercles on the border moder- 
ately elevated, generally seven or eight pairs present, about equally 
spaced. Posterior border furrow deep ; posterior border straight from 
axial furrow to sharp geniculation which is located not far from genal 
angle and is marked by a short spine. A characteristic feature of 
the border is a very narrow, shallow furrow parallel and close to the 
posterior margin that sets off a slight, obtuse expansion. The artic- 
ulated specimen shows that this feature corresponds to a similar 
one at the fulcrum of the anterior margin of the first thoracic seg- 
ment. However, the geniculation of the posterior cephalic border 
with its spine is situated farther outward. In front of the spine the 
cephalic border curves downward and forward to join the lateral 
border which as usual is at a lower level ; no sharp angle is formed, 
and the cephalic border is narrowest at this point. 

First thoracic segment with anterior margin distally from the above- 
mentioned fulcrum sharply bent backward to form a well-developed 
facet. Axis not preserved. Second segment showing a very convex 
axial lobe and deep axial furrow. Pleural articulation between first 
and second segment with features similar to those present between 
the cephalon and the first segment, but more distally located. Anterior 
margin beyond the geniculation bent downward but not backward. 
Posterior margin with geniculation situated still farther outward, dis- 
tally strongly bent forward and downward. Third thoracic segment 
not preserved. 

Pygidium with strong relief. Axis prominent, defined by deep axial 
furrow, convex in both directions, totally unfurrowed, not quite 
reaching the border furrow. Articulating half -ring expanded medially 
by a rearward median inbend of the articulating furrow. Axis bearing 
a strong median spine at about four-fifths of its length ; this spine 
is broken off in all pygidia except one specimen where it could be 
partly restored. Pleural regions strongly convex, near posterior end 
forming a narrow, convex band between the end of the axis and the 
border furrow. Border furrow deep ; border narrower than in cepha- 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 33 

Ion, extended downward into a series of short spines somewhat 
visible in dorsal view by producing a wavy outline; seven or eight 
pairs of such spines are usually present. A. R, Palmer (private com- 
munication) suggested to the writer that such spines may fit the 
reverse side of the tubercles of the cephalic border when the animal 
is enrolled. The structures in the present species may support this 
interpretation since the tubercles and spines are in about equal num- 
bers and similarly spaced. 

Surface of cephalon and pygidium densely covered with fine gran- 
ules. Length of largest cephalon 11 mm, width 11 mm. The entire 
pygidia recovered are somewhat smaller. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — Even though the close affinity to typical species of 
Serrodiscus can hardly be doubted, this form presents numerous 
differences from all those previously described. The most conspicu- 
ous features are the great convexity of the cephalon, depth of the 
axial furrows, unusual length and somewhat clavate shape of the 
glabella, and un furrowed pygidial axis bearing a spine. The most 
similar form is an undescribed species from the Purley Shales of 
England (Rushton, private communication). 

Types.— Uo\oty^e: U.S.N.M. 146022. Paratypes: U.S.N.M. 
146023. 

SERRODISCUS SPINULOSUS Rasetti, new species 

Plate 7, figures 7-11 

Available material. — A few cephala and one pygidium. 

Description. — Glabella with undifferentiated occipital ring widest 
at posterior end, narrowed forward for a short distance, then parallel- 
sided, strongly tapered in frontal portion and rather pointed medi- 
ally, un furrowed. Glabella of moderate convexity, anteriorly reaching 
the border on account of a sharp median inbend of the border furrow 
which thus merges for a short distance with the axial furrow. Occipi- 
tal ring bearing a short spine. Cheeks slightly convex, downsloping. 
Border widest medially on account of the above-mentioned feature 
of the border furrow, narrowing toward the genal angle, bearing 
several pairs of very low, somewhat indistinct tubercles. Posterior 
border wide (exsag.), extended into short, sharply pointed genal 
spine. No geniculation features on posterior cephalic margin between 
axial furrow and genal spine. Cephalic border narrowest at postero- 
lateral angles in front of genal spine. 

Pygidium referred to the species with long, totally unfurrowed 
axis almost reaching posterior border. Articulating half-ring expanded 



34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

medially as in preceding species. Pleural lobes of moderate con- 
vexity; border furrow well impressed. Border fairly wide, convex, 
extended ventrally into a series of short spines, producing in dorsal 
view a waviness of the margin. Seemingly there was a spine on the 
posterior part of the axis. 

Surface of test of cephalon and pygidium perfectly smooth. Length 
of largest cephalon 5.6 mm, width 5.2 mm. Length of pygidium 
4.7 mm, width 5.6 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — This form is fully typical of Serrodiscus in all respects 
excepting one unusual feature, the inbend of the anterior border 
furrow causing it to merge with the axial furrow. Other distinguish- 
ing features are the occipital and genal spines, the shape of the 
glabella, and the unfurrowed pygidial axis. 

Ty/>^.j.— Holotype: U.S.N.M. 146026. Paratypes: U.S.N.M. 
146027. 

SERRODISCUS LATUS Rasetti, new species 
Plate 10, figures 12-15 

Available material. — Three cephala, of which one excellently pre- 
served. 

Description. — Glabella with totally undifferentiated occipital ring 
slightly tapered, straight-sided, well defined by deep axial furrows, 
somewhat pointed in front, almost reaching the border, unfurrowed. 
Cheeks convex, rising somewhat above the axial furrows, steeply 
sloping to border furrow at the sides. Border furrow deep all around 
the cheeks, medially almost meeting the axial furrow. Border some- 
what convex and on the average horizontal, widest medially and but 
slightly tapering to the genal angle, bearing a few pairs of low 
tubercles. Posterior border furrow and border about as wide as 
lateral border ; posterior cephalic margin straight and transverse from 
axial furrow to geniculation, then turning downward and forward to 
the genal angle which bears a minute spine. Surface of test smooth. 
Length of largest cephalon 5.0 mm, width 6.2 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — The cephalic features agree with Serrodiscus, but in 
the absence of a pygidium it is questionable whether the species 
should not rather be referred to Calodiscus, or possibly Cohholdites. 
The cephalon differs markedly from C. speciosus and other described 
species in the general outline, regularly curved in front rather than 
pointed, deep axial furrows, and great convexity of the cheeks. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 35 

Types.— Uolotype: U.S.N.M. 146024. Paratypes: U.S.N.M. 
146025. 



SERRODISCUS, species tmdetermined 
Plate 10, figure 19 

Available material. — One incomplete cephalon. 

Description. — Glabella approximately parallel-sided, rounded in 
front, not greatly elevated, occupying with the occipital ring two- 
thirds of the cephalic length. One pair of glabellar furrows, very 
broad and shallow, is impressed all across the glabella. Occipital 
furrow visible as a pair of shallow, broad depressions at the sides. 
Occipital ring somewhat elevated medially, rounded, lacking node or 
spine. Cheeks moderately convex, preserved only in their anterior 
part. Preglabellar field flat, fairly extended. Border furrow shallow ; 
border wide, flat, apparently lacking tubercles. Anterior outline of 
cephalon unusually pointed medially. Surface of test smooth. Length 
of cephalon 5.6 mm. 

Occurrence. — Collection cs-4. North Chatham. 

Discussion. — This cephalon cannot be referred to any described 
species, but is too incomplete to warrant a name. The proportions 
of the various parts are somewhat like S. speciosus, but the glabella 
is shorter and less tapered, the entire cephalon more nearly triangular, 
the border wider, and the occipital ring is raised at the posterior 
margin. 

Disposition of material. — Figured specimen: U.S.N.M. 146028. 

STIGMADISCUS Rasetti, new genus 

Description. — Cephalon semielliptical, lacking lateral spines. Gla- 
bella approximately parallel-sided, rather pointed in front, rising 
above the downsloping cheeks, elevated in front of the occipital 
furrow. Glabellar furrows impressed as two pairs of deep lateral pits 
close to the axial furrow. Occipital furrow similarly deepened into a 
pair of pits. Occipital ring well differentiated, bearing a node or 
spine. Cephalic border narrow, defined by shallow border furrow. 
Posterior border bearing a pair of short spines, located either about 
halfway between the axial furrow and the genal angle, or close to 
the genal angle. Surface of test smooth. Other parts of exoskeleton 
unknown. 

Type species — Stigmadiscus stenometopus Rasetti, new species. 

Occurrence. — Late Lower Cambrian of New York. 



36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Discussion. — The genus is proposed for two species whose most 
distinctive character is the pit-Hke structure of the glabellar furrows, 
a feature so far never observed in the Eodiscidae. The type species 
shows marked affinity with Acidiscus, where the glabellar furrows 
are relatively short and deep and the occipital furrow has a similar 
structure. The other described species, Stigmadiscus gibbosus, shows 
some resemblance to an Agnostid cephalon in the proportions of the 
various parts. Whether this similarity is purely accidental, or we 
are dealing with an Eodiscid evolving into an Agnostid, cannot be 
decided at present, especially in the absence of thorax and pygidium. 

STIGMADISCUS STENOMETOPUS Rasetti, new species 
Plate 3, figure 5; plate 12, figures 1-7 

Available material. — Several cephala, of which two fairly complete. 

Description. — Cephalon of low convexity. Glabella relatively nar- 
row, slightly tapered from the occipital ring to the anterior pair of 
lateral furrows, very slightly expanded in front, somewhat pointed, 
occupying about two-thirds of cephalic length. Axial furrow deep 
posteriorly, shallower anteriorly. Longitudinal profile of glabella ris- 
ing gradually from front to back, where it reaches its highest eleva- 
tion in the form of a rounded ridge that drops abruptly to the level 
of the occipital furrow. In some of the specimens there is an indica- 
tion of a small, broken spine at this highest point, whereas other 
individuals where the test at this place is well preserved do not show 
a spine. Occipital ring moderately long (sag.), bearing a short spine. 
Cheeks slightly convex, downsloping ; lateral border narrow, of even 
width, defined by a border furrow that becomes progressively shal- 
lower and broader forward. Posterior border furrow deeper than 
lateral border furrow, almost straight, slightly convex forward, join- 
ing the lateral border furrow near the genal angle which is fairly 
sharp but seemingly not extended into a spine. Posterior cephalic 
border wider and better defined than lateral border, extended into 
a short, horizontal spine located somewhat closer to the axial furrow 
than to the genal angle. The portion of the posterior border beyond 
the spine is somewhat slanted forward. Surface of test smooth. 
Length of holotype cephalon 9.0 mm, width 9.9 mm. The largest 
glabella indicates a cephalon 12.5 mm in length. 

Occurrence. — Collection cs-4. North Chatham. 

Types.— Holotype : U.S.N.M. 146029. Paratypes: U.S.N.M. 
146030. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 37 

STIGMADISCUS GIBBOSUS Rasetti, new species 
Plate 3, figure 4; plate 12, figures 8-13 

Available material. — About half a dozen cephala, mostly in medi- 
ocre state of preservation. 

Description. — Cephalon equally wide and long, moderately convex, 
semielliptical. Glabella narrowed forward in its posteriormost portion 
from the wider occipital ring, almost parallel-sided in its medial 
part, rapidly tapered and somewhat pointed in its anterior fourth. 
Two posteriormost pairs of lateral furrows deep, short, pit-like ; no 
indication of other pairs. A broad transglabellar depression is located 
somewhat in advance of the anterior pair of lateral furrows. The 
glabella rises in bulbous shape behind this depression and drops 
sharply to the occipital furrow. The occipital furrow is impressed 
at the sides in form of a pair of small pits, shallower than the glabellar 
furrows, not connecting with the axial furrow, and is extended medi- 
ally into a shallower, still well-impressed portion. Occipital ring 
short, bearing a small node. Cheeks rather flat in front of the 
glabella, not forming a definite depression. Border furrow shallow 
and poorly defined anteriorly, gradually becoming narrower and 
deeper toward the genal angle. Border poorly defined, somewhat 
convex, reduced in width toward the genal angle. Posterior border 
furrow directed outward and forward, forming a considerable angle 
with the posterior cephalic margin and hence producing an elongate, 
triangular posterior border which extends into a short spine located 
very close to the genal angle. The posterior cephalic margin slopes 
down somewhat in connecting the posterior with the lateral border. 
Surface of test smooth. Length and width of largest cephalon 6.8 mm. 

Occurrence. — Collection cs-4. North Chatham, 

Discussion. — This form seems closely related to the type species, 
with which it shares the pit-like glabellar furrows and the elevation 
of the posterior portion of the glabella. In other respects there are 
conspicuous differences, which made the writer hesitate whether the 
two should be referred to the same genus. In Stigmadiscus gibbosus 
the glabella is larger in proportion to the whole cephalon, the occipi- 
tal ring is shorter and lacks a spine, the glabellar boss is defined both 
in front and back, instead of rising gradually in the frontal part as 
in 5*. stenometopus. Perhaps the most significant difference of all is 
in the position of the spine on the posterior cephalic border, in the 
present species close to the genal angle so that it may be called a 
"genal" spine. These various differences give to Stigmadiscus gib- 



38 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

bosus a somewhat Agnostid-like aspect that is completely lacking in 
the type species. 

73,^^j._Holotype : U.S.N.M. 146031. Paratypes: U.S.N.M. 
146032. 

Undetermined pygidia 

Several pygidia, undoubtedly belonging to the family Eodiscidae 
and possibly to some of the named species, are described hereafter. 
Possible assignments are suggested in some cases. 

"Undetermined pygidium No. 1 
Plate 11, figures 17-21 

Available material. — Three examples. 

Description. — Pygidium of strong convexity especially in the trans- 
verse direction. Axis strongly prominent, moderately tapered, reach- 
ing the posterior border furrow, showing eight rings plus a terminal 
section defined by exceedingly shallow furrows ; articulating half-ring 
short (sag.), articulating furrow straight. Pleural regions convex, 
laterally sloping down vertically to border furrow. Border very nar- 
row, ventrally extended into 8 to 10 pairs of short, somewhat back- 
ward-directed spines. Outline of border arched in posterior view. 
Surface of test with very shallow puncta, not equally distinct in the 
available specimens. Length of largest pygidium 4.4 mm, width 4,4 
mm. 

Occurrence. — Collection cs-4. North Chatham. 

Discussion. — The narrowness of the border and the shallowly punc- 
tate surface suggest the possibility that this is the pygidium of 
Leptochilodiscus punctulatus.^ 

Disposition of material. — Figured specimens: U.S.N.M. 146033. 

Undetermined pygidium No. 2 
Plate 11, figures 14-16 

Available material. — Three more or less complete examples. 

Description. — Pygidium with considerable relief. Axis prominent, 
relatively wide, tapered to a rather sharp point, almost reaching the 
posterior border furrow, composed of six rings plus a terminal sec- 

^ Copious material, collected from another locality after this paper was written, 
unquestionably supports this assignment. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 39 

tion. Ring furrows with peculiar structure, deepening to pair of pits 
at the sides some distance from the axial furrow ; the medial portion 
of the ring furrow narrower and shallower, concave toward the front. 
The axial rings bore spines of decreasing length, broken off in the 
available specimens. Pleural regions un furrowed, downsloping ; bor- 
der furrow narrow but deep ; border narrow, but expanded into four 
pairs of wide, short, somewhat blunt spines about evenly spaced. 
The spines are directed outward, not downward as in many species 
of Serrodiscus. Surface of test smooth. Length of largest pygidium 
5.7 mm. 

Occurrence. — Collection cs-4. North Chatham. 

Discussion. — It is questionable whether this peculiar pygidium 
belongs to any of the cephala known from the locality. 

Disposition of material. — Figured specimens: U.S.N.M. 146034. 

Undetermined pygidium No. 3 
Plate 10, figure 11 

Available material. — A single, well-preserved example. 

Description. — Pygidium of low convexity, almost semicircular. 
Axis defined anteriorly by very shallow axial furrows, the remainder 
undifferentiated from the pleural regions. Articulating half -ring and 
furrow well defined. Anterior outline straight in dorsal view, with 
geniculation about halfway between axial furrow and anterior angle, 
with border bent downward but not appreciably backward. Border 
furrow well impressed, border flat, of almost even width throughout. 
Doublure vertical, narrow, with smooth margin. Surface of test 
smooth. Length of pygidium 7.0 mm, width 10.3 mm. 

Occurrence. — Collection cs-4. North Chatham. 

Discussion. — In the general shape this pygidium recalls Litomefo- 
pus longispinus, but differs markedly in the lesser convexity and 
especially in the almost complete obsolescence of the axial furrows. 
It should presumably be associated with a cephalon with poorly 
differentiated glabella, but no such form is present in the collection. 

Disposition of material. — Figured specimen: U.S.N.M. 146035. 

Family OLENELLIDAE Vogdes, 1893 

Olenellids are relatively common in the faunule, but owing to the 
thinness of their test, they are usually much more fragmentary than 
the Eodiscids. Cephala of three different species have been identified. 



40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

These are all represented by small, evidently immature specimens. 
No fragments of either cephala or thoracic segments seem to indicate 
the presence of animals much larger than the cephala illustrated. 

Genus PAEDEUMIAS Walcott, 1910 
Type species. — Paedeumias transitans Walcott. 

PAEDEUMIAS, species undetermined No. 1 

Plate 12, figures 23-25 

Available material. — Fairly numerous, complete cephala from 1.5 
to 4 mm in length. 

Description. — Glabella well-defined, narrow, parallel-sided, with 
frontal lobe not wider than the posterior lobes. Frontal lobe ovate, 
defined by a furrow deep at the sides, shallow but distinct medially. 
Next three lobes of about equal length, separated by deep, trans- 
verse furrows at the sides, not extended medially. Occipital furrow 
similar to the preceding glabellar furrows; occipital ring apparently 
extended into a short spine, not well preserved in any of the cephala. 
Palpebral lobes separated by a shallow depression from frontal gla- 
bellar lobe, with curvature increasing backward, almost reaching the 
posterior cephalic margin. There is a fairly wide, well-defined space 
between the glabella and the palpebral lobe. Border wide, convex, 
of about the same width frontally and laterally. Distance from ante- 
rior end of glabella to anterior border furrow almost equal to length 
of frontal glabellar lobe. A median ridge connecting the front end 
of the glabella with the border furrow is visible at least in the larger 
specimens. From the posterior end of the palpebral lobe a narrow 
outward-directed ridge reaches the posterior cephalic margin at the 
base of a moderately long intergenal spine. Beyond this spine, the 
posterior margin turns slightly forward to the base of the genal spine, 
which is less conspicuous than the intergenal spine. 

The preceding description was based on cephala about 4 mm in 
length. In a fairly well-preserved cephalon 1.5 mm in length illus- 
trated herein, the intergenal spines are very close to the genal angle ; 
in addition, there is a pair of small procranidial spines. These changes 
in the relative size and position of the spines, as far as can be ascer- 
tained from the meager material available, seem to parallel those 
observed by Palmer (1957) in the ontogeny of Olenellus gilberti. 

Occurrence. — Collection cs-4. North Chatham. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 41 

Discussimi. — The reference to the genus is chiefly suggested by 
the considerable length of the preglabellar field and the presence of 
a preglabellar ridge ; however, these may be juvenile features. The 
present form is almost identical with an immature cephalon attributed 
to Paedeumias from a conglomerate boulder near Levis, Quebec, 
figured by the writer (Rasetti, 1948, pi. 2, fig. 5). If this cephalon 
is conspecific with the larger one from the same locality (Rasetti, 
1948, pi. 2, fig. 6), the reference to Paedeumias seems well founded. 
Comparison with immature cephala of Elliptocephala asaphoides 
shows that the present species differs in several respects. 

Disposition of material. — Figured specimens: U.S.N.M. 146036. 

PAEDEUMIAS?, species undetermined No. 2 
Plate 12, figures 19, 20 

Available material. — A few, incomplete cephala. 

Description. — Glabella flat, hardly elevated above the cheeks, 
defined by a shallow axial furrow only in the portion corresponding 
to the posterior lobe ; the two preceding lobes extend, undifferentiated 
from the cheek, as far as the palpebral lobe. Glabella tapered, with 
frontal lobe considerably narrower than the posterior lobe and the 
occipital ring. Three pairs of glabellar furrows increasing in depth 
rearward, fairly well impressed at the sides, fading out medially, 
oblique and approximately parallel to each other. Occipital furrow 
of identical character ; occipital ring as long as the last glabellar 
lobe, bearing a node. Palpebral lobes broad, scarcely elevated, pos- 
teriorly reaching the level of the midlength of the occipital ring. A 
narrow rim, set off by a narrow furrow, encircles the palpebral lobe. 
All the cephala are broken at the outer edge of this rim, i.e., at the 
upper boundary of the visual surface of the eye, where the facial 
suture is located in opisthoparian trilobites ; the remainder of the 
pleural portions of the cephalon is completely missing. The area 
comprised between the glabella and the palpebral lobe is very narrow, 
and defined only posteriorly as previously indicated. Length of gla- 
bella plus occipital ring 5-6 mm. 

Occurrence. — Collection cs-4. North Chatham. 

Discussion. — This form has features unusual among the Olenellids 
of the late Lower Cambrian, especially the tapered glabella and the 
well-defined narrow rim around the palpebral lobe. It cannot be 
identified with any described species known to the writer. 

Disposition of material. — Figured specimens: U.S.N.M. 146037. 



42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Genus OLENELLUS Billings, 1861 
T)^e species. — Olenus thompsoni Hall. 

OLENELLUS, species undetermined 
Plate 12, figures 21, 22 

Available material. — A few, incomplete cephala. 

Description. — Glabella well defined by a deep axial furrow, on 
the average somewhat expanded forward. Frontal lobe large ; second 
lobe short and wide, set off by narrow, fairly deep lateral furrows 
at the sides both from the frontal lobe and the third lobe ; both pairs 
of furrows become very shallow medially. The second lobe expands 
laterally to touch the palpebral lobe, from which it is separated by an 
oblique furrow, extension of the first pair of glabellar furrows. Third 
and fourth glabellar lobes narrower, bounded by the axial furrow 
laterally, far from reaching the palpebral lobe; third pair of lateral 
furrows and occipital furrow similar to second pair of furrows. There 
was a node, broken off in the available specimens, across the occipi- 
tal furrow, rather than on the occipital ring as usual. Palpebral lobes 
wide, long, set off by a very shallow furrow from the frontal glabellar 
lobe, showing a poorly defined rim, set off by an exceedingly shallow 
furrow, representing about one-third of the width of the palpebral 
lobe. Other cephalic parts not preserved. Length of glabella plus 
occipital ring 4-5 mm. 

Occurrence. — Collection cs-4. North Chatham. 

Discussion. — The features of this species, as far as can be observed 
on the incomplete cephala, agree with Olenellus, but reference to 
other genera of the family cannot be excluded. The shape of glabella 
and palpebral lobe shows a marked resemblance to Holmia kjerulfi 
(Linnarsson). 

Disposition of material. — Figured specimens: U.S.N.M. 146038. 

Family DORYPYGIDAE Kobayashi, 1935 
Genus KOOTENIA Walcott, 1889 
Type species. — Bathyuriscus (Koo tenia) dawsoni Walcott. 

KOOTENIA, species undetermined 
Plate 12, figures 14, 15 

Available material. — A single, incomplete pygidium. 

Description. — Pygidium of relatively low convexity. Axis wide, 
moderately tapered, straight-sided, composed of six well-defined rings 
plus a terminal section, reaching the posterior border furrow. All 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 43 

the axial rings except the last have a median node. Pleural regions in 
proximal portion not downsloping at all, convex and downsloping 
only in marginal portion. Five pairs of pleural furrows very broad 
and moderately deep ; narrow interpleural furrows well defined espe- 
cially in the proximal portion. Border furrow broad and poorly 
defined ; border flat, extended into several pairs of spines of about 
equal size, evenly spaced, and directed perpendicularly to the margin. 
All spines are broken and their length cannot be ascertained; the 
bases of five pairs of spines are visible, but there must have been 
another pair on the anterior, unpreserved portion of the border. The 
distance between the spines of the sixth pair is much greater than the 
distance between successive pairs. 

Surface of test with ornamentation that consists of shallow puncta 
on the axial rings and becomes rather of reticulate type on the pleural 
regions. Length of pygidium 6.0 mm, width 10 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — This pygidium is referred to Kootenia which it 
resembles more than any other described genus, but its unusual fea- 
tures might suggest a new genus if the cephalic parts were known. 
Compared to the described forms of Kootenia, the axial rings are 
proportionately much wider and shorter, the pleural regions are flat 
rather than convex in their proximal portion, and the interpleural 
furrows are unusually developed. In particular, there is little resem- 
blance to the species of Kootenia or Fordaspis described from the 
Lower Cambrian of the Taconic area (Lochman, 1956). 

Disposition of material. — Figured specimen: U.S.N.M. 146039. 

Genus BONNIA Walcott, 1916 

Type species. — Bathyurus parvulus Billings. 

Several species of Bonnia seem to be represented by cranidia, asso- 
ciated with one form of pygidium definitely referable to the genus. 
It cannot be determined whether all the cranidia belong to Bonnia 
rather than to Kootenia, since the two are not always generically 
distinguishable in the absence of the pygidium. For these reasons 
each cranidium is described as an undetermined species of Bonnia 
and the pygidium is not referred to any of the cranidia. 

BONNIA, species undetermined No. 1 
Plate 11, figures 23-25 

Represented by several examples, mostly too immature for spe- 
cific identification. Entire cranidium proportionately wide and short. 



44 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I48 

Glabella slightly expanded forward, with traces of lateral furrows. 
Occipital furrow deep laterally, shallow medially; occipital ring but 
partially preserved, Fixigenae convex and downsloping, about half 
the glabellar width. Ocular ridges low and broad, paralleling the 
border furrow. Border not well preserved, seemingly very narrow 
at least in front of the glabella. Palpebral lobes shorter than average 
for the genus ; posterior area wider (tr.) than occipital ring. Surface 
of test with indistinct ornamentation. Length of largest cranidium 
3.5 mm. 

Occurrence. — Collection cs-4. North Chatham. 

Discussion. — This form cannot be identified with any of the 
species of Bonnia previously described, in particular with the nu- 
merous species illustrated by the writer from the conglomerates of 
Quebec (Rasetti, 1948). The chief characteristic is the breadth of 
the cranidium, the glabella and the fixigenae. 

Disposition of material. — Figured specimens: U.S.N.M, 146040. 

BONNIA, species undetermined No. 2 
Plate 11, figure 22 

Represented by an immature example. Cranidium of average shape 
for the genus. Glabella but slightly expanded, of average convexity, 
un furrowed. Occipital furrow narrow but well impressed ; occipital 
ring incomplete, possibly spinose. Fixigenae, palpebral lobes, and 
anterior border of average form. Length of cranidium 2.7 mm. Sur- 
face of test smooth. 

Occurrence. — Collection cs-4. North Chatham. 

Discussion. — In the general proportions and lack of ornament 
this form might be compared with Bonnia similis Rasetti. As far as 
can be ascertained from one small, somewhat imperfect cranidium, 
it seems to differ in the more posterior position of the palpebral 
lobes. 

Disposition of material. — Figured specimen: U.S.N.M. 146041. 

BONNIA, species undetermined No. 3 
Plate 12, figure 16 

Possibly represented by a few, incomplete examples. The descrip- 
tion is based on the best specimen illustrated herein. Glabella of 
average convexity, slightly expanded in posterior half, slightly tapered 
anteriorly, with but traces of lateral furrows. Occipital furrow wide 
and deep throughout; occipital ring long (sag.), extended into a 
short, somewhat blunt spine. Fixigenae relatively narrow; anterior 
border narrow in front of the glabella, wider laterally. Posterior area 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 45 

not preserved. Test with shallow puncta, close together so that the 
ornamentation, which is not very conspicuous, might be described 
as intermediate between punctate and granulate; anterior border 
with irregular raised lines. Length of cranidium 5.5 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — This form might be compared with Bonnia busa 
(Walcott) which, however, has visible glabellar furrows and stronger 
ornamentation. 

Disposition of material. — Figured specimen: U.S.N.M. 146042. 

BONNIA, species undetennined No. 4 
Plate 12, figure 18 

Represented by a single, incomplete, somewhat deformed example. 
Glabella seemingly more convex both transversely and longitudinally 
than in the preceding form, although this feature may have been 
accentuated by slight lateral compression. Glabella on the average 
parallel-sided, with exceedingly shallow lateral furrows. Occipital 
furrow deep and broad; occipital ring incomplete, seemingly 
triangular and presumably spinose. Fixigenae incompletely pre- 
served ; anterior border of average width, strongly slanted backward 
laterally. Surface of test finely granulate, the granules on the pos- 
terior part of the glabella showing a tendency to become arranged 
in irregular, transverse ridges. Length of cranidium 7.5 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — The proportionately short and wide, strongly con- 
vex, nonexpanding glabella seem to distinguish this form from de- 
scribed species. It is quite possible that, were the pygidium known, this 
form should be referred to Kootenia. The cranidium does not greatly 
differ from Kootenia troyensis Resser, as redescribed and figured by 
Lochman (1956), but no pygidia resembling that species were found 
in the collection. 

Disposition of material. — Figured specimen: U.S.N.M. 146043. 

BONNIA, undetennined pygidium 

Plate 12, figure 17 

Represented by a few examples, the only complete specimen being 
the one illustrated. Pygidium with relatively narrow, somewhat ta- 
pered axis showing three rings plus a terminal unsegmented section, 
reaching the border furrow. Pleural regions with four pairs of pleural 
furrows, counting the anterior border furrow, and but traces of one 
pair of interpleural furrows. Border furrow shallow, border flat. 



46 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

seemingly lacking the small spine at the anterolateral angle. Orna- 
mentation indistinct. Length of complete pygidium 2.8 mm, width 
4.6 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — This unmistakable pygidium of Bonnia presumably 
belongs to one of the cranidia described herein. It may be compared 
with the pygidium of Bonnia senecta (Billings) illustrated by the 
writer (Rasetti, 1948) which it resembles in the narrow axis and 
well-impressed pleural furrows. 

Disposition of material. — Figured specimen : U.S.N.M. 146044. 

FAMILY, GENUS, AND SPECIES UNDETERMINED 

Undetermined pygidium No. 4 

Plate 6, figures 20, 21 

Available material. — Several incomplete examples. 

Description. — Entire pygidium subtriangular, of moderate convex- 
ity. Axis well defined, somewhat tapered, straight-sided, almost 
reaching the posterior margin. Axial rings numerous, probably 13 
or 14, all well defined by ring furrows that, at least in the anterior 
portion of the axis, show a median backward inflection. At least the 
first few rings seem to have borne a node or spine. Pleural regions 
downsloping, with straight, narrow, somewhat backward-directed 
pleural furrows that, at least for the first 10 segments, correspond 
to the ring furrows on the axis. About 11 or 12 pleural furrows are 
visible ; there is no trace of interpleural furrows. All furrows end in 
a broad, poorly defined border furrow that sets off a narrow, some- 
what convex border. The anterior outline of the pleural lobes shows 
a sharp geniculation very close to the axial furrow ; past the genicula- 
tion the margin turns backward in a wide curve and finally assumes 
the straight backward and inward course that gives the pygidium a 
subtriangular shape. Surface of test smooth. The length of the 
largest pygidium, if complete, would be about 14 mm, the maximum 
width 12 mm. 

Occurrence. — Collection cs-4, North Chatham. 

Discussion. — This peculiar pygidium cannot be referred to any 
described genus of Cambrian trilobites, and not even a plausible 
family assignment is suggested. It is virtually certain that this is not 
the pygidium of an Olenellid or Ptychoparioid trilobite, and it seems 
unlikely that it belongs to one of the numerous Eodiscids present 
in the collection. 

Disposition of material. — Figured specimens: U.S.N.M. 146000. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 47 

REFERENCES 

Dale, T. N. 

1904. Geology of the Hudson Valley between the Hoosic and the Kinder- 
hook. U.S. Geol. Surv. Bull. 242, pp. 1-63. 
Fisher, Donald W. 

1962. Correlation of the Cambrian rocks in New York State. New York 
State Mus. Sci. Serv., Geol. Surv., Map and Chart Series : No. 2, 
Hutchinson, R. D. 

1962. Cambrian stratigraphy and trilobite faunas of southeastern Newfound- 
land. Geol. Surv. Canada, Bull. 88, pp. 1-156. 
LocHMAN, Christina. 

1956. Stratigraphy, paleontology, and paleogeography of the Elliptocephala 

asaphoides strata in Cambridge and Hoosick quadrangles. New 
York. Geol. Soc. Amer. Bull., vol. 67, pp. 1331-1396. 
LocHMAN, Christina, and Wilson, James L. 

1958. Cambrian biostratigraphy in North America. Journ. Paleontol., vol. 

32, pp. 312-350. 
Palmer, A, R. 

1955. Upper Cambrian Agnostidae of the Eureka District, Nevada. Journ. 
Paleontol., vol. 29, pp. 86-101. 

1957. Ontogenetic development of two olenellid trilobites. Journ. 

Paleontol., vol. 31, pp. 105-128. 

POKROVSKAVA, N. V. 

1959. Trilobite fauna and stratigraphy of the Cambrian deposits of Tuva (in 

Russian). Publ. Geol. Inst. Acad. Sci. Soviet Soc. Rep. (Moscow), 
No. 27, pp. 1-197. 
Rasetti, Franco. 

1945. Fossiliferous horizons in the "Sillery formation" near Levis, Quebec. 

Amer. Journ. Sci., vol. 243, pp. 305-319. 

1946. Cambrian and early Ordovician stratigraphy of the lower St. Law- 

rence valley. Geol. Soc. Amer. Bull., vol. 57, pp. 687-706. 
1948. Lower Cambrian trilobites from the conglomerates of Quebec (ex- 
clusive of the Ptychopariidea). Journ. Paleontol., vol. 22, pp. 1- 
24. 
1952. Revision of the North American trilobites of the family Eodiscidae. 
Journ. Paleontol., vol. 26, pp. 434-451. 
Raymond, P. E. 

1913. Quebec and vicinity. Geol. Surv. Canada, Guide Book No. 1, pt. 1, 
pp. 25-47. 
Theokritoff, George. 

1964. Taconic stratigraphy in northern Washington County, New York. 
Geol. Soc. Amer. Bull., vol. 75, pp. 171-190, map. 
Westergard, a. H. 

1946. Agnostidea of the Middle Cambrian of Sweden. Sveriges Geol. 
Unders., ser. C, No. 477, Arsbok 40, No. 1, pp. 1-140, 16 plates. 
Zen, E-An. 

1964. Taconic stratigraphic names : definitions and synonymies. U.S. Geol. 
Surv. Bull. 1174, pp. 1-95. 



48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

EXPLANATION OF PLATES 
GENERAL STATEMENT 

To avoid unnecessary repetition, locality and collection numbers 
are only indicated for the few illustrated specimens that are not 
part of the writer's collection cs-4 from the North Chatham locality. 
Three specimens (pi. 7, fig, 18; pi. 9, figs. 14-16; pi. 11, figs. 6, 7) 
are from U.S.G.S. collection 4216 at the same locality. One specimen 
(pi. 5, figs. 13, 14) was collected near Elgin Station, Quebec, 
Canada. 

All figured specimens show the outer surface of the test. 

Plate 1 

Page 

Fig. 1. Calodiscus reticulatus Rasetti, new species 24 

Dorsal and lateral views of cephalon, X3. 
Fig. 2. Acidiscus birdi Rasetti, new genus, new species 11 

Lateral and dorsal views of cephalon ; pygidium ; X2. 
Fig. 3. Bathydiscus dolichometopus Rasetti. new genus, new species . . 17 

Dorsal, frontal, and lateral views of cephalon; posterior, lateral, and 
dorsal views of pygdium ; X4. 
Fig. 4. Oodiscus subgranulatus Rasetti, new genus, new species ... 29 

Dorsal, frontal, and lateral views of cephalon ; pygidium ; X4. 
Fig. 5. Leptochilodiscus ptmctulattts Rasetti, new genus, new species . . 26 

Cephalon, X6. 

Plate 2 

Fig. 1. Serrodiscus suhclavatus Rasetti, new species 31 

Dorsal and oblique anterior views of cephalon; oblique posterior and 
dorsal views of pygidium ; X4. 

Fig. 2. Analox bipunctata Rasetti, new genus, new species 15 

Dorsal and lateral views of pygidium ; lateral and dorsal views of 
cephalon ; X6. 
Fig. 3. Acimetopus bilobatus Rasetti, new genus, new species .... 14 
Dorsal and lateral views of pygidium; oblique and dorsal views of 
cephalon; X4. 

Plate 3 

Fig. 1. Bolboparia superba Rasetti, new genus, new species 19 

Dorsal and oblique views of cephalon, X4. 
Fig. 2. Bolboparia elongata Rasetti, new species 20 

Pygidium, XS. 
Fig. 3. Litometopus longispinus Rasetti, new genus, new species ... 27 

Dorsal and lateral views of cephalon ; pygidium ; X2. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 49 

Page 

Fig. 4. Stigmadiscus gibbosus Rasetti, new species 37 

Dorsal and lateral views of cephalon, XS. 
Fig. 5. Stigmadiscus stenotnetopiis Rasetti, new genus, new species . . 36 

Dorsal and lateral views of cephalon, X3. 

Plate 4 

Figs. 1-14. Acimetopus bilobatus Rasetti, new genus, new species ... 14 
1-4, Dorsal, oblique, anterior, and lateral views of cephalon, X5; 
U.S.N.M. 145991, holotype. 5, Cephalon, X6. 6, Cephalon, X4. 
7, Cephalon, XS. 8-10, Dorsal, lateral, and posterior views of py- 
gidium, X5. 11-13, Dorsal, lateral, and posterior views of pygidium, 
X5. 14, Lateral view of pygidium preserving part of axial spine, X5. 
U.S.N.M. 145992, paratypes. 

Plate 5 

Figs. 1-6. Bolboparia superba Rasetti, new genus, new species .... 19 
1-4, Dorsal, anterodorsal, frontal, and oblique views of cephalon, X4; 
U.S.N.M. 145998, holotype. 5, Thoracic segment, X5. 6, Cephalon 
with broken-off glabellar spine, showing occipital ring, X5. U.S.N.M. 
145999, paratypes. 

Figs. 7-12. Bolboparia elongata Rasetti, new species 20 

7-9, Lateral, dorsal, and frontal views of cephalon, X5 ; U.S.N.M. 
146001, holotype. 10, Cephalon, X5. 11, 12, Lateral and dorsal views 
of pygidium, X4. 13, Pygidium, X7.5. U.S.N.M. 146002, paratypes. 

Figs. 13, 14. Bolboparia canadensis Rasetti, new species 21 

13, 14, Dorsal and lateral views of cephalon, X8. G.S.C. 19887, holo- 
type. Collected from the Charny formation near Elgin Station, 
L'IsIet County, Quebec. 

Plate 6 

Figs. 1-10. Analox bipunctata Rasetti, new genus, new species .... IS 
1-3, Dorsal, frontal, and lateral views of cephalon, X6; U.S.N.M. 
145993, holotype. 4, Cephalon, X6. 5, 6, Lateral and dorsal views 
of pygidium, XlO. 7, 8, Lateral views of two cephala, X6. 9, py- 
gidium, X5. 10, Pygidium, X6. U.S.N.M. 145994, paratypes. 

Figs. 11-19. Acidiscus birdi Rasetti, new genus, new species 11 

11, 12, Dorsal and lateral views of cephalon, X2; U.S.N.M. 145987, 
holotype. 13-15, Dorsal, lateral, and frontal views of cephalon, X2. 
16, 17, Dorsal and lateral views of pygidium, X2. 18, Lateral view 
of pygidial doublure showing short spines, X5. 19, Portion of py- 
gidium showing granulate surface, X7.5. U.S.N.M. 145988, para- 
types. 

Figs. 20, 21. Undetermined pygidium No. 4 46 

20, 21, Two examples, X2.5 ; U.S.N.M. 146000. 



50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Fagre 
Plate 7 

Figs. 1-6. Acidiscus hexacanthus Rasetti, new species 13 

1-3, Dorsal, frontal, and lateral views of cephalon, X3; U.S.N.M. 
145989, holotype. 4, 5, Lateral and dorsal views of cephalon, X5. 
6, Pygydium, X6. U.S.N.M. 145990, paratypes. 

Figs. 7-11. Serrodiscus spinulosus Rasetti, new species 33 

7-9, Lateral, dorsal, and frontal views of cephalon, XS; U.S.N.M. 
146026, holotype. 10, 11, Dorsal and lateral views of pygidium, X5; 
U.S.N.M. 146027, paratype. 

Figs. 12-18. Calodiscus reticulatus Rasetti, new species 24 

12-14, Dorsal, frontal, and lateral views of cephalon, X4; U.S.N.M. 
146006, holotype. 15, Cephalon, X5, 16, Glabella of another specimen 
showing ornamentation, XlO. 17, Lateral view of the same cephalon, 
X4. U.S.N.M. 146007, paratypes. 18, Incomplete cephalon, showing 
occipital ring and posterior border, X5 ; U.S.N.M. 146008, paratype. 

Plate 8 

Figs. 1-9. Litometopus longispinus Rasetti, new genus, new species . . 27 
1-3, Dorsal, frontal, and lateral views of cephalon, X3; U.S.N.M. 
146012, holotype. 4, 5, Lateral and dorsal views of cephalon, X4. 
6, Pygidium, X2. 7, Pygidium, X2. 8, Lateral view of doublure of 
the same pygidium, X5. 9, Pygidium, X3. U.S.N.M. 146013, para- 
types. 

Figs. 10-19. Serrodiscus subclavatus Rasetti, new species 31 

10, 11, Dorsal and oblique views of cephalon, X4; U.S.N.M. 146022, 
holotype. 12, 13, Dorsal and lateral views of cephalon, X3. 14, Por- 
tion of same cephalon, showing ornamentation and characteristic 
furrow parallel to posterior margin, X7.5. 15, Lateral view of 
pygidium, X5. 16, Lateral view of pygidium, with portion of axial 
spine restored, X4. 17, 18, Oblique and dorsal views of pygidium, 
X4. 19, Cephalon with two thoracic segments attached, X3. U.S.N.M. 
146023, paratypes. 

Plate 9 

Figs. 1-16. Bathydiscus dolichometopus Rasetti, new genus, new species . . 17 
1-3, Dorsal, frontal, and lateral views of cephalon, X4; U.S.N.M. 
145995, holotype. 4-6, Dorsal, frontal, and anterodorsal views of 
cephalon, X3. 7, Portion of cephalon, XS. 8, Frontal view of the same 
cephalon, X3. 9, 10, Posterior and lateral views of pygidium, X4, 
exposing doublure. 11, 12, Dorsal and posterior views of pygidium, 
X3. 13, Pygidium, X3. U.S.N.M. 145996, paratypes. 14-16, Lateral 
dorsal, and posterior views of pygidium, X4; U.S.N.M. 145997, 
paratype. 

Figs. 17-21. Calodiscus fissifrons Rasetti, new species 22 

17, Cephalon, XS; U.S.N.M. 146004, holotype. 18, 19, Incomplete 
cephala, X4. 20, Small pygidium, XlO. 21, Pygidium, X5. U.S.N.M. 
145005, paratypes. 



NO. 9 NEW CAMBRIAN TRILOBITE FAUNULE — RASETTI 51 

Page 

Figs. 22, 23. Calodiscus occipitalis Rasetti, new species 24 

22, 23, Lateral and dorsal views of cephalon, X5; U.S.N.M. 146003, 
holotype. 

Plate 10 

Figs. 1-10. Oodiscus subgranulatus Rasetti, new genus, new species . . 29 
1-3, Dorsal, frontal, and lateral views of cephalon, XS; U.S.N.M. 

146014, holotype. 4, Portion of the same cephalon, showing one of 
the marginal spines and ornamentation, X7.5. 5, Cephalon, X4. 

6, portion of cephalon, showing positions of the marginal spines, XS. 

7, Portion of pygidium showing ornamentation, X7.5, 8, Pygidium, 
X3. 9, 10, Dorsal and lateral views of pygidium, X3. U.S.N.M. 

146015, paratypes. 

Fig. 11. Undetermined pygidium No. 3 39 

Dorsal view of specimen, X3. U.S.N.M. No. 146035. 

Figs. 12-15. Serrodiscus latus Rasetti, new species 34 

12-14, Lateral, dorsal, and frontal views of cephalon, X6; U.S.N.M. 
146024, holotype. 15, Larger cephalon, X4; U.S.N.M. 146025, 
paratype. 

Figs. 16-18. Oodiscus binodosus Rasetti, new species 30 

16-18, Dorsal, frontal, and lateral views of cephalon, X5; U.S.N.M. 

146016, holotype. 

Fig. 19. Serrodiscus, species undetermined 35 

Dorsal view of cephalon, X5 ; U.S.N.M. 146028. 
Figs. 20, 21. Oodiscus longifrons Rasetti, new species 30 

20, Cephalon, X3; U.S.N.M. 146019, paratype. 21, cephalon, X4; 
U.S.N.M. 146018, holotype. 

Plate 11 

Figs. 1-7. Leptochilodiscus punctulatus Rasetti, new genus, new species . 26 
1-3, Dorsal, lateral, and frontal views of cephalon, X7.5; U.S.N.M. 
146009, holotype, 4, 5, Dorsal and oblique views of another cephalon, 
X7.5; U.S.N.M. 146011, paratype. 6, 7, Dorsal and frontal views of 
incomplete cephalon, X7.5 ; U.S.N.M. 146010, paratype. 

Figs. 8-11. Oodiscus, species undetermined No. 1 31 

8-10, Dorsal, lateral, and posterior views of pygidium, X3. 11, Py- 
gidium, X4. U.S.N.M. 146020. 

Figs. 12, 13. Oodiscus, species undetermined No. 2 31 

12, 13, Pygidia, X4. U.S.N.M. 146021. 

Figs. 14-16. Undetermined pygidium No. 2 38 

14, 15, Dorsal and lateral views of specimen, X5. 16, Smaller speci- 
men, X7.5. U.S.N.M. 146034. 

Figs. 17-21. Undetermined pygidium No. 3 38 

17, 18, Lateral and dorsal views of small specimen, X7.5. 19-21, 
Posterior, lateral, and dorsal views of larger specimen, X5. U.S.N.M. 
146033. 

Fig. 22. Bonnia, species undetermined No. 2 44 

Cranidium, XS. U.S.N.M. 146041. 



52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 

Page 

Figs. 23-25. Bonnia, species undetermined No. 1 43 

23, Immature cranidium, XlO. 24, 25, Lateral and dorsal views of 
cranidium, X5. U.S.N.M. 146040. 

Plate 12 

Figs. 1-7. Stigmadiscus stenometopus Rasetti, new genus, new species . Z6 
1, 2, Dorsal and frontal views of cephalon, X3; U.S.N.M. 146029 
holotype. 3, 4, Dorsal and lateral views of cephalon, X3. 5, 6, 
Dorsal and lateral views of incomplete cephalon, X3. 7, Largest 
glabella observed, X3. U.S.N.M. 146030, paratypes. 

Figs. 8-13. Stigmadiscus gibbosus Rasetti, new species 37 

8, 9, Dorsal and lateral views of cephalon, X4; U.S.N.M. 146031, 
holotype. 10, 11, Lateral and dorsal views of cephalon slightly com- 
pressed longitudinally, X5. 12, 13, Dorsal and lateral views of small 
cephalon slightly compressed laterally, X7.5. U.S.N.M. 146032, 
paratypes. 

Figs. 14, 15. Kootenia, species undetermined 42 

Posterior and dorsal views of pygidium, X4. U.S.N.M. 146039. 

Fig. 16. Bonnia, species undetermined No. 3 44 

Cranidium, X5. U.S.N.M. 146042. 

Fig. 17. Bonnia, undetermined pygidium 45 

Dorsal view of specimen, X4. U.S.N.M. 146044. 

Fig. 18. Bonnia, species undetermined No. 4 45 

Cranidium, X3. U.S.N.M. 144042. 

Figs. 19, 20. Paedeumiasf, species undetermined No. 2 41 

Incomplete cephala, X5. U.S.N.M. 146037. 

Figs. 21, 22. Olenellus, species undetermined 42 

Incomplete cephala, X5. U.S.N.M. 146038. 

Figs. 23-25. Paedeumias, species undetermined No. 1 40 

23, 24, Incomplete cephala, X5. 25, Meraspid cephalon, XlS, showing 
small procranidial spines. U.S.N.M. 146036. 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 1 




Calodiscus, AciDiscus, Bathydiscus, Oodiscus, and UEPTOCHILODISCUS 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 2 




Serrodiscus, anauox, acimetopus 

(see explanation of plates at end of text.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 3 









BOLBOPARIA, LITOMETOPUS, STIGMADISCUS 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 4 




EODISCIDAE (ACIMETOPUS) 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. q, PLATE 5 




EODISCIDAE (BOLPARIA) 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 6 




EODISCIDAE lANALOX, ACIDISCUS); UNDETERMtNED TRILOBITE 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 7 




EODISCIDAE (ACIDISCUS, SERRODISCUS, CALODISCUS) 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSOMIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 8 




EODISCIDAE (LlTOMETOPUS, SERRODISCUS) 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 9 





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7 . - >^ *^'^ 




EODISCIDAE (BATHYDISCUS, CAUODISCUS) 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL, 148 NO. 9, PLATE 10 




EODISCIDAE (OODISCUS, SERRODISCUS, UNDETERMINED GENUS) 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 11 




25 l^/**^^v: . ^ 



EODISCIDAE (LEPTOCHILODISCUS, OODISCUS. UNDETERMINED GENERA); 
DORYPYGIDAE (BONNIA) 

(SEE EXPLANATION OF PLATES AT END OF TEXT.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 148 NO. 9, PLATE 12 




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OLENELLIDAE (OUENELLUS, PAEDEUMIAS) 

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