1856.] Ill
AssiMiNEA. CARiXATA. Testa rcgulariter conica, lutea, vittata, subcrassa ura-
bilicata, laevi ; spira ad apicera acuta ; suturis paulisper impressis, infra lineatis ;
anfractibus instar septenis, planulatis ; apertura elliptica, subcanuliculata, iutus
vittata
;
umbilico spiraliter carinato ; columella incurvataad basim subangulata.
Hah. Siam, S. R. House, M.D.
'
Desa-iptions of New Species of Acephala and Gasteropcda., from the Tertiary forma-
tions of Nebraska Territory, loith some general remarks on the Geology of the
country about the sources of the 3fissouri River.
By F. B. Meek and F. V. Hayden, M. D.
That portion of the great Tertiary basin from which the fossils described in
the following- paper were obtained, occupies an extensive area of country near
the head waters of the Missouri, chiefly between the 46th and 49th parallels of
north latitude, and the 100th, and 108th degree of longitude west from Green-
wich. According to the Barometrical measurements made by the party charged
with the exploration of the proposed northern route of the Pacific railroad, this
district varies in its elevation from 1800 to 2700 feet above the present flow of
the tidal wave.*
In regard to the geographical, topographical, and phj'sical features of this
country, its native tribes, its botany, zoology, &c., much interesting information
was long since laid before the public by the reports of Lewis and Clark's and
Long's expeditions, by Mr. Catlin, the Prince of New Wied, Mr. Nuttall and
others. More recently, much information of a similar nature has been added by
the report of the Pacific Railroad Survey. All these enterprising travellers
mention the occurrence of sandstones, clays, lignite, &c., but without giving us
much information in regard to the age of these formations, the extent of country
occupied by them, or as to the character of their organic remains.
In 1849 Dr. John Evans traced a great Lignite formation from below Fort Clark,
along the Missouri to a point twenty miles below the mouth of the Yellow Stone;
and in 1850 Mr. Thaddcus A. Culbertson, who visited this country under the
patronage of the Smithsonian Institution, saw this formation at two or three
points above Fort Union. In a map accompanying a highly interesting memoir
on the geology of the Hudson's Bay Territories, published recently by Mr. A. K.
Isbister, in the Journal of the Geological Society of London, a large area about
the sources of the Missouri, is colored as Tertiary, but so as to convey an in-
correct idea of the extent of country occupied by it. About the same time, Mr.
Jules .Marcou published in the Bulletin of the Geological Society of France, a
memoir on the Geology of the United States and the British Provinces, accom-
l^anied by a map, on which he colors nearly all the country about the headwaters
of the Missouri as New Red Sandstone, surmounted along the west shore of that
stream by Cretaceous outliers. Between this and the Black Hills he brings up
to Cannon-ball River, from the White River basin, a continuous belt of Tertiary.
West of this he places a belt of Jurassic, and along the supposed position of
the Black Hills he runs a stripe of Eruptive and Metamorphic rocks, flanked on
the east and west by Carboniferous formations. On the west side of the Black
Hills he colors another extensive district of Jurassic. In all this Mr. Marcou
is certainly mistaken, excepting in regard to the Eruptive and Metamorphic rocks
of the Black Hills
;
there may also be Carboniferous formations tliere, but
they have not yet been recognized as far north by two or three hundred miles,
as laid down by him.
Leaving for a future occasion all local and other details, we now propose to
give a brief general sketch of the extent and boundaries, as far as we can, of
that porticn of the great Tertiary lignite formation from which our fossils were
collected, with a few remarks wpon its probable age, and relations to the White
river basin, as well as to the Cretaceous formations upon which it reposes.
* Some points not crossed by these explorers may be a few hundred feet higher.
112 [June,
Ascending the Missouri from Fort Pierre, we find on reaching a point five miles
below Heart river, about the 47th parallel north, that the Cretaceous formations
which are so conspicuous for many hundred miles along the river below, pass
by a gentle north or north-west dip beneath the water level, to be succeeded on
both sides of the river by Tertiary. Although this is the first point where the
Tertiary beds come down to the water level, they are known to occupy the higher
country back from the river, on the west side, as far south as the vicinity of
Sau-acanna or Moreau river, and still further west they go as far south as some
of the north-west branches of the Cheyenne. Cannon-ball river, Watahoo, and
other small tributaries, however, cut down to the Cretaceous beds some little
distance back from the Missouri. On the east side of the ]\lissouri the Tertiary
is bounded on the south, nearly opposite the mouth of Cannon-ball river, by a
range of upper Cretaceous hills bearing off to the north east. South of the
Moreau, a similar range, known as Fox Hills, extends from near the Missouri to
about the 102 of west longitude, where it is interrupted by a small tributary
of the Cheyenne. West of this small stream, the same range of upper Cretaceous
hills, known perhaps by other local names, bears round to the north-west,
crossing the head branches of the Little Missouri so as to strike the Yellow Stone
river about ten miles below the mouth of Powder river
; forming nearly all this
distance the south and south-west boundaries of that portion of the great Ter-
tiary basin lying in the immense bend formed by the Missouri and Yellow Stone
rivers. To comprehend how this range of hills could traverse the country in
this way, it must be borne in mind that the Black Hills are laid down on most
of the published maps of this country as extending a long distance too far north.
Returning to the point near Heart river, from which we first set out, we find
on ascending the Missouri, that the Cretaceous strata again rise to view at a few
points not far below Fort Clark, but even here the country on each side is com-
posed of Tertiary. It was at one of these localities the Prince of Kew Wied
collected a nearly entire skeleton of Mosasaurus Maximiliani (Goldf.) From the
vicinity of Fort Clark we know of no other place where the Cretaceous beds
make their appearance until about twelve miles below the mouth of Milk river,
(lat. 47 N. long. 104 W.) the country on both sides of the Missouri all this
great distance being made up of Tertiary formations, the northern and eastern
limits of which are unknown to us. Immediately along the margins of Milk
river, Cretaceous beds are seen on both sides as far up as we have any knowledge
of the country, though the higher country back from the river is Tertiary. From
the point below the mouth of this stream on the Missouri, where the Cretaceous
beds first make their appearance, they are seen to rise higher and higher as we
ascend the ?iIissouri, in consequence of their inclination to the east or north-east.
On the north side of the Missouri, between it and Milk river, the higher portions
of the country back from the Missouri, are also composed of Tertiary beds.
The same formations likewise occupy nearly all the country between the Mis-
souri and Yellow Stone, as far west as the vicinity of Muscleshell river, where
they thin out on the summits of Cretaceous hills. The hills, however, near the
Missouri, between Milk and Muscleshell rivers, are also mainly Cretaceous, the
Tertiary being for the most part worn away by atmospheric agencies.
On both sides of the Yellow Stone, only Tertiary strata are seen from near the
mouth of Powder river as far up as the mouth of the Big Horn. How far be-
yond this they extend we do not know, though we have received Tertiary fossils
from intellisfent traders, collected as far up the Big Horn as one of its tributaries
known as Little Horn river. From another point as far west on the Yellow
Stone as Rose river, we received a few Cretaceous fossils. As to the limits of
the Tertiary up Powder and Tongue rivers, we have no definite information.
The traders say the same kind of lignite beds seen along the Yellow Stone, occur
along the l)anks of the former as much as one hundred and fifty miles above its
mouth.
The foregoing hasty sketch is given more with a view of showing the extent
of country occupied by this great Tertiary lignite formation, than with any
hope of conveying a definite idea of its precise limits. If it should prove to be
1856.] 113
only a part of the same extensive fresh water lignite formation observed by Sir
John Richardson on the Saskatchawan, of which we have little doubt, then it
is highly probable the Lignite and Goal formations mentioned by Mr. Isbister as
flanking the eastern slope of the Rocky Mountains, in the form of a continuous
belt from the Saskatchawan to the Arctic Ocean, belong to the same epoch.
For the most part, these deposits in Nebraska consist of beds of gray, yel-
lowish, whitish, and blue sand, sandstone, clay, &c., with alternating strata of
lignite of variable purity, and carbonaceous matter mingled with much sand
and clay. These beds of lignite often take fire spontaneously, from heat gene-
rated in the decomposition of iron pyrites, and burn for many years at a time,
sending forth suffocating sulphurous vapors, and causing such an intense degree
of heat as to fuse the contiguous clay and sand into masses presenting every de-
gree of compactness, from that of obsidian to light vesicular lava. In some of
the argillaceous beds, great numbers of beautiful fossil plants are found, a fine
series of which was collected and placed for investigation in the hands of Dr.
J. S. Newberry, the well known fossil botanist of Cleveland, Ohio. The remains
of Mollusca collected from these formations, over a wide extent of countrj-, pre-
sent a remarkable uniformity of character, and as maybe seen by the following
paper, are all, excepting a few land shells, referable to genera usually found in
fresh and brackish waters. It is an interesting fact that the most nearly allied
living representatives of many of these species are now found inhabiting the
streams of Southern Africa, Asia, China, and Siam, apparently indicating the
existence of a tropical climate in these latitudes at as late a period as the Tertiary
epoch.*
Although there can be no doubt that these deposits hold a rather low position
in the Tertiary System, we have as yet been able to arrive at no very definite
conclusions as to their exact synchronism with any particular minor subdivision
of Tertiary, not having been able to identify any of the Mollusca found in
them with those of any well marked geological horizon in other countries.
Their general resemblance to the fossils of the Woolwich and Reading series of
English geologists, as well as to those of the great Lignite formations of the
south-east of France, would seem to point to the lower Eocene as their jjosition.
Yet it may be possible these resemblances have resulted from the action of pre-
cisely similar causes at a somewhat later period.
It is a little remarkable that these formations differ in many respects from
those of the White river basin lying so near on the south. In the first place they
generally contain more sand, are usually characterized by beds of lignite, and
as yet have furnished no remains of Mammalia ; while the White river basin is
more argillaceous, appears to be destitute of lignite, and is well known to be one
of the most remarkable repositories of extinct mammalian remains on the face
of the globe. In addition to this, not one of the species of Mollusca in our col-
lection from the Lignite formations, is identical with any of those described by
Dr. Evans and Dr. Shumard from the White river basin.
Formations immediately beneath the Tertiary in this district.
It would seem that the change of physical conditions which closed the Cre-
taceous epoch and ushered in the Tertiary, in this part of the world at least, was
gradual, not violent. We find that even while the Cretaceous conditions still
existed, (during the deposition of No. 5 of the seriesf ) the approaching close of
that state of things, and tlie coming of the Tertiary era, were foreshadowed by
the introduction of Fasciolaria^ Pleurotoma, and Belemnitella, with many shells of
other genera, quite as near in their specific affinities to Tertiary as to Cretaceous
* We are under many obligations to Dr. Isaac Lea, of Philadelphia, for the
privilege of comparing our fossil species with analogous forms in his magnifi-
cent collection of recent shells.
I For a section of the rocks of this country see a paper by James Hall and F.
B. Meek in the Memoirs. Am. Acad. Arts and Sci. vol. 5, New Series. Likewise a
paper by F. B. Meek and F. V. Hayden in Proceed. Acad. Nat. Sci. Phila., March
1856.
114 [June,
forms
;
while the sea was gradually becoming more shallow, as is shown by the
increase of gasteropoda. We even know from the presence of a few remains of
lycopodiaceous plants, and an occasional unbroken leaf of some exogenous tree,
that there was dry land at this time somewhere not very far away. Gradually,
as we ascend in the series, the strictly marine animals disappear, and we meet
with Ostrea, Corbula, and Ceriihium, mingled in the same bed with Mclania, Palu-
dina, Physa, Cyrena^ &c., all of Tertiary types; while a little higher in the
series, we find at some places only the remains of land and fresh water mollusca.
From the above facts, especially the presence of Pleurotoma, Fasciolaria, and
Belemnitclla, in this upper member of the Cretaceous system of this country,
we cannot think it represents any part of the Green Sand of English geologists.
Numerous well marked Cretaceous forms show it cannot be Tertiary, conse-
quently we think it must represent some portion of the true Chalk. We are by
no means inclined, however, to adopt the views of M. Alcide D'Orbiguy,
who regards all the Cretaceous formations of the United States and Western
Territories as referable to a later epoch than the Green Sand, as the next suc-
ceeding formation below that of which we have just been speaking, (No. 4 of
the series), is characterized by numerous fossils of unquestionable Green Sand
type. We think confusion has been created in tracing out the parallelism be-
tween American and European Cretaceous formations, by fossils from different
positions in this country having been mingled together and described as if they
occurred in the same bed.
Formations at the base of the Cretaceous Scries of this district.
As previously stated, near the mouth of Milk river, Cretaceous strata which
are not seen for a long distance below this on the Missouri, again rise to vievi'.
They consist of the upper two members of the series (No. 5 and No. 4) which,
in consequence of their inclination to the east, are found to rise higher and
higher as we ascend the river, so that nearly all the hills close to the Missouri,
between Milk and Muscleshell rivers, consist of these formations. Some four or
five miles below the mouth of Muscleshell river, a lower rock, a sandstone,
rises above the water level. This is probably No. 1 of the series. No. 2 and No.
3 not being represented here. It is worthy of note that out of two species of
Mactra^ two of Tellina, two of Inoceramus, one of Pholodomya, two of Nat/ca, and
one Bacuiite, found in this rock, not one is known to occur in any of the higher
formations, and some of these species are not unlike Neocomicn forms.
In consequence of the increasing inclination of the strata, this last mentioned
sandstone rises in the vicinity of North Mountain river as much as 250 feet above
the Missouri. Here, or near this, begins a wild and desolate region, known as
the Mauvaises Torres or Bad Lands of the Judith. At various places in these Bad
Lands a sandstone similar to No. 1 was seen alternating with beds of clay and
lignite, all of which are upheaved and much distorted. It was found impossible
to devote to the examination of these formations time enough to determinetheir
relations to the Cretaceous and Tertiary strata of this region, without running
the risk of being cut off from the party and murdered by the Indians. Amongst
a few fossils that were collected here, however, Prof. Leidy finds teeth which
he refers to two or three genera of large Saurians allied to the Iguanodon,
Megalosaurus, &c. There arc also in the collection from some of these beds, one
or two species of Unio, one or more of Cyclas or Cyrcna, and a few crushed
specimens of Gasteropoda like Paludina and Mclania. From these facts, we are
strongly inclined to think with Prof. Leidy, there may be here, at the ba.' e of the
Cretaceous System, a fresh water formation like the Wealden. In as much, how-
ever, as there certainly are some outliers of fresh water Tertiary in these Bad
Lands, we would suggest that it is barely possible these remains may belong to
that ei)och, though the shells appear to be all distinct species from those found
in the Tertiary at all the other localities in this region.
We remember seeing in 1853, between the mouth of Big Sioux and Piatt
rivers on the Missouri, some exposures very similar to those of the Bad Lands
of the Judith, excepting that there appeared to be no beds of Lignite. We saw
1856.] 115
no fossils ill these beds, but were at that time impressed with the opinion that
they belonged to the lower part of No. 1, which is well exposed a little higher
up the river at the mouth of the Big Sioux, but soon dips beneath the water
level to be seen no more between there and the far distant point already men-
tioned, near the mouth of Muscleshell river.*
DESCRIPTIONS OF SPECIES.
CyCLAS FORMOSA.
Shell small, oval, oblique, scarcely ventricose ; cardinal margin straight
buccal end rounded
;
anal extremity obliquely truncate ; basal margin semi-el-
liptical or broadly rounded ; beaks obtuse, tumid, rising somewhat above the
hinge, nearly touching, placed a little in advance of the middle ; surface orna-
mented by very fine, regular, distinct, concentric wrinkles. Length .11 inch ;
breadth .08 inch
; height .14 inch.
Locality. Three miles above Fort Union.
Cyclas pragilis.
Shell small, subcircular, slightly oblique, scarcely ventricose, very thin and
fragile ; extremities and base rounded ; posterior end wider than the anterior ;
beaks moderately elevated, tumid, slightly in advance of the centre ; surface ap-
parently marked with fine indistinct lines of growth. Length .24 inch ; breadth
about .13 inch
; height .22 inch.
All our specimens of this species being more or less worn, it is possible the
lines of growth may be more distinct on perfect specimens. Sometimes the
posterior slope, from a little behind the beaks, appear to have been obliquely
subtruncate.
Locality. Same as last.
Cyclas subellipticds.
Shell small, elliptical-ovate, somewhat ventricose, thin and fragile ; posterior
end narrower than the anterior, both narrowly rounded ; base semi-elliptical or
semi-ovate
;
cardinal border apparently rounding gradually to both extremities ;
beaks not much elevated, pointed, incurved, not oblique, located near the
middle
;
surface indistinctly marked with lines of growth. Length -24 inch ;
height -14 inch.
The beaks are so near the middle, and curved so nearly at right angles to the
longitudinal diameter of the shell, that it is not easy to determine, especially
from the examination of mutilated specimens, which is the posterior, or which
the anterior end. As we have only seen imperfect specimens, we are not sure
the surface markings are indistinct on unworn shells.
Ijocality. Three miles above Fort Union.
Cyrena Moreauensis.
Shell ovate, nearly elliptical, compressed, extremities rounded; anterior end
narrower than the posterior, base semi-ovate, most promincntbehind the middle;
beaks not much elevated, placed a little in advance of the centre ; surface marked
with fine distinct lines of growth ; cardinal edge rather thick, and having under
the beaks three diverging central teeth in each valve, the anterior of which is the
smallest
;
lateral teeth two, (in the left valve) long, parallel to the cardinal edge,
and fitting into corresponding grooves in the other valve ; muscular impressions
deep. Length about -90 inch ; breadth -36 inch ; height -66 inch.
Each of the cardinal teeth has, in its upper end, a small notch which is occu-
pied, when the valves are closed, by a small projection between the teeth of the
other valve. The anterior lateral tooth appears to be larger and approaches the
central teeth more nearly than the posterior. Our specimens are generally more
or less worn, and thickly coated with firmly adhering sand.
* The foregoing remarks are based upon the observations and collections of
Dr. Hayden.
116 [June,
Locality. Near Moreau river, in a sand bed, associated with bones of Titano-
thcrium? Probably a distant outlier of the White river bone beds.
Ctrena inteemedea.
Shell oval-ovate, compressed, rather thin ; estremities'rounded ; base semi-
elliptical ; beaks moderately elevated, not gibbous, placed nearly half way from
the middle to the anterior end
;
surface marked with fine lines of growth, oc-
casionally rising into obscui-e concentric wrinkles ; edge of the cardinal border
thin
;
cardinal teeth close under the beaks, posterior one very oblique. Length
76 inch
;
breadth -22 inch
; height -68 inch.
Thisspecies approaches some varieties of C.^M??),of Deshay's(Coq.foss. page
ll^,) but is more inequilateral, the posterior end being comparatively longer,
the beaks are also less elevated. From the last it will be distinguished by its
shorter and more rounded form, more elevated beaks, and much thinner cardinal
edge.
Locality andposition. Same as last.
Cyrena occidentalis.
Shell sub-triangular, very thick, rather ventricose ; anterior end and base
rounded, posterior end sloping abruptly fi'om the beaks, and ventrically sub-
truncate at the extremity ; beaks located a little in advance of the middle, and
elevated, pointed, incurved, and approximate ; surface marked with strong
lines of growth. Length 1 inch; breadth -71 inch; height 1 inch.
Appears to be intermediate between C cordata of Morris {Proceed. Geol. So-
ciety, vol. 10, joZ. Ijfifjs. 7, 8, 9,) and C. antiqua of Ferussac, {see Deshays' Coq. foss.,
pi. 18, figs. 19,20,21) both of which are Eocene species. From the first, it dif-
fers in being relatively higher ; its posterior end is also shorter, and more dis-
tinctly subtruncate. From the latter, it differs in being less elevated, not so
concave in front of the beaks, nor so regularly arcuate on the posterior slope
from the beaks to the base. In front, it presents the same symmetrical cordate
outline common to both these species.
Locality. Bad Lands of the Judith.
CORBDLA SUBTRIGONALIS.
Left valve subtrigonal, very convex, obliquely truncate from the beaks to the
extremities, the two slopes diverging at an angle of 95''; basal margin rounding
up abruptly in front, and converging towards the postei-ior slope at an angle of
about 48; beaks elevated, located in advance of the middle ; surface marked by
faint lines of growth, and having below the middle three or four concentric
wrinkles, which become stronger towards the extremities. The right valve is
much more compressed, and without concentric folds. Length -74 inch ; breadth
25 inch
; height -55 inch.
The larger, or left valve of this species, has an obscure ridge passing from the
beaks obliquely backwards and downwards to the posterior extremity, along
which the valve is abruptly deflected towards the hinge margin. This and the
foUowino- species may have possessed other surface markings not now preserved,
the specimens being all considerably worn, as if they had been exposed to the
action of waves on a beach.
Locality. Mouth of the Judith, associated with Oslrea svbtrigonalis (Evans and
Shumarci), also Melania, raludina, and other fresh water shells.
CORBULA PERDNDATA.
PJo-ht valve sub-trigonal, rather compressed, obliquely sub-truncate from the
beaks toward both extremities, the slopes diverging at an angle of about 82 ;
basal margin rounding up in front, straight towards the posterior ; beaks small,
much elevated, and placed a little in advance of the middle; surface ornament-
ed by five or six strong, elevated, concentric folds, otherwise apparently smooth.
Length ^32 inch; breadth -13 inch; height -27 inch.
The left valve of this species is yet unknown to us.
Locality and position. Same as last.
1856.] 117
CORBULA MACTRIPORMIS.
Shell subtriangular, scarcely ventricose ; right valve a little larger, thicker
and more gibbous than the left ; extremities narrowly rounded ; posterior end
longer than the anterior, slightly truncate at the extremity, and having an ob-
tuse ridge passing from the beaks obliquely backwards to the lower posterior
edge ; base semi-ovate, most prominent in advance of the middle ; beaks con-
siderably elevated, pointed, incurved, and directed forward ; surface marked with
fine line's of growth. Length -64 inch ; breadth about -33 inch ; height -50 inch.
The tooth of the right valve is thick, and located immediately under the
beaks, while that of the left is flattened, and placed a little behind them.
The lateral edges of the cardinal border of the left valve, as well as its basal
margin, which are sharp and prominent, fit into a distinct groove in the edge of
the opposite valve. The muscular im jressions are indistinct, and the sinus of
the palleal impression triangular, very broad and shallow.
Locality. Fort Clark, where it is associated with Melania, Paludina, &c.
Unio priscus.
Shell ovate, rather compressed, very thin and fragile ; anterior extremity
short, rounded ; posterior end narrower, contracting with a regular curve from
above, and having at the extremity below a very obtusely rounded angle ; car-
dinal border broadly arcuate ; basal margin nearly straight behind the middle,
rounding up in front ; beaks very small, rising little above the hinge, located
about one-sixth the entire length of the shell behind the front, and ornamented
with small regular concentric wrinkles ; surface of other portions of the shell
smooth, or only marked with fine lines of growth. Length 2-78 inches; breadth
unknown
; height 1-63 inches.
Has much the aspect externally of an Anodonta, but a fragment in our collec-
tion shows enough of the hinge to prove it to be a Unto, without exhibiting the
details of the teeth. Judging from the beaks, young specimens not more than
half an inch in length must be beautifully ornamented with regular concentric
wrinkles. It is usually found in a crushed condition between the laminae of
clay.
Locality. Yellowstone River, forty miles above the mouth.
BULIMUS ? TERES.
Shell small, sinistral, much elongated, terete ; volutions ten to ten and a half,
narrow, closely wound, and increasing very gradually from the apex, slightly
convex near the summit of the spire, but flattened lower down ; suture very
faintly impressed between the lower volutions, but becoming more distinct to-
wards the apex ; surface marked with fine, regular lines of growth, passing
straight across the whorls at right angles to the suture ; aperture ovate, acutely
angular above, rounded below ; lip thin. Length -76 inch; breadth -19 inch;
apical angle slightly convex, divergence 18.
A few dextral shells were found associated with the above, which, as far as
we have been able to see, diifer from them in no other respect. It is possible,
however, they may belong to a distinct species, though we are now inclined to
regard them as merely a variety of the same. This and the following species
are evidently closely related to a shell described by M. Matheron, from the Ter-
tiary lignites near the mouth of the Rhone, south-east of France. (See Melania
adcula, p, 219, pi. 36, fig. 25 ; Catalogue Methodique, &c.) Like some of ours, his
is a sinistral shell, and has much the same general appearance, but it is even
more elongated, and has nearly twice as many volutions. We doubt very mnch
the propriety of referring such forms to the genus Melania., as they appear to us
to have much more the aspect of land shells. Unfortunately all our specimens
have the aperture more or less broken or distorted, as was the case with those
studied by M. Matheron. The spire looks very like Clausilia, but the aperture
was evidently more like Bulimus or Achatina. It is not improbable they may
9
118 [June,
form a distinct group, holding an intermediate position between Clausilia and
Bulimus.
Locality. Three miles below Fort Union.
BULIMCS? VBRMICOLUS.
Shell small, sinistral^ greatly elongated, cylindrical ; volutions about thirteen,
narrow, closely wound, increasing very gradually from the apex, somewhat con-
vex near the summit of the spirefbut flatteaed lower down; suture very faintly
impressed between the lower volutions, bat becoming more distinct above ; sur-
face marked with fine regular Hues of growth passing straight across the whorls
at right angles to the suture; aperture unknown. Length about -60 inch;
breadth -13 inch
; apical angle slightly convex, divergence 13.
This is very near the last, and may be only a variety of the same. It differs,
however, in being more nearly cylindrical in form; the volutions are more nu-
merous, more closely wound, and do not increase so rapidly from the apes,
while the suture is less oblique, especially between the lower volutions.
Locality and position. Same as last.
Bulimus limneaformis.
Shell narrow ovate, rather thick; spire conical, obtuse at the apex; volutions
Sve to five and a half, convex ; suture distinct ; surface marked with faint lines
of growth ; aperture ovate, angular above, rounded below; outer lip apparently
a little obtuse, or abruptly bevelled ; inner lip very thin on the body whorl above,
thicker and slightly reflexed below; columella regularly curved. Length -42
inch
;
breadth -ZO inch; length of aperture -20 inch, breadth of do. -10 inch.;
apical angle corvex, divergence 38.
From the same locality and position we have a single specimen agreeing in
ail respects with the above, excepting that the volutions are much flatter and
the suture less distinct. This may be another species, but without seeing more
specimens we are unable to satisfy ourselves it is not a variety of the same.
Locality. Fort Clark.
Bulimus Nebrascensis.
Shell ovate
; spire rather short, conical, obtuse at the apex ; volutions fonr
and a half, convex ; suture distinctly impressed ; surface polished and marked
with nearly obsolete lines of growth ; outer lip apparently sharp ; inner lip very
thin above, thicker and slightly reflexed below ; aperture narrow ovate, acutelj'
angular above, somewhat narrowly rounded below. Length -27 inch ; breadth
-13 inch; length of aperture -15 inch, breadth of do. -07 inch; apical angle cob-
vex, divergence 47.
It is possible this may be only a variety of the last, which it resembles in many
respects. It differs, however, in being a relatively thinner shell, has one whorJ
less, the spire is comparatively shorter, and the apical angle is considerably
greater.
Locality and position. Same as last.
Pupa helicoides.
Shell very small, oval or ovate; spire moierately elevated, apparently obtuse
at the point ; volutions five, convex, increasing gradually from the apex ; surface
marked with strong lines of growth, which cross the whorls obliquely ; suture
distinctly impressed ; aperture very oblique, subcircular, rounded on the lower
and outer sides, nearly straight next the body whorl ; lip slightly reflexed ; um-
bilicus quite small. Length -12 inch ; breadth -08 inch ; length of aperture -05
inch, breadth of do. .04 inch.
So far as we have been able to see from examining distorted specimens of
this species, it is without teeth. In this, as well as in many other respects, it
appears to have been very much like the recent /*. simplex (Gould,) but is about
1856.] 110
three times as large, aud differs in baviag stronger and more elevated linea of
growth. It may be an elevated Helix.
Loc dity. Three miles above Fort Union.
LlMN^A TENUICOSTA.
Shell small, turrited, very slender ; spire acutely elevated ; volutions four to
four and a half, vertically flattened, (or slightly convex,) increasing rapidly in
the direction of the longitudinal axis of the shell, and each so much smaller
than the succeeding one below it, as to form a shoulder or offset at the suture ;
surface ornamented by sharply elevated, equidistant, linear folds parallel to the
minute lines of growth ; suture very oblique, rather strongly impressed ; aper-
ture unkiown. Length -29 inch; breadth -08 inch ; apical angle regular, di-
vergence about 26.
This exceedingly slender, delicate little Limnea, is not apt to be confounded
with any other fossil or recent species with which we are acquainted. Its at-
tenuated form, vertically flattened whorls, and peculiar linear folds, are charac-
ters by which it will be easily identified. None of our specimens show the
aperture, though it must be narrow, and a little shorter than the spire. It is ii
very rare shell.
Locality. Three miles below Fort Union.
PhYSA liONGIUSCULA.
Shell elongate ovate ; spire slender, rather elevated, acute at the apex; whorls
about six, flattened or slightly convex ; suture not very distinct ; surface marked
with fine, straight, nearly obsolete lines of growth, which cross the whorls at
right angles to the suture ; aperture apparently narrow ; outer lip meeting the
body whorl at an acute angle above. Length -59 inch ; breadth -27 inch ; apical
angle regular, divergence 43.
Our specimens are too imperfect to show the exact form of the aperture,
though it appears to have been narrow, very acutely angular above, and nar-
rowly rounded below. The lines of growth are faint, and the substauce of tiie
shell thin. This species quite closely resembles some varieties of P. hypnorun
(Lin.,) but the body volution is relatively wider, the spire somewhat less ele-
vated, and the aperture narrower.
Locality. Three miles above Fort Union.
Physa rhomboidea.
Shell small, oval, narrowing abruptly from the middle towards both extremi-
ties
; spire rather short, conical, pointed ; volutions four and a half, slightly con-
vex, last one large, but scarcely ventricose ; surface marked with fine lines of
growth ; suture distinct ; aperture narrow, acutely angular above, narrowly
rounded below
;
inner lip closely spread upon the body whorl above, and forrti-
ing a fold below the deeply impressed umbilical region. Length -26 inch ;
breadth -10 inch
; length of aperture -15 inch, breadth of do. -07 inch ; apical
angle nearly regular, divergence 57"'
The smaller size, less elongated form and shorter spire, will serve to distiii-
guish this species from the last. From the same bed we have a few other specv
mens, which have a relatively wider and more oblique aperture, and a more
ventricose body whorl, but they are so nearly identical in other respects with
this, that we can only regard them as a variety of the same.
Locality and position. Same as last.
Physa Nebrascensis.
Shell large, ovate, thin ; spire rather short; whorls about five, flattened or
slightly convex ; suture very oblique, not strongly impressed ; surface marked
with coarse lines of growth ; aperture narrow, acutely angular above, narrowly
rounded below
;
columella impressed in the umbilical region, and having a kimd
120 [June,
of fold at its junction with the outer lip below. Length about 1 inch ; breadth
57 inch; length of aperture -55 inch, breadth of do. -26 inch.
It is probable the above description will have to be modified somewhat, when
perfect specimens are obtained, as all those we have seen are more or less
broken.
Locality. Three miles below Fort Union.
Physa subelongata.
Shell elongate ovate ; spire elevated, acute at the apex ; volutions about six
and a half, nearly flat ; suture oblique, linear, scarcely distinct ; surface faintly
marked with lines of growth; aperture unknown; columella twisted into a kind
of fold below the impressed umbilical region. Length 1-16 inches ; breadth -53
inch
; length of aperture about -57 inch ; apical angle very convex, divergence
49''.
This Physa belongs to the same type as two or three elongated species de-
scribed by Matheron, from the Great Lignite formations of the south of France,
(^Catalogue Methodique, &c., pi. 36.) It differs, however, from his P. Gardanennis,
which it most neirly resembles, in having much flatter volutions, a le-s dis-
tinctly impressed suture, and relatively smaller body whorl. Our specimen is
so much broken and worn, that if there were other markings than those pre-
served they would have been obliterated.
Locality. Bad Lands of the Judith.
Planorbis subumbilicatus.
Shell very small, subdiscoidal ; spire flat ; volutions two and a half to three,
nearly cyliudrical ; surface marked with very fine, rather indistinct lines of
growth ; sutures strongly defined ; umbilicus large, showing the volutions to the
apex ; aperture round or obliquely a little oval. Larger diameter -IS inch ;
smaller do. -14 inch.
Locality. Three miles below Fort Union.
Planorbis convolutus.
Shell large, discoidal, nearly equally concave, and exhibiting all the whorls on
both sides
;
volutions slightly embracing, very strongly separated by the sutures,
more broadly rounded on the right than on the left side ; surface (of cast)
having faint undulations parallel to the obsolete lines of growth, which pass
round very obliquely forward from the right to the left ; aperture ovate, nar-
rower on the left than the right side, slightly concave within, for the reception
of the succeeding whorl ; right lip projecting considerably beyond the left.
Greater diameter 1.01 inch
;
smaller do. .32 inch.
In its general appearance this species approaches P. rotundatus of Brong., but
is much less compressed. It differs also in the form of the aperture, which is
wider than high, while that of P. rotundatus is higher than wide (See Deshays'
Coq. foss. pi. 9, fig. 7 and 8.)
Locality. Little Horn river.
Velletia (Ancylus) minuta.
Shell minute, ovate or elliptical-pattiform, exceedingly thin and fragile; ex-
tremities rounded
;
anterior end apparently a little wider than the posterior ;
apex moderately elevated, obtuse, nearer the posterior end than the middle,
turned to the left
;
front slope convex ; posterior and postero-sinistral slopes
concave, dextral convex ; surface marked with fine concentric striic. Length
.08 inch
;
breadth .06 inch
; height .03 inch.
Resembles Velletia elegaiis of Edwards, {Ancylus elegans of Sowerby, Min. Conch,
pi. 533) but is much smaller, and wants the radiating striae of that species.
Locality. Three miles below Fort Union.
Paludina mcltilineata.
Shell conical-ovate, rather thin ; spire elevated ; volutions six to six and a
half, rounded convex, increasing gradually from the apex ; suture strongly im-
1856.] / 121
pressed ; surface ornamented by more or less distinct lines of growtli, which are
crossed by numerous small, thread-like, revolving lines ; aperture comparatively
small, obliquely-ovate ; inner lip thin and reflexed below so as to partly cover
the small umbilical perforation. Length 1 inch ; breadth .71 inch ; length of
aperture .47 inch ; apical angle convex, divergence 54 to 60.
Sometimes the lower volution, which generally forms less than half the entire
length of the shell, is slightly flattened above the middle, so as to leave an ob-
scure angle a little below the suture. On the upper half of the volutions the
revolving lines are separated by spaces from two to five times their width, but
decrease in size and become closely crowded on the lower part of the last whorl,
excepting near the umbilicus, where they are again stronger, more distant, and
minutely flexuous. On worn specimens the revolving lines are often obscure.
Locality. Fort Clark.
Paludina vetula.
Shell conical-ovate, not very thick ; spire relatively small, moderately elevated;
volutions about five and a half, convex, narrow, increasing gradually from the
apex, last one large and ventricose ; surface marked with fine lines of growth,
which are crossed by obscure revolving lines ; suture strongly impressed, very
slightly oblique ; aperture narrow ovate ; umbilical perforation closed or \cvj
small. Length about .81 inch ; breadth .60 inch ; length of aperture .40 inch ;
breadth of do. .24 inch
; apical angle nearly regular, divergence 60.
Associated with this species a few specimens about one third larger were found,
which have a more elevated spire, in consequence of which the divergence of
the apical angle is some four or five degrees less. The revolving lines also ap-
pear stronger. It is very difficult to determine, without a larger number of in-
dividuals in a better state of preservation, whether they are a variety of this
species or whether they may not be identical with the last. It is even possible a
more extensive collection may prove both these to be only varieties of the last,
though as we now see them, they present quite a different aspect, especially the
smaller variety, which has a more slender and much less elevated spire, with
more depressed whorls, smaller umbilical perforation, and much less distinct re-
volving lines. The body whorl is also relatively larger and much more extended
below.
Locality. Bad Lands of the Judith.
Paludina Leai.
Shell conical-ovate, oblique ; spire not much elevated, pointed at the apex ,
volutions five and a half to six, convex, sometimes ventricose, last one obscurely
angular below the middle ; suture well defined ; surface marked with fine lines
of growth, which are crossed by extremely fine, nearly obsolete revolving striae,
and at regular intervals by revolving rows of minute, shallow punctffi ; aperture
broad ovate, obtusely angular above, rounded below ; outer lip thin ; inner lip
thin above, thicker and slightly reflexed below the small umbilical pit ; columella
deeply arcuate. Length .97 inch ; breadth .75 inch ; length of aperture .47 inch ;
breadth of do. .40 inch
; apical angle convex, divergence 65 to 80.
This shell varies so greatly in the elevation of its spire, and the divergence of
its apical angle, that its varieties might be mistaken for three or four distinct
species. We have satisfied ourselves, however, by examining a large number of
specimens, that all these varieties are connected by a regular series of interme-
diate forms. In some individuals the upper volutions are slightly flattened on
top immediately below the suture, in others they are rounded convex, while in
a few instances all the whorls are more or less depressed, so as to give the shell
a subtrochiform aspect. Generally the fine revolving stria3 and rows of minute
punctae are nearly obsolete, and they are never visible without the aid of a good
lens.
It is an interesting fact that this species is so nearly allied, both in form and
surface markings, to a Paludina now inhabiting the streams of Southern Asia,
{P. Bengalensis, of Lea) as to give rise to a doubt whether or not they really are
122 [June,
distinct. By comparison, however, with authentic specimens of the latter in the
cabinet of Dr. Lea, at Philadelphia, we find his species is generally larger and
slightly more elongated than ours, and the body volution more rounded and
I'iss extended below.
We name this species after Dr. Isaac Lea,, the well known conchologist, who
first made known one of its nearest living representatives.
Locality. Fort Union.
Paludina retosa.
Shell obli([uely obovate ; spire depressed conical, obtuse at the apex ; volutions
fjur and a half to five, convex, last one large, obliquely depressed above, and
obscurely angular below ; suture well defined ; surface marked with distinct
oblique lines of growth, and faint traces of extremely fine revolving striae;
aperture (broad ovate?) obtusely angular above, rounded below; pillar lip
thin above, thicker and closely folded back upon the deeply arcuate columella
below. Length .84 inch ; breadth .64 inch ; apicial angle very convex, diver-
gence about 90.
It is barely possible this may be one of the extreme varieties of the last ; it
differs however from any of the forms we have considered referable to that
species, in having a much less elevated and more obtuse spire. The lines of
growth also pass round the volutions much more obliquely, and the body volu-
tion is relatively larger. None of our specimens have the aperture entire.
Locality. Three miles below Fort Union.
Paludina Consadi.
Shell elongate-trochiform, thick ; spire raher elevated, acute at the apex;
volu'ions apparently about six, flai, last one more or less angular below the
middle, and obliquely extended below ; surface marked with fine lines of growth,
crossed by delicate, nearly obsolete, revolving lines ; suture linear ; sperture sub-
circular, or broad ovate, obtusely angular above, (broadly rounded below?);
columella profoundly depressed in the umbilical region ; umbilicus none. Lergth
about 1 inch
;
breadth -70 inch
; length of aperture -44 inch ; apical angle slight-
ly convex, divergence 54.
In young specimens the angle on the lower part of the body whorl is quite dis-
tinct, and modifies the form of the aperture, but is more obscure in older shells.
Like P. Leui (of this paper), this species also has its near living representntives
amongst .Asiatic species, of which . Fra"cif>ci (Turbo Francisci of Wood,) is aa
example. We nume it in honor of Mr. T. A. Conrad, of Trenton New Jersey.
Locality. Bad Lands of the Judith.
Paludina peculiaris.
Shell trochiform, rather thin, oblique ; spire conical, acute at apex; volutions
(five and a halt?) flattened convex, last one distinctly angular a little below the
middle
;
surface marked with fine, rather indistinct lines of growth, crossed by
neaily obsolete, exceedingly fine revolving striae; suture moderatelj dtfined ;
aperture round ovate, or sub-quadrate.
Our specimens of this species arc imperfect at both extremities ; some of them
have a breadth of 53 inch, and indicate a length of about -f inch The apical
angle of a specimen consisting of the lower two whorls is 47; but as it waa
probably greater near the apex, the mean may have been as great as 50. In
form and general appearance it is very much like the last, and may possibly
prove to be onl, a variety ot that species; it is, however, a thinner shell, and the
voluii'ms are more convex.
Locality. Fort Claik.
Paludina trochiformis.
Shell trochiform, thin ; spire conical, pointed at the apex ; volutions five and a
half to i-ix, nearly flat, and ornamented by two slightly elevated revolving ririges;
last whorl strongly angular below the middle ; surface marked with ver\ fine lines
of growth, and exceedingly slender, raised, revolving lines ; suture linear, scarce-
1856.] 123
If distinct ; aperture sub-quadrate, or rounded ovate, more angular above, broad-
ly rounded below ; lip thin, reflexed on the colutnf-llar side below, but leaving a
small umbilical groove; columella strongly arcuate. Length -S*] inch; breadth
73 inch
; apical angle convex, divergence 73 to 77.
^
This interesting shell is so unlike the usual forms of PalUdina, that we would
have referred it to that genus with much doubt, had it not been for the fact that
we have from the same bed some intermediate gradations between it and the
risual typical forms of the genus. One of these, P. Leidyi of ih'S paper must be
(judging from the upper volutions,) in its young state, almost exactly like this,
both in form and surlace markings, yet at maturity, its last volution loses
almost entirely the angular outline characterizing this species at all stages of its
growth. We have seen fragments of this species indicating a size at least three
times as great as that of the specimen from which the above measurements were
taken.
P. cingulata of Matheron (see Catalogue Methodique, &c., p. 223,) from the
Lignite formations near the mouth of the Rhone, resembles this more than any
fossil species with which we are acquainted, but ditFersin the surface markings.
Amongst recent species it has two or three closely allied representatives, now in-
Ijahitingthe rivers of China and Siam, of which P. pyrimidata (Phillippi) is an
exam [lie.
LoculHy. Ten miles below Fort Union.
Palt'dina Leidyi.
Shell very large, conical-ovate, oblique, thin ; spire elevated ; upper volutiona
flattened, and ornamented by two indistinct revolving ridges ; lower ones more
rounded, last rather ventri-ose, and obscurely angular below ; suture linear and
scarcely distinct above, but well defined between the lower whorls ; surface
marke(l with distinct lines of growth, crossed by very fine, elevated revolving
lines, generally obsolete on the lower volutions; aperture apparently ovate; in-
ner lip spread upon the body whorl, but leaving partly uncovered a small, d(!ep,
oblique umbilical pit. Length about 1 86 inches; breadth 1-32 inches; apical
angle convex, divergence 65.
The most remarkable ftatures about this fine Paludina, are is large size, and
the peculi'irity of having the lower volutions smoothly rounded, or more or less
convex, while those nearest the apex are flattened and ornamented by two ob-
scure revolving ridges. The angle on the lower part of the last whorl is very-
obscure near the aperture, but becomis more distinct higher up, and must be
quite conspicuous on young shells. Unfortunately we have no specimens with
the aperture entire. (Jnr best specimen consists of four volutions, and judging
from the appearance of the broken apex, it must have had about two more.
We name this species after Prof Joseph Leidy, of the University of Pennsyl-
vania.
Localiiij. Ten miles below Fort Union.
Valvata parvula.
Shell very small, much depressed or subdiscoidal ; spire rising little above
the body whorl ^ volutions about three, nearly cylindrical, and having near the
middle, on the upper and lower sides, a distinct linear carina ; surface marked
with strong regular lines of growth ; sutures distinct ; umbilicus wide and deep,
showing all the volutions to the apex, aperture round or transversely oval.
Height .05 inch ; breadth .10 inch.
Frnm V. tricarinata (Say,) some varieties of which this resembles more than
any spec es known to us, it differs in having a wider umbilicus, less elevated
spire, and much stronger lines of growth.
Localvy. Three miles below Fort Union.
Melania minutdla.
Shell minute, elongate conical ; volutions seven to seven and a hilf, convex,
increasine gradually from the apex and flattened obliquely outwsrd fiom above,
near two-thirds of the way down, whence they round abruptly in to the suture
124 [June,
below, so as to form an obscure angle below the middle ; suture very distinct ;
surface faintly marked with fine lines of growth ; aperture ovate or sub-rhom-
boidal, angular above, widest near the middle, very narrowly rounded and ob-
scurely sinuate on the inner side below; columella somewhat less arcuate than
the outer side of the aperture ; lip thin and slightly refiexed at its junction with
the lower part of the columella. Length -16 inch ; breadth -05 inch ; length of
aperture -04 inch, breadth do. -03 inch ; apical angle regular, divergence 20" to
This beautiful little Melania approaches very near in size as well as in form,
M. spina, a Miocene species described by M. Grataloup {Conch. Melan. 10, t. 5,
fig. 6 and 7,) but differs in having fewer and more convex volutions.
Locality. Three miles below Fort Union.
Melania Anthonyi.
Shell very small, conical-ovate ; spire not much elevated ; volutions five to five
and a half, slightly convex, increasing somewhat rapidly from the apex, last one
rather large and obtusely angular below; surface marked witb fine, indistinct
lines ofgrowth, crossed by extremely fine, nearly obsolete, revolving striae ; suture
well defitied; aperture ovate, angular above, widest a little telow the middle,
narrowly rounded and very faintly sinuate on the inner side below; lip thin,
elighily reflexed on the lower and inner side, but leaving open a small umbilical
perf )ration ; columella regularly arcuate. Length -18 inch ; breadth -10 inch ;
length of aperture -OG inch; breadth of do. -01 inch ; apical angle slightly convex,
div. rgence 41.
Without a very careful examination with a good lens, in a favorable light, (he
extremely fine revolving strias on this neat little shell would be overlooked. In
form it is almost an exact miniature of M. Xebrascensis of this paper, but a care-
ful comparison with the young of that species of its own size, shows it to be quite
different. In addition to this, it occurs in great abundance at localities where
no authentic specimens of that species were met with. We have no doubt of
its being an adult shell. We name it after Mr. John G. Anthony, of Cincinnati,
Ohio, to whom we are under obligations for suggestions in regard to it and two
or three other species described in this paper.
Licaliiy. Yellow stone river, thirty miles above the mouth.
Melania mcltistriata.
Shell small, elongate-ovate ; spire conical, somewhat elevated, acute at the
apex ; volutions five and a half to six, convex ; surface marked with fine indis-
tinct lines of growth, and exceedingly fine, closely arranged revolving striae ;
suture well defined
; aperture narrow-oval, or ovate, contracted, but scarcely
sinuous below; columella regularly curved. Length -23 inch ; breadth 12 inch ;
length of aperture -10 inch ; breadth of do. -06 inch ; apical angle regular, diver-
gence 39.
This may be distinguished from the last by its more elevated spire, and more
elongated body whorl, which is never angular below. The aperture is also
narrower, and the columella imperforate. From the young of M. Nebr^iscensis
of its own size, it differs in bemg more elongated, and in having one or two more
whorls. The revolving striae are also more uniform, and so very fine as to be
only visible by the aid of a strong mHgnifier.
Locality. Ten miles above Fort Union.
Melania Nebbascensis.
Shell elongate-ovate ; spire conical, not very much elevated, acute at the apex ;
volutions about six, flattened convex; surface marked by fine lines of growth,
crossed by numerous more or les^ elevated revolving lines, some of which, on the
middle of the whorls, are sometimes so much larger than the others as to form
distinct carinas; suture strongly impressed; aperture ovte, angular above,
narrowly rounded and very faintly sinuous below ; outer lip prominent below the
middle
;
columella regularly curved. Length -78 inch ; breadth -42 inch ; length
1856.] 125
of aperture -37 inch; breadth of do. -21 inch; apical angle convex or nearly
regular, dlvprgence (variable) 44.
This sppcies presents numerous varieties of forna, apparently dependent upon
age. In younger individuals the spire is relatively less elevated, the whorls more
rounded and the aperture larger and more oblique. In its surface njHrkitigs it
also varies greatly, even in specimens of the same size. The carinoe formed by
the laiger revolving lines being in some specimens quite distinct, while in others
they are scarcely larger than the finer revolving lines which may be seen by the
aid of a lens to form, with the lines of growth, a delicate sub-cancellate surface
on all parts of the shell. On other specimens, all these surface markings are
almost euiirely wanting.
Locality. Ten miles above Fort Union.
Melania convexa.
Shell rather large, much elongated, sub-cylindrical or terete ; volutions (about
ten?) fi'it, closely wouud, and increasing very gradually from the apex; surface
ornamented by fine lines of growth, ciossed by distinct, regular, thread-like, re-
volving: lines, and extremely fine, nearly obsolete revolving striae ; suture general-
ly indistincr; aperture apparently ovate ; lip thin, having a broad very shallow
sinus helow \h^. suture, and another near the base of the columella. Length
about 1-60 inches
;
breadth -48 inch; length of aperture -45 inch ; apical angle
convex, divergence 21.
Our b^st specimen of this interesting species consists of seven volutions, and
appears to have lost two or three others from the apex ; the aperture is also dis-
torted. Tbe larger revolving lines, about seven of which may be counted on
the .second volution, are quite distinct, and near one-third as wide as tbe spaces
between, while the liner revolving strias are closely crowded, and so small as to
be only seen by the aid of a good lens. The divergence of the apical angle, be-
low the middle of an adult shell, is noc more than 13", while above, (and in
yout)g shells,) it is as mufh as 28 to 30.
In tlie last number of tbe Proceedings of the Academy, we described a shell
resembling this very closely in form, from the Yellow Sione river, where it was
found associated, in a loose mass, with fragments of an Ostrea and a small Cre-
taceaus species of Oardnim, (C. rarum, Evans and Shumard). Our specimens
being worn and imperfect, we supposed, from its associates, it must be a marine
shell, and referred it to tbe genus Turrilella, under the name of T. convex i We
now think it may possibly be a specimen of this species, from the junction of tbe
Cretaceous and Tertiary beds.
Locality. Bad Lands of the Judith.
Cerithium Nebrascensis.
Shell elongate-conical, very slender, whorls (nine?) convex, and ornamented
by three revolving rows of sharply elevated granules, placed upon obscure
vertical folds; surface marked with very fine lines of growth, crossed by much
stronger, elevated, thread-like, revolving lines, two, three, or more ot which
may be counted between each row of granules, suture distinct; aperture ap-
parently nearly circular, but teiminating below on the inner side, in a small
notch. Length about 1 inch ; breadth -29 inch ; apical angle regular, diver-
gence 19.
On the lower part of the body whorl there are three or four small revolving
lines, two of the upper of which are sometimes granular, making on this whorl
five rows of granules. Between these and the next row above, one of the revolv-
ing liiif^s is also minutely granular. Inform and general appearance, this re-
semhl it: two or three species described by Deshays, from tbe Paris basm, but on
close cmnparison, we find it quite distinct from them all. Amongst existing
species, it appears to be nearest C. granulosum, and estuary species from the
Western coast of Africa.
Locality. Near head waters of Little Missouri.
126 [June,
We are under obligations to Prof. James Hall, of Albany, New York, for
the free use of his extensive collection of books on Palaeontology, as well as
for occasional sugestions while investigating the Nebraska fossils, described in
this and our former papers.
Correction.
In a paper communicated by us to the Academy in March last, and published
in the preceding number of the Proceedings, we referred to the genus Pyrula
a shell (P. Z?a!rf/f, page 66), which we have since satisfied ourselves belongs
more correctly to the genus Busycon of Bolten ;. we now change the name to
Bmycon Bairdi.
Ceratites Americanus.
By Professor L. Harper, University of Mississippi.
The Ceratites, a Cephalopodus mollusk, subgenus of Ammonites, has been
discovered in Europe long ago. All the European species, without any excep-
tion, belong to the new red sandstone or Triassic formation. Twenty-one species
have, according to Bronn, been placed in the St. Cassian formation in Tyrol, to
which the lowest place in the Trias has most probably to b^i assigned. One
species is found in the St. Cassian rocks and also in the Muschelkalk ; one in
the Bunter sandstein and the Muschelkalk, and of the remaining eight species,
three belong certainly and five probably to the Muschelkalk of the Trias. The
Cerrttiips were therefore considered as characteristic, and belonging exclusi^-ely
to the nciv red sandstone formation, and exclusively a European fossil, until a
few years ago L. V. Bach, the late great German Geologist, discovered a Cera-
tites in the cretaceous rocks of the Caucassus, which he called Ceratites Syriacus.
No species of the Ceratites has heretofore been found on the continent of Ame-
rica.
About three years ago, in summer, 1853, when I was in the State of Alabama,
I examined the bed of the Tuscaloosa or Black Warrior River, near the little
village of Erie in Greene County, about 12 miles above the confluence of the
Tombigbee and Black Warrior rivers, between the 32d and 33d degrees of north
latitude, where the river cuts through the lowest part of the cretaceous forma-
tion of our southern State^", corresponding most probably to the Turonien ot
D'Orhigny. The bluff of the river consists here entirely of different strata of
green sand, divided in several parts by thin seams of a hard co' glomerate of
peroxide of iron and green sand, and is from 50 to 95 feet high. The river was
then unusually low, and more than one-half of its bed perfectly dry and acces-
sible.
On a sand-bank in the middle of the river, immediately below a very deep
place, were found, among other evidently cretaceous fossils, three specimens of
a smalJ Ammonite, which, after a careful examination, I immediately recognized
to be a species of Ceratites, in which opinion I was later confirmed by as high
an authority as Prof. L. Agassiz, of Cambridge, who pronounced it to be a new
species of Ceratites, closely allied to Ceraticus Syriacus of L. V. Btich.
This bfiog the first Ceratites ever found on the continent of America, I pro-
pose for it the name of
Ceratites americanus.
Testa compressa, disco baud dissimili, paulisper deneata ad aperturam, val-
deque at.tenua'a ad apicern, et pra3cipue subito accrescente a medio usque ad
apenuram; aufractibus duabus, secundo amplecto primi ventre et tanquara in
Btriam posito ; apertu-a semi-ovata ; loborum numero, in vita, sex, toti-
demquf sidhe, loho ventrali attamen nonnihil indistincto ; lobis dentibus tribns
raunitis, qui magnitudinis causa etiam lobi secundarei vocarentur; septis angu-
larihus dorso relrorsum flexis
; siphunculo dorsali.
The two specimens, still in my possession and here represented, are both very