ARTICLE. XIII.-New Species of Fossils from the Lower Silurian Rocks of Canada. BY E. BILLINGS.

(From the Report of the Geological Survey for 1860.)
STRAPAROLLUS CIRCE. N. s.

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 1.-Straparollus Circe. Front view.
2.-Vertical view of the spire.

3.-View of the umbilicus.

Description.-Depressed conical, height a little more than half the width, apical angle about 125°; apex rounded, not acute; whorls four or five, with a nearly circular section; umbilicus deep, conical, extending quite to the apex, about one third the width of the shell. Aperture nearly circular, the height slightly exceeding the width, scarcely indented by the preceding whorl Surface nearly smooth. Suture distinct.

CAN. NAT.

1

VOL. VI..

Width of the only specimen examined eight lines; height five lines; width of aperture three lines.

This species closely resembles the original Straparollus Dionysii upon which Montfort established the genus. It also approaches Euomphalus cyclostomus, (Hall). Geology of Iowa Pl. VI. fig., 6 (Hamilton Group Iowa).

Locality and Formation.-Pauquettes Rapids, Ottawa River, Black River, and Birdseye. (very rare).

Collector.-Sir W. E. Logan.

STRAPAROLLUS EURYDICE. N. s.

Fig. 4. Straparollus Eurydice. Front view.
5.-Side view.

Description.-Conical, apical angle about 60°, rounded not acute; height and width about equal; whorls five, with a nearly circular section, uniformly ventricose; suture distinct; umbilicus small, deep, one sixth the width of the base of the shell; the body whorl obtusely carinated close to the edge of the umbilicus; the aperture nearly circular, its height slightly exceeding the width. Surface with obscure lines of growth, which cross the whorl a little obliquely from the suture downwards and backwards; a few wide shallow undulations parallel with the lines of growth.

Height seven lines; width the same; width of aperture three lines, height three and a half.

Locality and Formation.-Pauquettes Rapids, River Ottawa, Black River, and Birdseye.

Collector.-Sir W. E. Logan.

STRAPAROLLUS ASPEROSTRIATUS.

N. s.

Description.-Shell small, depressed-conical; apical angle between 80° and 90°; whorls about three with a nearly circular section, regularly ventricose above; obscurely carinated along the middle on the underside, suture distinct, umbilicus about one fourth the width of the shell, penetrating to the apex; aperture circular. Surface with strong sharply elevated lines of growth,

which on crossing the whorl are deflected gently backwards until on approaching the base of the body whorl, they turn a little forward and pass vertically into the umbilicus. There are six striæ in the width of one line. Width of only specimen seen five lines, height four lines; width of aperture two and a half lines.

This species differs from S. Circe in being much smaller, and in having the surface so strongly striated as to present a peculiarly rough file-like appearance; only one specimen has been collected, but as it exhibits the aspect of a mature shell, I am inclined to think the species is small.

Locality and Formation.-Pauquettes Rapids, Ottawa River, Black River, and Birdseye, (apparently rare).

Collector.-Sir W. E. Logan.

The following species of Pleurotomaria have been usually referred to P. lenticularis, (Sowerby) but they all appear to be distinct from that species.

PLEUROTOMARIA PROGNE. N. s.

Fig. 6.

Fig. 6.-Pleurotomaria Progne.

Decription.-Lenticular; about one inch and a half in width; spire depressed conical, apical angle about 140°, seldom more but often a little less; surface of spire presenting an uniform nearly flat, smooth slope from the apex to the margin, the sutures in perfect specimens being scarcely distinguishable although in casts of the interior they are somewhat strong and deep. The margin is narrowly rounded and does not exhibit the acute edge possessed by such species as P. qualteriatus. On the under side the whorls are uniformly depressed convex and the base, or all that portion of the shell which lies below the margin, is usually nearly double the bulk of the spire. When perfect the umbilicus is completely closed, but in the casts of the interior, there is a small perforation. The aperture is transversely sub-oval, scarcely sub-rhomboidal

and in perfect specimens the width must be nearly twice the height. There are about four whorls. The surface appears to be nearly smooth, but as the only specimens with the shell preserved, that I have seen are silicified, they do not exhibit it perfectly.

This species differs from all those described by Hall in the Paleontology of New York in having the umbilicus closed and from the P. lenticularis and P. qualteriatus of the European authors, not only in the same respect, but also in having the margin rounded instead of acute.

Locality and Formation.-City of Ottawa; near Montreal; Belleville; Trenton, and numerous other localities in Trenton Limestone; good specimens extremely rare.

Collectors. Sir W. E. L.; A.M.; J. R.; E. B.

PLEUROTOMARIA AMERICANA.

P. lenticularis?-Hall, Pal. N. Y., p. 172.
Not P. lenticularis.-Of European Authors.

Fig. 7.

Fig. 7.-Pleurotomaria Americana. A section through the umbilicus. General form same as P. Progne, (see fig. 6) from which species it only differs in having an open umbilicus.

Description.-Lenticular, one or two inches wide; whorls four or five, nearly flat above, elevated into a depressed conical spire with a nearly smooth continuous slope from the apex to the margin; the latter obtusely rounded. On the under side the whorls are moderately convex, forming a depressed conical base, the bulk of which is always somewhat greater than that of the spire. The umbilicus penetrates to the apex, and is in general somewhat less than one third of the whole width of the shell. The aperture is transversely sub-rhomboidal, the width about one third greater than the height.

The surface is rarely preserved, but from such fragments of the shell as I have seen it must be nearly smooth or at least very finely striated.

This is the most common species of Pleurotomaria in the Trenton Limestone, and is I have no doubt the same as that figured by Prof. Hall in the work above cited, but surely it cannot be the European species P. lenticularis to which it has been referred. That species has a sharp edged margin. There are several European species under the name P. lenticularis, but it is the Silurian form to which I refer.

P. rotuloides.-(Hall) has not the smooth spire, and concealed suture of P. Americana, and there is no other in the Palæontology of New York, to which this species can be compared. It may be that P. Progne and P. Americana should be classified as one species, but at present I think the great difference in the umbilicus is sufficient to separate them.

Locality and Formation.-Trenton Limestone at Ottawa, Montreal, Beauport, Trenton, Belleville, and St. Joseph's Island, Lake Huron. Good specimens exceedingly rare.

Collectors.-Sir W. E. L.; A.M.; J. R.; E. B.; R. B.

So.

Fig. 8.

Fig. 8.-Pleurotomaria Helena.

Description.-Sub-lenticular, with an elevated narrowly rounded margin; spire depressed conical; apical angle varying from 110° to 125°, apex rounded not acute; whorls about four, the last one rather strongly concave on the upper side, the others only slightly On the under side of the shell the whorls are moderately convex, and the umbilicus closed. The aperture is a little wider than high, the upper part of the inner lip slightly indented by the body whorl, the lower half somewhat vertical, but rounded, the lower part of the outer lip from the umbilicus to the margin of the whorl gently convex, the portion above the margin concave. In most specimens the suture is enamelled, the shell appearing to be continuous from the apex to the margin, but in some, especially