LINGULA MANTELLI. (N. s.) Description.-Elongate-oval, sides sub-parallel, gently convex for rather more than half the length, then gradually curving to the beak, front moderately rounded. Surface, when partially exfoliated, covered with longitudinal radiating striæ. Length four or five lines, width rather more than half the length. Both valves are very convex, and do not appear to have the plane surfaces of L. Lyelli. Although the form is somewhat like that of the young specimens of L. Lyelli, yet it is clear that this is a distinct species. It occurs in a different locality, and although very abundant, none of the specimens are more than six lines in length, the average size being from four to five lines. It is a smaller, and also proportionally more convex species than L. Lyelli. · None of the specimens that I have seen have the shell well preserved, and I am unable, therefore, to say what the character of the surface may be when perfect. Dedicated to the late Dr. Mantell, author of the Medals of Creation, &c. Locality and formation.-Near the Village of St. Eustache, Calciferous sandrock. Collectors. A Murray, J. Richardson. ORTHISINA GRANDÆVA. (N. s.) Fig. 1-g, h, i. Description.-Ventral valve depressed pyramidal, nearly semicircular, area large, inclined backwards at an angle of about 125°; foramen closed, all except a small space at base, the apex perforated; surface with fine radiating striæ, of which there are four or five in one line at the margin; width of the only specimen seen, at hinge line, seven lines; length, from hinge line to front, three lines and a half; length from beak to front, six lines; height of area, two lines. Dorsal valve unknown. It is not certain that this species belongs to the genus Orthisina; but, as the foramen is nearly closed, it appears more closely allied to that genus than to Orthis. A single, but very perfect valve is all that has been collected. There are, besides the above, in the White Limestone at the Mingan Islands, numerous casts of a species of Orthis or Orthisina, which have the same form as O, grandava, and appear to me to be the same species. If so, then the dorsal valve is convex, and the species attains a much larger size than that indicated by the single valve in our possesion. The specimens range from six lines to one inch in width, and are very abundant. Locality and formation.—Mingan Islands,Calciferous Sandrock. Collector.-Sir W. E. Logan. LAMELLIBRANCHIATA. CONOCARDIUM BLUMENBACHII. (N. s.) Description. Triangular, ventricose, sub-cordiform, umbones prominent incurved, the posterior or truncated extremity flattish or gently convex with an oval outline, the greatest width being at about one third the length from the beak; the length from the beaks to the posterior ventral margin in the best preserved specimen is sixteen lines, greatest width thirteen lines. On a side view the form is sub-triangular, the posterior angle rather sharp, about 80°; the ventral margin rounded; the posterior edge or ridge which runs from the beak to the posterior ventral angle is nearly straight or but slightly convex in the lower half and thence becomes more and more strongly curved until it reaches the beak. The anterior side is a little longer than the ventral margin and appears to have been nearly straight. Surface with rather strong radiating ridges four or five in the width of two lines at the ventral edge. The cast of the interior of the right valve indicates six or seven crenulations on the posterior edge of the shell in the length of two lines. The siphonal tube is not preserved in any of the specimens but there are indications of its existence. There is a small species of this genus in the Black River limestone but this is the first that has been discovered in strata of such great antiquity as the Calciferous sandrock. Locality and formation.—Mingan Islands, White Limestone. Collectors.-Sir W. E. Logan, J. Richardson. GASTEROPODA. HOLOPEA TURGIDA, (Hall, Sp.) PLEUROTOMARIA? TURGIDA, Hall, Paleont. N. Y., Vol. 1, p. 12, Plate 3, Fig. 9, 10. Several specimens have been collected in the Calciferous Sandrock, Mingan Island, which appear to be of this species. Collectors.-Sir W. E. Logan, J. Richardson. Description.-Oval, moderately ventricose, four whorls, the body whorl at the aperture occupying two thirds the whole length, the whorls depressed convex, the suture deep,giving the cast a turreted appearance, apical angle about 75°. Length one inch and a half, width fourteen lines. Locality and formation.-Second Concession of Godmanchester, Calciferous Sandrock. Description.-Shell trochoid, acutely conical, spire much elevated, whorls five or six perfectly flat, apical angle about 60°. Outer margin of body whorl with a sharply rounded edge; aperture sub-rhomoidal, umbilicus small; surface with fine striæ curving backwards from the upper to the lower edge of the volutions Base s'ightly concave. Height of only specimens collected fourteen lines, width of base about the same, width of umbilicus one line. The spire of this species, owing to the perfect flatness of the whorls, presents at first sight an uniform plane surface, the suture The outer edge of being so fine that it is barely visible. the body whorl shows what may be called a spiral band, which on its upper side is bordered by a fine continuous line, half a line from the edge; the outer angle of the mouth has a moderately deep angular notch as in the other species of this genus; the striæ on the base after leaving the edge curve abruptly forward, and then at the distance of less than a line from the edge rather suddenly change their direction, and with a barely preceptible backward curve proceed to the umbilicus in a nearly straight line; there are several strong wrinkles that follow in the direction of the striæ. The course of the striæ over the edge cannot be distinctly seen but they appear to make a sharp curve backward corresponding to the form of the notch. The upper and outer sides of the aperture are straight, the lower side is also straight for about half the width of the volution, and it then curves up gradually to form the inner lip, a small portion of which is reflected. This species much resembles a Trochus, but the notch in the outer angle of the aperture, the direction of the striæ on its surPleurotoface and the apparent band shew that it is more likely a maria. Dedicated to the eminent geologist Professor A. C. Ramsay, Director of the Geological Survey of Great Britain. Locality and formation.-Mingan Islands, Calciferous Sandrock. Collectors.-Sir W. E. Logan, J. Richardson. FIG. 5. a Pleurotomaria calcifera. b A more depressed variety. c. View of the spire shewing the backward curving striæ. Description.-Lenticular, with a sharp elevated margin; spire much depressed; apical angle varying from 130° to 145°; whorls four or five, rather slender with a thin elevated outer edge which is more or less distinctly visible all the way to the apex; they are also slightly concave on their upper surface, the concavity being deepest near the lower edge; in some specimens there is a gentle convexity in the upper half of each volution and in others the surface is nearly flat. On the under side of the shell the whorls are convex and appear to have a prominent obtuse angle at the edge of the umbilicus; the latter is large, conical, penetrating to the apex and at least half as wide as the whole shell. The surface is covered with fine stria which turning backward at an acute angle indicate a deep notch in the outer angle of the aperture. The last whorl in some of the specimens on approaching the aperture drops a little below the margin of the second, shewing a tendency to become disengaged. The aperture judging from the form of the volutions must be sub-rhomboidal. The largest specimen seen is one inch and a half wide, and about half an inch in height. This species is closely allied to R. aperta (Salter), but differs therefrom in the following particulars. 1st. The height R. aperta is about half the width, in this species about one third. 2nd. In R. aperta the edges of the whorls on both sides of the suture sink below the general surface, and there is consequently a rather deep spiral channel running to the apex, but in this species the outer edge of the whorl rises above the general surface and forms an elevated spiral line following the upper side of the suture from the aperture to the apex. 3rd. In R. aperta the inner half of the width of the volution is always strongly convex and the outer half as strongly concave but in R. calcifera the whole surface of the whorl is concave or only very slightly convex towards the inner side. As all the specimens that I have seen are embedded in the rock, I have only been able to ascertain the characters of the underside of the shell from fragments. The base seems to be more like R. aperta than the spire. The two species are closely allied and should, perhaps, be considered as varieties of each other. Locality and formation.-Near Beauharnois, Calciferous Sandrock. Collector.-J. Richardson. CANADIAN NAT. 3 VOL. IV. No. 5. |