. The geology of Nova Scotia, New Brunswick, and Prince Edward Island, or, Acadian geology [microform]. Geology; Geology, Stratigraphic; Paleontology; Geology, Economic; Géologie; Géologie stratigraphique; Paléontologie; Géologie économique. pr Pi I :'! I I'l 294 THE CARBONIFEROUS SYSTEM. that Phillips himself figures a specimen of his Terebratula rhomboidea with a simple mesial fold, we need not be surprised to find the same peculiarity in one of those from Nova Scotia. Indeed, after carefully examining the three examples forwarded by Dr Dawson, I cannot bring myself to believe that they shou
. The geology of Nova Scotia, New Brunswick, and Prince Edward Island, or, Acadian geology [microform]. Geology; Geology, Stratigraphic; Paleontology; Geology, Economic; Géologie; Géologie stratigraphique; Paléontologie; Géologie économique. pr Pi I :'! I I'l 294 THE CARBONIFEROUS SYSTEM. that Phillips himself figures a specimen of his Terebratula rhomboidea with a simple mesial fold, we need not be surprised to find the same peculiarity in one of those from Nova Scotia. Indeed, after carefully examining the three examples forwarded by Dr Dawson, I cannot bring myself to believe that they should be specifically separated. It is well known that the same peculiarity occurs with Rhynchonella acuminata; and any one who examines plates 20 and 21 of my 'Mono- graph of British Carboniferous Brachioi)oda' must feel surprised at the immense variability of which some species are susceptible. Fig. 93.—Uhynehonella Datosoniana, Davidson ; nat. size and " Rhynchonella Dawsoniana, n. sp. (Fig. 93, a, b). "Shell very small, almost circular, a little wider than long; dorsal valve moderately and uniformly convex to about half its length from the umbone, at which point a very slightly elevated and flattened mesial fold begins to rise, and extends to the front; the surface of the shell is also either almost entirely smooth or ornamented with from eight to twelve .slightly marked ribs. The ventral valve is gently convex, with a wide sinus; beak small and incurved. Length three and a half lines, width four lines, depth two and a half lines. "This small species does not appear to be rare in a black Lower Carboniferous limestone at Lennox Passage, and is not unlike, except in size, certain examples of M. de Verneuil's Terebratula superstes ; but this last-named Permian shell belongs to the genus Camarophoria, while the one under description belongs to Rhynchonella. I have compared it with a number of equally small young examples of Rhyn- chonella pugnus,
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