l6o NEW YORK STATE MUSEUM 



The relations of these shells appear to be wholly with the pterineoids, 

 the conformation of the anterior parts indicating the structure of Mytilarca. 



Localities. At Fruing's, Indian Cove and elsewhere along the Grande 

 Greve coast. We have already noted the presence of this shell in the St 

 Alban beds. 



Leptodomus canadensis Billings 



Leptodomus canadensis Billings. Palaeozoic Fossils. 1874. v. 2, pt i, p. 

 54, pl- 5, fig- I 



Original description. Transversely elongate, oblong. Dorsal margin, as seen in the 

 cast of the interior, nearly straight, gently concave, slightly the most elevated at the 

 umbones. Ventral margin gently convex; a small portion at the anterior third concave; 

 the posterior third ascending with a moderately convex curve. Anterior extremity slightly 

 sinuated at about the mid-hight; below the sinus, a little projecting and narrowly rounded; 

 nearly vertical above; rounded over the umbones. Posterior extremity with the most pro- 

 jecting point just above the mid-hight; gently rounded below; obliquely truncated 

 above. 



The shell is rather strongly convex, most prominent about the middle or a little in 

 front thereof. The umbones are large, beaks incurved. From the anterior third of the 

 ventral margin an obscure shallow depression in the surface ascends obliquely upwards 

 and forwards, dying out on the umbo, before reaching the beak. The umbones are sub- 

 carinate on their upper and posterior edge. The- dorsal margin is inflected, with some 

 indications of a long narrow lunule. 



Surface, as appears by the cast of the interior, with strong concentric undulations, 

 three or four lines wide towards the posterior; narrower and deeper on the umbones. 



Length, about two inches; hight at the umbones, ten lines; depth of a single valve, 

 six lines. 



This species is very rare in our collections from the Grande Greve 

 limestones. 



Localities. Grande Greve and Indian Cove. 



Modiomorpha varia (Billings) 



Plate 22, figures 1-5 

 .SV^ p. 115 



Modiolopsis varia Billings. Palaeozoic Fossils, p. 56 



This species was described without illustration and its locality was 

 given as " between Cape Gaspe and Cape Rosier." We find on inspection 

 of the originals, figures of which are here given, that they are from localities 

 of the Grande Greve limestone ; Indian Cove, Little Portage and Grande 

 Greve. Similar shells we have found to be of frequent occurrence in the 

 shore outcrops of the Forillon. 



The species is very similar in type of outline and exterior to M. al ta 

 Conrad, a common form of the Hamilton fauna \see Hall, Pal. N. Y. v. 5, 

 pt I, pl. 37], and approaches some of the described forms from the earlier 

 Devonic faunas of New York like M. ponderosa of the Onondaga 



