1898-1902. No. 32.] FOSSIL FAUNAS FROM SERIES B. 19 



Neotremata. 



Discinidae. 

 Orbiculoidea d'ORB. 



Orbiculoidea sp. 



An exterior mould of a very small depressed conical ventral valve 

 with diameter 2 mm. is seen on a piece of black argillaceous limestone 

 bearing Monograptus sp. The pedicle groove is indistinctly indicated 

 while the concentric striation is well marked. 



Occurrence: B, upper part, south of Point to the north of the 

 Beautiful Valley. 



Protremata. 



Strophomenidae. 

 Stropheodonta HALL. 



Stropheodonta patersoni HALL var. antiqua nov. var. 

 PI. VII, fig. 23. 



On some pieces of dark limestone we observe several isolated ven- 

 tral and one dorsal valve, which agree with Stropheodonta patersoni 

 from the Schoharie Grit and the Onondaga Limestone of New York 

 in all respects except the size, which is decidedly smaller. The out- 

 line is sub-semicircular with acute angles. The ventral valve is mode- 

 rately and regularly convex, varying somewhat in different specimens, 

 flattening out in the well defined cardinal extremities. The dorsal 

 valve is nearly flat except near the anterior margin, where it is strongly 

 curved. The surface shows the typical system of strong striae, be- 

 tween two of which come from six to eleven finer ones, and the 

 well marked small arched wrinkles. As mentioned above, the size is 

 considerably smaller than in the New York species. The largest speci- 

 men seen measures only 15 mm. in length and 25 in width. The Arctic 

 form differs in this respect also from the two varieties of S. patersoni 

 which Dr. J. M. CLARKE described from the Gaspe district of Eastern 

 Quebec 1 , S. bonamica (from the Bon Ami Beds) and precedens (from 

 the Grand Greve limestone). From Stroph. corrugatella DAV. the form 

 differs by its greater convexity. 



Occurrence: B, upper part, over the fragment limestone, Valley 

 south of Borgen, Gaasefjorden. 



1 See New York State Museum, Memoir 9, Early Devonic History of New York 

 and Eastern North America, Part. 1, p. 186, Part. 2, p. 44. 



