REPORT OF THE STATE PALEONTOLOGIST 1902 903 



mm in thickness. The ventral valve has a wide sinus flanked 

 by six plications on each side, the innermost on either side 

 being wider than the others. The dorsal valve has a broad, 

 low fold with five ridges on each side running about two thirds 

 of the way to the beak. There is also the beginning of a sixth 

 ridge forming next to the median fold. The beaks are blunt 

 and not prominent; area low. The form is suggestive of 

 S. g r i e r i Hall (Onondaga). It approximates closely to the 

 beak of S. m e d i a 1 i s , except in being much smaller than a 

 normal S. medialis of that degree of development. 



Localities. Abundant at Canandaigua lake, common at 

 Livonia salt shaft and rare in the Moscow localties. Total 

 specimens 35. 



Spirifer tullius Hall, mut. belphegor Clarke 



Plate 3, fig. 3, 4 



Spirifera belphegor Clarke. U. S. Geol. Sur. Bui. 16. 1885. p. 30 

 This form is nearly round in outline, about as broad as high, 

 with rounded extremities and a very high area. It measures 

 4 mm in breadth, 4 mm in hight and 3 mm in thickness. The 

 extremely gibbous ventral valve has a narrow median sinus, 

 flanked on either side by six ridges, which reach nearly to the 

 beak. The beak of this valve is acute and prominent. The 

 dorsal valve is less convex; beak low and not prominent; the 

 median fold is low and flanked by six ridges on each side. The 

 area is triangular and high. This corresponds to a young 

 shell of S. tullius. 



Localities. Rare at Canandaigua lake and near the Delaware, 

 Lackawanna and Western Railroad at Moscow. Total speci- 

 mens 3. 



Spirifer granulosus Conrad, mut. pluto Clarke 



Plate 3, fig. 7, 8 



Spirifera pluto Clarke. U. S. Geol. Sur. Bui. 16. 1885. p. 31 

 This is a large, broadly oval form, with rounded extremities. 

 It measures 4 mm in breadth, 2y 2 mm in hight and nearly 2 mm 

 in thickness. Both valves are equally convex. The ventral 

 shell has a broad obtuse beak; the median sinus wide and deep, 

 flanked by eight broad, low ridges, each running three fourths 



