476 



NEW YORK STATE MUSEUM 



Schroederoceras eatoni Whitfield (sp.) 



Plate 20, figure 3, 4 ; plate 23, figure 1 



L i t u i t e s eatoni Whitfield. Am. Mus. Nat. Hist. Bui. 1886. v. 1, 



no. 8, p. 331, pi. 28, fig. 5-7; pi. 32, fig. 1 

 Discoceras eatoni Schroder. Pal. Abhandl. von Dames & Kay- 



ser. 1891. Bd. 5, Heft 4, p. 22. 

 Schroederoceras eatoni Hyatt. Am. Phil. Soc. Proc. 1894. 



32:470, pi. 6, fig. 28-35; pl- 7, rig- 7~8 



Our material of this small species from the west side of the Cham- 

 plain basin is only fragmentary. Moreover, since the mature form 

 has been fully described by Whitfield and the growth stages elabo- 

 rately worked out and figured by Hyatt, it will suffice here to state 

 that this type is present in the Valcour beds A 3 and A 5 , though 

 by no means very common there. 



We figure here transverse and longitudinal sections which will 

 serve to show the slightly depressed character of the volutions, the 

 propiodorsan position of the rather large siphuncle and the close 

 arrangement of the quite concave septa. From the most complete 

 material of Fort Cassin, it has also been concluded that this species 

 does not attain large size, that the living chamber comprises nearly 

 three fourths of a volution and that in the gerontic stage the last 

 portion of the living chamber becomes uncoiled. The beautifully 

 preserved specimen reproduced here on plate 23, figure 1 exhihits 

 these characters very perfectly and shows that the evolute gerontic 

 whorl does not become deflected in a straight line, as the author of 

 the species suggested, but merely describes a considerably flatter 

 curve than the preceding volutions. 



Position and localities. At Fort Cassin and in A 3 and A 5 of 

 the Fort Cassin beds at Valcour. 



Schroederoceras cassinense Whitfield (sp.) 



Plate 20, figure r, 2 



Lituites eatoni var. cassin en sis Whitfield. Am. Mus. Nat. Hist. 



Bui. 1886. v. 1, no. 8, p. 332, pl. 32, fig. 2 

 S c h ro ed e r'o c eras cas s i n e n s e Hyatt. Am. Phil. Soc. Proc. 1894. 



^^2:47^. j)l. 6, fig. 36-38; pl. 7. fig- 4-6 



( )nly a few specimens in our Valcour collections represent this 

 type which was originally described as a variety of the more com- 

 mon S . e a ton i , but later on given full specific rank by Plyatt. 

 The latter author states regarding the relations of this species, which 

 he had occasion to study from both the collections in the American 



