■ BEEKMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 463 



of the whorls and in other features, this form bears much resem- 

 blance to E. gibbosus, a species described (but not figured) by 

 Hyatt [1894, p. 443] from the Beekmantown of Port au Choix, 

 Newfoundland. This latter type is described however as not being 

 very involute. 



The type specimen exhibits the first chamber with the cicatrix and 

 a faint surface sculpture, consisting of concentric and radiating 

 lines [see pi. i8, fig. 6, 7]. 



Eurystomites rotundus Hyatt 



Nautilus kelloggi Whitfield (pars). Am. Mus. Nat. Hist. Bui. 



1886. V. I, no. 8, p. 328, pi. 31, fig. 4, 5 

 Eurystomites rotundus Hyatt. Am. Phil. Soc. Proc. 1894. 



32:443, pi. 5, fig. 21-25 



The probable presence of this species in the Valcour rocks (Ao) 

 is indicated by a small fragment only, which, on account of its 

 rotundity^ large size and close position of the siphuncle to the ventral 

 side, may be more safely referred to this species than to E . 

 kelloggi. 



E . rotundus has been separated from E . k e 1 1 o g g i by 

 Hyatt on account of the presence among the figured types in the 

 American Museum of specimens which " increase more rapidly in 

 the growth of the ventrodorsal diameters than in kelloggi and 

 retain the siphuncle near the venter for a longer time during the 

 growth. This may be due, however, to the difference in the size 

 and not a matter of age, since in large whorls it assumes a similar 

 position to that of kelloggi." 



Sections through the center and early whorls have brought out 

 the fact, which is illustrated by Hyatt's figures, of " the large size 

 of the umbilical perforation and the correlative rotundit}' of the 

 dorsi of the meta- and paranepionic substages." 



This form is apparently very rare in the Beekmantown beds of 

 the Champlain basin and complete specimens have not yet come 

 under observation. The types of the species come from the Fort 

 Cassin beds at Fort Cassin Vt. 



Eurystomites virginianus Hyatt 



Eurystomites Virginia n a Hyatt. Am. Phil. Soc. Proc. 1804. 

 32 :444 



Hyatt states under the description of this species, the types of 

 which were found near Lexington Va., that ''there is a young speci- 

 men in the American IMuseimi under the name of kelloggi, 



