293 



Hyol. 



conglomerate limestone out-cropping on the ridge east of Troy, 

 N. Y. Others have been found in similar cong. limestone beds 

 at Bic, and St. Simon, Canada. (Larger specimens occur in the 

 Big Cottonwood Canon shales of Utah.) In Georgian {Lower 

 Cambrian) slates. Z. C. — See foot-note to p, 13 i. 



Hyolithes {Theca.) Walcott, Bulletin U. S. G. S. No. 10, 



PI 2 plate 2, fig. 4, cast of inside 



surface of a lid (operculum) 



I of this pteropod ; fig. 4(2, o^lt- 



side surface ; both magnified 



/^wr diameters. — M, C, 



Hyolithes acadica. ( Theca acadica^ Hartt's label.) WaL 



, -^CN ^^^^^ Bulletin, U. S. G. S. No. 10, page 



LC.PIl.^-. ..^.-r^^ .20, plate 2, fig. 5, ventral face of the 



pteropod shell, natural size, — New Bruns- 

 wick, in Saint John formation^ Middle 



Cambrian, M. C. — See foot-note to page 134. 



Hyolithes aclis. {Theca aclis.) Hall, Palaeontology of 

 New York, V. 2, 1879, page 197, plate 32, figs. 22 to 30; plate 

 32 A. figs. 21 to 25. — In the semicalcareous shales of Cayuga 

 lake, N.Y. Hamilton. VIII c, 



Hyolithes aculeatus. ( Theca aculeatus.) Hall, Palaeon- 

 tology of New York, V, 2, 1879, page 192; described in 1860 

 as Pugiunculus aculeat a irom. Rockford,Ind. Lower Carboni- 

 ferous goniatite beds. XIII? 



Hyolithes americanus. ( Theca triangularis. Hall, 1847, 



ca u 6/ I'^l- N- Y. I, 313, plate 



MO.A ^^^ A ..r^-^^ A 87, 1 ^ to 1 6?.— Ford, 



1871, Am. Jour. Sci. [3] 

 II, 33.— Billings 1872, 

 Can. Nat. [2j VI, 215, 

 figs. 2 (^, b ; Am. Jour. 

 S. [3] III, 353, figs. 2 a, 

 b.) Walcott, Bull. U.S. 

 G. S. No. 30, page 132, 

 plate 13, fig. 6, ventral 

 view, enlarged three 

 times ; fig. 6 a.^ dorsal 

 view, of a narrow speci- 

 men enlarged 2 1-2 



PlAtelS 



J 



