295 



Hyol. 



Hed from three to tour times,— {c Hyolithes imp ar. Fori,)— 

 Lower Cam.hrian. Z. C.—See foot-7iote to page 1S4. 



Hyolithes communis, var. emmonsi. ( Salter ella^Yord. 



hAC .^ Am. J. S. 1S71, Vol, 2, 

 ^p °' p. 33. Hyol. emmonsi 

 pUte \K. Ford. Am. J. S. 1873, 

 V. 214, figs. 3 1? to 3 e.) 

 Walcott, Bull. U. S. G. 

 ^ S. No. 30, page 137, 

 plate 14, fig. 4, back 

 view, showing three layers of shell and a septum ; fig. 4 a^ front 

 view of a specimen showing constriction at point ; both magni- 

 Aed three times. — Even bedded and Conglomerate limestone, 

 Troy,N.Y. Loioer Cambrian, L. G. — See foot-note to page ISJ^, 

 Hyolithes danianus. {Camarotheca daniana.^ Matthew, 



Lm>* w * 



la 



''?.X 



1884, Mss.) Walcott, Bulletin U. S. G. 

 S. No. 10, page 20, plate 2, fig. 7, back 

 view of a portion of a shell; 7 ^, front 

 view ; 7 />, side view to show the curvi- 

 ture ; all enlarged twice. Middle Cam- 

 Irian {Saint John) formation, New 

 Brunswick, M. C. — A considerable 

 range of variation in this species. In 

 some the ventral side is not flattened, 

 and the dorsal side has a narrow line each 

 side of the center. Curvature varies. 

 Hyolithes gibbosus. ( Theca gihlosa, Hall and Worthen.) 

 See Hairs history of the genus in Pal. N. Y. Vol. 5, part 2,1879, 

 pp. 191-195, where it is placed in the Potsdam which Walcott 

 calls Upper Camhrian., Bull 30, p. 131. — See Appendix. 

 Hyolithes impar. (Ford, 1872, Am. J. Sc. [3] vol. 3, p. 



419, figs. \a, I. 2a, h.) Walcott? 

 Bulletin U. S. G. S. No. 30, page 

 139, plate 14, fig. 1, side view, 1 a 

 Iront view, of type specimen, fig. 

 1 (/, lid (operculum), from Troy. 

 Fig. 1 6% cast of tube, showing con- 

 striction at the septum, enlarged 

 tvnce. — Lower Cambrian ( Georgi- 

 an) conglomerate and even bedded 

 limestone, Troy, N. Y. L. C. 



