203 



Mensurements. — Large specimen: width. 11 nun.; height, 

 8 mm. 



Chonetes LEPiDus. Hall. (Fig. 101).) (Pal. N. Y., Vol. 

 IV., p. 132, PI. XXL) 



Distinguishing Clinvncters. — Small size; semi-ellijitical in 

 outline; sub-hemispherical in convexity; slender, angular, 



x^^j^^^^^i' 



Fig. 109. Chonetes lepidus. Ventral and dorsal views of a specimen, natural size, and 

 the former enlarged ; enlargement of interior of bracliial valve, with cardinal process 

 broken away (from Hall). 



bifurcating surface strirV, of which there are ten or twelve 

 near the uiiiIm), and twice as many, or more, near the front; 

 sinus outlined by two stronger stri.e near the center, with 

 hiier ones between them in ;i depressed area; cardinal spines, 

 sometimes as many as ten. 



Found in the Goniatite bed of the Naples shales, at Sec- 

 tions 1 and 2 (rare); Styliolina band, at Section 1 (rare); 

 lower Moscow shales, at Sections 4 and 5 (rare) ; Hamilton 

 shales, everywhere associated with the preceding, but usually 

 more abundant; also in the Transition shales, on the Lake 

 Shore. 



Chonetes coroxatus. (Conrad.) (Fig. 110.) (Pal. 

 X. Y., Vol. IV., p. 133, PL XXL) 



Distinguisliing Cliaracters. — Large size; moderate convex- 

 ity, with occasionally a shallow undefined sinus in the pedi- 

 cle valve; numerous closely-arranged surface striffi; five or 

 six oblique tubular s})ines on each side of the beak ; interior of 

 the pedicle vahe shows diverging dental lamellge, a narrow 

 median ridge, and wide-si)reading adductor impressions, out- 

 side of which the shell is strongly pustulose; in the brachial 

 \-alve a median ridge runs foi'ward from the cardinal pro- 

 cess ; the muscular impressions are faintly marked. 



Found in the Encrinal limestone, at Section 5 ; Stictopora 

 and Demissa beds, and immediately below, at Sections 5 



