203 



Measurements. — Large specimen : width, 11 mm.; height, 

 8 mm. 



Chonetes lepidus. Hall. (Fig. 109.) ( Pal. N. V., Vol. 

 IV., p. 132, PL XXI.) 



Distinguishing Characters. — Small size; Semi-elliptical in 

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



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

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

 broken away (from Hall). 



bifurcating surface striae, of which there are ten or twelve 

 near the umbo, and twice as many, or more, near the front; 

 sinus outlined by two stronger striae near the center, with 

 finer ones between them in a 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 coronatus. (Conrad.) (Fig. 110.) (Pal. 

 N. Y., Vol. IV., p. 133, PL XXI.) 



Distinguisliing Characters. — Large size; moderate convex- 

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

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

 six oblique tubular spines on each side of the beak ; interior of 

 the pedicle valve shows diverging dental lamellae, a narrow 

 median ridge, and wide-spreading adductor impressions, out- 

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

 valve a median ridge runs forward 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 



