201 



Cho.\ete!s MU(it().\ATr.s. Hall. ( f"ig'. 105.) (Pal. N. Y., 

 Vol. IV., p. 125, Pis. XX.. XXI.) 



Distinguishing Characters. — ^nmW size; semi-oval outline: 

 moderately convex character: rather distant and strong', 

 radiatinu'. rounded or sub-angular stride. v\'hich are not as 



I 



Fig. 105. Chonetes mucronatus. Pedicle valve, natural size and enlarged, with profile 

 of same; enlargement of another specimen, dorsal view (from Hall). 



wide as the spaces between them ( or are more or less closely 

 crowded) : abruptly outward-curving- cardinal spines, of 

 which there are two. or rarely three, on each side. 



Found rarely in the u}»per Moscow shale, below the tran- 

 sition beds; hi the lower Moscow shale, at Sections 4 and 5 

 (not very common) : Encrinal limestone ( var. laticosta), at 

 Section 5 (rare); shale below the Trilobite beds, in Avery's 

 Creek (rare): Pleurodictyum beds (rai-e): Transition shales, 

 in Erie and Athol Springs Cliffs (rare): Marcellus shales, in 

 Athol Springs and Bay View Cliffs (rare). 



Choxetes yicixus. (Castelnau.) (Fig. 10(5.) (Chonetes 

 defiectus. Hall. Pal. X. Y.. Vol. IV.. p. 1 26, PL XXI. ) 



Distinguishing Cluivactevs. — Semi-elliptical outline ; strong 

 convexity: deflected cardinal margins (as seen from the con- 



FiG. 106. Chonetes vicinus (deflectus). Ventral, dorsal and profile views of a charac- 

 teristic specimen, natural size: enlargement of interior of a brachial valve, showing cardi- 

 nal process and muscular impressions (from Hall). 



vex side) : abruptly outward-curving cardinal spines: finer, 

 more numerous, and more closely crowded stri;e than occur 

 in C. mucronatus. 



