LOWER SILURIC SHALES OF THE MOHAWK VALLEY 95 



29, page 378) and Schuchert in his Synopsis of the American Fossil 

 Brachiopoda (title 37, page 183) as a synonym to C. divers us. 

 C. americanus was described from the upper Trenton group 

 (Galena horizon) of Wisconsin, and Hall and Clarke (title 18, plate 

 15A) have figured it from the Trenton of Minnesota. A compari- 

 son of our specimens with Whitfield's original description and fig- 

 ures does not appear ^to bring out any differential characters. The 

 pedicle valve at our disposal appears higher than the original descrip- 

 tion requires, but it is somewhat laterally compressed and more- 

 over Hall and Clarke (title 18, plate 15 A, figures 7 and 8) figure 

 a still higher variety from the Trenton of Minnesota, later separated 

 by Winchell and Schuchert ( title 29, page 381) as var. a 1 1 i s s i m a. 



Whiteavesia cincta nov. 

 PL 5, fig. I 



Description. Shell small, obliquely ovate, nearly twice as high 

 posteriorly as anteriorly; strongly convex. Hinge line apparently 

 short, extending posteriorly one-third the distance from the beak 

 to the posterior extremity of the shell. Outline passing almost 

 imperceptibly from the hinge line into the oblique well-rounded pos- 

 terior margin and thence into the more abruptly rounded basal 

 extremity. Basal margin slightly convex, extending obliquely 

 upward. Anterior end apparently short and fairly well rounded. 

 Beak rather prominent, situated between one-fifth and one-sixth of 

 the length of the shell from the anterior extremity; umbonal ridge 

 broad, strongly rounded, very prominent in the upper half, where it 

 is as high as the umbo, then rapidly declining to the posterior extrem- 

 ity. Surface marked by strong, broad, flat concentric folds that 

 appear as elevated bands. On these many fine concentric lines are 

 seen, and very fine raised radiating lines are observable on the 

 cardinal slope. Muscular impressions not seen. 



Horizon and locality. Grayish black sandy shale of Snake Hill 

 beds at Snake hill, Saratoga county, N. Y. 



Remarks. As Doctor Ulrich has pointed out to me, this species 

 is allied to Whiteavesia cincinnatiensis H. & W., 

 but much smaller and relatively shorter. It also resembles, in our 

 view, W. subcarinata Ulrich, but is less subalate and 

 convex. 



The species is apparently rare in the Snake Hill beds, but a single 

 specimen having been collected. 



