FOSSILS OF THE CLINTON GROUP. 561 



anterior muscular impression is not well marked, but it was thought pos- 

 sible to trace a sort of impression similar in its interior outline to that 

 published by Mr. Simpson for his type, in the Dictionary of Fossils of 

 Pennsylvania. The surface was marked by concentric striae. 



The type used by Mr. Simpson came from the Clinton shale above 

 the fossil ore, at McKee's ore bank, northeast of McKee's house, Fergu- 

 son Valley, seven miles northwest of L,ewiston, Mifflin county, Penn- 

 sylvania. (Plate 37, Fig. 7 b.) 



Cypricardites Caswelli, Foerste. 



(Plate 26, Figs 12 a, b ; Plate 37, Figs. 1 a, b, c). 



Since the publication of this species in the Bulletin of Denison 

 Univ., Vol. I., additional specimens have been found at Soldiers' Home, 

 and one was also collected at Fauver's Quarry north of Dayton. The 

 same species occurs also in the flinty rock of the Clinton and in the 

 shales of the Niagara, near Lockport, New York, as witnessed by flat- 

 tened specimens in the collections of Dr. E. N. S. Ringueberg. 



The generic relations of the species cannot be determined with cer- 

 tainty owing to the absence of interiors or interior casts, but it has an 

 exterior similar to that of some species referred to Cypricardites. The 

 valves are strongly inequilateral. The total length of the shell is about 

 40 mm.; from the beak to the anterior extremity of the lunule was 8 mm. 

 and from the beak to the posterior end of the hinge line was about 22 

 mm. Measured in vertical projection the beak is 8 mm. from the ante- 

 rior end of the shell and 32 mm. from its posterior end. The height of 

 the shell posterior to the slopes of the beak was about 24 mm. The 

 beaks rise about 2 mm. above this height. The greatest thickness of the 

 shell lies near its middle and amounts to about 23 mm. From these 

 measurements it may be seen that it is strongly and quite equally ventri- 

 cose. The anterior and lower margin is quite regularly convex, round- 

 ing into the posterior margin which slopes anteriorly so as to meet the 

 hinge line. The anterior lunule is short, and distinct, the hinge line 

 forming a median ridge for the same. The beaks are strongly incurved. 

 Posterior to these the character of the hinge line is practically unknown, 

 no specimen preserving the same. There is no evidence of ridge lines, 

 curved or otherwise in addition to the line of junction of the two valves. 

 From the beak a rounded umbonal ridge runs backwards and downwards 

 towards the posterior extremity but merges very soon into the general 

 rounded surface of the valves. Concentric series of low rounded ridges 

 ornament or rather wrinkle the shell. Probably it once had also finer 

 concentric striae but these have so far not been observed. 



Cypricardinia undulostriata, Hall. 



(Plate 37, Figs. 9, a b.) 



In the collection from Soldiers' Home occurs a left valve and in that 

 from Brown's Quarry a better preserved and more typical right valve, which 



36 G. •). 



