FOSSILS OF THE CLINTON GROUP. 527 



die Silurian rocks. Its chief characteristic is its large size ; the broad 

 frontal border rather flattened; the deep lateral furrows defining the 

 glabella, especially anterior to the middle pair of lobes ; this middle pair 

 of lobes is connected with the high fixed cheeks; anteriorly the fixed 

 cheeks curve a little inwards but do not connect with the anterior end of 

 the glabella as in the case of C. camerata, Conrad, from the Niagara of 

 New York. The figures of C camerata, are certainly not exact for our 

 form, but they are so similar in many ways that, not having seen actual 

 specimens of C. camerata, it is possible to imagine that the differences are 

 more due to the imperfect preservation of the New York forms than to 

 any actual distinctive characteristics. This larger, more typical form oc- 

 curs at Centreville, Soldiers' Home, Huffman's Quarry in the upper 

 shaly courses ; and in the limestone at the Eaton Pike Quarry, Todd's 

 Pork, Ohio, and Hanover, Indiana. It occurs also in the Clinton lime- 

 stone of New York, near L,ockport. (Plate 25, Fig. 25; Plate 27, Figs. 

 12, 13, 16.) 



A medium sized form with heads about 13 mm. long is found in the 

 middle limestones at Soldiers' Home. (Plate 25, Fig. 24; Plate 27, 

 Figs. 14, 15.) 



A small form with heads 8.6 mm. long, and pygidia 7 mm. long oc- 

 curs in the limestone at Brown's Quarry. The anterior border of its. 

 head appears more rounded, and the groove behind it is of almost equal 

 size, so that these forms would agree very well with Calymene 

 Niagarensis. 



Most species of Calymene are founded upon . slight varietal, rather 

 than marked specific characters. Establishing C. Vogdesi in this sense, 

 it has lately become doubtful whether it deserves to be separated from 

 C. Blumenbachii under any circumstances. 



Ceraurus ( Pseudosp/taerexockus) Clintoni, sp. nov. 



(Plate 27, Fig-. 17.) 



This species was described in the Bulletin of Denison University, 

 Vol. II. Only the glabellse have been found and these are fairly icom- 

 mon at the southern end of the quarry at Brown's Quarry. Since the de- 

 scription was published the occipital segment has become better known. 

 The occipital groove is distinct. The occipital segment is inversely and 

 very broadly triangular, being very obtusely pointed posteriorly, becom- 

 ing very much attenuated and depressed laterally, and lying close, and 

 almost under, the posterior lobes near their lateral termination. From 

 drawings sent to him, Mr. J. M. Clarke judged these specimens to 

 belong to the proposed sub-genus Pseudospluzrexochus of Schmidt. 



Glabella oval, strongly convex, with three pairs of furrows — the pos- 

 terior pair is situated about a third of the length of the glabella from 



