FOSSILS OF TDE POTSDAM (iKOUP. 215 



This species approaelios more nearly to ConofepliuJiles Shiiniarili Hall 

 (IGth I^ept. State Cab., p. ir)4,.pl. 1, fig. 7, and pi. 8, tig. 2) than to any 

 other (lescribetl species, but diti'ers very conspicuousl}' in the greater breadth 

 of the front of the head between the facial sutures. No other parts of the 

 organism have been detected. Although the fragments of i-ock containing- 

 the heads are tilled with Trilobitie remains, there are none showing the 

 granulose surface corresponding to this one ; and, where the entire crust of 

 the head is so thickly covered with granules, it would seem natm-al to sup- 

 pose the other parts of the animal would be similarly marked. 



Formation and hcality. — In compact limeslone of the Potsdam group at 

 Eureka, Nevada. Collected by J. E. Clayton, esq. 



CUEPICEPUALUS (LOGANELLrs) MACULOSUS 11. S[). 

 PI:it.'. II, Jitjs. 24, •-•.'), aud 2G.'. 



Glabella and fixedcheeks quadrangular; glabella rounded, conical, a little 

 higher than wide, and highly convex, prominent and giltbous ahmg the 

 median line, marked by very oblique furrows, onl)- two pairs of wliich show 

 upon the cast, excejit on critical examination, the anterior pair being very 

 obscure, and situated very near the anterior end of the glabella; middle 

 pair more distinct, and situated at alsout the anterior thir<l of the length; 

 posterior pair commencing a little behind the ml<ldle of the length, at the 

 margin, and directed backward so as to unite with the occipital furrow just 

 before reaching the center of the glabella, separating the jiosterior glalu'l- 

 Inr lobes, wliich form triangular areas of large size; occijiltal furrow wide, 

 and ring distinct 



Fixed cheeks nearl}^ half as wide as the central diameter of the glabella, 

 moderately prominent in the middle near the eye-lobe, and gently declining 

 in front and posteriorly; ocular ridges strongly marked. Frontal liml) 

 longer than tla; width of the fixed cheeks, strongly convex in front of the 

 glabella, and rapidly declining to the front margin, which has been bordered 

 by a narrow rim, the form and extent of which has not ])een determined. 

 Lateral limbs unknown. Surface of the cast, except the glabella, which is 

 smooth, marked by distant elevated pustules of moderate size. 



A movable cheek, associated In tiie same blocks, and possessing a simi- 



