Contributions to Palaeontology. 



135 



der extension in front, and posteriorly produced into a 

 distinct spine. 



This species is given in this place for comparison, since it has 

 been regarded as identical with the 0. minor of Wisconsin. They 

 are much alike, and, on cursory examination, might not be distin- 

 guished. From specimens which have been kindly given me by 

 Mr. Bradley, the form of glabella and fixed cheeks have been 

 determined, and a figure of the movable cheek has subsequently 

 been added to the plate from a specimen in Mr. Bradley's col- 

 lection. 



The figures are four times enlarged. The greater width of the 

 fixed cheeks, and the smaller movable cheek of this species, are 

 distinctive features. The straight anterior border and wide fixed 

 cheeks give the aspect of Olenus to the frontal limb. 



Fig. 5. The glabella and fixed cheeks of C. minutus, four times enlarged. 



Fig. 6. Profile of the same. 



Fig. 7. A movable cheek of the same. 



This species occurs in the Potsdam sandstone at Keeseville, N. Y. 

 CONOCEPHALITES EOS ( n. s.). 



PLATE II, FIGS. 24 & 24 ; AND PLATE III, FIGS. 8 & 9. 



Glabella very gibbous, width at base equal to its length 

 from the occipital furrow; sides curving and gently 

 narrowing anteriorly: anterior extremity abruptly 

 rounded at the angles, and slightly curving in front. 

 The posterior furrow is obliquely curved, reaching 

 nearly to the base of the glabella, leaving the posterior 

 lobe as a prominent node. The middle farrow is less 

 distinct, slightly curving, and reaching nearly one-third 

 across the glabella. The anterior furrow is not visible 

 in the cast. The occipital furrow is comparatively 

 broad, deep and well defined, curving forwards at the 

 extremities : occipital ring, very convex, rounded, and 

 a little more elevated than the back part of the glabella. 



