CONTRIBUTIONS TO PALAEONTOLOGY. 151 



Fixed cheeks comparatively wide, with the posterior limb short : 

 ocular ridges distinct, reaching the dorsal furrow just behind 

 the anterior glabellar furrow. Frontal limb extended, with a 

 thickened and elevated anterior border which is a little wider 

 in the middle. 



Movable cheeks narrow, with ocular sinus comparatively large : 

 the border is thickened and produced in a slender extension in 

 front, and posteriorly produced into a distinct spine. 



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

 garded as identical with the C. minor of AVisconsin. They are much alike, 

 and, on cursory examination, might not be distinguished. 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 

 collection. 



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. 



Fia. 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 VII, FIGS. 24 & 25; AND PLATE VIII, FIGS. 8 <fe 9. 



Glabella very gibbous, width at base equal to its length from 

 the occipital furrow ; sides curving and gently narrowing an- 

 teriorly : 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 furroAv 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 con- 

 vex, rounded, and a little more elevated than the back part of 

 the glabella. Dorsal furrow deep and strongly defined, particu- 

 larly in the middle of its length : fixed cheeks very narrow; 

 at the sides, and arching longitudinally ; the palpebral lobe 

 separated from the cheek by a long sigmoid groove which 

 reaches nearly to the groove in the posterior limb : the latter is 



