NO. 9 NEW YORK POTSDAM-HOYT FAUNA 2/1 



Head semicircular, convex. Glabella truncato-conical, moderately 

 convex ; width at the base nearly equal to the length ; anterior margin 

 straight, abruptly rounded at the angles ; sides straight and regularly 

 converging ; the posterior and middle glabellar furrows oblique and 

 well marked, the anterior furrow indicated by a smooth line upon the 

 granulose outer shell, and a slight depression when the outer shell is 

 removed. Occipital furrow broad and well impressed. Occipital 

 ring narrow at the sides, widening at the center to form the base of a 

 strong, slightly curved spine, which extends obliquely backward ; the 

 length of the spine in large individuals equals the length of the head. 

 The glabella in very young individuals is more convex, the glabellar 

 furrows more strongly impressed, and the spine projecting from the 

 occipital ring shorter and less obliquely inclined backward. Dorsal 

 furrows equally impressed at the sides and front of the glabella. 

 Facial suture, curving slightly outward from the frontal margin, 

 passes directly to the anterior angles of the palpebral lobe opposite 

 the anterior glabellar furrow, thence curving to the posterior angle 

 of the palpebral lobe, it extends obliquely outward to the lateral 

 margin of the posterior limb. 



Fixed cheeks narrow ; frontal limb extending a distance equal to 

 one-half the length of the glabella, sloping somewhat abruptly to a' 

 comparatively broad, thickened margin ; posterior limb narrow, elon- 

 gate, with a strongly defined furrow along the center. Palpebral lobe 

 separated from the fixed cheeks by a sigmoid groove, which unites 

 anteriorly with the dorsal furrow. Surface of glabella and fixed 

 cheeks granulose ; on the frontal limb the granules are so arranged 

 as to give the appearance of lines running from the dorsal furrow to 

 the broad margin, which has lamellose stride subparallel to the mar- 

 gin. The largest head of this species obtained is nearly 25 mm. in 

 length, with a spine of equal length projecting from the occipital ring. 



Observations. — -This species is closely related to Lonchoccplialus 

 zvisconsinensis (Owen). It differs in having a relatively shorter 

 frontal limb and longer palpebral lobes and it occurs at a somewhat 

 higher horizon. 



The fragment provisionally referred to L. calcifcnis by Dr. Stuart 

 Weller may possibly belong to it, but it is too doubtful to base any 

 conclusion on. 



Some of the specimens of L. calcifcnis from south of Poughkeep- 

 sie are larger than those from Hoyts quarry. One cranidium is over 

 21 mm. in length, exclusive of the occipital spine. 



Formation and locality. — Upper Cambrian, Hoyt limestone: (76) 

 Arenaceous limestone at Hoyts quarry, 4 miles (6.4 km.) west of 



