NO. 5 UPPER CAMBRIAN TRILOBITES RESSER 9I 



to the sharp depression of the anterior angles, the divergence of the 

 anterior facial suture is not apparent. Back of the eyes the postero- 

 lateral limbs, also sharply depressed, are about three times the width 

 of the occipital ring. Laterally the glabella stands completely above 

 the fixigenes with very steep sides. Longitudinally the entire cranid- 

 ium is very convex. 



Deadwood formation; (loc. 88a) Deadwood, Black Hills, South 

 Dakota. 



Holotypc— U.S. NM. No. 108787a; paratype, No. 108787b. 



BERKEIA SARATOGENSIS, new species 



Plate 15, Figures 22-25 



Although this species is not fully typical of the genus in that the 

 rim is narrower than the preglabellar area, the difference in appear- 

 ance may be due to the fact that on these specimens the test is pre- 

 served. HoweA-er, since this form does not fit in any other existing 

 genus and because its departure from the characteristics of Bcrkcia 

 is confined to the narrowness of rim, the species is placed in that genus. 



As usual the large glabella tapers to a rounded front and has three 

 pairs of recurved furrows. The brim width is somewhat less than 

 a third the glabellar length. The preglabellar area is more than twice 

 the width of the slightly upturned rim. Opposite and behind the eye 

 the fixigenes average about half the glabellar width. Divergence of 

 the suture creates fairly large anterior angles. In cross section the 

 total convexity across the eyes is moderate, although both the glabella 

 and fixigenes are individually convex. By depression of the anterior 

 angles and of the posterolateral limbs, both the front and back portions 

 of the cranidium attain considerable convexity. Longitudinally the 

 cranidium is strongly convex, attained by a rather even curvature 

 throughout. 



Potsdam sandstone ; Greenfield, northwest of Saratoga, New York. 



Holotypc and pamtypcs. — New York S. ]\L ; casts U.S.N.M. Nos. 

 io8792a-c. 



BERKEIA NEVADENSIS, new species 



Plate 15, Figures 26, 27 



B. nevadensis, represented at several localities, differs from B. 

 affinis chiefly in its lesser convexity in longitudinal direction. This 

 difference is not merely a matter of preservation, for B. nevadensis 

 is represented by nearly a score of specimens. 



