XO. 5 UPPER CAMBRIAN TRTI.OBITES RESSER 35 



width at tlifir widest point. The very long eyes are curved so sharply 

 tliat the two hah-es are almost at right angles to each other. Anterior 

 ftxigenes practically wanting and on the whole are nearly flat, sloping 

 down from the dorsal furrow. The posterolateral limbs are very 

 sharply depressed. 



St, Charles limestone; (loc. 54X) Two Mile Canyon, 2 miles south 

 of Malad. Wasatch Mountains, Idaho. 

 ' IIolofyhc.—lJ.S.NM. No. 108683. 



UNCLASSIFIED GENERA 

 CHEILOCEPHALUS Berkey, 1898 

 CHEILOCEPHALUS WICHITAENSIS, new species 

 Plate 5, Figure 39 



Several cranidia of this interesting genus have been found in the 

 Oklahoma collections. It is a very simple' trilobite, the cranidium 

 consisting of a large glabella with no furrows except a shallow 

 occipital furrow. The fixigenes are simple. The glabella tapers 

 slightly to a nearly straight anterior margin. In cross section it stands 

 well above the dorsal furrow, rising at a fairly even rate to approxi- 

 mately the center. Longitudinally, the head has considerable relief, 

 attained by even curvature. The brim is narrow and consists of a 

 simple, slightly concave, and nearly horizontal extension, the outer 

 edge of which is very slightly thickened but does not form a rim. The 

 fixigenes have nearly the same width throughout, and are about equal 

 to one-fourth the glabellar width. Test smooth. 



Compared to C. stcroixcnsis the Oklahoma species is slightly smaller 

 and differs in the distribution of convexity in both directions. 



Honey Creek limestone; (loc. 9p) 15 miles northwest of Fort Sill, 

 Wichita Mountains, Oklahoma. 



f/o/ofy/T.— U.S. N.M. No. 108685. 



CHEILOCEPHALUS TEXANUS, new species 

 Plate 5, Figures 36-38 



The one small cranidium in the Texas collections has a smooth 

 rectangular glabella, rounded in front. In cross section it forms a 

 continuous curve with the fixigenes, which are barely separated by 

 the dorsal furrow. Longitudinally, the cranidium is convex, with a 

 rather even curvature, increasing in the anterior portion. The brim, 

 on the whole, is slightly concave. No anterior furrow is developed, 

 but a thickened rim turns up slightly, and is thereby separated from 



