TRILOHriES OV IHF. ClIAZV Ll.MES'I'ONR. 347 



(ienus ILL.^.NUS Dalman. 

 lUaenus indeterminatus Walcott. (Plate 13, figures 1,2.) 



IlUeiius indeterminatus Walcolt, 1877, Advance Sheets, 31st Annual Report New 



York State Museum Natural History, page 19. 

 nUeniis iniieter/ninattcs Walcott, 1879, Thirty-first Annual Report New \ovk State 



Museum Natural History, page 70. 

 Illa-niis, cf. /. ini/ete>-winatns C\sirke, 1897, Paleontology of Minnesota, volume III, 



part II, page 716, figure 34. 



A couple of large, but slightly imperfect cranidia, and two fairly 

 well preserved free cheeks of this trilobite have been found on Valcour 

 Island. The well developed dorsal furrows and strongly striate an- 

 terior margin, with the large size, serve well to characterize this species. 



Description. 



Cephalon more than twice as wide as long, the free cheeks extended 

 as broad genal spines. Surface only moderately convex, sloping 

 gradually to the front. The dorsal furrows start back of the eyes on 

 the fixed cheeks, run inward and almost parallel to the posterior mar- 

 gin for a short distance, then turn forward, and, after passing the mid- 

 dle of the length of the cranidium, turn outward, reaching to the striate 

 portion of the convex margin. Eyes very large and depressed, 

 situated far apart and some distance from the margin. Free cheeks 

 large, extending back of the posterior margin of the cranidium as 

 broad genal spines. The whole border is marked by four or five 

 deep furrows which start at the sides and extend around the front. 



Thorax and pygidium unknown. 



Measurements. — A cranidium: length 53 mm.; width 78 mm.; 

 width between eyes 74 ram. A smaller cranidium: length 36 mm.; 

 width 52 mm. 



Locality. — This si)ecies has been found so far in only one locality, 

 the reef material at Smugglers Bay, Valcour Island. The species has 

 been found in the Trenton at Janesville, and Plattesville, Wisconsin, 

 and in the Black River in Herkimer County, New York. 



Illaenus punctatus sp. nov. (Plate 13, figure 10.) 

 A rare trilobite in the Chazy is a small It/ceniis with an extremely 

 punctate and wrinkled surface. Of this species the collections afford 

 one whole specimen, four cranidia and one j^ygidium, but the surface 

 is so characteristic that no confusion should arise from a description 

 of this small amount of material. 



