Trilobites ov the C^hazv Limestone. ;>71 



This species differs from Pseiidosph(erexoc]uis vulcanus in having a 

 much narrower and more convex glabella, and from P. vulcanus hil- 

 lingsi by being much more tapering and in having the posterior part 

 of the glabella much less elevated above the neck segment. 



Loi-a/i/y. — Rather common in the upper part of the Chazy at Val- 

 cour Island and in the lower part at Chazy, New York. Types in 

 the author's collection. 



Pseudosphaerexochus ( Nieszkowskia ) satyrus f>illings. (Plate 14, 



figure 21.) 



Cheirttrus Satyrus Billings, 1S65, Paleozoic Fossils Canada, volume I, page 324, 

 figure 309. 



Unfortunately we are in a position to add little to Mr. Billings' 

 description of this species, as it is represented in our collection by 

 only a single individual. The specimen consists of the glabella and 

 a portion of one fixed cheek. 



Description. 



Glabella very strongly convex, almost conical, and extending into 

 a stout spine which projects vertically a little in front of the neck seg- 

 ment. There are three pairs of glabellar furrows. The posterior pair 

 extends upward to the back of the spine, while the other pairs are 

 shorter and do not turn back so far. Unfortunately the spine was 

 broken off and lost. The neck segment is wide, almost flat, and has 

 a small tubercle on the median line. The fixed cheek is large and 

 coarsely pitted, while the glabella appears to be smooth. 



Measurements. — The cephalon of our specimen is 20 mm. long 

 and 38 mm. wide, while Billings' specimen, from Montreal, is only 

 5 mm. in length. 



Locality. — In the coarse, gray, limestone on the north end of Sloop 

 Island, east of Valcour Island, New York. Specimen figured, the 

 property of Carnegie Museum. 



Subgenus Sph.*:rocorphe Angelin. 

 Sphaerocorphe goodnovi sp. nov. (Plate 14, figure 23.) 

 About half a mile south of Chazy, New York, in Mr. Robert Mc- 

 Cullough's sugar bush, there occur, in pockets of fine, gray lime- 

 stone, great numbers of exuviae of trilobites, chiefly small species of 

 IllcFJius, Asaphus, Lichas, Ampyx and Sphcerexochus. Among them 



