334 AxxALS OF JHE Carxkgie Muskum. 



from Rysedorph Hill. The pleura show three or four pairs of rather 

 indistinct ribs. The margin is abruptly deflected all around. 



\'ery closely related to this species are Ampyx nonualis and Ampyx 

 semicostalits from the division P of the Quebec group in Newfound- 

 land. The cranidium of Ampyx nonualis has the same long fluted 

 rostrum and the same scars on the cast of the glabella. The pygidium 

 figured with Ampyx normalis does not greatly resemble that of an 

 Ampyx, but the pygidium figured as Ampyx semicostaiiis differs from 

 Ampyx Iia Hi o\\\s in size. The cranidium o{ Auipyx nonualis differs 

 from that of ^w/.v.v //(?/// in having the fixed cheeks much more ex- 

 tensive, as they extend to the base of the rostrum in the former 

 species, and only about half that distance in the latter. 



Locality. — The figured specimen is from Valcour Island. The 

 species seems to occur in only a limited area in the region of the typi- 

 cal Chazy deposits. It has not been reported south of Valcour, New 

 York, nor north of St. Dominique, Quebec. At Chazy the specimens 

 are all found in one horizon, about the middle of the group. At 

 Valcour it is common in the lower portion, and on Valcour Island it 

 occurs from a horizon about three hundred feet above the base to 

 within about one hundred feet of the top. 



Order OPISTHOPARIA Beecher. 



Family OLENID.E Salter. 



Genus REMIPLEURIDES Portlock. 



Remipleurides canadensis Billings. (Plate lo, figures 8-10.) 



Keinil^letiridcs Ca)tadensis Billings, 1S65, Paleozoic Fossils Canada, X'olunie I, page 

 182, figure 164. 



This interesting fossil can not be said to be common except in one 

 or two small localities, although it has been found in a number ot 

 places. The best specimens so far obtained are from the dolomitic 

 reef material on the east side of Valcour Island. 



Description. 

 Cepiialon. — Glabella high, nearly flat on top, but with steep sides 

 and front. It occupies nearly three fourths of the whole width of the 

 cephalon. (rlabellar furrows very faint, three pairs showing on the 

 cast, while the outer shell sometimes shows two ])airs, but generally 

 none. Surface finely granulose. 



