P. E. Raymond — Fauna of the Chazy Limestone. 361 



85 miles north of Chazy. To the west it is found as far as 

 Hawkesbury, 75 miles northwest of Chazy and 55 miles west 

 of Montreal. 



Mlngan Islands Region. 



The fauna of the Chazy at Mingan Islands is very closely 

 related to that of the typical Chazy of the Cham plain Valley, 

 as is shown by the following list of species common to the two 

 regions : — 



Bolboporites americanus. Orthoceras bilineatum. 



Phylloporina incepta. 0. multicameratum. 



Columnaria f f parva. Pleisoceras jason. 



Rafinesquina incrassata. Pliomerops canadensis. 



Camarotcechia orientalis. Illmnus globosus. 



Gamarella longirostris. Eoharpes antiquatus. 

 C. v avians. 



Ottawa Valley Region. 



The Chazy deposits of this region have been described in 

 detail by Logan, * Ells,f and Ami.J The formation is not 

 more than 200 feet in thickness, usually less, and is divided 

 into two parts, the lower including shales and sandstones, and 

 the upper, limestones. It outcrops in a narrow belt extending 

 along the north and south sides of the Ottawa River, from 

 Hawkesbury west to Arnprior, and is again exposed south of 

 Ottawa, whence another narrow belt runs to Cornwall, where 

 it again turns northward. West of Arnprior there are a few 

 outliers of the same formation. One large one occurs at Allu- 

 mette Island, north of Pembroke, and another 10 or 15 miles 

 south of this and west of Renfrew. 



The coarse character of the sediments at the base of the for- 

 mation in this region points to very shallow water and shore 

 conditions and a probable erosion interval between the. end of 

 Beekmantown time and the deposition of the strata of Chazy 

 age. 



The writer has studied the rocks of this area chiefly in the 

 vicinity of Ottawa and Aylmer, and the fauna there represented 

 seems to consist of about 25 species, only 7 of which occur in 

 typical Chazy deposits. The fauna of the sandstone at the 

 Aylmer region is quite different from that found in the over- 

 lying limestone, and for that reason a list is here given of the 

 species found ill each. An asterisk denotes that the species is 

 found also in the typical Chazy : — 



* Geology of Canada, 1863. 

 f Kept. Geol. Survey of Canada, 1899. 



% Ibidem ; also Trans. Roy. Soc. Canada, vol. ii, 1896, vol. vi, 1900, and 

 various other papers. 



