[ami] SYNOPSIS OF THE GEOLOGY OF CANADA 209 
The following succession of Devonian formations obtains in Ontario, in 
descending order : 
5.—The Chemung. 
4.—The Portage and Genesee. 
3.—The Hamilton. 
2.—The Corniferous. 
1.—The Oriskany sandstone. 
The Oriskany consists of some thirty feet of light yellowish, at times 
calcareous sandstones, holding fossil remains in abundance, some eighly 
species have been recorded by Billings, Schuchert, and others. The 
Oriskany is overlaid by coralline limestones and dolomites teeming with 
corals, shells, and other fossil remains including fishes, constituting the 
Corniferous formation, followed upwards by the shales, limestones, and 
clays of the Hamilton formation. These shales also abound in corals 
and various groups of invertebrates with a few large fishes. The 
Hamilton formation is overlaid by a series of dark brown or black bitu- 
minous plant-bearing shales, with an occasional series of limestone 
bands, and brownish sandstones interstratified, which constitute the 
upper or Neo-Devonian of Ontario. These strata correspond to the 
Chemung, Huron and Erie shales of Ohio and Michigan. The petro- 
leum-bearing strata of the Huron-Erie peninsula belong to this system. 
The Interior Continental Plain.—Limestones of Devonian age have 
long been recognized in the Lake Winnipegosis and L. Manitoba regions 
of northern Manitoba, and the North West Territories. The rocks con- 
sist of cream-coloured dolomites and limestones teeming with organic 
remains. Mr. Tyrrell divides the Devonian of this region into three 
series; the Upper Devonian or Manitoban formation, the Middle 
Devonian or Winnipegosan formation, the third or Lower Devonian, not 
being yet clearly defined. It is from these limestones that Dr. 
Whiteaves recognized the “ Stringocephalus zone,” or horizon overlaid 
by the beds which probably represent the “ Cuboides zone!” These 
Devonian strata are also met with in the district of Saskatchewan. In 
the MacKenzie river basin, limestones, shales, and dolomites usually 
dark gray in colour are recorded by Mr. McConnell; also on the Liard 
river, a branch of the MacKenzie, and from the MacKenzie itself, they 
form an important trough of paleozoic rocks from Lake Athabasca to 
Great Slave and Great Bear lakes, northward covering the uneven sur- 
face of the Archæan floor. It was from these limestones that the fossils 
described by F. B. Meek were obtained. 
The Cordilleran Region —In the Rocky mountains, in the Cascade 
belt and the Fairholme mountains, dark gray cherty dolomitic limestones 
