362 T. S. Hunt on the Geology of Southwestern Ontario, ee 
rels of petroleum were obtained. The limestone here restson 
the white unfossiliferous Chazy sandstone, beneath which ar — 
found only ancient crystalline rocks, so that it is difficult to — 
avoid the conclusion that this limestone of the Trenton group — 
is, like those of Upper Silurian and Devonian age already no- — 
ticed, a true oil-bearing rock. ; 
In concluding these observations on the geology of Ontario, — 
it may be remarked that throughout the southwestern counties — 
the distribution of the middle and upper Devonian rocks has — 
been determined almost wholly from the results of borings u- — 
dertaken in search of petroleum. From these it appears that — 
the wide spread of these rocks in this region is connected, re : 
with a tranverse north and south synclinal depression, wil 
that passing by Cincinnati, and may be regarded as part of the = 
Sass antichinal of the great axis of vleeanee which divides the 
The Devonian rocks are found in the region under cone : 
tion, at depths not only far beneath the water-level of thea» — 
jacent lakes of Erie and St. Clair, but aetually below the hore a 
zon of the bottom of those shallow lakes. Thus at big 5 
in Bayham, at a point said to be about forty feet above * 
level of Lake Erie, the underlying rock was met with bao 
240 feet of clay, while at Port Stanley, twenty feet rere a 
lake, the Hamilton shale was struck beneath 172 nia de: 
and at the Rondeau, just above the level of Lake Erie, pray : 
was 104 feet thick. A similar condition of things rg 
the south side of the lake, at Cleveland, where no T0¢ gait 
countered at a depth of 100 feet below the water-level in ae 
a well ten feet 4 
above the river passed through 100 feet of clay Det0ry an 
the black shales at the Pande group, while in Maidstone 
the shore of Lake St. Clair, and a very few feet ae ia 
109 feet of clay were found overlying the Corniferou thirty 
stone. The greatest depth of Lake St. Clair 18 scat sa EO 
fect, and that of the southwestern half of Lake Bne 
* 
out of the paleozoic rocks, and including in i 
western part of the peninsula of Ontario. 
