228 W. E. Logan on the Rocks of Canada. 
eastern area. But while in the western division there is no want 
e conclusion to be drawn from these facts appears to be, that 
some cause producing folds in the stratification in one general di- 
rection has been in operation from at least the cessation of the 
Lower Silurian epoch to the termination of the carboniferous ; 
and it only requires the inspection of a map of Atlantic America 
to observe how the features of its physical geography, display 
in the configuration of its coast, in its valleys of undulation and 
those of transverse fracture, are almost entirely dependent on the 
and the Ottawa, upon a series consisting of micaceous and horn- 
blendic gneiss interstratified towards the south with great bands 
the Arctic Ocean. ; 
The Canadian rocks on the north side of this granitic ridge, # 
displayed toward the head of Lake Temiscamang, consist, in as 
cending order, of chloritic slates and conglomerates with a slaty 
matrix; the volume of these is probably not less and may 
much more than 1,000 feet. On them rests a set of massive pale 
greenish-white or sea-green sandstones, the total amount of which, 
as determined by the height of hills which they compose 1? 7 
horizontal layers, is between 400 and 500 feet. These are nee 
ceeded by about 300 feet of buff and whitish fossiliferous lime- _ 
# 
re 
