HURONIAN FORMATIONS, TIMISKAMtNG REGION. 
9 
The diabase which intruded all the above-mentioned for- 
mations is probably of the same general age as the similar in- 
triisives of Cobalt and Sudbury districts. 
Blind River Area. 
The great fault that crosses Bruce area is continuous across 
Blind River area also, lying parallel to and from half a mile to 2 
miles north of Lake Huron. As in Bruce area the southern side 
is upthrown several thousand feet. The rocks brought together 
along this great plane of displacement are so unlike that they 
require more or less independent description. 
South of the fault the granite-gneiss of Bruce area, or Kil- 
lamey granite, is continuous eastward into this area. Here it 
contains ribbons and angular masses of black hornblende-gneiss, 
which probably represent inclusions of the igneous complex found 
at Thessalon. At Dean lake it also includes small bodies of finely 
crystalline hornblende-schist in which original bedding planes 
are still visible. In the eastern part of this area, east of Algoma, 
there is also a thick series of slate, quartzite, and conglomerate 
resembling the Sudbury series of Sudbury district, and these are 
intruded near Cutler station, by dykes of granite. Hence the 
crystalline complex south of the great fault in Blind River area 
comprises batholithic granite-gneiss intrusive into an older met- 
amorphosed and closely folded sedimentary series. Quartzite 
and limestone like the Huronian of Bruce area also occur on the 
south side of the fault but always dipping from 50 degrees to 90 
degrees, or even overturned, and in faulted relations to the granite 
and older sediments. 
North of the fault the crystalline basement is represented by 
granite eilone, and upon this granite younger sedimentary rocks 
rest in the same unconformable manner as they do in Bruce area. 
These sediments form a gentle monocline dipping southwest- 
ward toward the great fault, but this main structure is compli- 
cated by minor folds, and within 2 miles of the fault the beds 
are much more disturbed than are those in Bruce area. Fre- 
quently they are on edge or overturned, like those south of the 
