Conindiim-Bearing Rocks of Canada. — Miller. 277 
Having determined the character of the rock at the two 
known deposits, other deposits were searched for, and, at the 
end of the season's field work in 1897, numerous outcrops of 
these igneous rocks carrying corundum had been found. These 
outcrops are situated along a belt or strip of country which 
has a length of about 30 miles and an average breadth of be- 
tween 2 and 3 miles. 
In the report made to the Bureau of Mines in 1897, it was 
stated that the belt would likely be found to have a much 
greater length than time had permitted proving during that 
season, and that what had been considered to be isolated out- 
crops of syenyte lying farther to the southwest would be found 
to be part of a belt similar to that already worked out.* On 
continuing the work in 1898, such was found to be the case. 
At the end of this season's explorations the strip of country 
along which outcrops of corundum-bearing rock had been 
found had a length of about 75 miles. Starting from the east- 
ern end, the belt runs pretty regularly westward for about 30 
miles; thefi it bends rather abruptly to the southward and con- 
tinues this course to the westward. Neither the eastern nor 
western extremity of the belt has yet been determined. 
This belt forms what may be called a somewhat unique 
structure in the Archean. It would appear from it that the 
structure of the Archean is on a larger scale than is usually 
considered and by studying only minor structures a great deal 
is lost. Were it not for the presence of corundum, it would be 
difficult if not impossible to trace up these rocks in the field 
and to finally prove their relationship, as they possess different 
characteristics in dififerent parts of the district. 
During 1898, the writer traced out two other belts in which 
corundum-bearing rocks occur. These are each some miles in 
length. It seeems likely that, had time permitted, they could 
have been proved to be connected in some way with the main 
belt. These three strips of country taken together, partly sur- 
round a region whose diameter is 50 miles or over. The long- 
est belt bounds the region on the north. One of the^ smaller 
belts lies to the southwest and the other to the southeast.! 
*The location of these belts is shown on the index map which ac- 
companies this paper. 
tBureau of Mines, Toronto, 7th Report, p. 229. 
