22 



Iron Ores of Canada. 



their Tipturned edges ; and in the second place, in Western Ca- 

 nada, another formation lies between the Laurentian ami Silurian. 

 This fact is illustrated by the following figure which rcprosents a 

 section from the county of Eenfrew westerly to Lake Huron. 



Fig. 2. 



I. — Laurentian or iron formation. 

 C. — Huronian or cop2:)er formation. 

 S. — Silurian. 



The above figure gives the order in which our mineral wealth 

 is laid up in the crust of the earth. The Laurentian contains iron 

 in great abundance, but, only insignificant traces of copper. The 

 Huronian is fall of copper veins, but with very little iroai, while 

 the Silurian holds neither iron nor copper. Again, as the Huronian 

 lies between the Silurian and the Laurentian, the Silurian does 

 not belong to the age immediately succeeding the period during 

 which the latter was deposited ; and farther, as the Huronian rocks 

 rest upon the upturned edges of the Laurentian and the Silurian 

 upon the upturned edges of the Huronian, great intervals of 

 time must have elapsed between the period of any two of the 

 three. The Laurentian epoch was the age of iron, and long after 

 its termination came the Huronian epoch when copper was pro- 

 duced. In the valley of the Ottawa below Lake Temiscamangue 

 Huronian rocks were never deposited, consequently as we find the 

 Silurian in this part of the country where the line of contact can 

 be seen always resting upon the Laurentian rocks, our chances 

 therefore of finding great quantities of copper in this part of the 

 country are exceedingly small. 



The above remarks are intended to give an idea of the geolo- 

 gical position of our iron ores, and we shall now proceed to the 

 discussion of their extent and cost of working. It must be borne 

 in mind that the Laurentian rocks constitute the surface of Ca- 

 nada throughout an area of 150,000 square miles, that a vast 

 proportion even is still a wilderness, and that therefore the beds of 

 ore as yet discovered in all probability constitute but a small 



