59 



vince's mineral industry and has led to the development of 

 Porcupine and other areas tributary to the railway. The 

 value of the ore produced at Cobalt, in less than ten years, 

 is equal to about five times the cost of constructing and 

 equipping the 252 miles of railway from North Bay to 

 Cochrane, together with branch lines, and the dividends 

 alone are equal to two and a half times the total cost of the 

 railway. 



Moreover, the discovery of Cobalt, which lies near the 

 southern edge of the great pre-Cambrian regions that occupy 

 nearly one-half the surface of Canada's 3,750,000 square 

 miles of territory, has given confidence in these regions as 

 storehouses of economic minerals and ores that future pros- 

 pecting will bring to light. 



THE ROCKS AND THEIR RELATIONSHIPS. 



At first, owing to the surface being covered with green 

 timber and to the presence of much drift material, contacts 

 and good exposures were difficult to find. Now, that the 

 timber has been removed parts of the area have almost the 

 appearance of a large model, e.g. between the northwestern 

 face of Mount Diabase and Peterson and Cart lakes, or on 

 the Nipissing property to the west of Peterson lake, where 

 the loose deposits have been removed from the surface by 

 hydraulicing. 



From the maps of the area that have been published, it 

 will be seen that there is considerable variety in the pre- 

 Cambrian series. On the shores and islands of Lake 

 Temiskaming, a few miles to the north or northeast of 

 Cobalt station, the Clinton and Niagara of the Silurian 

 system also show prominent outcrops. Between the 

 Niagara and the Pleistocene or Glacial there are no form- 

 ations represented in the district. 



The following table shows the subdivisions, based on age 

 relations, that have been made among the rocks of the 

 Cobalt area proper. Representatives of most of these sub- 

 divisions of the pre-Cambrian are found in other areas that 

 have been carefully mapped in the surrounding region. 



