Geological Survey of Canada. S3 



descriptions of manyimportant fossils, and carefully prepared essays 

 on theoretical and practical points that have occurred during the 

 work of the explorers in past years. 



The portion of the volume relating to the personal explorations 

 of the head of the survey, is occupied with the intricate and diffi- 

 cult subject of the structure of that great Laurentian district ' 

 stretching along the whole northern side of the settled portion of 

 Canada, and as we have long thought practically limiting the 

 extension of population in this direction. This question must, 

 however, depend on several points only to he ascertained by such 

 labour as that at present being performed by the survey. The 

 streams and valleys of a country such as that in question are sure 

 to extend along its better parts ; and the ordinary traveller passing 

 along these, and knowing nothing of the intervening forest-clad 

 ridges and table lands, except their effect as distant objects in the 

 landscape, must form exaggerated ideas of the value of the 

 country as a field for immediate settlement. On the other hand, 

 he sees little of the mineral riches which may be present, and 

 which in a different way may render such regions available. 



The previous reports of Sir W. E. Logan have left on the minds * 

 of Geologists the conviction that all that part of Canada lying 

 north of a line drawn from the S. E. angle of Georgian Bay to 

 Kingston, and thence along the north side of the St. Lawrence to 

 Labrador, consists mainly of gneissose rocks, like those of the 

 highlands of Scotland and Scandinavia, with the exception of a 

 triangular patch between the mouth of the Ottawa and the St. 

 Lawrence, and a narrow stripe reaching thence as far as Quebec. 

 In short, those great regions lying north of the river and great 

 lakes, and of the lines above indicated, are mapped as consisting 

 of the rock formations of which a specimen is seen in the Thou, 

 sand Islands, and are presumably similar to these in their agricul- 

 tural capabilities. Canada, for practical purposes, thus appears to 

 consist of the Silurian regions lying south of the river and around 

 the mouth of the Ottawa, and of the great Silurian and Devonian 

 peninsula of the Upper Province. The remainder, though pre- 

 senting cultivable valleys, may in the main be regarded as unpro- 

 ductive, and not likely for some time to enter into competition 

 with the rich lands of the west. 



It is very probable that these views may have had some con- 

 nection with the selection of Ottawa as a seat of Government. 

 Situated nearly at the apex of the triangular tract above referred 

 to, it forms the last outpost to the northward, of the great Silurian 



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