TOPOGRAPHICAL. 35 



over a wide expanse of country between Grand Lake, the Humber 

 and Exploits rivervS, In fact it may be safely affirmed that more 

 than half the island is Laurentian. 



HURONIAN KOCKS. 



Three-fourths of the great Peninsula of Avalon are Huronian 

 (equivalent to the Cambrian of English geologists). The Hu- 

 ronian consists mainly of a set of slates with conglomerate bands. 

 The city of St. John's, and in fact nearly all the settlements be- 

 tween Fortune Bay on the soutli, and Bonavista Bay on the east, 

 are built upon this formation. 



SILURIAN ROCKS. 



The Lower Silurian rocks have a large develoyment and it is 

 in. these that the metallic oi-es occur which seem destined to ren- 

 der the island a great mining centre. The Lauzon division of 

 the Queljec gioup, which is included in the Silurian, has an im- 

 mense spread in the island. It consists of serpentine rocks, 

 associated with dolomites, diorites, etc. As in other jmrts of 

 North America, it gives evidence in Newfoundland of being 

 more or less rich in metallic ores; and hence the strong proba- 

 bility that many portions of the island will become important 

 mining centres. 



The middle Silurian division of rocks is also widely spread ; 

 and the most fertile belts of land and the most valuable forests 

 are nearly all situated on the jjortion of the country occupied by 

 this formation. The valleys of the Exploits, Gander and several 

 smaller tracts, which contain arable lands, belong to the middle 

 Silurian foi'mation. 



CAKBOMFEKOUS. 



The Carboniferous series, in wliich the coal-beds are to be 

 found, occupies a large area on the western side of the island, in 

 the neighbourhood of St. George's Bay and Grand Lake ; and 

 also along the \ alley ot the Hunil)er and around the shores 

 of Deer Lake. Tlie l)est land rests upon the, rocks of this for- 

 mation. 



