Iron Ores of Canada. 2 1 



Fig. 1. Jbi ideal section/ram £4e iron mine in Mali across the 

 valleys of the Ottotra and SiXaiereuee to the »vn mines iu ike 



Adirondack moantain-s in iiie State of New YorJc. 



Rg. 1. 



sy'if 



E. — Iron mine in Hull. 



A- — Ditto Adirondack. 



O. — Channel of the Ottaipa. 



L — Ditto of the St. Laurence. 



In &e aboTe ^etion, i3ie dark ma^ io which ihe beds of the 

 tworiveisare escarated is Siluriajo, conastiiig of sandstoii^ lime- 

 stones and shales SiU of oiganie T P-mairiR. The base of the Sgare 

 represei^ the Laurentian formatioii eemposed ei raiioGS kin^ of 

 hard rocks, snch as gnei^ (commonly called granite in tiiis coon- 

 try) and white cirstaDine lime^onew ' Frcsn the hills on the 

 norfli shore of the Ottawa where they hold iron in great imtsses^ 

 these rocks dip nnder the Silurian sandstones and limestones, aad 

 come ont again to the sor&ce in the State of New Yoik at the 

 point A. where they also contain many laffge beds of Talua3>le tae. 

 It is evident that the valley between these hflk BE and A was, 

 during the SHaiian age, occupied by the ocean, because the 

 greater portion of the depo^ represented by the dark part of ike 

 £gQre is fcQl of petrined marine smirnalsL The Soor of that ocean 

 was formed of the Lanrentian rocks, bnt when iiieaa are dos^ 

 examined, they are clearly seen to have been also of aqneoos 

 origin althoogh they do not contain &^k. They are stratined, 

 and some of the beds have been ascertained by Sir V. E. Logan 

 and Mr. Murray to consist of conglomerates or rocks made up in 

 part of ronnded pebbles, which no donbt had been worn by iiie 

 action of water. These fects are sofficient to proTe tibat they 

 were formed nnder water, but then oth^ circnmstanc^ ^iow that 

 they w^e not the product oi the same ocean which accumulated 

 the Silurison strata now lying upon them. In the first place. theT 

 are bent twisted, and tilted up at all angles, while the Silurian loeks 

 are in general nearly horisontal, and lie in broad sheets across 



