212 The Ottawa Naturalist. [March 



River limestone which occur along the Opeongo Road on a 

 ridge south of Clear Lake, at a height of nearly fourteen hundred 

 feet above sea-level.* Some of these blocks are five to eight 

 feet through and very angular. As far as known the Black 

 River formation nowhere occurs in the vicinity of Clear Lake at 

 a greater height than eight hundred feet, so that if the relative 

 levels of the country have not changed since the glacial period, 

 these boulders have been carried u[)ward a distance of five to six 

 hundred feet. Travelled boulders in similar positions have been 

 frequently noted. Sir J. W. Dawson records large Laurentian 

 boulders on Montreal Mountain which, he says, must have been 

 carried probably a hundred miles from the Laurentian region to 

 the north-east.j Dana states that Mount Katahdin in Maine 

 has many boulders on its northern face derived from the Devo- 

 nian rock of the low country to the north, three thousand feet 

 below it in level. | In Nova Scotia sandstone boulders are 

 common on the Cobequid Mountains at a considerable height 

 above the present level of the Carboniferous beds, from which 

 they were derived. The position of these boulders at such 

 heights forms a most interesting subject for study, and many 

 theories have been advanced in regard to it. Among the 

 theories put forward the following may be mentioned. Some 

 writers claim that these erratics were placed in their present 

 position by floating ice. They claim that the land was sub- 

 merged to a depth sufficient to allow icebergs or ice jams to pass 

 over or become stranded on the higher ground, where they 

 deposited whatever material was embedded in them, or carried 

 on their surface. Another explanation is that the land was 

 covered by a glacier to a depth equal to or more than the 

 greatest height at which these boulders are found, and that this 

 mass moved over the country, carrying boulders, etc., along with 



* The Ottawa Naturalist, December, 1896, p. 171. 

 t Canadian Ice Age, p. 201. 

 :;: Manual, p. 690. 



