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boulders of various kinds, at points far removed from their native 

 place, and such boulders often furnish conclusive proof of the direction 

 in which the glacier moved. Thus if the glacier oi- boulders from a 

 certain range of hills are found to the north of that range, the inference 

 is that the ice moved northward. Such evidence is not always, how- 

 ever, strictly conclusive as to the agency of a glacier, for though ice in 

 some form must have been largely instrumental in the moving of 

 boulders, in very many cases the active agent has been in the form of 

 floe or floating ice, either in bergs or huge pans, such as now float up 

 and down the St. Lawrence, and which have carried huge masses of 

 Laurentian rock from their original place on the north shore of the 

 river to the south side, where they can now be seen for hundreds of 

 miles along the beaches of the Gaspe coast. 



Subsequent to the ice age we find a period of depi-ession and sub- 

 mergence, during which the present surface was hundreds of feet 

 under water, and the arctic currents from the north carried huge trains 

 of bergs, with their loads of dirt, stone and gravel, just as at the 

 present day are seen off the coast of Newfoundland, which by their 

 stranding and subsequent melting deposited their debris at points now 

 many hundreds of feet above present sea level. The proofs of sub- 

 mergence are well seen in the presence of beds of clay, containing often 

 great quantities of marine shells of forms similar to those now found in 

 northern waters. These can be picked up at many ))oint3 about 

 Ottawa and Montreal as well as elsewhere, while bones of seals have 

 been found in the brickyards in this vicinity. With the nodules of 

 Green's Creek you are also, most of you at least, familiar. 



The amount of submergence has also been a fruitful source of con- 

 troversy, some holding to the view that this must be determined by the 

 present elevation of known shell beds above the sea level, ignoring the 

 evidence of drift boulders, and thus limiting it to some 500 feet. 

 Others, again, maintain that as much of the glacial phenomena is due 

 to the action of ice bergs and floating ice, the submergence should be 

 measured by thousands instead of hundreds of feet, and in certain 

 places there is unmistakable evidence of the presence of old sea beaches 

 several thousands of feet above the present level. The various claims 

 of the rival schools can be found in most text books on geology, but it 



