BELT — ON THE GLACIAL PERIOD 1]N NORTH AMERICA. 93 



2. JDnJl-heJs. — It is, however, in the composition and distribution 

 of the drift-beds that we find the most convincing evidence of the 

 supra-marine character of the glaciating agent. In Nova Scotia 

 the hollows are comparatively free f^rom drift excepting where 

 mounds across valleys mark the position of old terminal moraines. It 

 has generally been pushed into recesses in the ranges, or to the south 

 end of hills where it was sheltered from the ice moving southward. 



Thus Lake Thomas near Waverly is bounded to the Mest by a 

 rather steep range running north and south parallel to the lake, 

 down to and into which it rapidly slopes. The structure of this hill 

 has been well exposed by cuttings made in search of auriferous 

 quartz veins. The northern end and the side next the lake has a 

 thin covering of clay, gravel and boulders. The bed-rock is rounded, 

 scored and grooved. Masses of quartz have been broken oil from the 

 lode and carried southwards. The southern end of the hill is com- 

 posed entirely of clay, gravel and large angular stones. A tunnel 

 was driven into it for about two hundred feet and no solid rock 

 could be found, nothing but huge stones and other drift pushed in 

 under the lee of the rocky beds to the north. 



The transported blocks and the direction of the scratchings show 

 that the glaciating agent moved from the north. If it had been 

 floating ice and the hill at the time a submerged rock, the icebergs 

 ought to have stranded on and deposited their freight at the north- 

 ern, and not at the southern end. If on the contrary it was glacier 

 ice the phenomena are just such as we might expect to find. 



Again, if this drift had been dropped from icebergs floating over 

 a submerged land, and we could imagine any possible means by 

 which it could be arranged as we find it, we have still to account for the 

 greater difficulty, that whilst the land sloAvly rose again from beneath 

 the waters of the supposed glacial sea, and was exposed to the action 

 of the waves on the spreading coast line, these ridges of incoherent 

 drift were left unlevelled, and these bare hollows were left unfilled. 



o. Gold in the Drift. — Through much of the drift grain gold is 

 sparingly disseminated, and its distribution affords another argu- 

 ment in favour of the supra-marine theory. In Australia all the 

 most important deposits of alluvial gold have been found in valleys 

 lying immediately above the bed rock, beneath beds of gravel and 

 clay ; wherever surface washings have been discovered much richer 

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