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finer material being scanty and in a finely-divided or comminuted state. 

 Such a deposit is one which " land ice " alone produces and one which 

 resembles wonderfully the " moraine-profonde " of the ancient Rhone 

 glacier as they may be seen near the Westei-n extremity of Lake Geneva 

 (a mile and a-half below) and in the adjoining districts. In further 

 corroboration of these boulder clays being due to land ice is the fact that 

 none of the organisms which would be expected to characterize marine 

 clays are present therein. The total absence of organic remains (so far 

 as ascertained) in these glacial clays, coupled with the fact of their 

 occurrence in abundance in the Leda clays above, points clearly to a 

 wide difierence in the mode and condition of deposition of both, the 

 one being laid at a great elevation above the sea level, the other below 

 the level of an ocean or arm of a sea. 



In examining the surface geology of Ottawa, one is struck with 

 the diversity in the distribution and extent of this " boulder clay for- 

 mation :" In some places, the only indexes present, which point to it 

 existence at one time, ai'e the striae and grooves over the bare rocks, such 

 as are exposed principally about Hull and Ottawa in the vicinity 

 of the Grand River, whilst there are also numerous fields and tracts 

 of country which exhibit that formation very clearly. In such 

 I)Ost-gUicial valleys and districts, from which the Leda clay, and 

 Saxicava sand and overlying strata, have been removed by denudation, 

 there occurs a large quantity of these boulders. Amongst these are no 

 doubt included, at the present day, the erratics which were dropped 

 by ice-bergs at a period subsequent to the Great Ice Age. The Rideau 

 River Valley,of Post-Tertiary Age, and very recent, geologically speaking, 

 presents numerous points of interest from its mouth at the falls in New 

 Edinburgh to the Hog's Back. Nearly the whole of the Post-Tertiary 

 formations were canied away by the once wide stream which flowed 

 there, and even the glacial clays suflTered not a little, as the materials 

 cementing the pebbles are to a great extent entirely wanting. The 

 Rideau Rifle Range extends, for the most part, over this formation, 

 whilst the southern portion of the range, as well as its northern limit 

 (at the 600 yard butte) are on the outskirts of the newer overlying 

 marine clays. We have already spoken cf moraines. These vary very 

 much in extent and distribution just as the " boulder clay " or " till,'* 



