=58 



PREHISTORIC EUROPE. 



6. 



predominating. Immediately above the 

 till came an irregular bed of similar 

 coarse shingle (Sh), which was succeeded 

 by diagonally-bedded sand and gravel (S), 

 passing here and there into a very coarse 

 shingle and " alpine diluvium " or con- 

 fused assemblage of rounded and sub- 

 angular and angular fragments. Upon 

 the denuded surface of these false-bedded 

 accumulations rested a layer of sandy 

 silt (Sc), gray above and passing into yel- 

 low below. It varied from two to four feet 

 in thickness, and contained many root- 

 lets. Immediately upon it came a bed 

 of peat (P), one inch to eight inches thick, 

 of the same description as that already 

 mentioned. It was covered by gray silty 

 sand or sandy clay (Sc),one to two feet, and 

 that in turn by coarse earthy sand and 

 shingle (Sh). The overlying till (B 2 ), it 

 will be observed, cuts down through all 

 the beds, and rests eventually on the lower 

 till and the Carboniferous strata (C). 



These instructive sections justify us in 

 coming to the following conclusions : — 



1st, The lower till is a true bottom- 

 moraine, and could only have been laid 

 down in its present position when Scot- 

 land generally was covered with a great 

 ice-sheet. It cannot possibly be due to 

 a mere local glaciation of the low grounds 

 of Midlothian. This is evident from 

 the fact that all the Lowlands lying be- 

 tween the Southern Uplands on the one 

 hand, and the Highlands on the other, 

 must have been covered with ice before the particular neigh- 



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