QTJATERNAEY FORMATIONS — THE DRIFT. 



219 



Fig. 11. 



tTsually such specimens have heen derived from the immediate vicin- 

 ity, but such does not seem to be always the case. 



An interesting peculiarity, 

 sometimes observed, consists of 

 cavities filled with fine uniform 

 gravel, which presents the appear- 

 ance of having been deposited in 

 the form of gravel howlders, either 

 cemented, or, as suggested by Dr. 

 E. Andrews, in the frozen state. 

 These have been observed of va- 

 rious sizes, from six inches to two 

 or three feet in diameter, and of 

 irregular, though usually some- 

 what rounded, forms, as shown in 

 the accompanying figure. 



This figure also imperfectly il- 

 lustrates the irregular stratifica- 

 tion and lamination which fre- 

 quently characterize portions of 

 this deposit. Contorted lamina- 

 tions, un surpassed by anything pre- 

 sented in the metamorphic rocks, 

 are sometimes to be seen, closely associated with bowlders, stratified 

 clays, pockets of gravel, stratified sand deposits, gravel beds and un- 

 stratified hard pan, constitutiijg a most changeable and irregular struc- 

 ture. The surface area of this formation is shown on Atlas Plate lY. 

 In harmony with the irregular nature of this formation, the rock 

 here and there was left uncovered by it, and at some points it was 

 swept away by subsequent agencies, but with these exceptions, it is to 

 be regarded as covering the immediate surface of the rock over the 

 entire district. 



MODIFIED DRIFT — CHAMPLAIN. 

 I. Beach Formation A. 



During the deposit of Bowlder Clay, there is abundant reason for 

 believing that the general surface was more elevated to the northward 

 than at present. Subsequently, however, perhaps cotemporaneously 

 with the retreat of the glacier, and possibly also the cause of its re- 

 cession, there occurred a relative depression to the northward. This 

 depression was accompanied by a vast accumulation of water in the 



A, Bowlder Clay. _, . 

 C. Stratified Sand Deposit. 



ified bowlder clay. . 

 d, Gravel (bowlders). 



Stratified Eed Clay. 

 . a, Obscurely strat- 

 Clayey sand, c, Sand. 



