1852.] ACTION ON THE LAND. 147 



and I have rejected all the former conclusions, because 

 these are not invariably, even in winter, " snow-clad" re- 

 gions ! The discussion of the causes operating on upper 

 levels must be referred to other authorities and forces, 

 and, as far as I know, must ever remain theoretical ; no 

 proof can exist. 



The first cause is plainly illustrated by pressing a flat 

 board, having a smooth rectangular edge, against a slight 

 ridge of sand on a table : this will produce the first ridge, 

 or terrace. Possibly the inner edge of the board may 

 rise, and slide up the sand some inches : comparing great 

 things with small, this is Nature's first movement here. 

 The fine bay ice, say six inches thick, forced very slowly 

 by millions of tons weight and impelled by wind or tide, 

 presses on some beach, a noise like that of a rushing 

 wind is instantly heard, and ice is noticed travelling up 

 the beach, forcing before it all the light gravel. This of 

 course planes the subjacent matter. It has possibly re- 

 moved one great shaving, and the upper abutting gravel 

 resists but for an instant,. it buckles, breaks, and turns 

 up, forcing layer after layer, and " piling" the beach un- 

 til the motive power is arrested, possibly miles distant ! 

 This is Act I.; it may be repeated, and the successive 

 forces, possibly with planes of four feet in thickness, do 

 their work with unerring certainty, until arrested by the 

 general freezing of such a mass so accumulated on the 

 shore as will compel the outer ice to buckle, break, and 

 pile, overwhelming the strongest works of man. These 

 are plain, unmistakable facts. The spring thaws reveal 

 these facts these apparently " tide terraces," and leave 

 new comers to dream of their origin. 



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