Hypothesis of Glacial Action. 279 



an old birch which a resident informed me used to grow out- 

 wards towards the river, now bent in the opposite direction, not 

 from displacement of the roots, but from sheer over-stretching 

 of the fibres of the trunk. As formerly stated, so enormous 

 is the vis-a-tergo of these bergs, that they have been known 

 to impinge on jetties of wood, and remove them entirely. In 

 one instance a projecting mass caught a house on the bank, and 

 shaved away the upper story, leaving the lower portion intact. 

 The general conclusions, therefore, elicited from what has just 

 been detailed might stand as follows. There may have been 

 a greater elevation of the country during the Glacial epoch 

 than at present, when the glaciers, moving generally from the 

 high lands to the north (not in every case, however, but with 

 slight deviations to the east and west according to slopes), 

 scored the underlying rocks and bore boulders from centres of 

 dispersal to lower levels. At this time, or subsequently, the 

 river terraces were formed as the land began to subside. The 

 thaws then setting in, there would be a damming back of the 

 waters in many of the valleys and lakes, which brought about 

 the deposition of their gravels, " horsebacks " and " mounds 

 of detritus," while portions of the land becoming submerged 

 under the sea, would explain the presence of marine shells in 

 the clays along the coasts and high reaches of gulfs, and so 

 forth. Finally, there was a partial elevation, which brings us 

 to our times. I allow, however, that this view of the case 

 admits of question ; but, without being dogmatic, I cannot 

 agree with Dr. Dawson* that the land-ice theory demands the 

 most " portentous changes," for surely the depression of the 

 country to the extent of 6,000 feet, to allow for the striae on 

 Mount Washington, implies a far more exorbitant demand 

 on our belief than an elevation of a few hundred feet, which 

 is all the glacialists ask for, if indeed that is requisite, to 

 account for the entire phenomena. I should like to conceive 

 that the conditions of the epoch referred to were in kind, but 

 * " Acadian Geology," 2nd edition, p. 68. 



