BucJcley — Ice Ramparts. 161 



by Dr. Buckley is the manner in which pools and lakes of water 

 form on the ice along folds and fractures which occur within the 

 ice sheet itself. In this case it is well known that the water is 

 heavier than the ice, yet the water issues through the cracks in 

 great pools and even in lakelets upon the ice adjacent to the ice 

 ridges. The rise of this water is due to two causes. In the 

 first place on each side of an anticline is a natural place for syn- 

 clines to form, as result of the downward thrust of the limbs of 

 the anticline. Tims there is a direct tendency, due to the 

 thrust of the ice, for the ice to be jammed below the water, which 

 therefore rises to tlie surface through the cracks. As fast as it 

 rises its weight is added to that of the ice and thus there is an 

 added tendency for the process to continue. In the second place, 

 the weight of the piled-up mass of ice along the ice ridge is 

 transmitted to the adjacent ice, and this combined with the nor- 

 mal amount of ice above the water is more than sufiicient to 

 overcome the greater weight of the water, and the water rises to 

 the surface. So far as the rise of the water to the surface is due 

 to this second reason, it is caiised by gravity. Upon the lake it 

 is impossible to separate these two causes. In another place I 

 have held, following Dutton and others, that gravity is one of 

 the main factors which have caused lava to rise to the surface 

 and have compared the rise of the lava to that of water through 

 ice where ice ridges form. ^ In the case of the ice the thrust is 

 produced by another force than gravity. ^ However, in the case 

 of the earth the thrust of the crust is ultimately produced by 

 gravity, and therefore the dominating influence of gravity in the 

 rise of lavas. The relative sizes of the ice ridges and the pools 

 of water are very interesting, the latter being many times the 

 height of the former. The relations are somewhat the same as 

 those of the great volcanic plateau of the west to the adjacent 

 mountain masses. 



Another notable point in this connection is that where an ice 

 ridge once forms and water exudes to the surface, this freezes ; 

 and this results in greatly thickening the mass of ice for that 

 belt. When expansion ceases and a cold period follows, the 



1 Earth Movements, by C, R. Van Hise. Trans. Wis. Acad. Sci., Arta, and Letters, Vol. 

 XI, lo93, pp. 495-436. 

 «Loc. cit.,pp. 512-514. 



11 



