HIGH MOUNTAIN DISTRICT 169 



countered the sea soon after reaching the basal plain, 

 they may have been wasted so rapidly along the line of 

 contact as to determine there a principal line of morainic 

 accumulation, and the ramparts of the coast may constitute 

 the record of a successful resistance by the sea to glacial 

 invasion. 



If this explanation is correct, the Pleistocene submer- 

 gence of the coast probably extended considerably above 

 the zone of terraces. The oceanic resistance determining 

 the deposition of drift would not be effective after the 

 moraine ridge had been built so high as to become a 

 partition between ice and water, and the theoretic posi- 

 tion of the old sea plane is therefore along or above the 

 highest crests of the moraine. 



The hypothetic conditions are similar to those at the 

 foot of Davidson Glacier. If that glacier should shrink, 

 and the sea-level should be lowered in Lynn Canal, the 

 Davidson moraine, if composed wholly of rock debris, 

 would survive as a crescentic rampart with a flat top; 

 and if the ramparts of the Fairweather region are strictly 

 homologous they should have broad and level crests. If, 

 however, the Davidson moraine is not wholly built of 

 rock debris, but consists rather of an apron of debris 

 resting against a concealed ice slope, the resulting ram- 

 part, when ice and water are withdrawn, would have an 

 acute crest, with uneven sky-line ; but the crest, instead of 

 representing the plane of the present water-level, would 

 stand somewhat below it. In viewing the old moraines 

 of the Fairweather coast I recognized a few local flat 

 summits, but the general character of the crest line is 

 acute and its height is not uniform. If, therefore, the re- 

 lation of the old glaciers to the sea was like the present 

 relation of the Davidson Glacier, the sea then stood much 

 higher against the land than now or else the land then 

 stood lower. 



