46 TARR AND MARTIN CHANGES OF LEVEL IN YAKUTAT REGION 



1899, as the time when, during a series of vigorous earthquake shocks, 

 the remarkable deformation of the coastline of Yakutat bay, Disenchant- 

 ment bay, and Eussell fiord took place. 



Evidence of Depression 



Less varied in character, yet equally conclusive, is the evidence of de- 

 pression, shown on a much smaller stretch of coast and naturally masked 

 by the sea. The encroaching of beach sand on forest and the consequent 

 killing of trees by sand-smothering, and by salt water reaching their roots, 

 is especially well seen at the head of Eussell fiord (see plate 18, figure 2). 



In a number of places on the islands and shores of the foreland on the 

 southeast shore of Yakutat bay this encroaching of the sea is also well 

 seen. The best instance in this vicinity is on the south shore of Knight 

 island (see plate 19, figures 1 and 2), where beach sand extends back into 

 the spruce forest a hundred feet or more, and where waves of present 

 storms are overturning great trees and piling their wreckage among the 

 living spruce. Here also the rank, sedgy beach grass is found growing 

 back in the forest, illustrating once more the battle for the shore strip 

 between land plants and sea or shore forms. As has been stated (page 

 35), Ensign Miller speaks of dead trees on the shores of Miller lake; but 

 their relation to the lake is not made clear. 



None of the instances of depression can be referred to encroachment by 

 waves, for they occur not on the exposed, but on the lee coasts. That it 

 is actual depression of the surface is proved by the fact that over consider- 

 able areas tree roots are now bathed by salt water. It is not certain, 

 however, that all these areas of depressed surface are actual instances of 

 a downward movement of the crust. They all occur in unconsolidated 

 deposits, and the depression may be due to a shaking down of these loose 

 beds during the earthquakes. This, however, does not seem probable, 

 since the trees are not thrown down, nor even inclined, excepting where 

 the waves are now undermining them. That the change is a recent one 

 is proved by the fact that many of the trees reached by the storm waves 

 are as yet only partly dead, some of their branches still supporting the 

 needle-like leaves. 



Regions of slight or no Movement 



Long stretches of coastline were not moved either up or down; but it 

 was often difficult to be certain that there had been absolutely no move- 

 ment, since a change of a foot or two one way or the other would leave 

 only faint and uncertain evidence of the movement, In these cases simply 



