52 TARR AND MARTIN CHANGES OF LEVEL IN YAKUTAT REGION 



The straight, mountainous east shore of Yakutat bay north of Knight 

 island, also explained as a result of faulting by Eussell, certainly suggests 

 this origin by its form. 



Geological evidence in the form of abrupt difference in rock structure 

 in a short distance (less than a quarter of a mile) seems to demand a 

 fault line between the Coal series and the older Yakutat series along the 

 mountain face west of Yakutat bay, and between the Yakutat series and 

 the still older Crystalline series along the straight stretch of the lower, 

 or northwest, arm of Eussell fiord. One of- these inferred lines of an- 

 cient faulting is approximately parallel to one of the recent movements. 



OLDER ELEVATED SHORELINES 



That faults of older date occur in this region, and that the deformation 

 of 1899 is but one of a series of movements, associated with a progressive 

 mountain uplift at present in progress, is suggested by the recognizable 



,010 WAVE CUT CUFF. 



UPRAISED BEACH OF 1899. 



MODERN BEACH. 



FIORD. 



OLD TREE-COVERED BEACH. 



Figure I.— Cross-Section of northeast Shore of Russell Fiord, opposite Marble Point. 

 Illustrating the two uplifts recorded there. 



remnants of older uplifted shorelines. An example of this is a wave-cut 

 cliff with a narrow beach at the base on the northeastern shore of Eussell 

 fiord opposite Marble point (figure 1). The older beach and cliff (see 

 plate 15, figure 1) are occupied by a dense alder thicket with bushes esti- 

 mated to be over 25 years old. It rises about 4 feet above the beach which 

 was uplifted in 1899, which is here 9 feet above present sealevel. 



On the east side of Yakutat ba}', just north of Logan beach, there is an 

 elevated beach with a wave-cut cliff behind it, from which the forest has 

 been partly stripped by the tidal wave (see plate 23 and plate 20, figure 1) . 

 One spruce tree, broken by this wave, but still in place on the beach, had 

 75 rings, proving this uplift to have occurred at least 75 years ago, 

 whereas the recently uplifted strand in front of it bears only annual 

 plants. Both the older and newer uplift on this coast vary decidedly in 



