LOCATION AND GENERAL PHYSIOGRAPHY 33 



inlet where it passes beyond the mountain front out into the foreland. 

 A small bay, Seal bay, up whose valley lies Hidden glacier, forms the 

 greatest irregularity in the coastline of the south arm; but at the angle 

 between the south and northwest arms a large fiord extends eastward, 

 under the name of Nunatak fiord. The tidal Nunatak glacier forms its 

 head. 



The entire inlet, — Yakutat bay, Disenchantment bay, and Eussell 

 Fiord — omitting its branch, the Xunatak fiord, has the general shape 

 of a bent arm with the shoulder at the Pacific, the elbow at the head of 

 Disenchantment bay, and the fist at the expanded head of the bay where 

 the fiord extends into the foreland to within 13 or 14 miles of the ocean. 

 From the ocean around to the head of Eussell fiord by boat is a distance 

 of 70 or 75 miles. Thus our studies extended along more than 150 miles 

 of shoreline in the bay and fiord, all parts of which were seen and most 

 of which were studied critically. 



Everywhere the indications are that the fiord is deep. Soundings have 

 been made by the U. S. Coast Survey in Yakutat bay, showing an irreg- 

 ular bottom deepening toward Disenchantment bay. At the mouth of 

 the latter bay, near point Latouche, there is a depth of 167 fathoms; and 

 between Haenke island and Hubbard glacier Eussell reports 40 to 60 

 fathoms. Beyond this no accurate soundings have been made ; but the 

 shape of the coast and the absence of kelp indicate deep water throughout 

 the fiord. 



GEOLOGICAL STRUCTURE 



The northeastern shore of Eussell fiord, from Hubbard glacier to Xun- 

 atak fiord, is made of highly inclined slates of undetermined age. Our 

 expeditions into the mountains along this shore discovered a variety of 

 crystalline rocks, both igneous and metamorphic, and the glaciers bring 

 down only these classes of rock. All the north shore and the eastern 

 two-thirds of the south shore of Xunatak fiord are also bordered by 

 crystalline rocks — granite, and steeply dipping gneiss, schist, slate and 

 stretched conglomerate. These crystalline rocks end abruptly against a 

 younger, practically unmetamorphosed series both in the Hidden Glacier 

 valley and on the south shore of Nunatak fiord. This line of separation, 

 interpreted as a fault, if continued would extend down the northwest 

 arm of Eussell fiord, on one of whose shores the rocks are crystalline, 

 while on the other (southwest) the unmetamorphosed series is present. 



From these crystalline rocks to the foreland there is a complex, called 

 the Yakutat series by Eussell, forming all the mountains bordering this 

 part of the fiord. It consists of thinly bedded black shales and sandstones, 



