34 TARR AND MARTIN CHANGES OF LEVEL IN YAKUTAT REGION 



thick beds of black shale conglomerate, and a massive gray rock which, 

 with the incomplete petrographic work so far done on it, is tentatively 

 classed as an indurated tuff. There are other rocks in lesser quantities, 

 and the entire mass is complexly folded and faulted, both on a large and 

 small scale. Small faults and folds occur in all the outcrops, and fre- 

 quently a score or more appear in a single outcrop a few square yards in 

 area. The series is literally crushed and "kneaded." The Yakutat 

 rocks are very barren of fossils, and from those which we were able to 

 collect it has not been possible to determine their age. Ulrich* classifies 

 this series as Liassic. 



A third series of rocks occurs in a few outcrops two or three miles from 

 the head of Yakutat bay, on the west side. These rocks are mainly gray 

 sandstones, clays, and carbonaceous shales, with some small beds of lignite 

 coal. They stand at a high angle, but are not complexly folded and 

 faulted like the Yakutat series, from which they are apparently separated 

 by a fault. A tentative determination of Pliocene age, based on a pre- 

 liminary examination of the plant fossils, has been placed by Knowlton 

 on this coal-bearing series. 



Outside of the mountain front, as already stated, a foreland of glacial 

 gravels extends to the sea ; but near the head of Eussell fiord it is under- 

 laid by planated Yakutat series and granitic rocks. Elsewhere no hard 

 rock was found in the foreland; but a low, butte-like hill rising above it 

 some, distance from the mountains is evidently rock. 



PREVIOUS EXPLORATIONS 



Professor I. C. Eussell explored Yakutat bay and Disenchantment bay 

 in 1890. f He describes the earlier explorations, discusses the general 

 physiography and geology, and pays particular attention to the glaciers. 

 In 1891 X Eussell extended his explorations to the head of Eussell fiord. 

 In his descriptions he clearly points out the faulted and folded condition 

 of the rocks of the Yakutat series and assigns to faulting an important 

 part in the production of the physiography of the region. With the ex- 

 ception of some gravel terraces, which our work leads us to assign to other 

 origin, Eussell mentions no elevated shorelines. He does call attention to 

 a submerged forest at the head of the bay which we also saw. 



The Harriman expedition visited the inlet in June, 1899, three months 

 before the earthquake, and went to the head of Eussell fiord, landing at 



several points, among others on Haenke island, which now has very dis- 



- 1r ^ 



* Harriman Alaska Expedition, vol. iv, 1004, pp. 125-140. 



t Nat. Geog. Mag., vol. iii, 1891, pp. 53-203. 



$ Thirteenth Annual Report U. S. Geol. Survey, 1891-2, part ii, pp. 1-91. 



