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GEOLOGICAL MEMOIRS. 



ever, wishes this to be regarded merely as a sketch-map, — the first 

 attempt at mapping the geognosy of this region, without any pre- 

 tensions to the accurate determination of the boundaries of the de- 

 posits there observed. 



Appended to the Map is a profile-sketch of the mountains of the 

 region under notice. Of these Mt. S. Elias (143° W. long., 60° lat.) 

 on the continent is the highest, being 16758' high ; in the Aleutian 

 Isles the volcano Schischaldin (164° W. long., 54° 40' lat.) is the 

 highest elevation (8953') ; and in Kamschatka the loftiest is Kljut- 

 schewskaja Sopka (56° 4' lat.), being 13876' high. 



Diluvial formations were recognized, by means of their Mastodon 

 remains, at Unalaschka, the Pribiilow Islands, Norton Bay, Kotzebue 

 Sound, and the coast further north of this ; and indications of these 

 deposits were observed at Cook's Inlet and on the Aliaska coast. 

 The distribution, however, both of alluvium and diluvium can only 

 be correctly defined when the country is better known. 



The Tertiary formation is chiefly represented by the Brown-coal 

 beds. These occur on the Pribiilow and Fox Islands, both coasts of 

 Aliaska, Kadjak, east coast of Cook's Inlet, Altna Bay, Great and 

 Little Bodega, the mouth of the Sacramento, and from St. Jose to 

 Monterey. The fossils from the Aleutian and Pribiilow Islands, 

 Aliaska, Unga, Kadjak, and the Great Bodega belong to one period. 

 Although they are very closely allied to the existing molluscs of 

 Beering's Straits, and in some cases exhibit, perhaps, perfect identity 

 (see Appendix No. 1), yet material differences present themselves in 

 the recent and fossil faunae, and the author is induced to ascribe these 

 fossils to the Newest Tertiary period. Herein, says he, we have been 

 especially guided by the surprising similarity of the fossils from the 

 Tertiary basin of Beauport, near Quebec, on the St. Lawrence*, which 

 appear to be very nearly allied to the Newest Pliocene beds of Scot- 

 land. Moreover, the Kamschatka Tertiary formations, noticed by 

 Erman, will, perhaps, after more accurate research, exhibit the same 

 analogies ; and herein we have another proof that a general unifor- 

 mity of the northern fauna, corresponding to the existing distribution 

 of animals in the north, had existed at early periods. The author 

 points, also, to the possibility of the existence of analogical conditions 

 with regard to the Pliocene Tertiary beds on the northern slopes of 

 the Caucasus. 



Jurassic rocks were met with only in Katmai Bay, on the S.E. 

 coast of Aliaska. 



Indications of the Coal-formation occur on the Columbia river, at 

 Vancouver, and Unga ; and it is probably present on the northern 

 parts of the east coast of Beering's Straits, as also in the Icy Sea, 

 from Cape Thompson to Capes Lisburn and Beaufort. 



The existence of Silurian rocks in this region, and that to a great 

 extent, is considered probable ; but no decided evidences were met 

 with, excepting a rolled fragment of Catenipora escharoides, from 

 Sitcha, and indications of these rocks on the north coast of Beering's 

 Straits. [T. R. J.] 



* Lyell, Trans. Geol. Soc. vol. vi. pt. 1. p. 135-139. 



