686 g. c. martin triassic rocks of alaska 



Introduction 



One of the most important results of the investigations by the United 

 States Geological Survey in Alaska has been the discovery of thick sec- 

 tions of marine Triassic strata in many parts of the territory. These 

 occurrences are of extreme interest and importance, not only because they 

 constitute such a large and important part of the areal and stratigraphic 

 geology of Alaska that an intimate knowledge of them is essential for a 

 full understanding of the local geologic features, but because they show 

 important relationships with the known sections in other regions, and 

 because they will, when thoroughly studied, undoubtedly be found to 

 constitute one of the most important, extensive, and complete sections of 

 Upper Triassic rocks in North America, if not in the world. They will 

 fill out the American stratigraphic column at points where it is very 

 deficient in many other parts of the continent. 



It has become evident that the rocks of Alaska offer very valuable con- 

 tributions, not only to mineral wealth, but to pure science. In the 

 acquisition of Alaska Ave received a European and Asiatic inheritance, 

 both historically and geologically, for much of Alaska is essentially Rus- 

 sian in its geologic as well as in its human history. It is not a mere 

 accident that the most elaborate publication on Alaskan fossils deals with 

 faunas from the shores of both the Caspian Sea and of the Alaska Penin- 

 sula. It is perhaps a fortunate circumstance that the best of the early 

 collections of Alaskan Jurassic ammonites are in Europe, where they are 

 accessible for comparison with the closely related European and Asiatic 

 forms. The lately terminated Russian dominion on the eastern shore of 

 the North Pacific followed most fittingly after the often-repeated sub- 

 mergence of parts of both Alaska and Russia beneath a common sea in 

 Triassic, as well as in Jurassic, Cretaceous, and Permian times. 



Although no intensive stratigraphic and faunal studies of the Alaskan 

 Triassic rocks have yet been undertaken, a very considerable volume of 

 important stratigraphic data has already accumulated. These facts are 

 partly unpublished and are partly scattered through a large number of 

 reports on regional and economic geology, where they are not so accessible 

 as they should be, nor is their volume and importance fully appreciated. 

 There is need for a general preliminary discussion of these rocks, in order 

 to call attention to the available data, to render it more accessible, and 

 also, as far as possible, to coordinate the known facts, to present some 

 important conclusions, and to call attention to some of the problems 

 which further studies of the Alaskan rocks may help to solve or on which 

 additional data from other regions are necessary for the solution of the 

 Alaskan problems. 



