GEOLOGY — WILLIS. 1 93 



stated as those of continental histories and mountain growth. Con- 

 tinental evolution will be treated from the point of view of continu- 

 ous geographic changes, so far as the assembled data permit, and the 

 three continents will be compared. Mountain growth will be con- 

 sidered as a study of altitudes and depressions as phenomena of earth 

 warping, in contrast to mountain building, which is the study of the 

 internal structures. The latter represents an earlier view of the origin 

 of mountains, still dominant in Europe, but being superseded in Amer- 

 ica by the former, which is based on the modern science of physiog- 

 raphy. 



The preparation of this Report C involves reading to assemble 

 facts beyond the range of observation, particularly with reference to 

 Europe and Asia. It is thus a continued study, to which more or 

 less time might be given, but which can be adequately executed 

 within the year, to October 1, 1906. That being done, the purpose 

 of the original and supplementary grants for research in eastern 

 Asia will have been accomplished and the work be brought to a close. 



During five months spent abroad, February to June, inclusive, 1905, 

 leading scientists of Europe were consulted on questions of Asiatic 

 and European geology, and a mutual understanding of views was 

 established with a satisfactory degree of agreement. It is particu- 

 larly gratifying that opportunity was afforded to lay the results of 

 research in Asia before Baron von Richthofen, the great explorer cf 

 China, who has since died. In relation to a particular problem of 

 continental geology — the study of the mountains of Europe in com- 

 parison with those of North America and Asia — journeys were made 

 throughout central Europe, across the Balkan peninsula to Constan- 

 tinople, and into Asia Minor. In general two types of mountains 

 were seen : (a) The mountains of central Germany and northern Aus- 

 tria, which were folded at the close of the Paleozoic, were eroded to a 

 peneplain during the Cretaceous, and have since passed through a 

 complex history of warping and erosion ; and (6) mountains of the 

 Karpathian type, which were folded during the Tertiary, were sub- 

 sequently eroded to a surface of mature topography, still retaining 

 marked relief, and have since been strongly warped, in some cases 

 before the close of the Tertiary, in others during Quaternary time. 

 Mountains of the class (a) are similar in history to the Appalachians. 

 The Karpathian type (b) has no analogues in America so far as known, 

 but is probably closely related to the Himalayas. The interpretation 

 of the mountains of Europe is to some extent novel and offers a new 

 conception of the physiographic history. 



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