]NTR0DUCT10X 351 



Upper Silurian formations ranging from Uppor IJandoverv to tho 

 Ludlow. 



Thu^ for several years the evidence has been accumulating to prove 

 that outside the general Appalachian axis, in the region covered by the 

 State of Maine and the eastern Canadian provinces, more or less con- 

 tinuous sedimentation was going on during Silurian and early Devonian 

 time. The faunas of these sediments are not identical with faunas of 

 New York and the interior, but they exhibit intimate relationship with 

 the transatlantic faunas of Paleozoic time. 



During the preparation of U. S. Geological Surve\ Bulletin number 

 165 I was particularly struck not only with the general resemblance, 

 but with the fact that the faunal combinations in Maine, namely, the 

 generic associations of species in tlie successive faunas, bore a closer 

 resemblance to the terminal Silurian beds of Great Britain than to the 

 succession in the not-far-off district of New York. 



From the knowledge I then had of the several faunas 1 concluded that 

 the Cobscook Bay series, described roughly b}^ Shaler, probably gave the 

 best evidence of this relationship. This led me to urge the director of 

 the Federal Survey to provide a topographic map of the Eastport region, 

 so that it might be possible to work out in detail its very complex geology 

 and paleontology. The result was that the Federal Survey, in coopera- 

 tion with the State of Maine, prepared a topographic map of the East- 

 port quadrangle, Maine, which was published in the year 1908. In the 

 summer of 1907, while it was in preparation, a party, consisting of E. S. 

 Bastin, C. L. Breger, and myself began a geological examination of the 

 region. During the 3^ears 1907, 1908, and 1909 we collected a full series 

 of fossils carefully located stratigraphi(tally. The field work is now 

 complete. Mr. Bastin has the geological map in progress, and duriiii: 

 the past year the fossils have been under investigation. 



Although the preparation of the geological map and the description 

 of the fossils are still quite incomplete, it has seemed to us that the geo- 

 logical section of the district, in its bearings on correlations between the 

 two continents of America and Europe and on general problems of 

 paleography, is of sufficient importance to warrant a brief statement of 

 some of the more prominent facts already established by the evidence. 



Structural Subdivision of the Eocks of the Eastport Quadrangle 



Structurally the rocks are a confused mixture of igneous and sedi- 

 mentary rocks, broken uj) by faults into numerous irregular blocks and 



