10 GEOLOGY OF THE NARRAGANSEIT BASIN. 



to extensive dislocation of the deposits and to the formation of several 

 anticlines and synclines, as well as to the development of considerable fault 

 movements. In this part of their history the rocks which remain in this 

 field were probably deeply buried beneath accumulations which have been 

 entirely swept away. This fact, as will be shown in detail hereafter, is 

 indicated by the large amount of pebble deformation which has taken place 

 in various portions of this field. 



The foregoing statements make it plain that the detailed consideration 

 of the Narragansett Basin should be preceded by some study of the strati- 

 graphical and orogenic features of the district in which the basin lies. 



STRATIGRAPHICAL AND OROGENIC RELATIONS OP THE BASIN. 



The relation of the Narragansett Basin to the system of .disturbances 

 which have affected the eastern coast of North America involves certain 

 questions concerning the organization of the Appalachian system which, 

 so far as I am aware, have never been considered by the students of that 

 field. Those mountains are generally assumed to consist in part of an 

 ancient axis, which was developed perhaps by a succession of movements, 

 partly in Archean and partly in early Paleozoic time, the whole forming a 

 range extending from northern Alabama to the northern parts of New 

 England, with a somewhat obscure continuation through Nova Scotia and 

 Newfoundland to a contact with the old Labrador element of the Lauren- 

 tian Mountains. To the west of the ancient axis of disturbance of the 

 Appalachians, the Allegheny range or series of ranges has been recognized 

 as a development which took place after the close of the Carboniferous, 

 bringing about the formation of some score of considerable folds, all of 

 which, except those in the extreme south, retain their relief. This Alle- 

 g-henian division extends, with diminishing size of folds, as far north as 

 near Albany, New York * 



West of the Alleghenies, throughout their whole extent, from Alabama 

 to the Mohawk River, there is a table-land which manifestly owes its uplift 

 also to the orogenic work that resulted in the formation of the anticlines 

 and synclines which were produced to the west of the old axis after the 



1 It is characteristic of the Allegbenian division of the Appalachians that it consists of prevail- 

 ingly long folds, which are much compressed and generally lie in such a position that an east-west 

 .section of the field traverses four or live of the similar anticlines. 



