GEOLOGY OF THE NARRAGANSETT BASIN, 



PABT I.-GENERAL GEOLOGY. 



Bv N. S. Shalee. 



OHAPTEE I. 



POSITION AND SURFACE RELATIONS OF THE BASIN, AND 



ixlJcj i\0\jlVn ii OOlsi 1 Aiisl b. 



The field which in this monograph is termed the Narragaubett Basin 

 consisth of a considerable area of btratified rockb ranging* in age from the 

 babe of the Cambrian to about the later btages of the Carboniferous period, 

 llie eastern margin of this basin extends on its northeastern side to near 

 the Atlantic coast in the neighborhood of Duxbury, Scituate, and Cohasset, 

 or, in this section, to within about 6 miles of the sea. Its northern border, 

 including the small Norfolk Basin in the area of Carboniferous rocks, lies 

 in contact with the southwestern wall of what is commonly termed the 

 Boston Basin. On the west the area is limited by relatively high lands 

 which separate the trough from the Worcester syncline, a basin which 

 owes its construction mainly, if not altogether, to mountain-building action 

 occurring after the end of the Carboniferous period. On the south the 

 Narragansett Basin is partially separated from the sea, at least in those 

 portions of it which are above the water level, by a constriction formed of 

 ancient, highly metamorphosed, stratified rocks and a variety of intrusions, 

 together with some granitic areas which ai-e probably of great age» 



