GEOLOGY OF THE NARRAGANSETT BASIN. 



PART I-G-ENERAL GEOLOGY. 



By N. S. Shalee. 



CHAPTER I. 



POSITION AND SURFACE RELATIONS OF THE BASIN, AND 

 THE ROCKS IT CONTAINS. 



GENERAL FEATURES. 



The field which in this monograph is termed the Narragansett Basin 

 consists of a considerable area of stratified rocks ranging in age from the 

 base of the Cambrian to about the later stages of the Carboniferous period. 

 The 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 are probably of great age. 



