F. H. Lahee — Metamorphism and Geological Structure. 249 



Art. XXIY. — Relations of the Degree of Metamorphism to 

 Geological Structure and to Acid Igneous Intrusion in the 

 JYarragansett Basin, Rhode Island /* by F. H. Lahee. 



Part I. 



Contents. 

 Acknowledgments. 

 Introduction. 

 Structural Geology. 



Theoretical considerations. 

 The borders of the Basin. 

 The Basin strata. 

 Major folding 

 Strikes. 

 Dips. 

 Pitch. 



Axial planes. 



Continuity of the major folds. 

 Eelative number of folds across the Basin. 

 Minor folding. 

 Areal distribution of variations in the major and minor 



folding. 

 Conclusions. 



Acknowledgments. 



For the use of laboratory equipment and for valuable advice 

 in the preparation of the original thesis, the writer wishes to 

 express his gratitude to Professor J. E. Wolff and Professor 

 J. B. Woodworth, under whose direction the work was carried 

 on ; and for numerous suggestions and favors, to Professors 

 "W". M. Davis, A. Sauvenr, and C. Palache ; to Dr. Ernest 

 Howe ; and to Messrs. K. W. Sayles, J. A. S. Monks, "Win. 

 Burns, and W. P. Haynes. 



Introduction. 



The Narragansett Basin is a body of Carboniferous strata, 

 fifty miles long, from fourteen to twenty-five miles wide, and 

 with a total stratigraphic thickness of somewhat more than two 

 miles. f From the southern coast of eastern Bhode Island it 

 trends northward as far as a line between Fall River and Provi- 

 dence, including the major part of Narragansett Bay within its 

 boundaries, and thence, bending more to the east, extends in a 

 northeasterly direction to near Hanover, Massachusetts. 



Topographically the Basin is represented by a shallow 

 depression with an uneven surface, between bordering 



* The present paper is an abstract of a thesis accepted for the degree of 

 Doctor of Philosophy in Geology, at Harvard University, in June, 1911. 



f Shaler, N. S., Foerste, A. F., and "Woodworth, J. B., Geology of the 

 Narragansett Basin. U. S. G. S., Monog. XXXIII. 1899. See pp. 208-210, 

 336, 338, 345, 358, and 373, and Plate xxx. 



Am. Jour. Sci.— Fourth Series, Vol. XXXIII, No. 195.— March, 1912. 

 17 



