PREFACE. 



As tlie conditions under which this report has been prepared are of 

 importance as explaining the nature and scope of the investigations on which 

 it is based, it is fit that they should be briefly stated. In 1865 I became 

 interested in the geology of the Narragansett Basin, principally for the reason 

 that it afforded a convenient district in which students from Harvard Uni- 

 versity could be instructed in certain problems of field geology which were 

 not well presented in the lieighborhood of Boston. A number of the frag- 

 mentary results thus obtained were published in several papers, but the 

 greater part remained unpublished With the extension of this desultory 

 work a general idea as to the structure of the basin and its relations to 

 some of its more important groups of strata was obtained. In course of 

 time it seemed possible, with a moderate amount of labor, to prepare a 

 memoir on the field which would add something to the body of information 

 concerning the area. 



About ten years ago, at the request of Maj. J. W. Powell, then Director 

 of the United States Geological Survey, I undertook to devote the time 

 which could be spared from more pressing duties to the task of completing 

 this monograph. Experience soon showed that the mass of detailed work 

 which remained to be done was so large that it would be necessary to asso- 

 ciate other persons in the undertaking. To Dr. August F. Foerste was 

 assigned the southern or bay section, and to Mr. J. B. Woodworth the north- 

 ern portion of the field. The division of their work was not determined by 

 a precise line, but was left to mutual understanding. Dr. Foerste's studies 

 began in 1887. They were interrupted after a few months' labor, but were 

 resumed in June, 1895, and the field studies were closed in September of 

 that year. Mr. Woodworth has from time to time been employed in this 

 field since June, 1891, but the work was discontinuous until the field season 

 of 1896. 



MON XXXIII II ^^^^ 



