THE CAEBONIFEBOUS BASIN. 



121 



GENERAL STRUCTURE OP THE BASIN. 



The broader secondary features of the basin — the system of folds with 

 their axes and the parallel direction of the borders — are relatively simple. 

 The structural outline of the basin is that of a ship's knee, with the 

 angle on the northwest, one arm extending southward to the mouth of 

 Nari^agansett Bay, the 

 other eastward toward 





Cape Cod Bay, and the 

 inner curve forming the 

 border from Tiverton 

 northeastward to Lake- 

 ville. If a line be drawn 

 from the northwestern 

 corner near Diamond 

 Hill (see fig. 7) south- 

 eastward to a bisection 

 of the curvilinear border 

 near Fall River, it will 

 pass through the three 

 deep synclinal depres- 

 sions in which the upper- 

 most conglomerates of 

 the Carboniferous have 

 been infolded and pre- 

 served from denudation. 

 On the noi'thwest this 

 line also passes through 

 the small area of pro- 

 found dislocation and 

 uplift which brings the 

 granitite of Hoppin 

 Hill, the Cambrian, and 

 the lower Carboniferous 

 trend nearly north and 

 west This axis of pr 



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7/'*IS' 





7/og'd? 







7^30' 



70''-4S' 



FiQ 7 —Map showing general outline of the Narragansett Basm, A-B, Im© pass- 

 ing tkroQgh, deeper synclmesof middle of the area, aa, inher of gmnitite and 

 Cambiian at Hoppm Hill and the Diamond Hill qnartz mass on western border , 

 bb, granitic and gneissio mliers near Bnstol Ebode Island , cc, synchnes with 

 coarse conglomerates, oo, synolines along northern border of the basm, dd, 

 gneiss structnre in Kew Bedford area 



strata to the surface. West of this line the strikes 

 south; east of the line they trend about east and 

 essure, moreover, appears to have been that in 



