184 



STRUCTURAL GEOLOGY OF NORTH AMERICA 



wq,m 



SOUTHERN 



apg 



WOONSOCKET 



wq,m 



eg fg eg 



ngn 



wqm 



NARRAGANSETT BASIN, PAWTUCKET QUAD., R.I. 



eg __ q.d h -^- L .. ll g_ w q.a hg Cgp hg dd gg C u 



mb wq wq as ss 



NARRAGANSETT PIER 

 sga qbs Pr'lS 



QUAD., R.I. 



Pris 



MILES 



P P 



npg 



Fig. 11.30. Cross sections of Woonsocket and Narragansett basins. Top section after Richmond, 

 1952. ngn, Nipsachuck gneiss; apg, Absalona fm.; wqm, Woonsasquatucket fm.; pmd, metadiorite; 

 Sg, Scituate granite gneiss; eg, Esmond granite; fg, fine-grained granite; Pb, Bellingham con- 

 glomerate. 



Middle section after Quinn ef a/., 1949. mb, Mussey Brook schist; wa, Westboro quartzite; wqa, 



bles of the Esmond granite, their metamorphism was later than that of 

 the Blackstone series. The later intrusives rocks of the East Greenwich 

 group are essentially unmetamorphosed. The Pennsylvanian rocks are 

 folded and fault-tilted, and schistosity is widespread. It is commonly 

 not parallel to the bedding, and chloritoid, garnet, amphibole, biotite, 

 and muscovite are developed. 



Albion schist member; ss, Sneech Pond schist; hg, Hunting Hill greenstone; gg, Grant Mills 

 granodiorite; Cqp, Quiney granite; Cu, Carboniferous undifferentiated; dd, diabase dike. 



Lower section after Nichols, 1956. sgg, Scituate granite gneiss; qbs, Blackstone quartz-biotite 

 schist; Pris, Rhode Island formation; npg, Narragansett Pier granite; p, pegmatite. 



In the Narragansett Pier quadrangle a reddish, massive to gneissic 

 granite is clearly intrusive into the Pennsylvanian beds. It has been 

 named the Narragansett Pier granite by Nichols ( 1956 ) . A cross section 

 is shown in Fig. 11.30. Elsewhere granites intrusive into the Penn- 

 sylvanian beds have been reported but the modern mapping casts doubt 

 on such relations. 



