134 



GEOLOGY OF THE NAEEAGAN'SBTT BASIN. 



I am of the opinion that, were the several horizons of shales explored 

 for fossils, a sufficiently differentiated flora would be found on which to 

 base a more satisfactory subdivision of the great middle series of sandstones 

 and shales than is here proposed on purely physical grounds. 





Tabular vieto of the strata in 



the Narragansett Basin. 





- 



Northern field. 



Southern field. 





Group. 







Remarks. 



' 











Local areas. 



Characters . 



Local areas. 



Characters. 





Dighton fCd) 



Rocky Woods con- 



Coarse quartzite and 



Purgatory 



Coarse quartz- 



Probably, though not 



(1,000-1,500 



glomerate. 



granitic pebble con- 



conglomer- 



ite pebbles, 



certainly, identical in 



feet). 





glomerates, with finer 



ate. 



usually 



all parts of the field, ly- 





Seebonk conglom- 



conglomerates and 





much elon- 



ing in synclines above 





erate. 



sandstone. 





gated and 

 indented. 



the Coal Measures. 



Rhode Island 



WestTille shales 



Alternations of fine 



Aquidneck 



Mainly shales 



Both the Aquidneck and 



Coal Meas- 



and Seekonk 



and medium quartz, 



shales of 



with coal 



Kingstown series 



ures (Cc) 



sandstones. 



quartzite, and gra- 



Dr.Poerste. 



beds. 



of Dr. Foerste, when 



(10,000 feet). 



Tenmile River 



nitic pebble conglom- 







traced northward, ap- 





beds. 



erates, •with, pebbly 

 sandstones, sand- 

 stones (grauwaoke), 







pear to form equiva- 

 lent sections beneath 

 the Bighton group, 





Mansfield beds. 



shales, and coal beds, 



Kingstown 



Mainly sand- 



one on the eastern, the 





Cranston beds, 



becoming metamor- 



series of 



stones and 



other on the western 





Sockanasset 



phic southward. 



Dr.Foerste. 



conglomer- 



side of Narragan«ett 





sandstones, 



Colors: Black, blue, 





ates with 



Bay, and both extend 





Pa w tncket 



green, gray, locally 





coal shales , 



downward to the basal 





sbales. 



red. Odontopteris 





usually met- 



beds in this typical 







flora and insect beds. 





amorphic. 



area. 



"Wanasutta 



fslates 



Beds of quartz, quartz- 



The Wamsutta beds are 



(Cw) (1,000 



Warasutta-c and 



ite, felsites, felsite 







not traceable south of 



feet). 



[shales 



breccias and felsite 







Providence *, probably 





Attieboro sand- 



conglomerates, sand- 







represented by lower 





stone. 



stones, arkose, and 







strata of Dr. Poerste's 





IVamsntta con- 



shales. Colors: Red, 







Kingstown series. In 





glomerates. 



locally brown, and 

 green. Calamites, 







the vicinity of Paw- 

 tucket the Coal Meas- 

 ures underlie the 

 Wamsutta. 



PondTille (Cp) 



Millers River con- 



Quartz conglomerates. 



Basa beds. 



Quartzose 



Essentially similar prod- 



(100 feet). 



glomerates, ar- 



Coarse, white, gra- 





conglomer- 



ucts of decayed gra- 





kose beds. 



nitic waste or arkose. 





ates and 

 arkose. 



nitic land surface in all 

 parts of basin. 



tJnconiformlty. 



Widespread erosion interval, representing 



all of Silurian and Devonian 



time and probably upper 





Cambrian. 







Pre - Car'bonif- 



Broad exposures of granitite intruded into 



Same as in northern field. 



Pre-Carboniferous strata 



erons. 



lower and middle Cambrian and pre- 





not definitely deter- 





Cambrian sediments. 





mined; Cambrian or 

 pre-Cambrian. 



