PENNSYLVANIAN. 



469 



the earlier Pennsylvanian was confined to the center of the basin, the strata of later age extending 

 outward by overlap to the present Unaits of the coal field and beyond .^^^ 



The Pennsylvanian of Michigan appears to be all of PottsviUe age."' From a study of the 

 plants David White has suggested that the Verne coals, near the top of the series, may come at 

 about the horizon of the Mercer coals of Pennsylvania. The basal sandstone, or Parma sandstone, 

 may be of the age of the Sharon conglonierate member of the Pottsville of Ohio and Pennsylvania. 



K 19. RHODE ISLAND AND EASTERN MASSACHUSETTS. 



The Carboniferous strata in Rhode Island occupy the Narragansett Basin, 

 which has been described by Shaler, Woodworth, and Foerste. From fossil plants 

 obtained in these beds Lesquereux considered them equivalent to beds of the upper 

 Carboniferous (Pennsylvanian) in Pennsylvania. Woodworth ''^^ tabulates the 

 strata as follows : 



Tabular view of the strata in the Narragansett Basin. 



