Direction and Dip of the Strata. 



271 



Direction, Dip, and Thickness of the Strata. 



Graywacke is celebrated in other countries for the irregularities of 

 its stratification, and the tortuosities of jts slaty varieties. Nor is 

 this rock in New England lacking in these characteristics. The oh- 

 server will he satisfied, after an extensive examination, that the pre- 

 dominant direction of the strata of this rock is not far from east and 

 west, and the dip northerly, generally approaching to 45 degrees. 

 But he will he surprised to find in the western part of the principal 

 deposit, viz. from Randolph to Providence, and so on to the southern 

 extremity of Rhode Island, that the direction of the strata is nearly 

 north and south, and the dip east. The following table exhibits the 

 dip and direction of this formation in various places, as I find them 

 in my notes. 



Mansfield, ' .''' . ; 

 Berkley, >. . . -;. ;* ; ;r; ] 

 Attleborough, (west part,) . 



do. (center,) . 



Walpole, .... 

 Pawtucket, (Graywacke Slate,) 

 From Providence to Warren, 

 Rhode Island. 

 Seekonk, . . 

 Portsmouth, R. I. (Slate,) 

 Newport, R. I. near Fort Ad- 

 ams, (Slate,) 



do. South part, (do.) 



do. Southeast part (do.) 



do. do. Purple Quartz 



Rock, 



West side of Narraganset Bay 

 (Slate,) 



Middletown, R. I. Blue Quartz 

 Rock, 



do. do. Amphibolic 



Aggregate, 



Between Warren and Bristol, 

 Rhode Island, 



Direction. 

 N.W. and S.E. 

 N.E. and S.W. 

 North and South. 



do. 



N.E. and S.W. 

 S. 20 West. 



N. and South, 

 do. 



N.E. and S.W. 



N. and South. 

 E. and West. 

 N. and South. 



N. and South. 

 N. and South. 

 N. and South. 

 N. and South. 

 E. and West, 



Dip. 



45 N.E. 

 N.W. small. 

 East, small. 

 50 West. 

 50to60N.W. 

 70 easterly. 



45 East. 

 10 East. 

 S.E. 40 to 90. 



5tolOeasterly. 



Various. 



60to70West. 



80 East. 

 10 to 15 East 

 E. 80 East. 

 60 to 70 West 

 10to20North, 



