23 Geology, S/c. of the Connecticut. 



eriies of this, and often to pass into it. Hence it is no easy 

 matter, in many instances, to give a name to the Milford 

 slate rocks, and tiie ahernalions abo^e named, and also 

 with unstratified primitive greenstone, are numerous — so 

 that it was not possible in coloring the map to give to each 

 of these rocks the precise situation which they occupy on 

 the surface. 



The direction of the chlorite slate strata, of which we- 

 have been speaking, is from north-east to south west. They 

 dip to the south-east, and their angle of depression below 

 the horizon rarely exceeds 30°. Sometimes, however, it is 

 90°, I think it will be found that the rocks of Woodbridge 

 and Milford pass laterally into one another. Thus, the 

 chlorite slate at its northern extremity is usually somewhat 

 talcose in its appearance, approaching to argillite, and as 

 you pass south, its characters continue to be more and more 

 developed.* 



The chlorite slate colored in Whitingham, is the best 

 characterised I have ever seen in New-England. It seems 

 to be nearly pure chlorite, yet distinctly stratified, the lay- 

 ers being nearly perpendicular, leaning, however, a few de- 

 grees to the west. I know but little concerning the extent 

 of this stratum- Where I have crossed it, it was less than 

 half a mile in width. I have given it a place principally to 

 excite an attention to it. 



This rock also occurs in beds in argillite in Guilford, Vt. 

 but they are not extensive. 



7. SiENiTE. Cleveland, 



Colored Gamboge Yellow, and crossed by oblique parallel 

 black lines. 



This rock is marked in three places on the map. The 

 first is in Whateley and of very small extent — the second 

 extends from Whately to the south part of Northampton ; 

 and the third is in Belchertown and Ludlow. The rock in 

 the two last places is very much alike, being for the most 

 part a kind of sienilic granite. In the first mentioned lo- 

 cality the rock is considerably different from that in the oth- 



*I am indebted to Prof. SJlliaian for this snggestion. 



