25. Geology, Sc. of the Connecticut. 
erties 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 Kelis, and the alternations above 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 direstion 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°. | 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-Engiland. It seems 
to be nearly pure chlorite, yet distinctly stratified, the lay- 
ers béing nearly petpendicl, leaning, however, a few de- 
grees to the west. _f know but little concerning the extent 
of this stratum. Where I have crossed it, it was less than 
half a mile in width. Ihave 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. Srenite. 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 Whateiey and of very smal] 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 eres being for the most 
part a kind of sienitic granite. In the first mentioned lo- 
_ eality the rock is considerably diferent from that in the oth- 
*] am indebted to Prof. Silliman for this suggestion. 
