34 Geology, &fc. of the Connecticut. 



The greatest part of this greenstone is greenstone slate, 

 the strata having the same direction as that at Milford, and 

 being nearly perpendicular to the horizon, bearing a few de- 

 grees one way or the other occasionally. This slate is als» 

 more crystalline than the same rock at New-Haven. It is 

 however a less degree of cry stallization that chiefly distinguish- 

 es it from hornblende slate, towards which it verges and into 

 which it probably passes. Notwithstanding the very deci- 

 dedly fissile character of this slate, I have noticed in some 

 instances a tendency in it to the trappose form ; some of the 

 specimens having a cleavage, like many crystals, in two di- 

 rections, one coinciding with the direction of the strata and 

 the other running ajcross the strata. The proportion of fel- 

 spar in this rock is small, often almost imperceptible. Chlo- 

 rite, however, abounds as in the greenstone slate of Milford; 

 and often it becomes real chlorite slate. Seams and beds 

 of quartz are common in the Whately rock and also granu- 

 lar epidote. 



Some of the rock colored, as hornblende slate in Shel- 

 burne, &c. much resembles certain varieties of this green- 

 stone slate ; and were the two rocks contiguous, it would be 

 difficult to draw the line between them. Indeed, by some, 

 this Whately rock would probably be denominated horn- 

 blende slate : but I think there is a distinction between the 

 two rocks; and so long as any of the stratified rocks of Mil- 

 ford retain the name of greenstone slate, it would seem the 

 Whately rock, from its resemblance and similar associations 

 with unstratified primitive greenstone, demands the same ap- 

 pellation. An observer will be struck with the resem- 

 blance of the greenstone strata at these two places, and with 

 their similar situation in regard to mica slate; and he will 

 be disposed to enquire whether these rocks were not once 

 continuous between these two places ; — and in the interme- 

 diate space,^he will find suflicient evidence in the great quan- 

 tity of mingled detritus of other rocks, that the higher strata 

 have suffered much from some levelling agent in former 

 days. 



