26 Geology, t^c. of the Connecticut, 



In springs occurs a species of Lymnaca, Say, and in our lar- 

 ger streams, Planorbis trivolvis and Unio purpureus, Say, 

 or common river clam. 



5. Talcose Slate. jRees Cyc. BaJcetvell, 



Talcose Schist. Maccullock. 



Talcose Slate. Eaton. 



Colored Gamboge yellow, and dotted ivith India Ink, 



Bakewell defines this rock to be "slate containing talc/' 

 (Geology, p. 491,) and Eaton calls it "that kind of mica slate 

 which is distinguished from mica slate by a kind of talc 

 glazing.'' In this term I do not include soapstone. 



There is but one stratum of this rock in the region of the 

 map, of sufficient extent to render it necessary to delineate it. 

 I have sometimes noticed on the east side of Connecticut 

 river a kind of talco-micaceous slate: but not in abundance, 

 and rarely in place. I have crossed the stratum which is 

 colored on the map in Whitingham, Vt. where it is not less 

 than a mile and a half in width. I have traversed it also in 

 Havvley and Plainfield, and Professor Eaton says it extends 

 into Worthington — so that on his authority I have extended 

 it thither. The rock is of a much lighter color than mica 

 slate. At a distance, indeed, it has the aspect of gneiss. 

 The talc is nearly white, though sometimes of a light green, 

 and it contains a large proportion of silex. The strata are 

 but little undulating and nearly perpendicular, leaning a few 

 degrees to the west. On its east side, where it passes into 

 mica slate, an intermediate talco-micaceous rock is found, 

 containing numerous distinct crystals of black hornblende, 

 thrown in promiscuously, and exhibiting the most elegant 

 specimens. One variety has a ground that is green; anoth- 

 er has a white ground, and the contrast between these and 

 the imbedded crystals is striking. Large slabs of this rock 

 may easily be obtained; and if it will admit of a polish, it 

 wouM certainly be a beautiful addition to those* marbles and 

 porphyries that are wrought for ornamental purposes. The 

 varieties of this rock may be seen in any direction a few 

 rods from the meeting house in Hawley; as likevt'ise many 



