ea 
Geology, &c. of the Connecticut. 37 
* it seems “the terms peivitiee and transition are daily be- 
coming of less importa 
Quarries have nati pray in the Woodbridge engi 
and it is employed in New-Haven for building, 
mont also, they have been wrought in Guilford, and Poe 
two also in Dummerston, S. E. of the centre of the town, two 
in Putney, one and a half miles north of the meeting-house, 
and one in Rockingham, a mile north of Bellows Falls. In 
most of these the slate is of a good quality and easily ob- 
tained; but at present they are not much wrought on ac- 
count of the little demand for it, and consequent low price. 
10. LamesTone. 
«tend Leonstenes Eaton, inden, Se. 
ee 
_ This rock, in the country ‘covered by the map, always 
exists in beds in mica slate and argillite: never eccu- 
pying, however, so much as half the surface. I have co- 
lored it in that region where it occurs most abundantly, 
peck is, in the mica slate nearest the argillite and the sand- 
tone; although its beds exist in nearly all the mica slate 
sein of Northampton on the west side of the river. It is 
remarkably uniform in its appearance. Its exterior, when it 
has long been exposed to the weather, is of a dark brown 
color, showing more marks of decomposition than any 
other seek in this region. The carbonate of lime is usual- 
ly worn away at least an inch deep on the surface, and 
the silex and mica are left in coarse grains, or warts, or in 
projecting ridges. When newly broken the mica is uniform- 
ly of a light gray, and the texture is coarsely granular and 
dull, except the glimmering of scales of mica. The con- 
stituents of the rock are carbonate of lime, mica and silex, 
in somewhat bite. proportions. In a specimen sent to 
Prof. Dewey, he found about fifty per cent of carbonate of 
lime and fifty of silex and mica. He judged that the silex 
constituted about thirty five per cent and the mica fifteen: 
and he judiciously adds, “ the mica is in so great proportion 
you cannot call it silicious limestone. At least ht it 
not to be a : — aggregate, or silicious limestone 
mixed with mic 
