194 J. D. Dana—Age of the Green Mountains. 
to its greater hardness, high peaks consist of the quartzyte, and 
observations. The eats romica schist passes ‘into chloritie, mag: 
-netitic and feldspathic varieties, and into a hydromica gneiss.* 
(2) South of Vermont 
In New York, west of Massachusetts, occur slates like argyl- 
lite in aspect, but, largely, glossy slates which are hydromica 
schist; and the latter is the enw rock "of Dutchess 
County, except toward its eastern borde 
e rocks of the Taconic belt in Mauschuseue are, besides 
ordinary hydromica schist, chloritic and garnetiferous varieties 
of it, and then in Connecticut, mica schist and staurolitic and 
garnetiferous schists ; and farther south in Eastern New Yo rk, 
toward and below Pawling, 200 miles and more from the com- 
rieties, but pass into coarser and well charnstetiied kinds in 
Southern Massachusetts and in Connecticu 
hese different kinds of rocks in this weatérti section are 
throughout in conformable strata, as already stated. 
II. Eastern SectTion oF THE GreEN Mountain REGION. 
The following remarks are confined almost wholly to se 
mont. Since the highest of the Green Mountain summi 
in this State, we might here look for the strongest contrasts ‘in 
the rocks on going eastward to the mountain section and be- 
#0. H cock describes well these gradations in the Vieus Report (pP- 
507-509). He says ‘ ever e from soft nacreous schist to sandstone may be 
found.” In Cambridge, he says (p-524), there peas besides hydromica schist, 
hydromica varieties of gneiss, sandstones and a and plum eg 
and akg hg varieties of hydromica schist; also, all along the western part 
' ‘Vermont (p. 529), and on ae Connecticut River, i it passes insensibly into clay slate, 
The writer observed similar facts in his study of the region, 
