38 J. D. Dana— Geology of Vermont and Berkshire. 
with narrowing limits, and finally ends in a narrow strip among 
the flexures of hard gneiss rocks. It is one of the long Green 
Mountain formations 
(2.) The Quartzyte dene helaiied with the limestone belt, 
and following mainly its eastern border, there is a quartzyte 
series, consisting in Vermont of quartzyte and crystalline slate 
Massachusetts, and into Dahinkedens ec throughout, its close 
attendant. 
Herrick Mountains, in Ira, having a height of 2,661 feet, and 
Equinox Mountain, in Manchester, 8, a7 2 feet (auyot) above 
tide-level. It continues with unchanged course into Massachu- 
setts, or rather along the connecting borders of Massachusetts and 
ew York, and this part, south of Vermont, has long borne 
the name of the Taconic Mountains; and here it rises into 
peaks nearly as high as those of Vermont, Graylock being 3,600 
feet in height, and Mount Everett, 2, 634 feet. Further, the 
aconic Mountains consist chiefly of ‘hydromica slate more or 
less chloritic, like the southern portion of the same range in 
Vermont. 
Thus there is a marked unity in the area from north to south 
The lithological identity is not aoe eke. yet the 
differences are introduced by very gradual transitions, evident 
only as the whole area from north to south is surveyed, a and 
hence they are additional Soot of the unity. They are differ- 
ences mainly i in grade of metamorphism. 
t central slate-belt of Vernnotit commences to the 
north, according to the Vermont Report, in a clay-slate belt. 
Thirty miles or so south, hydromica slate, a more crystalline 
