134 J. D. Dana—Geology of Vermont and Berkshire. 
the west of the Taconic range, in the towns of Hillsdale, 
Copake, and North Hast, besides along its eastern border in 
Dover, Amenia and Pawling. The axis of the band of maxi- 
mum ore-beds appears hence to cross the axis of the limestone 
area in Bennington, Vermont; and to strike the Taconic range 
south of West Stockbridge, from which point, beds occur on 
both sides of the range. 
(3.) The stratigraphical relations of the beds. 
The ore-beds, to the north as well as south, occur near the 
junction of a stratum of limestone with one of hydromica or 
mica schist, the beds of both having usually a high dip (gene- 
rally between 40° and 55°); or they have schist on both sides; 
and sometimes they are cut through by one or two beds of lime- 
stone or schist. Quartzyte often lies along the east side in 
Vermont; but a stratum of schist usually, if not always, inter- 
venes between the quartzyte and limestone. 
This geological relation of the beds was recognized, at local- 
ities in Vermont, Berkshire, and Connecticut, more than fifty 
years since, by the late Prof. Chester Dewey, then Professor of 
eology and Mineralogy in Williams College, Williamstown. 
In the fifth volume of this Journal, 1822, in an article on the 
ore-bed of Bennington, he says (p. 251)—“It has been re- 
marked that the great bed of ore is not immediately connected 
with any rocks. It seems, however, to be associated with lime- 
stone rocks, and the whole to lie between two strata of mica 
slate. It lies in the same [mountain] range with the ore of 
Salisbury, Connecticut, and has the same range of mica slate 
lying on both sides of it.” The in situ position of the ore- 
beds is here brought out by Dr. Dewey, and a relation to the 
limestone is suggested. T'wo years later, in vol. viii, speaking 
of the ore-beds of Berkshire, he says (p. 30), that the beds “ are 
near limestone, but on beds of clay.” And “as mica-slate 18 
found on both sides of them, they must doubtless be con- 
sidered as lying in this rock, though the clay indicates that 
they are a later deposit than the rock itself:” in which the 
limonite beds are made a part of the mica slate, but not an 
original part. 
he facts at many of the ore-pits of Berkshire and New 
York, as well as Connecticut, sustain the statements of Pro- 
fessor Dewey. The schist often forms part of the walls of the 
ore-pits, or stands in ledges near by ; and when no rock is to 
be seen, the clays often show that. they are the decomposed 
schist in place by their having its schistose structure, its dip 
and strike, and also its flexures, all corresponding precisely 
with the stratification of the rock of the region. The schist 
makes sometimes the eastern wall, and sometimes the western? ; 
and it is also found dividing the ore of the beds.) Among the 
