708 THE SLATES OF THE TACONIC MOUNTAINS, ETC. 
clasping them. July 12th, 10 o’clock, a. m., nearly all the bristles 
are curving toward the bits of apple, but very few of the glands 
are touching them. 
THE SLATES OF THE TACONIC MOUNTAINS OF 
THE AGE OF THE HUDSON RIVER OR 
CINCINNATI GROUP.* 
BY PROFESSOR J. D. DANA. 
In my study of the Stockbridge limestone and the associated 
rocks in Berkshire county, Massachusetts, I have found that the 
ridges are often, if not always, synclinals. They consist of the 
slates or schists (and sometimes quartzite) overlying the lime- 
stone; and in the downward flexures of the limestone, during the 
period of disturbance and metamorphism which made the moun- 
tains, the overlying beds or part of them were folded together into 
a compact mass which has withstood degrading agents, while the 
same beds in the anticlinals or upward flexures were extensively 
broken and have disappeared. The slate ridges are then nothing 
but squeezes of the slate formation between the sides of a lime- 
stone synclinal. 
The Taconic mountains lie on the western border of the Berk- 
shire limestone region; and, in general, the dip of the limestone, 
as well as of the Taconic slates is to the eastward, and hence the 
slates being underneath are seemingly the older. They are actu- 
ally so, unless the Taconic ridges are also synclinals, with an east- 
wardly inclined axis, like some of the Berkshire mountains. Un- 
til recently I had regarded the apparent order of superposition as 
the true order of succession, that is, I had supposed that the lime- 
stones were newer than the Taconic slates. The conclusion 
seemed to be confirmed by finding at different places the slates: 
and limestone with the same high easterly dip, the slates under- 
most. 
But a few weeks since, on an examination of the eastern base 
of Mt. Washington, the highest part of the Taconic range in south- 
western Massachusetts, along the road just east of the highest 
_ * Read at the Portland Meeting of the Amer, Assoc. Adv. Science. 
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