274 J. D. Dana—Southward ending of a 
the same formation. They are not, however, horizontally- 
bedded fragments; for they have, generally, an eastward dip, 
often a high dip; and the facts seem to show that most of 
them are synclinal flexures; that they occupy the troughs of 
local synclinals in the limestone; that, as Mt. Washington con- 
sists of schist contained in a broad limestone trough, these 
isolated schist ridges, except in 
the case of an occasional mono- 
clinal or anticlinal, occupy nar- 
row troughs. Most of them were, 
apparently, half-overturned 
troughs, so pushed over westward 
ee . that the dip of the schist is gen- 
ea / erally eastward, as illustrated in 
fig. 6; and thus they are like those of the Taconic Range just 
north of Mount Washington. The ridges to the southwest 
of Mount Washington are of like character, though larger and 
less numerous. 
The statement that these isolated ridges are for the most 
part synclinals, I could illustrate by numerous sections from 
f ; 
other parts of the Taconic region; but this would lead me — 
from the special subject before us, and I leave it for another 
- occasion. — 
I close by enumerating some of the subjects illustrated by 
the facts that have been presented, and a few of the conclusions 
flowing from them. 
1. The facts have illustrated the features of a mountaiD 
synclinal; its compound synclinal structure; its variations 1D 
character as it dies out. “As the mountain is a synclinal with 
subordinate anticlinals and synclinals in its mass, so what 1s 
now a broad limestone area was (as I might make clear, if not 
so already) an area of anticlinals with subordinate synclin 
and anticlinals ; and the schist ridges occurring isolated in the 
limestone stand in general in the synclinal troughs of the lime 
o from the greatest 
height of Mt. Washington, was at least 2,000 feet thick. 
3. The limestone, which spreads to a width of three miles 
about Copake, west of Mt. Washington, continues southward 
and southwestward by two lines to the Hudson River. The 
wider and more northern belt reaches the river at Poughkeep- — 
sie, having one break of three miles in its course, and at some 
points it contains well-characterized Lower Silurian sbells, 
ne tet iY 
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* 
