TACONIC SYSTEM. 
423 
it is found, 1st, that the granular quartz either rests upon, or pitches immediately under the 
gneiss or granitic rocks ; 2d, that the limestones lie next in order from the gneiss or granite, 
either in super or sub-position ; and 3d, that the slates next follow. The observer may find 
much difiiculty in verifying this, as the rocks are almost universally much deranged from the 
position in which they were deposited ; but from numerous observations made, the above is 
believed to be the order of superposition. The observer may be referred to the gorge near 
Bennington iron works in Vermont, for the superposition of the granular quartz and limestone, 
although the latter is generally so much deranged as to make it difficult to trace it out. An¬ 
other locality where the connection maybe traced, is on the southwest side of Mount Stessing, 
in Pineplains and Stanford, Dutchess county.* Another, where the order of succession on 
the surface is the same, though the exact superposition was not seen, may be examined east 
of Fort-Ann, Washington county, where the Potsdam sandstone reposes on the Primary rocks, 
and is succeeded successively towards Hartford by the limestone and talcy slate. The same 
may be traced east from Whitehall, where the slate becomes talcy and chloritic. 
The sandstones of the Taconic system are grey, reddish, striped and white ; all of which 
are very hard, tough, indurated quartzose rocks. 
The limestones are grey and black, compact in some places ; crystalline, grey, and sparry 
or checkered limestone in others ; and not unfrequently they are granular, whitish, crystal¬ 
line limestones. The same continuous rock has undergone the above changes at different 
localities, in proportion as it has been less or more subjected to the influences that have 
modified them. 
The slate rock has undergone as great changes. It varies from argillaceous slate through 
graphic slate, plumbaginous slate, to chlorite slate and talcose slate. Modifications of the 
two latter are most common, sometimes mingled with blue, green, red and mottled slates. 
The slate rock is generally more or less permeated by veins and bunches of milky quartz, 
and the quartz often contains chlorite and brown spar disseminated in bunches. These mine¬ 
rals are most abundant where the rock is most intersected and permeated by the quartz, and 
in such localities the rock approaches most nearly to chlorite slate. 
The Taconic rocks can be seen well exposed to view on the road from Cambridge in 
Washington county, up the Battenkill to Arlington in Vermont; also between Salem and 
Rupert, and between Hebron and Rupert; on the road between Hoosick four corners in 
Rensselaer county, and Williams College in Williamstown, Masachusetts; between New- 
Lebanon in Columbia county, and Pittsfield in Massachusetts ; between Hillsdale and Egre- 
mont; between Pineplains in Dutchess county, and Northeast; between Attlebury and 
Leedsville ; between Amenia and Dover; between Beekman and Dover, and Unionvale and 
Dover. In some of the latter localities the rocks are more changed than in the proper rocks 
of the Taconic system, and more properly belong to those that will be described as meta- 
morphic rocks. 
* The sandstone and limestone at the southwest part of Mount Stessing, have already been referred to under the Champlain 
division. The sandstone is indurated by metamorphic agency, and may with propriety, perhaps, be classed with the Taconic 
rocks ; inasmuch as these latter are considered the same as the Champlain division, slightly modified. 
