STRATIGRAPHY AND STRUCTURE CASTLETON AREA VERMONT

S. L. Stone, Philip Osberg, and Verne Booth. Especial thanks go to
Alan B. Shaw for identifying such tattered organic fragments as were
discovered.
Plates and figures were drafted by Edward A. Schmitz.
Previous Work
The Taconic Question: The rocks of the Champlain Valley-Taconic
area, in which the Castleton quadrangle is located, were included by
Emmons (1842) in his Taconic system under the assumption that they
were all older than the Upper Cambrian Potsdam sandstone of the
Adirondack border. The Taconic Question was debated ad nauseam
for many years (Merrill, 1924). Dana (1887) wrote "R. I. P." over the
grave of the Taconic system, and Walcott (1888) concluded that the
system was "based on error and misconception originally, and used in
an erroneous manner since." Emmons, of course, was partly right; some
of the Taconic system is pre-Potsdam. Some, however, is of Potsdam
age, and the rest is post-Potsdam. Although Schuchert (1919) attempted
to revive the name Taconic as the designation for the Lower Cambrian
epoch, this usage happily has not been followed. Only confusion will
result from any attempt to use "Taconic" in a stratigraphic sense.
Present use of the name Taconic: Today the word "Taconic"is used in
three legitimate senses. In the first place, it is the name of a range of
low mountains extending from Brandon, Vermont in a direction slightly
west of south to the latitude of Poughkeepsie, New York (Fig. 1).
Another use of the name is to refer to a time of orogenic disturbance in
northeastern North America, probably near the close of the Ordovician
period. Thirdly, the name Taconic is applied to an inferred overthrust
by which argillaceous rocks that originated to the east of their present
location have been thrust over the carbonate sequence of the Champlain-
Hudson lowland and the connecting valleys to the southward. The
Taconic Allochthone is the mass of transported rocks above the overthrust.
Other work: Rev. Augustus Wing correctly delineated the structure
of the Middlebury synclinorium (Fig. 3) before 1860, and he extended his
work southward into the Castleton area. Dana (1877) published Wing's
discoveries and did considerable work in the Taconics. Logan (1863),
aided by E. Billings, discovered the Champlain overthrust, which helped
to resolve the Taconic Question. A forward stride was made when