STRATIGRAPHY AND STRUCTURE CASTLETON AREA VERMONT

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74 73 ° 72° 45° ---- ---.- .45° (_I I I4 •St.Albans •1 I - xz-I_-I L () -J Monkti • c: 44 0 Q) ( Mddlbury 440 ? V I Brendon N.H. Qj ) e .j.Rutland Bald'I Co ________ 2 I N.Y. l L 43 Bennington N.H. Albany _l Becreft Mtn. c_Il ç (fJ. lMass. 42° 42° 73° 72° N.Y ______________ 740 I Poughkeeosie 0 10 20 30 40 __ ' MILES i. Castleton Quadrangle 2. Saratoga District 3. Capital District 4. Taconic Quadrangle FIGURE 1. GEOGRAPHIC LOCATION OF CASTLETON AREA AND OTHER PLACES MENTIONED IN THE TEXT. 7
Much of the Castleton area is occupied by a small part of the Tacoruc Range, which lies in east-central New York and adjacent parts of Vermont and Massachusetts. Nearly forty years ago Arthur Keith concluded that the Cambro-Ordovician rocks of the Taconic Range in Vermont are a klippe or thrust outlier composed of an argillaceous facies that had been thrust westward over a carbonate facies of similar age. Although this concept has found general acceptance among geologists working in the area, the roots of the overthrust have not been found. Moreover, modern detailed stratigraphic and structural studies have not been made in much of the Taconic region. The Castleton area was chosen in order to ascertain the validity of the concept of a large Taconic overthrust. Originally this study was confined to the rocks of the Taconic sequence, but it became evident that a clear picture of the relation between the Taconic sequence and the rocks of the marble belt bordering the Taconic Range on the east required remapping of the part of the marble belt that lies in the Castleton quadrangle. This investigation, therefore, has carried the mapping of the Champlain and Vermont Valleys (Cady, 1945) to the southern border of the Castleton quadrangle. Folding, faulting, and metamorphism of the rocks have made accurate stratigraphic work difficult. Identifiable fossils are rare, and the thickness of several formations is obscure. The area was mapped by the pace-and-compass method aided by Paulin altimeter and aerial photographs. Data were plotted on photostatic copies of the Castleton and Proctor sheets of the United States Geological Survey enlarged to a scale of three inches to the mile. Twentyseven weeks were spent in field work during the summers of 1947 and 1948. Achnowledgments Professor Marland P. Billings directed this work and spent nearly two weeks with me in the field. I acknowledge with gratitude his aid in solving many problems. Professors E. S. Larsen, Jr. and P. E. Ray - mond have both given advice. Dr. Wallace M. Cady helped me both on details and in understanding the areal picture. Professor Charles G. Doll, State Geologist of Vermont, arranged for financial aid during the field season of 1948. Several geologists working in Vermont provided useful suggestions. Chief among these are: J. L. Rosenfeld, J. B. Thompson, P. H. Chang,
Page 1 and 2: STRATIGRAPHY AND STRUCTURE OF THE C
Page 3 and 4: PAGE Schodack formation ...........
Page 5: eak thmst. The Taconie sequence is
Page 9 and 10: Walcott (1888, p. 235) discovered O
Page 11 and 12: VALLEY SEQUENCE TACONIC SEQUENCE 0.
Page 13 and 14: The composite thickness of the Vall
Page 15 and 16: east of Lake Dunmore Foye (1917-191
Page 17 and 18: in the Cheshire (Keith, 1923-24, p.
Page 19 and 20: genera as Olenellus, Nisusia, Kutor
Page 21 and 22: egarded as eastern facies of the Po
Page 23 and 24: of very small and very large dolomi
Page 25 and 26: The "lower 10 to 40 feet of the Col
Page 27 and 28: directly above the Columbian marble
Page 29 and 30: West Rutland are among the most bea
Page 31 and 32: Thickness and age: The Orwell in Ir
Page 33 and 34: Age: Many crinoid columnals and oth
Page 35 and 36: northeast of Chippenhook the Whippl
Page 37 and 38: westward so as to overlie the strat
Page 39 and 40: elow under "Relations and correlati
Page 41 and 42: grains came from veins and some fro
Page 43 and 44: assume at least a ten-fold thickeni
Page 45 and 46: poraneity. Vaughan and Wilson (1934
Page 47 and 48: flattened in the plane of the regio
Page 49 and 50: andesine grains, slate fragments si
Page 51 and 52: teristic rusty appearance of the we
Page 53 and 54: Kaiser (1945, P. 1089) discovered a
Page 55 and 56: skill in the Castleton area. Severa
Page 57 and 58:
the former is an unconformity and t
Page 59 and 60:
30 0 C a- S In w 0RWE 7 Rusr THI I0
Page 61 and 62:
West Rutland anticline and adjacent
Page 63 and 64:
that Keith mapped at the northern e
Page 65 and 66:
folds in the Taconic sequence. Had
Page 67 and 68:
erosion the Taconic sequence overla
Page 69 and 70:
where more competent beds cross the
Page 71 and 72:
Silurian time. Under the present hy
Page 73 and 74:
dolomites of \ermont from red at th
Page 75 and 76:
tion of the Cheshire. Sands from a
Page 77 and 78:
much of the New England region. Pie
Page 79 and 80:
REFERENCES CITED AGAR, W. M. (1932)
Page 81 and 82:
(1941) The Taconic allochihone and
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STRATIGRAPHY AND STRUCTURE CASTLETON AREA VERMONT

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