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Metamorphosed Silurian brachiopods from New Hampshire

Boucut, Arthur J. and Thompson, James B., Jr. (1963) Metamorphosed Silurian brachiopods from New Hampshire. Geological Society of America Bulletin, 74 (11). pp. 1313-1334. ISSN 0016-7606. doi:10.1130/0016-7606(1963)74[1313:MSBFNH]2.0.CO;2.

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Generically identifiable Silurian brachiopods from rocks of the staurolite and sillimanite zones of regional metamorphism have been found at a number of localities in the Clough Formation of west-central New Hampshire. They include representatives of 19 brachiopod genera, 1 gastropod, 1 trilobite, and 1 pelmatozoan. The fossils occur as two faunas. The first, characterized by Stricklandia lens cf. S. lens ultima, is probably of C4 to C5 or C6 age; the second, characterized by Eocoelia hemisphaerica, is of C3 to C5 age. Paleogeographically these New Hampshire fossils demonstrate that during late Llandovery time Appalachia was quite narrow, even if allowance is made for subsequent deformation. The present distance from Utica, New York (where marine beds of Clinton age occur to the west and nonmarine beds to the east), to the Connecticut River valley (where the widely distributed Clough Formation contains marine fossils of late Llandovery age) is about 140 miles. The northern and southern bounds of Appalachia are not well delimited for this time interval. The northern limit may have been an area east of Lake Temiscouata, Quebec, and the southern limit an area in northwestern Georgia. Thus Appalachia during this time is reconstructed as a narrow, elongate island or archipelago extending from Quebec to Georgia. A brachiopod (Howellella sp.) from the Shaw Mountain Formation of eastern Vermont indicates an age of C3 to early Gedinnian for that unit. The brachiopods of Ludlow age from the type Fitch Formation of northern New Hampshire are redescribed.

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Additional Information:Copyright © 1963, The Geological Society of America, Inc. Received July 31, 1962. The bulk of the work was done with the assistance of N.S.F. Contract No. D.S.R. 8298 while Boucot was at the Massachusetts Institute of Technology. Boucot is very grateful to Prof. H. B. Whittington, Harvard University, for his courtesy in lending the brachiopods from the Fitch Formation figured by Billings and Cleaves (1934), to R. H. Konig for the loan of fossils (transmitted by Wallace Cady) from the Shaw Mountain Formation of Vermont, to Dr. William F. Oliver, U. S. Geological Survey, Washington, D. C., for his identification of the corals and preparation of them for photography, and to Dr. Michael Curtis, Bristol, England, for the original determination of Paleocydusporpila. Thompson is grateful to Prof. M. P. Billings, Harvard University, for his encouragement and counsel in the reinvestigation of the Croydon Mountain area, to the Department of Mineralogy and Petrography, Harvard University, for its support of the field work, and to Dr. P. J. Hart for his assistance in the field. The Blue Mountain Forest Association gave the authors its active co-operation and granted them access to the Corbin Park area where most of the fossils occur. The paper has benefited considerably from the pertinent suggestions of Prof. John Rodgers, Yale University.
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Issue or Number:11
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ID Code:48272
Deposited By: George Porter
Deposited On:11 Aug 2014 01:11
Last Modified:10 Nov 2021 18:30

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