Geological Terms and
Fossil ShellsSeveral sources were consulted in order to define the geological terms found in
the Allen and Peale journals in a readily accessible manner: The American Heritage
Dictionary ( Boston, 1976, 1985, 1992); The Concise Oxford Dictionary of Earth Sciences,
Ailsa Allaby and
Michael Allaby( Oxford: Oxford University Press, 1991);
and The Dictionary of Geological Terms, edited by
Robert L. Bates and
Julia A. Jackson
( New York: Doubleday, 1984). The geologic table is adapted from the Bates and Jackson dictionary.GEOLOGICAL TERMS
|agate: a fine-grained, fibrous variety of chalcedony with colored bands or irregular
|alluvium: sediment deposited by flowing water, as in a riverbed, floodplain, or delta.|
|anticline: a fold, generally convex and upward, whose core contains stratigraphically
|amygdaloidal spaces: spheroidal, ellipsoidal, or almond-shaped cavities in a lava
|auriferous: containing gold.|
|basalt: a hard, dense, dark volcanic rock, often having a glossy appearance.|
|breccia: literally, "rubble"; a rock composed of sharp-angled fragments cemented in
a fine matrix.|
|calcareous: composed of calcium carbonate, calcite, or limestone; chalky.|
|chalcedony: a translucent to transparent milky or grayish quartz with distinctive
microscopic crystals arranged in slender fibers in parallel bands.|
|chlorite: a generally green or black secondary mineral often formed by metamorphic
alteration of primary dark minerals.|
|conglomerate: a rock consisting of pebbles and gravel, generally embedded in a
sandy matrix; one variety is called "pudding stone."|
Questia, a part of Gale, Cengage Learning. www.questia.com
Book title: Yellowstone and the Great West:Journals, Letters, and Images from the 1871 Hayden Expedition.
Contributors: Marlene Deahl Merrill - Editor.
Publisher: University of Nebraska Press.
Place of publication: Lincoln, NE.
Publication year: 1999.
Page number: 283.
This material is protected by copyright and, with the exception of fair use, may
not be further copied, distributed or transmitted in any form or by any means.