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Revisions in Stratigraphic Nomenclature of the Columbia River Basalt Group

Description: From abstract: New stratigraphic nomenclature for units within the Columbia River Basalt Group is introduced to revise and expand that currently in use; it is based largely on subdivisions made informally by T. L. Wright, M. J. Grolier, and D. A. Swanson in 1973. The Yakima Basalt is raised to subgroup status, and three formations-the Grande Ronde Basalt, Wanapum Basalt, and Saddle Mountains Basalt, in order of decreasing age-are defined within it.
Date: 1979
Creator: Swanson, Donald A.; Bentley, Robert Donald; Hooper, P. R. & Wright, Thomas L.
Partner: UNT Libraries Government Documents Department

Stratigraphic Nomenclature of the Central Santa Monica Mountains, Los Angeles County, California

Description: From abstract: The stratigraphic nomenclature of the central Santa Monica Mountains is revised to conform with present knowledge of the age, distribution, and stratigraphic relations of about 35 bedrock units. The revision is based on 1:12,000-scale mapping of the entire stratigraphic sequence and its facies, the position and stage assignment of abundant fossils, and contact relations.
Date: June 16, 1979
Creator: Yerkes, R. F. & Campbell, Russell H.
Partner: UNT Libraries Government Documents Department

Nomenclature of Precambrian Rocks in Colorado

Description: Abstract: "The Precambrian rocks of Colorado consist of a metaphoric complex more than 1,700 million years in age, three groups of igneous rocks about 1,700, 1,400, and 1,000 million years in age, here designated informal age groups, and two areally restricted units of sedimentary rocks, one between 1,400 and 1,700 million years in age and one between 950 and 1,400 million years. A systematic nomenclature for many of the rocks does not exist, but the present state of knowledge will permit establishment of a comprehensive nomenclature. Numerous formal names that have been applied to elements of the Precambrian assemblage are appraised and classified in a table, and eight names are abandoned."
Date: 1977
Creator: Tweto, Ogden
Partner: UNT Libraries Government Documents Department