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American Old and Middle Tertiary Larger Foraminifera and Corals: PART I—AMERICAN PALEOCENE AND EOCENE LARGER FORAMINIFERA

By
Thomas Wayland Vaughan
Thomas Wayland Vaughan
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Published:
January 01, 1945

This paper is divided into two parts, the first of which, entitled “Paleocene and Eocene larger Foraminifera from Barbados,” is based on collections made by Dr. A. Senn in blocks of Paleocene age contained in the Joes River mud flows and the Lower and Upper Scotland formations of Eocene age. About 75 localities are represented, and 20 species were recognized, of which 17 were specifically named, and three were undetermined. In the Paleocene blocks in the Joes River mud flows seven determined and one undetermined species were recognized. In the Lower Scotland formation only one species was represented by identifiable specimens. In the Upper Scotland formation there were 14 species, two of them not specifically determined. One species, Discocyclina (Discocyclina) grimsdalei Vaughan and Cole, seems to occur in the Paleocene and the Eocene Lower and Upper Scotland formations. The families represented are Orbitolinidae, Camerinidae, Discocyclinidae, Asterigerinidae, and Orbitoididae; there are six genera, one of which is new and is named Orbitolinoides; ten species and one variety are described as new.

The species in the blocks in the Joes River mud flows are almost identical with those in Paleocene beds at Soldado Rock, Trinidad, and can be assigned to the same horizon. The equivalent horizon in the Gulf States is probably the upper part of the Midway group. The Upper Scotland formation, although its fauna is mostly peculiar, seems to be definitely middle, Claibornian, Eocene. The Lower Scotland formation is probably lower Eocene. The organisms lived in shallow, warm water.

The second part of this paper, “Catalogue of American Discocyclinidae,” begins with a rather elaborate account of the skeletal structure of the Discocyclinidae—canals, stolons, embryonic and periembryonic chambers, walls of the equatorial chambers, and thickness of the equatorial layer. Microtome thin sections of specimens of Discocyclina (Discocyclina) anconensis Barker, prepared by Dr. E. H. Myers according to a double-impregnation method devised by him, show definitely annular intramural and radial intraseptal canals, confirming opinions already held by others. The Discocyclinidae are dissociated from the Orbitoididae and Miogypsinidae and are referred to the same phylum as the Camerinidae.

In the Discocyclinidae there are recognized the genus Discocyclina, with its subgenera Discocyclina, Actinocyclina, and Asterocyclina; and the genus Pseudophragmina, with its subgenera Pseudophragmina, Proporocyclina, Alhecocyclina, and Asterophragmina. The Discocyclinidae are shallow-water organisms which lived in the warm waters of tropical or subtropical regions.

Notes or descriptions are given for 45 or 46 species and three varieties. Six species and two varieties are described as new. The species are listed according to geological age—Paleocene and lower, middle, and upper Eocene—and discussed according to geographic distribution. The greatest number of species is in the upper Eocene.

In a final table there are 97 entries. After deducting ascertained but not all probable synonyms the number of species, varieties, and undetermined species is as follows:

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GSA Memoirs

American Old and Middle Tertiary Larger Foraminifera and Corals

Thomas Wayland Vaughan
Thomas Wayland Vaughan
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John West Wells
John West Wells
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Geological Society of America
Volume
9
ISBN print:
9780813710099
Publication date:
January 01, 1945

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