Pachydiscus (Ammonoidea) from Campanian (Upper Cretaceous) rocks in the Western Interior of the United States

Examples of the Campanian-Maastrichtian ammonite genus Pachydiscus Zittel, 1884, occur as great rarities in the Western Interior of the US. Pachydiscus (Pachydiscus) cf. oldhami (Sharpe, 1855) and P. (P.) cf. arkansanus (Stephenson, 1941) are recorded from the Baculites compressus zone of Montana, a...

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Bibliographic Details
Main Authors: Cobban, W, Kennedy, W
Format: Journal article
Language:English
Published: 1991
Description
Summary:Examples of the Campanian-Maastrichtian ammonite genus Pachydiscus Zittel, 1884, occur as great rarities in the Western Interior of the US. Pachydiscus (Pachydiscus) cf. oldhami (Sharpe, 1855) and P. (P.) cf. arkansanus (Stephenson, 1941) are recorded from the Baculites compressus zone of Montana, and P. (P.) arkansanus (Stephenson, 1941) is recorded from the Exiteloceras jenneyi zone of Colorado and South Dakota. -Authors