The Late Cretaceous ammonite Baculites undatus Stephenson in Colorado and New Mexico

Journal of Research of the U.S. Geological Survey
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Abstract

Baculites undatus Stephenson, originally described from the Nacatoch Sand of northeastern Texas, has been found in the Pierre Shale at 25 localities in Colorado and two in New Mexico. An early form of the species occurs in the zone of Didymoceras cheyennense (Meek and Hayden), and the typical form occurs in the overlying zones of Baculites compressus Say, B. cuneatus Cobban, and B. reesidei Elias. The species is characterized by its stout cross section, broad venter, conspicuous lateral and ventral ribs, and suture of about average complexity for the genus.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The Late Cretaceous ammonite Baculites undatus Stephenson in Colorado and New Mexico
Series title Journal of Research of the U.S. Geological Survey
Volume 1
Issue 4
Year Published 1973
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Description 7 p.
First page 459
Last page 465
Country United States of America
State Colorado, Wyoming, New Mexico
Online Only (Y/N) N
Additional Online Files (Y/N) N
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