Evidence of reworked Cretaceous fossils and their bearing on the existence of Tertiary dinosaurs

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · Palaois; (USA)

DOI:https://doi.org/10.2307/3514776· OSTI ID:6918236

Eaton, J G ^[1]; Kirkland, J I ^[2]; Doi, K ^[3]

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1. Museum of Northern Arizona, Flagstaff (USA)
2. Univ. of Nebraska, Lincoln (USA)
3. Univ. of Colorado, Boulder (USA)

The Paleocene Shotgun fauna of Wyoming includes marine sharks as well as mammals. It has been suggested that the sharks were introduced from the Cannonball Sea. It is more likely that these sharks were reworked from a Cretaceous rock sequence that included both marine and terrestrial deposits as there is a mixture of marine and freshwater taxa. These taxa have not been recorded elsewhere after the Cretaceous and are not known from the Cannonball Formation. Early Eocene localities at Raven Ridge, Utah, similarly contain teeth of Cretaceous marine and freshwater fish, dinosaurs, and Eocene mammals. The Cretaceous teeth are well preserved, variably abraded, and serve to cast doubts on criteria recently used to claim that dinosaur teeth recovered from the Paleocene of Montana are not reworked. Another Eocene locality in the San Juan Basin has produced an Eocene mammalian fauna with diverse Cretaceous marine sharks. Neither the nature of preservation nor the degree of abrasion could be used to distinguish reworked from contemporaneous material. The mixed environments represented by the fish taxa and recognition of the extensive pre-Tertiary extinction of both marine and freshwater fish were employed to recognize reworked specimens.

• OSTI ID: 6918236
• Journal Information: Palaois; (USA), Journal Name: Palaois; (USA) Vol. 4:3; ISSN PALAE
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ABRASION
ANIMALS
AQUATIC ORGANISMS
CENOZOIC ERA
CRETACEOUS PERIOD
DIGESTIVE SYSTEM
EOCENE EPOCH
FEDERAL REGION VIII
FISHES
FOSSILS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
MAMMALS
MESOZOIC ERA
MONTANA
NORTH AMERICA
ORAL CAVITY
PALEONTOLOGY
RECYCLING
TEETH
TERTIARY PERIOD
USA
UTAH
VERTEBRATES
WYOMING