Author: Richard EstesPublisher:
ISBN:
Category : Paleoecology
Languages : en
Pages : 35
Book Description
Paleoecology of a Late Cretaceous Vertebrate Community from Montana
Author: Richard EstesPublisher:
ISBN:
Category : Paleoecology
Languages : en
Pages : 35
Book Description
The Geology and Paleontology of the Late Cretaceous Marine Deposits of the Dakotas
Author: James E. MartinPublisher: Geological Society of America
ISBN: 0813724279
Category : Science
Languages : en
Pages : 264
Book Description
Through the End of the Cretaceous in the Type Locality of the Hell Creek Formation in Montana and Adjacent Areas
Author: Gregory P. WilsonPublisher: Geological Society of America
ISBN: 0813725038
Category : Science
Languages : en
Pages : 396
Book Description
"The chapters represent a surge of field and laboratory research activity, illustrating the impacts of new and refined methods and tools. This volume explores geologic and biologic history preserved in the strata bounding the Cretaceous-Paleogene boundary"--Provided by publisher.
Non-dinosaurian Lower Vertebrates Across the Cretaceous-Tertiary Boundary in Northeastern Montana
Author: Laurie J. BryantPublisher: Univ of California Press
ISBN: 9780520097353
Category : Science
Languages : en
Pages : 128
Book Description
00 This study presents current data on vertebrate survival and extinction across the Cretaceous-Tertiary boundary in Montana. Nearly all the common taxa of reptiles (except dinosaurs), amphibians, and fish survived the end of the Cretaceous Period; extinctions were concentrated among rare groups and those found in near-shore habitats. The author concludes that ocean regression and climatic deterioration may explain these selective extinction patterns better than catastrophic hypotheses. This study presents current data on vertebrate survival and extinction across the Cretaceous-Tertiary boundary in Montana. Nearly all the common taxa of reptiles (except dinosaurs), amphibians, and fish survived the end of the Cretaceous Period; extinctions were concentrated among rare groups and those found in near-shore habitats. The author concludes that ocean regression and climatic deterioration may explain these selective extinction patterns better than catastrophic hypotheses.
A Study of Mammalia and Geology Across the Cretaceous-tertiary Boundary in Garfield County, Montana
Author: J. David ArchibaldPublisher: Univ of California Press
ISBN: 9780520096394
Category : Science
Languages : en
Pages : 306
Book Description
The Bug Creek Problem and the Cretaceous-Tertiary Transition at McGuire Creek, Montana
Author: Donald L. LofgrenPublisher: Univ of California Press
ISBN: 9780520915794
Category : Science
Languages : en
Pages : 204
Book Description
Bug Creek assemblages from Montana, transitional in composition between typical Cretaceous and Paleocene vertebrate faunas, are critical to K-T extinction debates because they have been used to support both gradual and catastrophic K-T extinction scenarios. Geological and palynological data from McGuire Creek indicate that Bug Creek assemblages are Paleocene and restricted to channel fills entrenched into older sediments, suggesting that the Cretaceous component of the assemblage was reworked. Thus, the author concludes, "Paleocene dinosaurs" are an illusion and the K-T survival rate of mammals is low because the presence of Cretaceous mammals in Bug Creek assemblages is also the result of reworking.
Abstracts of North American Geology
Author: Dawn of the Age of Mammals in the Northern Part of the Rocky Mountain Interior, North America
Author: Thomas M. BownPublisher: Geological Society of America
ISBN: 0813722438
Category : Science
Languages : en
Pages : 253
Book Description
Contributions to Geology
Author: The Vertebrate Fauna of the Judith River Formation, Montana
Author: Ashok SahniPublisher:
ISBN:
Category : Judith River Formation
Languages : en
Pages : 90
Book Description
"Geologic investigation of the late Cretaceous Judith River Formation in the area just north of the Judith River on the Missouri River in north-central Montana has resulted in the discovery of varied vertebrate forms. The beds are mainly freshwater continental deposits consisting of crossbedded channel sandstones, gray siltstones, and carbonaceous shales with occasional seams of lignitic coal. The stratigraphic sequence consists of the Marias River Shale overlain by the Eagle, Claggett, Judith River, and Bearpaw formations. The last four constitute Montana Group. The Judith River Formation is Campanian in age as determined by its position between the fossiliferous marine Claggett and Bearpaw shales. The fauna was obtained from the upper 50 feet of the formation. The bone concentration in the productive sandstone is the result of size sorting leading to underrepresentation of the larger dinosaurs. Three orders of mammals are represented, the Eutheria by a single genus, the Allotheria by five, and the Metatheria by at least three genera. Teiid and parasaniwid lizards are frequent. Only a fraction of the large number of described dinosaur genera, however, is represented in the collection by isolated teeth. Fish and amphibians form a sizable portion of the fauna. Vertebrates from the Judith River Formation are more primitive than, but generally similar to, later Maestrichtian species. The mammals differ from their descendants in the Lance Formation at the species level. The community structure and the paleoecology of the fauna of the Judith River Formation resemble those of the Lance Formation. The greatest difference between the two communities is the greater variety of dinosaurs in the earlier formation"--P. 325.