Paleoecology of an early oligocene biota from Douglass Creek Basin, Montana

Geological Society of America Bulletin



Douglass Creek basin lies west of the Continental Divide in the northern part of the Rocky Mountain physiographic province. Numerous minor environmental differences exist between the Douglass Creek area and the Pipestone Springs and Canyon Ferry areas east of the Divide. In the 19th century, however, the three areas had identical mammalian species representation, although not equally dense populations. Fossils of an early Oligocene biota have been collected from the Douglass Creek basin. Presence of all but one of the Douglass Creek mammalian species in the Pipestone Springs-Canyon Ferry early Oligocene fauna suggests that the three ancient ecosystems resembled each other in much the same way as the 19th century systems. The early Oligocene deposits and biota of the Douglass Creek basin indicate a moist, temperate climate with seasonal variations. Sediment size and distribution suggest that the cross-valley relief was no greater than it is now. The fish and invertebrate faunas show that a shallow, hard-water lake existed in the area. The flora included a lowland, lake-border association and an upland coniferous forest. Although the ancient Douglass Creek biota doubtless included many species not represented in the fossil collections, most of the mammalian species are probably represented in the combined Douglass Creek, Pipestone Springs, and Canyon Ferry fossil assemblages. If so, the number of mammalian species was about the same as in the 19th century ecosystem.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Paleoecology of an early oligocene biota from Douglass Creek Basin, Montana
Series title Geological Society of America Bulletin
DOI 10.1130/0016-7606(1961)72[1633:POAEOB]2.0.CO;2
Volume 72
Issue 11
Year Published 1961
Language English
Publisher Geological Society of America
Description 10 p.
First page 1633
Last page 1642
Country United States
State Montana
Other Geospatial Douglas Creek
Google Analytic Metrics Metrics page
Additional publication details