Rosebud County - Model Geologic Time
Background Info/ Historical Story:
The Tongue River Member of the Fort Union Formation holds many plant fossils that can give a huge insight into the ecology of ancient Rosebud County.
“The fossils were collected from a road cut on the north side of the village of Birney, Montana, on the east side of Tongue River road in siltstones of the Tongue River Member of the Fort Union Formation at 45°19.53384′N, 106°30.49632′W (Figs 1, 2), during one-day visits in the summers of 2002, 2003, 2007,
2008, 2011, 2013, 2014 and 2021 to 2024. The productive shale lenses occur high in the steep road cut, so that each year large pieces weather out and tumble to lower parts of the exposure where they can be split to expose abundant leaves, occasional flowers and fruits. Due to the abundance of leaves at this site, more commonly encountered taxa, such as Zizyphoides, Davidia, Aesculus, and Arthayesia, were selectively collected (with fragmentary, weathered, or less wellpreserved specimens left behind in the field), retaining the best preserved specimens for the museum collection. Hence, the museum collection is biased in favor of rarer species, but the more common taxa remain quantitatively dominant in the collection. Reproductive remains (flowers, fruits and seeds) are relatively rare in the sediments, so we collected all that were encountered.”- Fossil leaves, flowers and fruits from the Late Paleocene of Birney, southeast Montana, USA- Emily E. Wilder, Steven R. Manchester
Collections Spotlight:
Photos, Maps, etc:
- Between 1879-1930, View of Birney, Montana, also called White Birney. Log and frame buildings in foreground and school in background. Tongue River at center
- Birney Outcrop
- Stratigraphic Column
Links to other helpful sources:
- CENTRAL AND SOUTHERN ROSEBUD COUNTY MONTANA
- GEOLOGIC MAP OF THE FORSYTH 30' x 60' QUADRANGLE, EASTERN MONTANA
- geologic map of the porcupine dome area rosebud and garfield counties, montana
- PBDB Navigator