Description: The Fort Union Formation comes from the first geological epoch to follow the extinction of the dinosaurs. The Fort Union Formation covers much of Montana, eastern Wyoming, and the western Dakotas. It contains an extensive amount of minable coal, and has an extensive flora. It was a flora indicative of a lowland, sub-tropical to temperate climate. The depositional environment was both fluvial and lacustrine, with the fluvial deposits holding the most coal. This is a fine example of an uncommonly seen Glyptostrobus species. Glyptostrobus is an extant genus whose sole species G. pensilis is known as the Chinese Swamp Cypress. The species is nearly extinct in the wild due to extensive overcutting. The genus had a much wider distribution including much of the Northern Hemisphere, even penetrating into the high Arctic. Here is a fine specimen of 3 fronds from this unusual tree.