Existing comment:
Hayden Valley: Former Lakebed:
Though pine forest blankets much of the Yellowstone Plateau, Hayden Valley is treeless grassland. The broad valley floor, low hills, and vegetation pattern show the ghost-contours of a former lake.
Fed by melting glaciers, ancient Lake Yellowstone rose 270 feet during the recent Ice Age, and an arm of the lake flooded this area. The forested ridge across valley marks the former shoreline.
In Hayden Valley, you can see how glacial geology affects wildlife habitat. As the ice receded, a thick layer of silt accumulated on the lake floor. The fine-grained clays and sands favor shrubs and grasses that support large fields of bison and a variety of other animals. |