Donner Memorial Park

The museum offers a good introduction to the natural history of the Sierra Nevada.

To see some of this natural history for yourself, take a hike. One of the most dramatic workings of nature is the evidence left behind of recent glaciation. The great sheet of ice that slid through the region thousands of years ago left behind huge boulders and other rock debris.

The forest surrounding Donner Memorial State park is made up primarily of Lodge Pole pine, Jeffrey pine and White Fir. Because we’re at nearly 6,000 feet in elevation, there is no poison oak. You may see deer, squirrels, chipmunks, porcupines, raccoons, beavers and a wide variety of birds while visiting.

In and near the park are fascinating traces of the geologic process that shaped this portion of the Sierra Nevada. Rounded, smooth-surfaced rock outcrops are the result of giant bubbles of molten rock that cooled and hardened as they rose up into the earth’s surface (called “granitic intrusions). More recently, erosion has exposed that granite bedrock. The Sierra’s steep eastern face, which was such a formidable barrier for the Donner Party and other California immigrants, was formed over the last few million years by the tilting up of a gigantic section of the earth’s crust. The huge granite block tipped up dramatically on the east and tipped down on the west to disappear beneath the accumulated sediments that form the Sacramento Valley. Throughout much of the last million years, glaciers dominated the crest of the Sierra Nevada. One of them carved out the Truckee Basin, where the park is located, depositing gravel and some huge boulders in what is now a thickly forested area. When the glacier retreated, it left behind a terminal moraine of loose soil and gravel that blocked the creek channel and resulted in the formation of Donner Lake.