A Moraine is simply the rock debris left by a glacier. This debris is often called glacial till. Moraines appear as long lateral ridges along the path of a glacier. As rock and dirt fall onto the glacier from above, they collect, to be deposited later onto the sides of the valleys. Also, the pushing action acts as a giant bulldozer to push many of the rocks in its path to the side.
The moraine often consists of many differing kinds of rocks, often rounded from the glacial action of the current glacier as well as earlier ones. Terminal Moraines are merely the debris left at the end of the "bulldozer," when the glacier stopped moving forward. They often create dams that form "natural" lakes. Bear Lake is an example of such a lake.
Often you see many moraines crisscrossing or coming together as a result of many different ice advances and retreats. Several areas in Rocky Mountain National Park are good examples, the most notable being Bierstadt Moraine on the Bear Lake Road and the South Lateral Moraine on the south side of Moraine Park. Horseshoe Park on the north side of the park also has good examples of the signs of moraines.#
