Note:  Do not rely on this information. It is very old.

Moraines

Moraines are masses of debris found on glaciers. Stones and rocks are constantly falling from the sides of the mountains on to the glacier, and form a fringe of rubbish all along the edge of the ice. These fringes are the lateral moraines. When two glaciers meet, the adjoining lateral moraines of each unite to form one; and, as the double glacier moves slowly on its downward path, the mass of debris is carried with it, so that a central line of stones, etc., or a medial moraine extends to the end of this ice river. . As the stories come to the glacier's mouth, the ice melts from under them, and they are left to form constantly-increasing heaps and ridges, known as terminal moraines.