Then there is another source of supply,--the shell-heaps. It was the custom of all the aborigines who lived anywhere near the sea to go to the shore in summer--the whole band or a group of families together--and camp there for weeks or months. Certain spots were resorted to annually, just as we go year after year to our favorite sea-side hotel. The time there was spent chiefly in catching and eating salt-water food, and, most of all, oysters and clams. Our "clam-bake" is a survival of their feasts on the beach. Of course under such circumstances extended heaps of castaway shells and fish-bones would accumulate, and become of dimensions which seem extraordinary only when we forget the lapse of time since they were begun. Many objects, some castaway, some lost, would become intermixed with the loose surface shells and be rapidly buried beyond further disturbance. Thus an exploration of these heaps of refuse might be expected to disclose, and really does show, a great variety of indestructible indications of the people around whose summer-lodges they were formed,--how they lived, what they fed upon, and the degree of skill and culture to which they had attained. Scores of these shell-heaps from Maine to Texas have been excavated by private persons or by the agency of the museum, and the yield of each, however miscellaneous, is accessible to us. We may make out from the bones a list of the animals upon which the makers fed, we may tell from the stone implements how the men hunted and fished, from the awls, needles, skin-dressers, etc., of bone and horn with what skill the women worked, and largely what materials they used, while the bits of baked clay mark their position in the ceramic scale,--a well-accepted standard of progress. Nor are these things mixed and confused when deposited in the museum. All from each shell-heap are kept together, and specimens may thus be compared with one another all along the coast-line; or the visitor may go to another room, where the great Rose collection from Denmark is displayed, and compare them with the relics from the shell-heaps (_Kjoekken-moedings_) and village-sites of Jutland, where a parallel life was lived and the monuments of savage homesteads line the Baltic beaches.