_Shell Mounds_ (2).--Shell mounds of Europe and America furnish definite records of man's life. The shell mounds of greatest historic importance are found along the shores of the Baltic in Denmark. Here are remains of a primitive people whose diet seems to be principally shell-fish obtained from the shores of the sea. Around their kitchens the shells of mussels, scallops, and oysters were piled in heaps, and in these shell mounds, or Kitchenmiddens, as they are called (Kjokkenmoddings), are found implements, the bones of birds and mammals, as well as the remains of plants. Also, by digging to the bottom of these mounds specimens of pottery are found, showing that the civilization belonged largely to the Neolithic period of man. There are evidences also of the succession of the varieties of trees corresponding to the evidences found in the peat bogs, the oak following the fir, which in turn gave way to the beech. These refuse heaps are usually in ridgelike mounds, sometimes hundreds of yards in length. The weight of the millions of shells and other refuse undoubtedly pressed the shells down into the soft earth and still the mound enlarged, the habitation being changed or raised higher, rather than to take the trouble to clear away the shells from the habitation. The variety of implements and the degrees of culture which they exhibit give evidence that men lived a long time in this particular locality. Undoubtedly it was the food quest that caused people to assemble here. The evidences of the coarse, dark pottery, the stone axes, clubs, and arrow-heads, and the bones of dogs show a state of civilization in which differentiation of life existed. Shell mounds are also found along the {74} Pacific coast, showing the life of Indians from the time when they first began to use shell-fish for food. In these mounds implements showing the relative stages of development have been found.