The age of these shell-heaps is shown approximately by the presence of the auerhahn, proving the neighborhood of pine forests. The charcoal in the fireplaces came from oak wood, showing that oak forests are overspreading the country. The Baltic was more salt than at present, and the shore line was depressed. These facts indicate a period of transition from the Ancylus to the Litorina Epoch. The stone implements resemble those of western Europe during the late transition epoch, and do not occur in the oldest graves. There are no domestic animals except the dog, and no cultivated plants except some wheat in the later remains. All this seems to prove that genuine Neolithic culture had not yet reached the shores of the Baltic. They are composed mostly of oyster shells with a mingling of those of scallops, mussels, and periwinkles. The oyster has now disappeared from large parts of the coast and in others has decreased in size. Land elevation has narrowed the connection of the Baltic with the North Sea, and the water contains less salt. Remains of cod and herring show that the fishermen who lived on or near these harbors ventured out to sea in dugouts or on rafts, and that they must have made lines for fishing in fairly deep water. Remains of other fish occur. Bones of birds are often very abundant, especially swamp, shore, and swimming species; wild geese and ducks, swans and gulls, the _Alca impennis_ or wingless auk, now extinct. The blackcock, or "spruce (pine) partridge," was then common, but has now disappeared from Denmark with the pine whose buds formed a large part of its food. Bones of stag, deer, and wild boar form, according to Steenstrup, 97 per cent of all those of mammals found at Havelse.[31] Bones of seal, otter, wolf, fox, bear, beaver, and wildcat also occur. There are no traces of reindeer or musk-ox. These animals had already migrated or died out. Steenstrup noticed that the long bones of birds are about twenty times as numerous as others of their skeletons, and that the heads or ends of the long bones of mammals are generally missing. These were exactly the parts which are gnawed by dogs, whose remains also occur. Hence he drew the inference, now universally accepted, that the dog was domesticated in Denmark at this time. It was a small species, apparently akin to the jackal and of southeastern origin. No remains of other domesticated animals have been found, nor of cultivated plants, except a few casts of grains of wheat in the pottery of the upper layers of some of the heaps.