Thus, we find that of the Northern Athabaskans of western Canada, the southern Carrier and the Chilcotin Indians share with the Shuswap Indians of Salish stock the use of semi-subterranean huts which even in winter seem like ovens. Are we to recognize in this an adaptation to the inclemencies of the climate? Hardly, when we find that this type of dwelling is used precisely by those Athabaskans living farthest south, where of course the climate is much milder, while the more northern tribes of the family get along with crude double shelters about a central fireplace. The use of the semi-subterranean lodge by the Carrier and Chilcotin is perfectly explained as a contact phenomenon. They have simply adopted the idea from their Salish neighbors: the cultural environment has proved more effective than the physical environment in determining a cultural trait. Other members of the same family furnish corresponding instances. Though many of the Northern Athabaskans have long, snowy winters, only the Loucheux, who are in contact with the Eskimo, have adopted the wooden goggles of the Eskimo, which serve as a protection against snow-blindness. Similarly, they are the only members of the stock to substitute for the widespread Canadian toboggan the Eskimo sledge with runners.[6] As the physical environment is overshadowed in cultural significance by a neighboring culture, so it may vanish into nothingness in the face of what we may call cultural inertia--the tendency of a preëxisting cultural trait of indigenous growth to assert itself. A familiar example of this tendency is the exact imitation of forms of implements in quite different and often refractory material. Thus, the Central Eskimo generally make lamps and pots out of soapstone. In Southampton Island, where this material is lacking, they have not devised a new form but have at the expenditure of much ingenuity and labor cemented together slabs of limestone so as to produce the traditional shape.[7] The same phenomenon appears in other fields. Grooved copper axes have been found in parts of the United States; their shape is patterned exactly on the stone axes characteristic of the same localities. The beginnings of the copper and bronze ages in Europe are equally suggestive in this regard. The incipient metallurgist does not automatically make the most of his material but slavishly follows his stone or bone models. His copper ornaments imitate bear’s teeth or bone beads, his implements resemble the stone celts and hammers of an earlier era.[8] As Professor Boas points out on the basis of Bogoras’ descriptions, an equivalent development may be traced in the history of the Chukchee tent. This type of habitation is extremely clumsy and not at all well adapted to the roving life of the Reindeer division of the tribe, considerably hampering their progress. It represents, however, a variety of the older form of stationary house used when the Chukchee were a purely maritime people.[9]