When the Indians of central California were first seen, they wore but little clothing, and knew how to construct only the simplest dwellings for protection from the weather. They did not cultivate the soil, nor did they hunt a great deal, although the country abounded with game. Along the larger streams fish was an important article of food, but in other places, acorns, pine nuts, and roots constituted the main supplies. The acorns were ground in stone mortars and made into soup or into a kind of bread. These Indians have often been called Diggers because they depended so largely for their living upon the roots which they dug. It would seem natural that about San Francisco Bay the natives should have used canoes, but, according to early travellers, they had none. When they wished to go out upon the water they built rafts of bundles of rushes or tules tied together. At favorable points along the shore the Indians collected for their feasts, and these spots are now indicated by heaps of shells, in some places forming mounds of considerable size. Many interesting implements have been dug from these mounds, or kitchen middens as they are sometimes called. In the mountains the sites of the villages are marked by chips of obsidian (a volcanic glass used in making arrow-tips) and by holes in the flat surfaces of granitic rocks near some spring or stream. These holes were made for the purpose of grinding acorns or nuts. Many of the Indian tribes developed great skill in the weaving of baskets, which they used for many different purposes. The baskets are still made in some places, and are much sought after because of their beauty. The Indians of northern California in building their homes dug round, shallow holes, over which poles were bent in the form of a half-circle, and then tied together at the top. Bark was laid upon the outside, and earth was thrown over the whole structure. [Illustration: FIG. 61.--HOLES IN ROCK, MADE FOR GRINDING FOOD] "Sweat houses" were built in much the same manner, and were used chiefly during the winter. When an Indian wished to take a sweat, hot stones were placed in one of these houses, and after he had entered and all openings were closed, he poured water upon the stones until the room was filled with steam. After enduring this process as long as he desired, the Indian came out and plunged into the cold water of a near-by stream. As may be imagined, such a bath often resulted disastrously to the weak or sick. The fact that the California Indians could support themselves without any great exertion undoubtedly had the effect of making them indolent, while in the desert regions of the Great Basin the struggle for something to eat was so severe that it kept the natives in a degraded condition. [Illustration: FIG. 62.--CALIFORNIA INDIAN BASKET]