Basketmaker remains are found throughout the Four Corners country, the better specimens being recovered from dry caves where the more perishable materials are preserved. In open sites, only the stone and bone objects are left, along with the remains of house structures and storage pits. In the Animas Valley, north of Durango, Colo., there was quite a concentration of early Basketmakers. Earl H. Morris, who conducted the first scientific explorations of Aztec Ruins, excavated a number of these sites in 1938 and 1939. Here, in an open talus site, he found the first evidence that the early Basketmakers had actual house structures. He gives a graphic description of a typical one: A site for the dwelling was secured by digging a drift into the steep hillside and piling the excavated earth and stone out in front until a terrace large enough to accommodate the projected house had been provided. The floor area was scooped out to shallow saucer shape—in this case 9 m. in diameter—and coated with mud. At the margins, the mud curved upward to end against the half-buried foot logs which were the basal course of the wall. The walls were composed of horizontal wood and mud masonry. They rose with an inward slant to a little better than head height, then were cribbed for a distance to reduce the diameter of the flat portion of the roof, which was of clay supported by parallel poles. The arc of stones was a retaining device placed to hold back the ever-growing accumulation of refuse that was dumped at the brink of the terrace. Interior furnishings generally consisted of a heating-pit, slab-lined storage cists, some with above-floor mud domes, and usually grinding stones and metates. How such a structure was entered is not known; possibly it was through a smoke hole in the roof, as in the later and deeper pithouses, or perhaps it was through a lateral doorway with a high sill, traces of which no longer remain. By A.D. 700, the Four Corners country was evidently well populated. In this later part of the Basketmaker period, the houses in open sites were usually more subterranean. These later houses, often with slab-lined and adobe-plastered walls, had a smaller second room or antechamber added on the front through which entrance was made. A few such ruined dwelling sites are known along the Animas River south of Durango. Morris felt that an adequate archeological survey would reveal a great many more, but extensive plowing of the area in recent historic times has long since removed the evidence. In the latter part of this period, the early Basketmakers evidently moved downstream where there was better land for cultivation and the growing season was slightly longer.