The principal room in the upper ruin is situated nearly in the center of the cave, and is the one that has given the whole ruin its name. The walls are 2 feet thick, constructed of stone, 12 feet high in front and 7 feet high on the sides and inside. The exterior was finished with a coat of whitewash, with a decorative band in yellow; hence the name of Casa Blanca or White House. West of the principal room there is a smaller one, which appears to be a later addition. The walls of this room are only 7 inches thick, of adobe on the sides and back and of small stones in front. The top of the wall is about 2 feet below the top of the wall on the east. The coat of whitewash and the yellow decorative band are continuous over both rooms, but the white coat was also applied to the exterior western wall of the main room. In the main room there is a series of small sticks, about half an inch in diameter, projecting 8 inches from the wall and on a line 3 or 4 inches under where the roof was. The small room in the eastern end of the cave was located on a kind of bench or upper level, and was constructed partly of stone and partly of adobe. The stone part is the upper portion of the eastern half. On the west there is a small opening or window, with an appliance for closing it. It is probable that this room was used only for storage. In the western end of the cave there is another single room, which is clearly shown in plate XLVII. The front wall is 11 feet high outside and 5 feet high inside. The lower portion is stone, the upper part and sides are adobe, and the side walls rest on nearly 2 feet of straw, ashes, etc. The buttress shown in the illustration is of stone and the front wall that it supports is slightly battened. A close inspection of the illustration will show that this wall rests partly on horizontal timber work, a feature which is repeated in several walls in the main cluster of the ruins. The use of timber laid horizontally under a wall is not uncommon, and as it will be discussed at greater length in another place, it may be dismissed here with the statement that as a rule it failed to accomplish the purpose intended. But the use of the buttress is an anomalous feature which it is difficult to believe was of aboriginal conception. Its occurrence in this ruin together with so many other unaboriginal features is suggestive.