leaves are gray. A lowly vegetation grows on the white sand flats and gravel hills and clings to the bare rocks. Only when showers fall the ravines are filled in a short time with wild torrents, which overflow and irrigate the plain; for while in June, July, and August the clouds discharge daily upon the mountains, a whole year has often passed at Casa Grande, sometimes eighteen months, without its raining. The thermometer rises every day in summer to above 100° in the shade, and snow-falls are almost unknown. It is a hot, arid region, covered with desert plants, to which the coarser forms of the lower animal life, the disgusting bird-spider (Mygale heintzii), the great millipede (Scolopendra heros), the scorpion (Scorpio boreusand Telyphonus excubitor), the rattlesnake (Caudisono molossus), and the large warty lizard, appropriately called the Gila monster (Helodernm horridum), are eminently adapted. The mountain sheep (Ovis montana) formerly roamed in the mountains. The region has for many centuries been inhabited exclusively by the Pima Indians, who have always been a more or less settled, agricultural people, like the Pueblos of New Mexico, living in villages composed of round huts, and acquainted with the art of irrigation by canals.
I have already mentioned that the Punas claimed to be descendants of the inhabitants and builders of the Casa Grande. Casteñeda says that the "red house" was destroyed by the people who lived there at the time of his arrival, and describes them as completely savage.
The ruin of Casa Grande is composed of a whitish-gray calcareous marl, is three stories high, and
