In the autumn of 1904 I visited the ruins for the purpose of taking photographs and found a party of three pottery-hunters camped near the Balcony House. A part of their firewood that evening consisted of precious beams from this ancient house. For many years the visitors to the Mesa Verde noticed a huge tree-grown mound on the rim of the cañon-wall, directly opposite the Cliff Palace. A few dressed stones, apparently the corner of a wall, thrust above the surface of this mound. Probably there was a building beneath it. Behind and enveloping it lay a forest of low-growing and limby piñon pines and cedars. Over all was the ever-present and brooding mystery of the deserted Mesa Verde. In July, 1915, Dr. Fewkes put a crew of men to work excavating the mound. As a result of their labors, a prehistoric stone building now stands in the sunshine. It is the shape of the capital letter D. Its straight front, which faces southward, measures one hundred and thirty-two feet; its semicircular back, two hundred and forty-five feet. Plainly, it was built to a preconceived plan. There was no patchwork, no inharmonious combination. Precisely midway in the south wall was a recess. In another recess near the southwest corner was a fossil palm leaf. This strikingly resembles the rays of the sun, and together with a figure of the sun in the floor, suggests that the building was a Sun Temple. There is nothing to indicate that it was used or intended to be used as a dwelling-place. The masonry is the best thus far found on the Mesa. It was laid with mortar of tough, enduring clay. The stones of the walls and partitions were small and were cut, many polished, and a few decorated. The figures on a number of these decorated stones consist of triangles, and one is the outline of a typical cliff-house doorway. The outer walls are double. None have outside openings. Perhaps the entrances to the building were either through the roof or by means of subterranean passageways from the face of the cliff just in front and beneath. In the mound upon the ruins of this building was found a living tree that was more than three hundred and sixty years old. A long period, perhaps several hundred years, must have been required for the earthen mound to accumulate upon the ruins, and then three hundred and sixty years for the tree to grow. Apparently the Sun Temple must have been abandoned several hundred years ago, perhaps about the year 1300. It appears never to have been occupied, and probably was in process of being completed when it was abandoned.