The age of the Tyuonyi construction has been fairly well established by the tree-ring method of dating, so widely and successfully used by archeologists in the Southwest. Ceiling-beam fragments recovered from various rooms give dates between A. D. 1383 and 1466. This general period seems to have been a time of much building in Frijoles Canyon; a score of tree-ring dates from Rainbow House ruin, which is down the canyon a half mile, fall in the early and middle 1400’s. Perhaps the last construction anywhere in Frijoles Canyon occurred close to A. D. 1500, with a peak of population reached near that time or shortly thereafter. TALUS HOUSE. On the talus directly above Tyuonyi to the north, at the foot of the prominent cliff, there once stood a cluster of houses. The group here had as its nucleus 12 or 15 cave rooms which were supplemented by at least as many masonry rooms at the front. Excavation of these rooms was completed in 1909 and the name Sun House was given to the building, because of a prominent Sun-symbol petroglyph carved on the cliff above. A part of this house group has been restored on the old foundations, with its new ceiling beams placed in the ancient holes in the cliff. This restoration work, done by the Museum of New Mexico in 1920, serves to show faithfully the original appearance of this typical specimen of a talus house. Here again the rooms are small (by modern standards) with doors only large enough to squeeze through, and no windows. During the 1400’s, it is probable that several such dwellings were occupied along a 2-mile stretch of this cliff. [Illustration: _A restored talus house._] LONG HOUSE. About one-fourth of a mile up the canyon from Tyuonyi, also against the northern and sun-warmed cliff, is the ruin of one of the largest combination cave-and-masonry dwellings to be found anywhere on the plateau. This great ruin is known as Long House for an obvious reason—it stretches almost 800 feet in a continuous block of rooms. For all of this distance, the masonry walls are backed by a sheer and largely smooth wall of tuff some 150 feet high. Into this cliff are dug many cave rooms, several kivas, and a variety of storage niches, all of which were incorporated into a single dwelling of over 300 rooms, rising 3 stories high. At Long House the rows of viga (roof-beam) holes in the cliff are particularly conspicuous, defining the onetime roof levels for hundreds of feet at a stretch. The site of Long House is especially pleasing, having an elevation of 40 or 50 feet above the canyon bottom, but close enough to the creek so that the sound of running water may be heard, and near enough to the huge stream-bordering cottonwoods to partake of the coolness of their foliage. If it is conceivable to envy any of the people of prehistoric times, surely we should envy the dwellers of Long House.