base of the cañon stood an ancient pueblo in ruins, but with parts of the first and second stories still erect. Fifty feet in a perpendicular line, above and immediately back of the first edifice, in a shelf, or in the mouth of a cavern in the cañon’s walls, stood another building constructed of sandstone and mortar, and measuring one hundred and forty-five by forty-five feet, with walls eighteen feet high still standing. Broken pottery was plentiful, as around all the ruins we have described. The building was lighted by square windows and provided with a circular estufa.[475] The most surprising results in all the history of archæological exploration in this country were obtained in September, 1874, by a party connected with the United States Geological and Geographical Survey Corps. This party was composed of only three persons, Mr. W. H. Jackson and Mr. Ingersoll with their guide, Captain John Moss, a resident of La Plata, who possessed both a knowledge of the country and an acquaintance with the language of the Indians. In the south-western corner of Colorado, the cañons of two of the tributaries of the San Juan were examined, namely, the valleys of the Rivers Mancos and McElmo.[476] The former stream rises among the western foothills of the Sierra La Plata, and flows south-westerly through fertile valleys to a great table-land known as the “Mesa Verde,” thence to the San Juan near the crossing of the boundary lines of the four territories. In the upper valley of the Mancos, between the mountains and the mesa, groups of undistinguishable ruins were discovered in great numbers. An examination of the shapeless heaps revealed foundations composed of great square blocks of adobe. The great multitude of these heaps of masonry overgrown with pines indicates a general and unsparing destruction of the houses of the people who once inhabited the valley, at the hands of their enemies. The cañon through the Mesa Verde is quite uniformly two hundred yards wide, with perpendicular walls of grayish cretaceous sandstone ranging from six hundred to one thousand feet in height. Numbers of the mounds of ruined adobe were met with at each advance into the cañon, and upon promontories jutting out towards the stream, remains of stone walls were seen as high as fifty feet from the river’s bed. Every step revealed great quantities of broken pottery, and with this statement we will let the subject of these fragmentary relics of the by-gone civilization rest for the present.