In his account of ruins in the region visited, Prof. W. H. Holmes[3] considers several other ruins, as “the triple-walled tower” (here called Mud Spring village, p. 20), ruins at Aztec Spring (p. 23), cliff-dwellings and towers of the San Juan and Mancos, the “slab cysts” or burial places on the Dolores, and the promontory at the junction of the Hovenweep and McElmo (p. 60). The best preserved towers and castellated buildings which his article considers occur on the San Juan and Mancos Canyons, districts on the periphery of the region covered by this account. [3] Report on the ancient ruins of Southwestern Colorado. Tenth Ann. Rept. U. S. Geol. Surv. Terr. (Hayden Survey) for 1876, Washington, 1879. These pioneer reports of Jackson and Holmes not only called attention to a new archeological field, but also introduced to the archeologist several new types of prehistoric American architecture of which nothing was previously known. They have been repeatedly quoted and are still constantly referred to by writers on southwestern archeology. Although Jackson made many photographs of the castles and towers of the Hovenweep, none of these were published in his reports, possibly because halftone methods of reproduction were then unknown. The illustrations that appear in the text of early reports are mainly reproductions of sketches. These reports, in which the discovery of the tower type of architecture and its adjacent cliff-dwellings were announced, should thus rightly rank as the first important steps in the scientific investigations of the stone-house builders of this district of our Southwest; although the allied “Casas Grandes” or great houses of the Chaco had been described a few years before by Gregg, Stimpson, and others. We have, in addition to these pioneer reports, several magazine articles of about the same date, the material for which was largely drawn from them. One of the most important newspaper articles of that date was written by Mr. Ernest Ingersoll, published in the New York Tribune, and another, of anonymous authorship, is to be found in the Century Magazine for the year 1877. New forms of towers and castellated buildings were added in these accounts to those of the earlier authors. One of the most important contributions to the antiquities of the region about Mesa Verde was made by the veteran ethnologist, Morgan, who published notes contributed by Mr. Mitchell on a cluster of mounds near his ranch. As no name was given this village it is here called the Mitchell Spring Village. Morgan likewise mentions the ruin at Mud Spring and a tower in the ruin near his spring. Professor Newberry was the first author to affix the name Surouaro to a ruin situated at the head of the Yellow Jacket Canyon.