This extensive region embraced in the valley of the Little Colorado and its tributaries is pre-eminently a region of pueblo ruins, though some cave dwellings are found. It is especially rich in prehistoric pottery. Because of its wealth of relics this region has suffered more than any other from the traffic in prehistoric wares. However, we are fortunate in that Dr. J. Walter Fewkes of the Bureau of American Ethnology has made the districts of the Little Colorado a subject of research for many years. His voluminous reports on this region have put us in possession of a vast amount of information on the archæology and ethnology of the Southwest. His collections from Sikyatki for the National Museum, made in 1895, with the assistance of Mr. F. W. Hodge of the Smithsonian Institution, together with the collections made from the Holbrook district by Doctors Fewkes and Hough, form, probably, the most valuable collection of prehistoric pottery in existence. Another extensive collection of pottery from this region may be seen in the Field Columbian Museum in Chicago. IV. GILA BASIN. This is another region that embraces practically every species of prehistoric ruins. It is of vast extent and comprises, besides the valley of the Gila proper, the large valleys of the Salt and Verde rivers. As a seat of prehistoric culture it was one of the most extensive and populous. Many ruins of these three great valleys are on irrigable lands, and, accordingly, have disappeared with the advancement of agriculture. It would not be possible within the limits set for this paper to describe the ruins of each of these twenty districts, but we may point out briefly the principal features of one district in each drainage area. 1. PAJARITO PARK DISTRICT. This district lies between the Rio Grande on the east and the Jemez Mountains on the west, and extends from Ojo Caliente on the north to Cochiti on the south. In the northern part are the ruins of Homayo, Houiri (Ho-we-re), and Pose on Ojo Caliente Creek. Ten miles west, below El Rito, is the large ruin of Sepawi (Se-paw-we). Near the village of Abiquiu, on the Rio Chama, is the important ruin of Tsiwari (Tsi-wa-re). These are all pueblo ruins, and not well preserved. The central portion of the district is the Pajarito Park proper, the region that has for some years been under withdrawal by the General Land Office and favorably reported on for a national park, for which it has many advantages, being of great scenic beauty, accessible, and one of the richest in the Southwest in well-preserved prehistoric remains. It contains innumerable cavate houses, a vast number of small pueblo ruins, and the ruins of the great communal dwellings of Puye, Otowi, Tsankiwi (Tsan-ke-we), Navakwi (Nav-a-kwe), and Pajarito or Tchrega. Vandalism has greatly diminished among these ruins since the park has been under withdrawal.