_a_, D-shaped tower in McLean Basin, showing cross section of wall. _b_, Round tower in McLean Basin, showing standing stone slab. 29. _a_, Holmes Tower, Mancos Canyon. _b_, Lion Tower, Yellow Jacket Canyon. 30. _a_, Tower above cavate storehouses, Mancos Canyon, below bridge. _b_, Tower on mesa between eroded cliffs and bridge over Mancos Canyon, on Cortez Ship-rock Road. 31. _a_, Tower above cavate storehouses, Mancos Canyon, below bridge. _b_, Eroded shale formation in which are small walled cavate storehouses. 32. _a_, Reservoir near Picket corral, showing retaining wall. _b_, Kiva, Unit type House, Square Tower Canyon. 33. Pictographs, Yellow Jacket Canyon. TEXT FIGURES Page 1. Ground plan of Aztec Spring Ruin 26 2. Ground plan of Wood Canyon Ruin 32 3. Metes and bounds of Emerson Ruin 34 4. Schematic ground plan of Emerson Ruin 35 5. Ground plan of Unit type House in cave 39 6. Square Tower Canyon 45 7. Ground plan of Hovenweep House 46 8. Ground plan of Hovenweep Castle 47 9. Ground plan of Twin Towers 50 10. Ground plan of Unit type House 51 11. Holly Canyon Ruins 52 12. Horseshoe (Hackberry) Canyon 53 13. Ground plan of Horseshoe House 54 14. Ground plan of Davis Ruin 55 15. Ground plan of Lion House 55 16. Ground plan of ruin with towers in McLean Basin 56 17. Doorway in Round Tower, McLean Basin 57 18. Megalithic stone inclosure, McElmo Bluff 61 PREHISTORIC VILLAGES, CASTLES, AND TOWERS OF SOUTHWESTERN COLORADO By J. WALTER FEWKES INTRODUCTION The science of archeology has contributed to our knowledge some of the most fascinating chapters in culture history, for it has brought to light, from the night of the past, periods of human development hitherto unrecorded. As the paleontologist through his method has revealed faunas whose like were formerly unknown to the naturalist, the archeologist by the use of the same method of research has resurrected extinct phases of culture that have attained a high development and declined before recorded history began. No achievements in American anthropology are more striking than those that, from a study of human buildings and artifacts antedating the historic period, reveal the existence of an advanced prehistoric culture of man in America.