(Photographs by Geo. L. Beam. Courtesy of the Denver & Rio Grande Railroad)] [Illustration: PLATE 17 STRONGHOLD HOUSE, SQUARE TOWER CANYON (Photograph by Geo. L. Beam. Courtesy of the Denver & Rio Grande Railroad)] [Illustration: PLATE 18 a, HEAD OF HOLLY CANYON] [Illustration: b, SOUTH SIDE OF HOVENWEEP CASTLE, SQUARE TOWER CANYON (Photographs by Geo. L. Beam. Courtesy of the Denver & Rio Grande Railroad)] [Illustration: PLATE 19 a, HOLLY CANYON GROUP, FROM THE EAST (Photograph by Jacob Wirsula)] [Illustration: b, GREAT HOUSE AT HEAD OF HOLLY CANYON, FROM THE NORTH (Photograph by T. G. Lemmon)] [Illustration: c, UNIT TYPE RUIN, FROM THE EAST (Photograph by T. G. Lemmon)] [Illustration: PLATE 20 a, GREAT HOUSE AT HEAD OF HOLLY CANYON, FROM THE SOUTH] [Illustration: b, RUIN B AT HEAD OF HOLLY CANYON, FROM THE WEST] [Illustration: c, GREAT HOUSE AT HEAD OF HOLLY CANYON (Photographs by Jacob Wirsula)] [Illustration: PLATE 21 a, GREAT HOUSE, HOLLY CANYON] [Illustration: b, STRONGHOLD HOUSE AND TWIN TOWERS, SQUARE TOWER CANYON (Photographs by Geo. L. Beam. Courtesy of the Denver & Rio Grande Railroad)] [Illustration: PLATE 22 a, HOVENWEEP CASTLE] [Illustration: b, SOUTHERN PART OF CANNONBALL RUIN, McELMO CANYON (Photographs by T. G. Lemmon)] [Illustration: PLATE 23 a, SQUARE TOWER WITH ROUNDED CORNERS, HOLLY CANYON (Photograph by Jacob Wirsula)] [Illustration: b, HOLLY TOWER IN HOLLY CANYON (Photograph by Jacob Wirsula)] [Illustration: c, HORSESHOE HOUSE (Photograph by T. G. Lemmon)] [Illustration: PLATE 24 a, HORSESHOE RUIN (Photograph by Jacob Wirsula)] [Illustration: b, BOWLDER CASTLE, ROAD (WICKYUP) CANYON (Photograph by T. G. Lemmon)] [Illustration: PLATE 25 a, CLOSED DOORWAY IN BOWLDER CASTLE, ROAD (WICKYUP) CANYON (Photograph by J. Walter Fewkes)] [Illustration: b, BROKEN-DOWN ROUND TOWER, SQUARE TOWER CANYON (Photograph by Jacob Wirsula)] [Illustration: PLATE 26 a, NORTH SIDE OF TOWER, SQUARE TOWER CANYON (Photograph by Jacob Wirsula)] [Illustration: b, D-SHAPED TOWER NEAR DAVIS RANCH, YELLOW JACKET CANYON (Photograph by Jacob Wirsula)] [Illustration: c, MODEL OF TOWERS IN McLEAN BASIN (Photograph by De Lancey Gill)] [Illustration: PLATE 27 ROUND TOWER AND D-SHAPED TOWER IN McLEAN BASIN (Photograph by J. Walter Fewkes)] [Illustration: PLATE 28 a, D-SHAPED TOWER IN McLEAN BASIN, SHOWING CROSS SECTION OF WALL] [Illustration: b, ROUND TOWER IN McLEAN BASIN, SHOWING STANDING STONE SLAB (Photographs by J. Walter Fewkes)] [Illustration: PLATE 29 a, HOLMES TOWER, MANCOS CANYON] [Illustration: b, LION TOWER, YELLOW JACKET CANYON (Photographs by T. G. Lemmon)] [Illustration: PLATE 30 a, TOWER ABOVE CAVATE STOREHOUSES, MANCOS CANYON BELOW BRIDGE] [Illustration: b, TOWER ON MESA BETWEEN ERODED CLIFFS AND BRIDGE OVER MANCOS CANYON ON CORTEZ SHIP-ROCK ROAD (Photographs by T. G. Lemmon)] [Illustration: PLATE 31 a, TOWER ABOVE CAVATE STOREHOUSES, MANCOS CANYON BELOW BRIDGE]