Coronado Lodge 34 23. Pioneer Amphitheatre 35 24. Train on Sad Monkey Railroad track 36 25. South face of Triassic Peak 36 26. Spanish Skirts 37 27. Catarina Cave 38 28. Santana’s Face 38 29. Picnic area at first water crossing 39 30. Colonel Charles Goodnight’s Dugout 40 31. The Lighthouse 41 32. Capitol Peak 42 33. Fortress Cliff 42 34. The Rock Garden 43 35. The Devil’s Slide 44 36. Campsite in south end of park 44 37. Entrance to Panhandle-Plains Historical Museum 45 [Illustration: Fig. 1. Aerial view of Palo Duro Canyon showing location of major points of interest: (1) Coronado Lodge; (2) Triassic Peak; (3) Timber Mesa; (4) Capitol Peak; (5) Fortress Cliff; (6) Prairie Dog Town Fork of Red River; (7) The Turnaround (termination of Park Road 5). (Courtesy of Charles A. Wolfin; photograph by W. A. Hester.)] The Geologic Story of Palo Duro Canyon William H. Mathews III[1] INTRODUCTION Like the early Spanish explorers who first saw Palo Duro Canyon, today’s visitor is likely to view the impressive canyon with surprise and awe. This great depression—it is more than 2 miles wide and as much as 800 feet deep within park boundaries—contains a fascinating assortment of multicolored geologic formations and erosion-produced rock sculptures of many shapes, colors, and size. The geographic setting of the canyon further heightens its impact on the visitor, for it is surrounded by the level, virtually treeless plains of the Texas Panhandle. (_See_ upper background area in fig. 1, frontispiece).