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 sizes. 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.

Upper Pensylvanian and lower Permian rocks of the Eastern Shelf in North-central Texas are composed of 10 to 15 repetitive sequences including open shelf, deltaic, fluvial, and interdeltaic depositional systems. Sediments derived from the Ouachita Mountains and associated piedmont were transported westward across a narrow coastal plain. Fluvial and deltaic sandstone fac1es define a southwest paleoslopc of about 5 feet per mile. Sandstone facies are delta front sheets, distributary mouth bars, distributary and fluvial channels, and destructional bars.

This classic publication is a syllabus published in conjunction with a Research Colloquium of the Bureau of Economic Geology, August 27-29,1969. It includes discussion notes, 168 maps and other text figures, and a list of 321 selected references pertaining to modern and ancient delta systems. The discussion notes are: Delta Systems and Deltaic Deposition, by A. J. Scott and W. L. Fisher.