PHOTO INTERPRETATION OF LANDFORMS IN A DRY GRASSLAND MARGINAL TO GLACIATED PLAINS

Stereoscopic photographs were utilized in identifying broad landform types. Each of these may then be analyzed with respect to the minor landform featured that it contains. To illustrate the method, use was made of 12 field areas located in the Northern Great Plains from 40 to 70 mi east of the Rocky Mountains. These areas were shown to topographic maps, in vertical aerial photopairs or stereograms, and in part by ground photographs in stereopairs. From an examination of airphoto stereograms and ground studies throughout the region, 10 basic landform typed were grouped into 4 classes upland plains, valley plains, steeply sloping margins of plains and benches, and erosion remnants controlled in form the rockbed structure.