Southwest-here the Moenkopi Plateau about 600 km north of the Plate. The Little Colorado River is on the front left. Small crescentic dunes are in most of the washes above the river. Their crests indicate that the dominant wind direction is from the bottom left in this figure. Red Rock Cliff is across the center of this picture, and linear dunes are on the plateau above the cliff.
Dunes are rare in North American deserts, and fluvial processes dominate much of the landscapes.
Compare the mountains and basins in this Plate and in Plate E-13, the Great Basin Desert, with Plates of other deserts throughout the world. The Sonoran Desert is a subtropical desert and is the most complex of the North American deserts. Because of its biseasonal rainfall, short duration of cold weather, and topographic and geologic diversity, the Sonoran Desert has the greatest variety of plants of any deserts on the Earth. Figure E-12.2 shows the giant saguaro, which is sometimes more than 15 m tall. This plant dots the Sonoran and reinforces a general concept of deserts as cacti-rich land.