GREAT EROSIONAL WORK OF WINDS
469
Fig. 2. Wind-graved Cliffs of the Mokattam Hills; on the borders of the Arabian desert opposite Cairo, Egypt.
as mighty as any swept into the seas by streams or laid down on the floor of the ocean, are new and important generalizations belonging distinctly to the first lenstrum of our new century.
Prior to the year 1900 wind-action had been always regarded as merely one of the minor geologic agents of erosion—a mere idler in its manifestations, and a denuding power at all times negligible. That its real role in geologic economy had been so long so completely overlooked
Fig. 3. Sharp Meeting of Hard Mountain Rock and Soft Plains Strata; Torreon, Mexico—a characteristic feature of regional eolation.
