Plate XIX 



FiG.l. A region iii a mature stage of erosion. Scale about 2 miles per inch. 

 (Kentucky, U. S. Geol. Surv.) 



FIG. 2. A plain in old age. Scale about 2 miles per inch. Contour interval, 

 100 ft. (Abilene, Kan., Sheet, U. S- Geol. Surv.) 



