Fig. 149— Part of Altanta, Missouri topographic sheet. Scale & Million or 1 

 Contour interval 20 feet. Illustrates post-Kansan erosion. 



FlG.150— PartofOelwein.Iowa.topographicsheet. Scalei or 1.666660. Con luur interval 

 20 feet. II! ustratcs erosin in the so-called Iowan drift. 



