3 i6 THE POPULAR SCIENCE MONTHLY. 



only rational course is that of bearing the misery which must be 

 entailed for a time by desistance. The transition from State- 

 beneficence to a healthy condition of self-help and private be- 

 neficence, must be like the transition from an opium-eating life 

 to a normal life — painful but remedial. 



ARE THERE EVIDENCES OF MAN IN THE GLACIAL 



GRAVELS ? 



By Major J. W. POWELL. 



THE geologist studying in the Rocky Mountains is ever aston- 

 ished at the rapid degradation of mountain forms. Cliffs, 

 peaks, crags, and rocky scaurs are forever tumbling down. The 

 rocks break asunder above and roll down in great slides on the 

 flanks and about the feet of the mountains. As the slopes are thus 

 diminished, gradually the slides are covered with soil, in part 

 through the decay of the rocks themselves, in part by wind-drifted 

 sands, but perhaps in chief part by the washing of the soils above. 

 In this manner a great mountain is ultimately buried by over- 

 placement. This overplacement gradually washes down, to be 

 distributed on still lower grounds, but it is replaced from above 

 from the newly formed soils. The process goes on until the 

 mountain is degraded into hills and the streams have carried 

 away the greater part of the material of the ancient mountain. 

 Now, in studying these mountains, the geologist is always on his 

 guard to distinguish overplacement from foundation structure. 

 When the mountains are all gone the hills are degraded in the 

 same manner, and the process continues until a grand base-level 

 is established, below which degradation can not take place ; then 

 the mountains and hills have all been carried away by rivers to 

 the sea. As mountains and hills are degraded, so valley slopes 

 are brought down. The river, meandering now on this side and 

 now on that, increases the length of its course, as every bend 

 throughout the valley is cut back ; but ultimately bend works 

 back against bend, until shorter channels are produced. By cut- 

 off channels the course of the river is diminished ; by increasing 

 its meanders the course of the river is lengthened ; but in the 

 grand operation the one about compensates for the other. In this 

 manner the river is forever rearranging the flood plain. The 

 banks of the stream, left dry by the vicissitudes of river cutting, 

 tumble down, and a bank goes through a process much like that 

 of the mountain slope ; and the geologist is ever on the lookout to 

 distinguish overplacement from the rocks of the foundation struc- 

 ture. There are many conditions where this distinction is plain, 



