Davis.] 478 [ May 18, 
8. Conditions of deposition of sand plateaus. . page 486 
9. Their origin as deltas, marginal to the decaying 
ice-sheet. ....... 488 
10. The feeding eskers. ..... 489 
11 . Rapid deposition of eskers and sand plateaus. . 490 
12. Their local and spasmodic growth. . . . 491 
13. Conclusion as to their joint origin. . . . 492 
14. Origin of eskers in superglacial channels. . 492 
15. Origin in subglacial channels. . . . 493 
16. Analogy with Alaskan glacial streams. . . 494 
17. Height of eskers. ...... 496 
18. Boulders in sand plateaus. .... 496 
19. Changes in eskers since deposition. . . 496 
20. Review and conclusions. . . . . 498 
1 . THE RELATION OF CLIMATE TO THE FORMS OF THE WASTE OF THE 
LAND ON ITS WAY TO THE SEA. 
During the present century of geological progress, it has come 
to be generally recognized that the forms of the land are for the 
most part the product of erosion upon forms once much larger 
than now, and that the waste that they have yielded has been 
borne to the sea. There is, however, another group of land forms 
to which attention should be directed ; that is, the forms which 
are produced by the waste of the land on its way to the sea. Soil 
♦ sheets, talus slopes and cones, alluvial fans, flood plains and del- 
tas belong under this heading, when erosion is controlled by ordi- 
nary processes under a sufficient rainfall ; but all these forms 
receive a peculiar interest fi-om their especial relation to climate. 
In an arid climate the slopes and the low ground become cov- 
ered with detrital material, because there is so little water to carry 
away the products of weathering. The accumulation is not the re- 
sult of the faster weathering of the rocks but of slower transpor- 
tation ol weathered detritus. The ratio of supply to transportation 
of waste is increased, and hence the lowlands become encumbered 
with waste from the mountains. The loitering waste may accu- 
mulate to a considerable depth, obliterating the forms produced at 
an earlier time by constructional processes or under different 
climatic conditions. The action of the wind is increased in such 
cases when the water fails, and unlike water action, it may lead 
