Febkuakv (i, 1903.] 



SCIENCE. 



227 



those of the Carolina coast contain many 

 fragments of potash feldspar, being essen- 

 tially the same in composition as the beach 

 sands, which may account for the presence 

 of the potash in the coastal plain soils, 

 while explaining the origin of some of the 

 topographic features. 



Recent Changes in the Nortli Carolina 

 Coast, with Special Reference to Hat- 

 teras Island: Collier Cobb, University 

 of North Carolina. 



Hatteras Island is being added to on the 

 sound side and taken from on the ocean 

 side north of the cape, and a new inlet is 

 being made between the cape and Kinna- 

 keet. South of Cape Hatteras the island 

 is growing on both sides, but is extending 

 in a southeasterly direction. The rate of 

 change has been noted by the planting of 

 cedar posts, and noting the changes of 

 shore line with relation to posts, trees and 

 various natural objects through the years 

 1892-1902. 



The Hanging Valleys of Georgetoivn, Col.: 

 W. 0. Crosby, Massachusetts Institute 

 of Technology. 



The paper describes chiefly the break of 

 several hundred feet between the floor of 

 the valley of Clear Creek and that of 

 Leavenworth Creek, one of its principaj 

 tributaries, and explains it as due, not to 

 fluvial or glacial erosion, but to faulting, of 

 which abundant independent evidence is 

 afforded by mining developments. Other 

 and similar featui'es in the vicinity Avere 

 correlated -with this, and it was shown that 

 the part of the main valley occupied by 

 Georgetown is a depressed fault-block or 

 graben, and that the valley is, therefore, 

 due in part to displacement and not wholly 

 to erosion, suggesting comparison with 

 Yosemite Valley. The idea was also ad- 

 vanced that the elevation of this oldest of 

 the Colorado ranges has been recently, 

 and may be still, in progress, and that 



while in the past the movement has been 

 chiefly massive, developing the great fault- 

 scarp overlooking the plains, it has in 

 later times aifected the axis more than the 

 axis of the orographic block, leading to a 

 marked tilting of the Cretaceous peneplain ; 

 and in part, at Iea.st, it is veiy locally dif- 

 ferential, and in the GeorgetoAvn instance 

 in a degree to accelerate the topogi-aphy. 



Further Notes on Lake Anckaree: J. E. 



Todd, Vermilion, S. D. 



Lake Arickaree was a glacial lake formed 

 in the valley of Moreau and Grand Rivers, 

 South Dakota, with its axis corresponding 

 with the Missouri River in that region. 

 The region was first visited by the author 

 in 1890, and a description of its peculiar 

 southern margin preserved as a bowldery 

 ridge above the north side of Fox Ridge, 

 reported in 'Bulletin 144' United States 

 Geological Survey. He visited the region 

 again this past smnmer, discovered an- 

 other outlet, and traced the margin more 

 definitely. 

 Tlic Problem of the Loess in the Missouri 



Valley Compared ivith that in Europe 



and Asia: G. Frederick Wright, Ober- 



lin College. 



The phj'sical resemblances between the 

 loess deposited in the Missouri Valley and 

 that in southern Russia and in Turkestan 

 and northern China are perfect ; but in 

 general distribution there is great diversity. 

 In China the deposits occur in vast wind- 

 blown masses near the summits of the 

 mountain-border on the east coast of Mon- 

 golia, up to five thousand feet above the 

 sea. Elsewhere, however, only in the 

 lower areas are they distributed over level 

 areas, evidently by water action ; while at 

 the head of the plain extending west from 

 Peking, near the Nankau Pass, there are 

 evident deltas six hundred feet above the 

 sea, consisting of loess mingled with large 

 transported blocks of rock. Along the 



