Geology. 349 



II. Geology. 



1. Research in China. Vol. I, Pt. I (April, 1907, 4°, pp. xiv, 

 353), Descriptive Topography and Geology, by Bailey Willis, 

 Eliot Blackwelder, and R. H. Sargent; Vol. II (July, 1907, 

 pp. 133), Systematic Geology, by Bailey Willis. Published 

 by the Carnegie Institution of Washington (vol. I, pt. II reviewed 

 in December number of this Journal). — In 1902 a geological 

 expedition was sent to China by the Carnegie Institution ; this 

 was in accordance with a plan first suggested by Charles D. 

 Walcott, the special object in view being the investigation of 

 the pre-Cambrian and Cambrian formations. The expedition 

 was in charge of Mr. Bailey Willis and he was assisted by Mr. 

 Eliot Blackwelder and Mr. R. Harvey Sargent. The party was 

 in the field from October, 1903, to June, 1904, during which 

 time they made a geological traverse of about 2,000 miles through 

 northeastern, northwestern, and central China. The results of 

 their work are given in these handsomely illustrated and well 

 printed volumes. They will take place beside the other three- 

 volume work, the classic " China," by Von Richthofen. The 

 reviewer regrets that the lack of space prevents more than a 

 brief notice of some of the more important results presented in 

 this monumental work. 



The widely distributed yellow earth deposit forming the Great 

 Plain of eastern China is discussed in Chapter x of vol. i. Willis 

 concludes as follows : " In central and eastern Asia, in conse- 

 quence of a change from moist to arid climate, a deep layer of 

 decayed rocks was denuded of vegetation and exposed to effects 

 of winds and occasional rains. The disintegrated material was 

 transported and sorted, both by wind and water ; wind being the 

 more effective agent during the dry seasons and on wide plains ; 

 waters doing a larger work during rainy seasons and in river val- 

 leys. Sorted and transported repeatedly and alternately by winds 

 and waters, the material came to consist in great part of fine dust, 

 the loess, which both agents could carry in largest amount ; but 

 this was always mingled, as it is now, with some coarser sand 

 and gravel introduced by flood waters. Beyond desert basins, 

 the path along which the Huang-t'u was distributed was chiefly 

 down the valleys of a j)revious physiographic epoch, as it is now 

 down the valleys of the present far more mountainous surface. 

 It was deposited on flood-plains and in lake basins. The lighter 

 portions of it were blown out onto mountain slopes and gathered 

 beneath wind eddies or in sheltered hollows. In course of distri- 

 bution it became thoroughly decomposed and oxidized ; and 

 where it accumulated and was exposed to subaerial conditions it 

 acquired vertical cleavage, a secondary characteristic due to 

 gravity and movement of ground waters, and became charged 

 with salts brought in by such waters. The processes of transpor- 



Am. Jotjr. Sci.— Fourth Series, Vol. XXV, No. 148.— April, 1908. 

 24 



