REVIEWS. 859 



cannot be urged in support of its eolian origin on this side of the 

 Atlantic. Where the ioess of the United States is typically developed, 

 and has any considerable thickness, its iron content is not often thor- 

 oughly oxidized below a depth of four to six feet.' The same is true 

 of the loess of some parts of Germany. So, too, it may be much more 

 troublesome to account for the presence of even a few aquatic shells in 

 an eolian deposit, than for the presence of many land shells in a water 

 deposit. The frequent inter-stratification of loess and sand at the base 

 of the formation, the occasional presence in the loess of stone quite 

 beyond the power of wind to transport, its general habit of following 

 river courses, the presence of aquatic shells, and its lack of oxidation 

 and leeching except for a short distance from the surface, are consider- 

 ations of sufficient weight to make it very doubtful if the larger part of 

 the American loess can be due to the wind. On the other hand, we 

 believe that some (quantitatively a small part) of the loess of the 

 United States is unquestionably of eolian origin. It has long seemed 

 possible to the writer that formations may have been grouped together 

 under this name which have had very different origins at very different 

 times. This notion is emphasized in the volume before us, where the 

 adobe of the United States, two or three thousand feet thick, is referred 

 to as the loess, though this is not the formation commonly known as 

 loess, and can hardly be one with it in origin. Many new facts are 

 given concerning glaciation in regions where the work of the ice has 

 not, until recently, been known. 



The incorporation of the great body of new facts and suggestions 

 throughout the volume has meant the digestion of a large body of 

 recent literature. Indeed, there appears to have been very little geo- 

 logical literature produced since the earlier edition of the work of 

 which the author has not made use, and to which we do not find ex- 

 plicit reference in the new edition. 



Rollin D. Salisbury. 



Bodengestaltende Wirkungen der Eiszeit. Vortrag von Dr. Aug. Bohm, 

 Privatdocent an der k. k. technischen Hochschule, Vienna. 

 The difficulty of finding satisfactory summaries of the physical 

 features of European countries makes such essays as the above espec- 

 ially welcome to the American student, particularly if he contemplates 

 a trip abroad. The essay is one of a series of lectures, published by 



