41(j OSBORN AND REEDS PREHISTORY OP MAN IN EUROPE 



definite data which lead us to question the applicability of Deperet's 

 method of using the altitude of river terraces to settle questions of 

 geologic age, since it furnishes a mass of data, both of the character of 

 the interglacial deposits and the altitude relations, which demonstrate 

 the inadequacy of terrace altitude relations to establish geologic and 

 archeologic correlations. 



(7) Brooks's discussion 11 of the Rhine terraces in the Smithsonian 

 Report (pages 289, 290) gives data on the question of their gradient 

 compared with that of the present stream. It appears that the slope of 

 the oldest gravels is so rapid that they descend to and below the level of 

 the gravels of the next or chief terrace. This chief terrace has the right 

 height at Wesel and Bottrop to be consistent with Deperet's Milazzian 

 stage, 54r-60 meters above the stream; but on following it up the valley 

 it is found at 73 meters at Duisburg, 90 meters at Diisseldorf, 106 meters 

 at Keulen, and 136 meters at Bonn. It thus gets too high for the 

 Sicilian stage of Deperet before reaching Bonn. On the other hand, the 

 low terrace, which is only 5 meters above the river at Bonn, is 11 meters 

 at Duisburg and still more above the stream at Weser and Dingden. 

 What value has the Deperet method of classification on the Rhine ? The 

 chief terrace seems to have been built up at the close of the oldest glacia- 

 tion of that region, which is interpreted to be the Second Glacial stage, 

 for its gravel covers this old drift between Crefield and Xijmengen. This 

 terrace is thus of the right age to be Milazzian, but it is only in the 

 vicinity of Weser that it is of the right height to fit in with Deperet's 

 altitude method. 



(8) Leverett (in a letter of January 19, 1922) contributes a revision 

 of the morainal lines of the "Middle Drift" [III] in Holland and western 

 Germany; also of the next older drift [II], published in the map of Van 

 Baren (1908). These lines have been inserted in the morainal map 

 by Dr. Reeds (figure 3). In Leverett's paper of the "Comparison of 

 Xorth American and European Glacial deposits" (1910.1), he remarks 

 that the "Middle Drift" has received very little attention by German 

 geologists; they have never tried to map its limits; it is in fact a thin 

 drift sheet, often 2 meters or less in thickness, which makes it difficult 

 to determine the limits. Gagel omits the "Middle Drift," and by so 

 doing has failed to establish the correlation. For example, he classes the 

 underlying heavy sheet of the "'Old Drift" as Third Glacial, but in all 

 probability it is Second Glacial. The drift under the Paludinenbank in 

 the vicinity of Berlin was correlated by Wahnschaffe with the First 



11 See Charles E. P. Brooks (1919.1) and Ellsworth Huntington (1922.1) 



