472 OSBOBN AND REEDS PREHISTORY OF MAN IN EUROPE 



antiquity of the genuine flint industry. Man is not only far older than 

 we formerly supposed, but human industry is far more ancient. 



III. Appendix: Eeview and Critique op the Penck-Bruckner, De 



Geer, Deperet Systems, from Xotes by Leverett, Alden, 



de Martonne, Johnson, and Davis 



commentators on the paper 



The full manuscript of the present communication to the Geological 

 Society of America was submitted to Frank Leverett, of the United 

 States Geological Survey, before its presentation to the Society. Somo 

 of Mr. Leverett's comments and corrections have been inserted in the 

 text; other comments are included in this Appendix. At the time the 

 paper was presented to the Society it was informally discussed by Prof. 

 W. M. Davis, Mr. Frank Leverett, and Dr. Ernst Antevs. An abstract 

 was subsequently given before the Xew York Academy of Science on 

 January 16, 1922, and valuable comments were made by Prof. Douglas 

 Johnson, geographer of Columbia University, who has also been in 

 correspondence with Prof. Emmanuel de Martonne, of the Sorbonne, on 

 the subject. 



It seems very important, in the interest of clarity of thought, to dis- 

 tinguish between Quaternary phenomena which are regarded by all 

 as practically determined and phenomena which are still sub judi-ce. 



VIEWS OF FRANK LEVERETT, OF THE U. S. GEOLOGICAL SURVEY 



(1) Leverett considers that Deperet has made the case entirely too 

 simple, and that future detailed study will bring out complications which 

 he has not taken into account. It appears doubtful if the uplifts have 

 really been as uniform as Deperet states; for example, for oldest 

 Quaternary 95-100 meters; for the next stage, 55-60 meters, etcetera. 

 In North America the uplift has been differential, so that one part of the 

 coast has suffered an uplift of 100 meters while a neighboring part has 

 had no uplift, and the intervening territory passes from up to 100 

 meters. It would take a lifetime of field-work in this country for a 

 geologist to run out the relations of the river terraces to the several 

 stages of glaciation, and only a small part of such correlation has yet 

 been done. So it would be impossible in North America to make any 

 such broad and full correlations as Deperet has done in the European 

 field. 



(2) Leverett considers that there is a fundamental error involved in 

 Deperet's new method of correlating fluvial plains, that head in the 



