Joseph Barrell. 271 



cene time, from New Haven northwest to Litchfield, a 

 distance of about 35 miles. It was a memorable and 

 proud day for the writer to see Professor Barrell pre- 

 senting his views and defending them against all comers 

 before a more or less dissenting audience, among which 

 were W. M. Davis, R. A. Daly, W. W. Atwood, and 

 D. W. Johnson. If these gentlemen were not at that time 

 convinced, they were at least unable to make headway 

 against the leader of the party. 



It was BarrelPs intention to spend some of the sum- 

 mer of 1919 and most of that of 1920 in the field to try 

 out in critical places between Virginia on the south and 

 Rhode Island on the northeast what he had observed 

 first about Lehigh and later in Connecticut. This plan 

 is now broken, but he has left a long manuscript treat- 

 ing of these terraces, and a great mass of annotated 

 folios and generalized drawings showing the various 

 facets in their present eroded condition. This manu- 

 script is now being edited by H. H. Robinson, and will 

 be published in the course of the year. 



Rhythms and Geologic Time. 



Barrell was one of the participants in a symposium 

 on the interpretation of sedimentary rocks at the Albany 

 meeting of the Geological Society of America in 1916. 

 Here he presented a part, but only the smallest part, 

 of a study on "Rhythms and the Measurements of Geo- 

 logic Time." This is his most important study, and will 

 long remain a source of information and stimulation to 

 research along several lines of philosophical thought. 



He had long been attracted by the cycles of sedimen- 

 tation, and now he states that "Nature vibrates with 

 rhythms, climatic and diastrophic. ' ' The viewpoint of 

 the six parts of the study is geological, though the evi- 

 dence furnished by radio-activity is thoroughly reviewed. 

 Part I treats of the rhythms in denudation, and shows 

 that "erosion is essentially a pulsatory process/' and 

 that "a single rhythm is the erosion cycle; and small 

 partial cycles are superimposed on larger." Here then 

 is developed the hypothesis of compound rhythms. This 

 part leads to the conclusion that the present rate of 

 denudation is high, and "very much greater than the 

 mean of geologic time." Part II deals with rhythms 



