Joseph Barrell. 275 



esis first stated, but cautiously, by Osmund Fisher in 

 1882. Barrell quickly demonstrated that oceanic basins 

 could not have arisen in this way. 



Barrell left a long manuscript on the genesis of the 

 earth that it is hoped may be published in book form 

 along with some of his other geologic essays. As an 

 instructor of historical geology, and because of ques- 

 tionings by the writer of this biography, but more 

 especially through the writings of Chamberlin, he was 

 gradually led to delve more and more deeply into this 

 subject. Then in 1916 appeared Chamberlin's book, 

 '.'The Origin of the Earth," a work "which has long been 

 desired by geologists as well as other scientists," and 

 as Barrell wrote a critical review of it in Science, those 

 who wish may obtain from this review some of the 

 points in which he differs from Chamberlin. Another 

 place where he presents his modified views of the 

 planetesimal hypothesis is in the book entitled "The 

 Evolution of the Earth and its Inhabitants," 1918, to 

 which he contributed the first chapter. 



Paleontology and Evolution. 



Since the days at Lehigh when Barrell taught zoology 

 as well as geology, he had remained deeply interested 

 in the more fundamental problems of paleontology and 

 zoology. He never was much concerned with species and 

 genera, however, or with classification, but rather with 

 the bony mechanism of vertebrates, evolution, and the 

 environmental causes that bring about the sweeping 

 changes in organisms. 



Through the determining of ancient climates as dis- 

 cerned in the nature of the geologic formations, and more 

 especially in the continental deposits of the Silurian and 

 Devonian, Barrell 's interest was directed to an hypoth- 

 esis first set forth by Chamberlin, as to the first habitats 

 of fishes and the origin of lungs and limbs in dipnoans 

 and amphibians. His ideas on these subjects culminated 

 in 1916 in his "Influence of Silurian-Devonian Climates 

 on the Rise of Air-breathing Vertebrates." The prob- 

 lems he seeks to answer are two: "first, as to the en- 

 vironment in which fishes develop ; second, the changes 

 in the environment and the associated organic responses 

 which brought forth amphibians from fishes. It is the 



