BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



VOL. 27, PP. 387-436 JUNE 7, 1916 



INFLUENCE OF SILTJEIAN-DEVONIAN CLIMATES ON THE 

 EISE OF AIE-BEEATHING VEETEBEATES x 



BY JOSEPH BARBELL 



(Presented before the Society December 28, 1915) 



CONTENTS 



Page 



Introduction and summary 388 



Environmental conditions surrounding the rise of amphibians 391 



Probable early history of chorda tes 391 



Environment of fishes of the Old Red Sandstone 399 



Faunal changes in the Old Red Sandstone 401 



Living dipnoans and crossopterygians 406 



Environment of the early amphibians 409 



Evaluation of causes in the rise of amphibians 414 



Action and reaction between environment and organism 414 



Enemies of the waters, an inoperative cause 414 



Food of the lands, an inadequate cause 415 



Lure of atmospheric oxygen, an inefficient cause 416 



The swim-bladder originally a respiratory organ 417 



Arterial and respiratory systems of fishes and amphibians 419 



Probable origin of the air bladder as an intestinal diverticulum 422 



Compulsion of seasonal dryness 428 



Consequence imposed by ganoid fishes on subsequent evolution 429 



Ultimate consequences of types of structure 429 



1 Presented in abstract to the American Society of Vertebrate Paleontology, December 

 26, 1907, through the kindness of an invitation extended by the Society at the request 

 of Prof. R. S. Lull. (See abstract in Science, 1908, vol. xxvii, pp. 254, 255.) Some of 

 the arguments on this subject are found also in a paper by the writer in Bull. Geol. Soc. 

 Am., vol. 18, 1907, pp. 472-474. The writer is indebted to his colleagues, Prof. R. S. 

 Lull, for carefully reading the original manuscript in 1908 and suggesting some changes, 

 and Professors Charles Schuchert and L. L. Woodruff, who have read the manuscript as 

 revised in 1915. Professor Schuchert's advice has been of especial value, from his large 

 knowledge of the literature of paleontology and his perception of its bearings. He has 

 also discussed this subject to such an extent as was "appropriate for that place in his 

 recent "Text-book of Geology." The theme of the paper is in sequence to certain studies 

 on sedimentation published by the writer in the Journal of Geology in 1906 and 1908, 

 but has been withheld until papers on the Devonian, which were necessary to form a 

 logical basis for the arguments of the present subject, should have appeared. These 

 latter papers are entitled, first, "The Upper Devonian delta of the Appalachian geosyn- 

 cline," published in the American Journal of Science, vols, xxxvi and xxxvii, 1913 and 

 1914 ; and, second, "Dominantly fluviatile origin under seasonal rainfall of the Old Red 

 Sandstone," published in connection with the present paper. 



Manuscript received by the Secretary of the Society January 25, 1916. 



(387) 



