

PROCEEDINGS 



AMERICAN PHILOSOPHICAL SOCIETY, 



HELD AT PHILADELPHIA, FOR PROMOTING USEFUL KNOWLEDGE. 



Vol. XX. January to April, 1883. No. 113. 



TABLE OF CONTENTS. 



PAGE. 



Obituary Notice of Edouard Desor. By J. P. Lesley. ( Continued 



from No. 112. ) 523 



Geological Notes. By E. W. Claypole (jjcith plate) 529 



Note on the progress of the Second Geological Survey of Pennsyl- 

 vania. By J. P. Lesley 537 



First Addition to the Fauna of the Puerco Eocene. By E. D. Cope. 545 

 On the Brains of the Eocene Mammalia Phenacodus and Periptychus. 



By E. D. Cope {uith 2 plates) 563 



Photodynamic Notes, VII. By Pliny Earle Chase, LL.D 566 



Some Microscopic Distinctions between Good and Bad Timber of the 



Same Species. By Dr. J. T. Rothrock {with plate) 599 



An improvement in the construction of the Hypsometrical Aneroid. 



By Dr. Persifor Frazer 604 



Some Comparative Tables showing the Distribution of Ferns in the 



United States of North America. By George E. Davenport 605 



Obituary Notice of the Rev. Dr. Charles Porterfield Krauth. By F. 



A. Muhlenberg 613 



Fourth Contribution to the history of the Permian Formation of 



Texas. By E. D. Cope 628 



Stated Meeting, January 5 63(5 



Stated Meeting, January 19 638 



Stated Meeting, February 2 640 



Stated Meeting, February 16 641 



Stated Meeting, March 2 643 



Stated Meeting, March 16 644 



Stated Meeting April 6 645 



On the Measurement of Electromotive Force. By George F Barker 



(with plate) 649 



Obituary Notice of Henry Draper. By George F. Barker 656 



Map of the Terminal Moraine (with plate) 663 



Note on a large Fish-plate from the Upper Chemung (?) beds of North- 

 ern Pennsylvania. By E. W. Claypole (with plate) 664 



