JAN 23 1923 



[This is the Concluding Number of Volume LXI 



^^iJ^T PROCEEDINGS 



OF THE 



American Philosophical Society 



HELD AT PHILADELPHIA 



FOR PROMOTING USEFUL KNOWLEDGE 

 Vol. LXI. 1922. No. 4. 



CONTENTS 



PACB 



The Age of the Earth from the Geological Viewpoint. By T. C. 



Chamberlin. ----------------- 247 



The Age of the Earth from the Paleontological Viewpoint. By John 



M. Clarke. ----------------- 272 



The Age of the Earth from the Point of View of Astronomy. By 



Ernest W. Brown. 283 



The Radio-active Point of View. By William Duane. - - - - 286 



Minutes -------------------- xiii 



PHILA-DELPHIA 



THE AMERICAN PHILOSOPHICAL SOCIETY 



104 South Fifth Street 



1922 



