SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOLUME 57. NUMBER i 



CAMBRIAN 

 GEOLOGY AND PALEONTOLOGY 



II 



ABRUPT APPEARANCE OE THE CAMBRIAN FAUNA ON 

 THE NORTH AMERICAN CONTINENT 



With One Map 



CHARLES D. WALCOTT 



(Publication 1940) 



CITY OF WASHINGTON 



PUBLISHED BY THE SMITHSONIAN INSTITUTION 



AUGUST 18, 1910 



