lO BULLETIN OF THE LABORATORIES 



of those sandstone beds underlying the Chester or Maxville limestone. 

 The great salient features concerned in the growth of the Ameri- 

 can continent are represented by the Archean nucleus with its essen- 

 tial importance in building up strata and protecting the life of the seas 

 washing its shores ; the Cincinnati geanticline further modifying and 

 hastening the processes long since inaugurated, and forming a basin 

 which exerted a profound influence not only physically but biologically; 

 and finally the Appalachian revolution which terminated to a great ex- 

 tent courses which had long been in operation for the preparation of 

 the world for the coming of man, but which, nevertheless, made tan- 

 gible the physical environments necessary for the higher existence. 



