46 



OSBORN. 



r UPPER. 



OLIGOCENE. 



EOCENE. 



AQUITANIEN 

 fSTAMPIEN 

 LOWER. (INFRA TONGRIEN 

 LIGURIEN 

 \ BARTONIEN 

 (LUTETIEN 



SUESSONIEN 

 j THANETIEN 



Imontien 



Lower John Day 

 (Diceratherium Layer) 



WHITE RIVER 



UPPER. 

 MIDDLE 

 LOWER. 

 BASAL. 



BRIDGER & UINTA 

 LOWER BRIDGER 

 WIND RIVER 

 WASATCH 

 TORREJON 

 PUERCO 



Preliminary Correlation Table of European and American Tertiary Horizons. 

 On all the levels above the Stampien the parallels are imperfectly established. 



The preliminary correlation sheet abbreviated in this table sets 

 forth the results of the geological succession and correlation so 

 far as it has been carried at present and illustrates the rapid prog- 

 ress of the knowledge of our own horizons. It includes the 

 latest results of the American Museum explorations in the Miocene 

 of Colorado and Kansas, as roughly studied by Matthew, but 

 these correlations are not to be understood as final. Scott has al- 

 ready transferred our John Day of Oregon, from the Miocene, 

 where it was formerly placed, to the Upper Oligocene. The lower 

 part at least of these beds belongs in the Oligocene, while the 

 Upper John Day may prove to correspond with the Lower 

 Miocene of Europe. Our Pliocene record as compared with 

 the magnificent Pliocene of Europe is extremely meagre, and 

 our Miocene succession rich as it is, is not as fully understood 

 as the Miocene of France ; we look for more exact results 

 from the American Museum explorations which are now being 

 collated. It is only when we pass into the great time period 

 from the Oligocene downwards that the American record be- 

 comes a superbly complete time standard for the whole Northern 

 Hemisphere or Holarctic Region. 



II. TERTIARY GEOGRAPHICAL DISTRIBUTION 



The importance of Geographical distribution was first recog- 

 nized by Humboldt, and set forth by Darwin in the ' Origin of 

 Species,' in 1858. In the same year Sclater divided the world 



