220 W. D. Matthew — Fossil Vertebrates and 



already pointed out strong confirmatory evidence in the 

 vertebrate correlations. 



From the above it will appear that : 



(1.) The Tiffany, Clark Fork and Cernaysian repre- 

 sent the top of the Paleocene. 



(2.) The Torre j on and Fort Union are Upper Pale- 

 ocene, correlated by the palseobotanists with the Lower 

 Thanetian of Europe (Gelinden and Sezanne). 



(3.) The Puerco, Lower Paleocene, is post-Senonian 

 but may be as old as the Lance or older. The fauna 

 shows it to be considerably earlier than the Torrejon-Fort 

 Union and the near relations in stratigraphy and flora 

 between Lance and Fort Union are strongly against 

 intercalating between them the very wide time gap which 

 is involved by placing the Puerco as later than the 

 Lance.^^ If so, we must conclude that the latest dinosaur 

 faunas were contemporary with the older Paleocene mam- 

 malian fauna, and that it is owing to some imperfectly 

 known differences in facies that they are not found 

 associated. Some indirect evidence in support of this 

 view is afforded by the Paskapoo, in which Lance mam- 

 mals and Paleocene placentals are found associated. 



(4.) The position assigned by Brown to the Edmon- 

 ton, intermediate between Lance and Belly Eiver, has 

 been fully and to my mind conclusively confirmed by the 

 researches of Brown and Lambe upon the finely preserved 

 dinosaur skull and skeletons from the three horizons. 

 Many phyla have noAV been traced through and compared 

 in detail. The flora according to Knowlton and Hollick is 

 of Fort Union age, except for one small lot of plant 

 remains which Knowlton regards as of Cretaceous 

 aspect; the formation is positively stated by Brown to 

 be a stratigraphic and faunal unit from top to bottom. 

 Brown's explanation of the discrepancy^^ seems reason- 

 able, but it should be observed that it weakens the force 

 of the evidence from the flora in the correlation sug- 

 gested in a preceding paragraph (2). 



^^ It has been suggested that the Puerco=zLower Port Union. But there is 

 not the slightest evidence in favor of this, and against it, in addition to the 

 considerations I have cited, is a small amount of very fragmentary evidence 

 indicating that the Fort Union carries the same mammal fauna from bottom 

 to top. 



"Brown, 1914, Bull. Geol. Soc. Am., vol. 25, p. 375. 



