the Cretaceous-Tertiary Problem. 221 



The position of the Edmonton as indicated by its 

 dinosaurs is about half way between the Lance and the 

 Judith-Belly River. It confirms the view that the faunal 

 change from Judith to Lance was due to time, not to 

 migration. 



( 5. ) The correlation of the Lance with the latest marine 

 Cretaceous of the American succession is very strongly 

 supported by Dr. Stanton's Cannonball memoir. This 

 and other evidence of invertebrates, plants and stratigra- 

 phy lie outside the limits of this contribution. 



(6.) "Whether the foregoing correlations be exactly 

 or only approximately correct they make it possible to 

 trace the evolution and succession of vertebrate faunas 

 between the Mesozoic and Tertiary. In my article of 

 1914 I stated briefly the reasons for regarding a faunal 

 break, involving extensive migrations as shown by the 

 sudden appearance of an identical new fauna in widely 

 separated regions, as the best practical evidence of 

 widespread diastrophism, and hence indicating the com- 

 mencement of a new period in theory, as it is convenient 

 in practice to draw the line at such a point. Direct 

 stratigraphic evidence is necessarily local, its correla- 

 tions over any wide regions are dependable only in so 

 far as they conform to the palseontological evidence, and 

 an unconformity is not a practicable or suitable basis for 

 a universal time-division. I do not mean to minimize its 

 practical importance in the making of geological maps. 



Interpretation and Conclusion. 



In my paper of 1914 I pointed out the wide differences 

 between the Lance and Paleocene vertebrate faunas and 

 concluded that it was in part due to difference in facies, 

 in part to migration, but that it probably did not repre- 

 sent any great time break. I regard it at present as 

 chiefly due to difference in facies. The placental mam- 

 mals appear to be in adaptation a largely terrestrial dry- 

 land or upland fauna, the dinosaurs in the main a swamp, 

 lagoon and lowland fauna, which was still in a flourishing 

 state in Judith time, but progressively reduced in numbers 

 and variety, and restricted in Lance time to a few highly 

 specialized survivors. The marsupials and multitubercu- 

 lates would represent arboreal types, likely to be found 

 in either facies, but comparatively rare, like most arbo- 



