2*72 Canadian Record of Science. 



gine the whole interior plain of North America submerged, 

 so that the continent is reduced to two strips on the east 

 and west, connected by a belt of Laurentian land on the 

 north. In the great Mediterranean sea thus produced, the 

 tepid water of the equatorial current circulated, and it 

 swarmed with corals, of which we know no less than one 

 hundred and fifty species, and with other forms of life appro- 

 priate to warm seas. On the islands and coasts of this sea 

 was introduced the Brian flora, appearing first in the north, 

 and with that vitality and colonising power, of which, as 

 Hooker has well shown, the Scandinavian flora is the best 

 modern type, spreading itself to the south. 1 A very simi- 

 lar distribution of land and water in the Cretaceous age 

 gave a warm and equable climate in those portions of North 

 America not submerged, and coincided with the appearance 

 of the multitude of broad-leaved trees of modern types in- 

 troduced in the early and middle Cretaceous, and which 

 prepared the way for the mammalian life of the Eocene. 

 We may take a still later instance from the second con- 

 tinental period of the later Pleistocene or early Modern, 

 when there would seem to have been a partial or entire clo- 

 sure of the North Atlantic against the Arctic ice, and wide 

 extensions seaward of the European and American land, 

 with possibly considerable tracts of land in the vicinity of 

 the equator, while the Mediterranean and the Gulf of Mexi- 

 co were deep inland lakes. 2 The effect of such conditions 

 on the climates of the northern hemisphere must have been 

 prodigious, and their investigation is rendered all the more 

 interesting because it would seem that this continental pe- 

 riod of the post-G-lacial age was that in which man made 

 his first acquaintance with the coasts of the Atlantic, and 

 possibly made his way across its waters. 



"We have in America ancient periods of cold as well as of 



1 As I have elsewhere endeavoured to show (Report on Silurian 

 and Devonian Plants of Canada), a warm climate in the Arctic 

 region seems to have afforded the necessary conditions for the great 

 colonising floras of all geological periods. Gray had previously 

 illustrated the same fact in the case of the more modern floras. 



' l Dawkins, Popular Science Monthly, 1873. 



