241 THE GEOLOGICAL HISTORY OF PLANTS. 



distributed ; and these show that further subsidence or 

 denudation in the north had opened a way for the arctic 

 currents, killing out the warm-water animals of the Nio- 

 brara group, and filling up the Mediterranean of that 

 period. Of the flora of these Upper Cretaceous periods, 

 which must have been very long, we know something in 

 the interior regions, from the discovery of a somewhat 

 rich flora in the Dunvegan beds of the Peace Kiver dis- 

 trict, on the northern shore of the great Cretaceous Medi- 

 terranean;* and on the coast of British Columbia we 

 have the remarkable Cretaceous coal-field of Vancouver 

 Island, which holds the remains of plants of modern 

 genera, and, indeed, of almost as modern aspect as those 

 of the so-called Miocene of Greenland. They indicate, 

 however, a warmer climate as then prevalent on the Pa- 

 cific coast, and in this respect correspond with a peculiar 

 transition flora, intermediate between the Cretaceous and 

 Eocene or earliest Tertiary of the interior regions, and 

 which is described by Lesquereux as the Lower Lig- 

 nitic. 



Immediately above these Upper Cretaceous beds we 

 have the great Lignite Tertiary of the West the Laramie 

 group of recent American reports abounding in fossil 

 plants, at one time regarded as Miocene, but now known 

 to be Lower Eocene, though farther south extending up- 

 ward toward the Miocene age. f These beds, with their 

 characteristic plants, have been traced into the British 

 territory north of the forty-ninth parallel, and it has been 

 shown that their fossils are identical with those of the 



* " Reports of Dr. G. M. Dawson, Geological Survey of Canada." Also, 

 " Transactions of the Royal Society of Canada," vol. i. 



f Lesquereux's "Tertiary Flora"; "White on the Laramie Group"; 

 Stevenson, " Geological Relations of Lignitic Groups," American Philo- 

 sophical Society, June, 1875; Dawson, "Transactions of the Royal So- 

 ciety of Canada," vol. iv. ; Ward, " Bulletin of United States Geological 

 Survey." 



