Il6 F. H. KNOWLTON 



found in the region at the present day and apparently finds its closest 

 affinity with the West Indies, though doubtless it also approached 

 originally from the north. 



Small deposits containing a Miocene flora have been found in 

 Esmeralda County, Nevada, the Similkameen Valley, and other 

 points in British Columbia, and in the Yellowstone National Park. 

 The so-called Muscall beds of the John Day Basin, Oregon, and 

 extending into central Washington, have yielded a rich flora of about 

 eighty species, among them oaks, maples, poplars, barberry, bread- 

 fruit trees, etc., indicating a warm, moist climate. Associated with 

 the auriferous gravels of California is a flora of about one hundred 

 and twenty-five species, some of which are of very modern appear- 

 ance, such as Zizyphus, Magnolia, Per sea, Acer, Artocarpus, etc. 



Pliocene. — The Pliocene flora of North America is almost a negli- 

 gible quantity, about the only known locality being the Falls of the 

 Columbia River. It includes species in the genera Woodwardia, 

 Sassajras,Sterculia, etc., and is very closely related to living American 

 species. 



Pleistocene. — The Pleistocene flora is better known than the last, 

 yet we are undoubtedly only on the borderland of a knowledge of 

 the plants of this period and their distribution. Small Pleistocene 

 floras are known from New Jersey, Maryland, Virginia, West Virginia, 

 North Carolina, Alabama, New York, Iowa, and Canada. The 

 most extensive exploitation of this flora is that made in Canada in the 

 vicinity of Montreal and Toronto, where Penhallow has been able 

 to make out at least three stages. The species are nearly ah living. 



