2IO F. H. KNOWLTON 



warm-temperate flora. Another Upper Eocene flora is found in the 

 Clarno formation of the John Day Basin, Oregon, and in the Payette 

 formation of western Idaho. It embraces walnuts, hazels, birches, 

 alders, oaks, elms, sycamores, maples, ashes, etc., and is temperate 

 or warm temperate, in character. 



Eocene floras in the Atlantic area are of very little importance as 

 thus far developed. 



Miocene. — The Miocene flora of North America is relatively not 

 a large one although it comprises probably five hundred species as 

 now known. The deposits occur often in isolated basins, widely 

 separated, and there is usually comparatively little in common between 

 them. A number of the more important areas may be briefly 

 mentioned. 



At Brandon, Vermont, in the midst of ancient crystalline rocks, 

 occur small pocket-like deposits of lignite which have yielded large 

 numbers of fossil fruits and a very few poorly preserved leaves. The 

 fruits have been studied by Lesquereux, Perkins, and others, and 

 about one hundred and fifty nominal species described belonging to 

 the genera Nyssa, Hicoria, Juglans, Bicarpellites, Cucumites, Tri- 

 carpellites, etc. 



At Florissant, Colorado, also in the midst of older rocks, there are 

 small lake-bed deposits which have afforded vast quantities of plant 

 and insect material in an admirable state of preservation. The 

 plants number upward of two hundred species, among them being a 

 great number of very modern types and even including not a few 

 herbaceous forms. This flora as a whole is very unlike anything 

 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 Aliocene 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 



