222 TREE ANCESTORS 



cene. Nearly 100 different kinds of leaves and fruits have been 

 described and figured by paleobotanists, and although it is not 

 certain that all of these numerous forms are true botanical species 

 and not variables of a fewer number of true species, the actual 

 number of true species was probably greater than exist in the 

 modem world. 



Of these numerous forms 1 or 2 are survivors from the Oligocene 

 of Europe, and it is in the Miocene deposits that the greatest 

 number have been found. For example, in the celebrated Httle 

 fossil lake at Oeningen on the Swdss border of Baden, these late 

 Miocene lake beds have yielded 14 different kinds of maple and 

 some of these are exceedingly abundant in the shales. The lake 

 waters must have been filled with the keys from the surrounding 

 slopes when the maples shed their fruits in the Spring. In the 

 similar Miocene Rocky Mountain lake at Florissant, Colorado, 

 where the muds were exceedingly fine grained and consisted largely 

 of volcanic ashes from the contemporaneous volcanos at Leadville 

 and nearby locaKties, 6 different maples have been discovered. 



From various horizons in the Miocene of France a score of dif- 

 ferent maples have been unearthed, and as many more are recorded 

 from Italian locaHties. Evidently the country bordering the 

 expanded Mediterranean sea of Miocene time was imusually well 

 forested, and the maples were a prominent element in those forests. 

 Other European localities of Miocene age where maples have been 

 found are Bohemia, where they were abundant; Styria; Switzer- 

 land; Croatia; Germany; Camiola; Carinthia; Transylvania; Hun- 

 gary; Bosnia and Greece. In Asia Miocene maples have been 

 found in Siberia, in the Altai mountains, and in Japan. 



Athough apparently not as abundant in North America at that 

 time, we know much less about the plant Kfe of this continent in 

 late Tertiary times, especially the Miocene and Pliocene of the 

 central and eastern parts of the continent. Ten different Miocene 

 maples have been discovered in Oregon and the surface of the Mio- 

 cene history in that region has scarcely been scratched. Four 

 maples are known from the Miocene of California, where also much 

 still awaits discovery. One is known from Yellowstone Park, and 

 one from British Columbia. 



