THE ASH 231 



been widespread, diversified and common, and probably more 

 abundant than at the present time— their geograpliical range was 

 certainly more extensive then than now. Over 30 different ashes 

 are known from Miocene deposits. They are found in North 

 America in Oregon on the west coast and in Virginia on the east 

 coast. A hint at their probable abundance at this time in the 

 Rocky Mountain region is given to us by the lake deposits at 

 Florissant, Colorado, where the fortunate preservation of the 

 sediments of this tiny lake basin furnish an unparalleled picture 

 of the insect and plant life of Miocene times in that region. 



No less than seven species of ash have been discovered in these 

 Florissant beds, thus indicating that the ash was much more 

 abundant and diversified at that time than would otherwise have 

 been suspected from a consideration of the rather infrequent Mio- 

 cene plant beds of other parts of North America. Fraxinus is 

 present in all of the more important Miocene plant bearing deposits 

 throughout Europe, and it appears to have been especially abun- 

 dant in late Miocene times along the shores of the Mediterranean 

 and in the uplands of central France, southern Germany, and in 

 the various crown-lands of the Austrian monarchy. An ash leaf 

 from the Miocene of Virginia is much like that of our modern 

 species. 



Ashes seem to have declined in variety during the succeeding 

 Pliocene times, and the few species that have been discovered all 

 show a near approach in their characters to those of the existing 

 species. Thus in Spain, France and Italy fossil leaves are found 

 in the Pliocene deposits that are indistinguishable from those 

 of the existing Manna-ash {Fraxinus ornus) of southern Europe, 

 whose range at that time Kke that of the so-called Hipparion fauna, 

 was much greater than at present, for its leaves have been found 

 in the PHocene deposits of the Altai mountains of central Asia. 

 Similarly modern looking ash leaves are found in the Pliocene 

 deposits along our Gulf coast in what has been called the Citronelle 

 formation. 



During the succeeding Pleistocene times, marked by continental 

 ice sheets, the ashes that have been found fossil are all still existing 



