GEOLOGICAL HISTORY OF THE WALNUTS 233 



The walnut of Europe, Juglans regia Linne, while extensively 

 planted in southern Europe as well as throughout the Orient 

 is only endemic in Greece 1 and eastward through Asia Minor, 

 Transcaucasia, the northwestern Himalayan region and in north- 

 ern Burma. 2 



In recent geological times its range has probably become greatly 

 restricted, since the oldest known occurrence of forms identical 

 with the modern tree are in the latest Miocene deposits of central 

 France. A considerable, number of occurrences have been re- 

 corded from the Pliocene deposits of this region and the central 

 plateau of France was evidently clothed with a considerable 

 stand of walnut in preglacial times. During the Pleistocene 

 this species is known from a number of localities in northern 

 Italy, in Hanover and in southern France (Provence), while the 

 nuts found associated with the Swiss lake dwellings were undoubt- 

 edly obtained from wild trees of the immediate neighborhood. 



The manner in which the fossils enable us to obtain a vista 

 into the life of bygone days is furnished by recent discoveries 

 in the Egyptian desert. At a time (latest Eocene or earliest 

 Oligocene) when Libya was separated from Europe and Asia 

 by a vast Mediterranean sea the Fayum was a delta with a heavy 

 rainfall (as shown by the flora) clothed with forests of an indo- 

 malayan type, and inhabited by ancestral elephants and other 

 curious forms of ancient animal life. No less than eight kinds 

 of figs as well as laurels and camphor trees have been described 

 from "this now arid and dessicated region. Among these fossil 

 plants are the remains of a species of walnut, a striking com- 

 mentary on the changes which have since taken place. 



I have attempted to give a graphic summary of the present 

 and past range of the walnuts on the accompanying sketch map 

 (fig. 2) where the areas of distribution of the existing species 

 (somewhat exaggerated) are shown in solid black. It is possible 

 that the part of the range of Juglans regia in southern Asia 

 should be extended eastward over Tibet through northern China 



1 Mentioned from Greece in Theophrastus and occurrence confirmed in recent 

 years by Heldreich and others. 



'- Possibly also in the mountains of northern China and Japan. 



