324 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. 



region to Alaska and Greenland in North America and from Saghalin 

 Island, off the east coast of Asia, to western Europe in the Old 

 World. 



The Oligocene walnuts are not quite so plentiful as are those of the 

 Eocene and are almost entirely confined to the Old World. This is 

 undoubtedly an expression of the incompleteness of the geological 

 record in North America, since there are practically no known Oligo- 

 cene plant beds in this country. 



The Miocene has furnished upwards of two score species, the 

 majority of which are Old World forms, distributed from Japan to 

 western Europe. This again is due more to lack of records in 

 America than to the absence of the genus. In this country nuts are 

 preserved in the curiously isolated lignite deposit near Brandon, Vt. 

 There are species in Idaho, several in California and Oregon, and 

 four in Colorado in the late Miocene at Florissant. Both fruit and 

 leaves are frequently found associated in the various Tertiary de- 

 posits and nuts also occur with the leaves in some of the Cretaceous 

 deposits. 



The Pliocene species are also numerous, a number of them surviv- 

 ing from Miocene times. In all, about 25 forms have been recorded 

 from the Pliocene deposits, and several of these are very close, if not 

 identical, with still-existing species. From the Upper Pliocene of 

 Germany nuts have been collected in the lignite deposits which are 

 exactly like those of the existing American species Juglans nigra and 

 Juglans cinerea. 



Walnuts are not common in Pleistocene deposits but the fruit of 

 Juglans regia Linne is recorded from the Pleistocene of southern 

 France, and our own black walnut, Juglans nigra Linne, has been 

 found in the late Pleistocene of Maryland and in the Pleistocene 

 river terraces of Alabama. Both of these occurrences are based upon 

 the characteristic nuts preserved in the impure peat of buried swamp 

 deposits. 



The walnut of Europe, Juglans regia Linne, while extensively 

 planted in southern Europe as well as throughout the Orient, is only 

 endemic in Greece^ and eastward through Asia Minor, Transcau- 

 casia, the northwestern Himalayan region, and in northern Burma." 



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 recorded from the 

 Pliocene deposits of this region^ and the central plateau of France 

 was evidently clothed with a considerable stand of walnut in pre- 

 glacial times. During the Pleistocene this species is known from a 



1 Mentioned from Greece in Theophrastus and occurrence confirmed in recent years by 

 Heldreicli and others. « 



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



