FUTURE OF THE CHESTNUT TREE 



553 



ably had formerly a much wider range than their present contracted 

 limits, for fossils of conifers belonging to the same genus have been 

 found even as far north as Greenland. And it is reasonable to assume 

 that, if conditions remain the same, such species will continue to weaken 

 and die out, although in this case also man's treatment can considerably 

 modify the result. 



Unfortunately, in the ease of the American chestnut, there is no 

 fossil evidence of its former distribution. Mr. F. H. Knowlton, of the 

 United States Geological Survey, writes us: "So far as I know, the 

 American chestnut has not been found fossil anywhere in this country, 

 but the parent form, that of Castanea sativa (the European chestnut) 



Fig. 1. Showing the Natural Range of the American Chestnut. The cross 

 hatching shows in a general way the extent of territory covered by the chestnut 

 bark disease. 



has been found at a number of localities in England and Italy, in de- 

 posits of inter-glacial or pleistocene age." As far as the genus is con- 

 cerned, Castanea once had a much wider range in North America than 

 at present, for, according to Sargent, 7 " Before the middle tertiary period 

 Castanea existed in northern Greenland, and in Alaska, where traces of 

 the leaves and fruit of Castanea Ungeri Heer have been distinguished: 



7 Sargent, C. S., Joe. tit., p. 10. 



VOL. LX XXIV.— 38. 



