WALNUTS AND HICKORIES BEERY. 331 



small tree of Japan and northern China, and its range is roughly 

 shown on the accompanying map (fig. 4) in solid black. Monotypic 

 genera usually have a very interesting geological historj'', as, for 

 example, Sassafras^ Comptonia^ Ginkgo^ and many others. However, 

 no fossil remains of Platycarya have been discovered, and this is 

 probably due to the fact that the vast continent of Asia is practically 

 unexplored. 



CONCLUSION. 



Forestry experts warn us that commercial hickory is growing 

 scarce, just as the black walnut is already scarce. Aside from our 

 enjoyment of their fruits and the very special practical ends which 

 the wood fulfills we should not forget the sentiment which attaches 

 to a family of such magnificent trees, a family with an ancestry, as 

 we have just seen, extending back millions of years to a far-off time 

 when the dominant animal population of the globe was the uncouth 

 reptiles of the Cretaceous, a time when the evolution of the mam- 

 malia had not yet been wrought out, and when man was a far-distant 

 promise, not even hinted at in the teeming life of that age. AVliile 

 we can never hope to bring back the primeval forests of our ancestors, 

 we can use the intelligence which has been sp slowly acquired through 

 the ages in conserving these magnificent tree relics of bygone ages. 



