HORNBEAM, HAZEL, BIRCH AND ALDER 



111 



of southern Mexico (Orizaba, Jalapa) and Guatemala, where they 

 are relics, like the cypress and Carpinus, of the former greater ex- 

 tent of these forms during Pleistocene times or earher, which have 

 become separated from their fellows by the arid country of the 

 Texas border and northern Mexico. 



Our American hop hornbeam, Ostrya virginiana, is a handsome 

 tree, of small or medium size, with an open crown, rarely over 70 



Fig. 22. Sketch Map Showing the Existing Range and Fossil 

 Occurrences of the Ironwood 



feet tall or 2 feet in trunk diameter, and usually much less. The 

 yellowish green leaves are almost indistinguishable from those of 

 the hornbeam. The wood is heavy, hard and tough, with a close 

 grain, and is utilized to some extent for fence posts, fuel, and small 

 wooden articles such as tool handles and mallets. 



The geological record is very incomplete, at least such of it as 

 has been deciphered doubtless partly because of the difficulty of 



