Locust 



Fia. /O. Hicoria 



PLATE IV. 



Fig. 9. Cross sections of a Locust growing in region 4 of the Aliquippa 

 district, showing a tendency toward a narrowing of annual rings. 



Fig. 10. Cross sections of a Hicoria growing on the hilltop near Nine Mile 

 Run. Shows a general tendency toward narrow annual rings on account of the 

 unfavorable conditions due to smoke and gases. 



