16 REPORT ON THE TIMBERS OF GRAYSON, 
n 
= 
~ 
3 
ss) 
2 
=) 
If the hill, D, be divided into three belts, as in the diagram,. 
each belt will be seen to have a growth somewhat peculiar to 
itself, wholly dependent upon its height above drainage. The 
timbers peculiar to each are indicated in the diagram. It will 
be noticed that the belt at the base of the hill is the narrow- 
est, showing that, as a rule, swamp timbers do not extend very 
high above drainage. The middle belt of timber is the widest. 
The reason is, that timbers on a hillside change but little after 
leaving local drainage, until the rocky outcrops or the poor, 
thin shales near the top of the hill are reached. These shales 
or rocky cliffs, again, have their own timbers, the whole making” 
three tolerably distinct belts, which can be easily traced on 
any considerable hill. 
I also give below, condensed into table form, a complete 
list of the trees met with in my study: 
74 
