GREENUP, CARTER, BOYD AND LAWRENCE COUNTIES. 25 
DISTRIBUTION OF SPECIES AS AFFECTED BY TOPOGRAPHICAL FEA- 
TURES. 
In the first tabular view the effects of these conditions which 
arise from the hilly character of Eastern Kentucky may be 
traced in considerable detail. A careful study of this table 
will place many of the facts which belong to this phase of the 
subject at the disposal of the reader, and any general conclu- 
sions touching the question may well be reserved for such 
modification as may follow from more extended observation. 
The effect of varying exposure is less satisfactorily shown 
than that of varying height from drainage. Generally the 
direction of slope is given; but a sufficient number of obser- 
vations have not been included to make the presentation rep- 
resent the facts for more than a small part of the almost 
numberless variations in exposure, which result from the irreg- 
ularities of the drainage. Some very good illustrations of the 
effect of exposure, as regards direction, are found in the hills 
formed by the Waverly sandstone, which are sometimes knob- 
like, and, therefore, present a good example of varying ex- 
posure in a small field. 
The diagram on the following page, which is made up from 
observations on some of the knoblike hills on Triplet creek, in 
Rowan county, will serve to call attention to some of the facts 
which belong to this branch of the subject. Special investiga- 
tion in this direction would develop many interesting facts. 
The steepness of the surface, as well as the direction of 
exposure, has much to do with the distribution of species; and 
as the peculiarities of hill profiles may often be referred to the 
character of the rocks out of which the hills are carved, as it 
were, by the agencies of erosion, the effects of varying ex- 
posure are more or less intimately associated and blended with 
those effects which properly belong to the question of geolog- 
ical distribution. A discussion of the relation of the two 
phases of the subject may, therefore, be left for a fuller pre- 
sentation of the whole question. 
25 
