PAPERS OX BIOLOGY AND AGRICULTURE 95 



their advance, driven by the prevailing westerly winds, 

 make greater inroads upon the western edge of the forest 

 than upon the eastern. Such destruction of trees and 

 tree seedlings lias been supposed to account for contrac- 

 tion of woodland areas along their western margins. In 

 order to test the truth of this hypothesis and to discover 

 whether the limits of the woodlands coincided with those 

 of the slopes of the stream valley, through the cour 

 of the State Forester, the junior author of this article 

 ran a number of sectional lines or transects from w« 

 east across the valleys of Little Indian Creek and Big 

 Indian Creek in groups of two or three at intervals of 

 from one-half mile to one mile. The position and extent 

 of one group of three of these lines are shown in Fig. 1. 



Along these lines the slope was determined accurately 

 by levels and the results have been reduced to uniform 

 scale, and a series of cross sections of the stream valleys 

 have resulted that exhibit graphically the relative width 

 and slope of the stream (Figs. 2, 3, 4). Each group of 

 sections may be considered independently. 



The sections A, B, and C across the valley of Little In- 

 dian Creek (Fig. 2) show that the valley is about 40 feet 

 deep and that an average of the three sections gi\ 

 strip of timber soil (formerly covered with forest) 1000 

 yards wide on the west slope and a corresponding strip 

 2300 yards wide on the east slope. Further, the limits 

 of the timber soil coincide exactly with the edge of the 

 stream valley. 



Another series of cross sections, D and E, from the 

 upper part of Big Indian Creek (Fig. 3) show a valley 

 30 to 35 feet deep with slopes 600 yards wide on the 

 and 1600 yards wide on the east. Here, too, the 

 angle of the western slope is decidedly greater than that 

 of the eastern and the coincidence of the vd^e of the 

 stream valley and the extent of the timber soil de- 

 cidedly marked. 



A third series, F. Gr, and H, come lower down the 

 stream where Big Indian Creek has been augmented by 

 the influx of the waters of the tributary. Tattle Indian 

 Creek, and the waters have cut into the underlying rock 

 (Fig. 4). Here the valley is about 80 feet deep, and the 



