574 



MARIUS R. CAMPBELL 



Figures i to 4 are a graphic representation of the manner in 

 which such an uplift would affect the drainage and cause the 

 divide to migrate towards its axis. Let A, E (Fig. i) represent a 



Fig. I. 



Fig. 2. 



Fig. 3. 



Fig. 4. 



cross-section through the divide C separating two streams flow- 

 ing in opposite directions, the profiles of which are represented 

 by the curved lines A^ B, C and E, D, C. Let us suppose still 

 farther that the streams are balanced against each other, con- 

 sequently the profile will be symmetrical. It is evident that 

 the divide C will remain stationary unless some external cause 

 interferes to disturb the delicate balance now maintained. Sup- 

 pose that such an external cause elevates the strata at the point D. 

 Since we are dealing with the effect of local movements, we will 

 suppose that this movement extends each way only so far as the 

 points E and B. Now if the point D were elevated by the force 



