THE WORK OF RUNNING WATER. 175 



of greatest elevation (AB, Fig. 166) was nearly parallel to the Appala- 

 chian River, and the effect of the differential uplift was to impose a 

 greater task on this river {a, Fig. 166), which flowed along the axis of 



FiQ, 167. — A stage later than that shown in Fig. 166. The sea is represented as 

 having withdrawn from a considerable area which was submerged at earlier stages 

 (Figs. 165, 166). 



uplift, than upon the rivers which flowed westward and south west ward 

 to the Mississippi embayment. The result was that the strongest of the 



