A NOTE .ON THE MIGRATION OF DIVIDES Sil 
divide, C, and the point E, is similar to the last in the movement 
of the crest of the faulted block toward D, or away from the line 
of faulting. In the former case, however, the initial movement 
(for the fault-block) was toward the fault-line, while in this case 
that feature is eliminated, as the faulted portion D" E excludes 
iG. 2: 
the original divide C. In this second case, this movement of 
the crest of the block D’ D" E is thus away from the divide, C, 
also, and the final result of the uplift is the establishment of a 
divide for the crust-block, at some point betwen D’ and E, 
depending on the relative attitude of these two points. 
If the faulting has been sufficient this resultant divide will 
form the main watershed for the region, the original divide, C 
being now of insignificant proportions. The faulting may, 
however, be such that the portion ABCD cannot be left out of 
account. If, as shown in Fig. 2, the final position of ABC D is 
more elevated than its original position, the slope CD will have 
been decreased, while ABC will have been slightly increased. 
As a consequence there will be a migration of C’ toward D’. 
If the faulting is sufficient in amount, the migrating crest will 
finally reach D’, and there will be no divide other than that of 
the faulted block, D’ D” E. As the movement of the crest-line 
in this case is toward E for the parts on both sides of the fault- 
line, the resultant crest must be at some point between C’ and E, 
whether the amount of faulting be great or small. 
If, on the other hand, the movement of ABCD is one of 
depression (Fig. 3), the result is more complicated, and the 
final position of the crest C’ will depend on the relative attitudes 
of the faulted portions AB’ C’ D’ and D’ D" E._In other words, 
if the sum total of movement in the two parts produces eleva- 
tion, the migration of the divide will be in the direction of E, 
