Drainage Changes in the Moot^s Run Area 
223 
Discussion of drainage factors, as applied to this area. Scheffel 
has well explained in his paper, ^^Significance of Drainage Changes 
near Granville, Ohio,” that there are three important factors 
which may interfere with or infiuence the normal development of 
a drainage system: piracy, diastrophism, and glaciation. 
That glaciation has been the chief factor in the development of 
the Moot^s Run area is proved, we believe, by evidence of both a 
positive and negative nature. That there have been reversals 
of drainage, even a superficial examination will show. Let us 
consider in their order the infiuence of these three factors on the 
drainage development of the area. In the paper referred to 
above, Scheffel roughly groups the various forms of piracy under 
three heads: those due to topography, to stratigraphy, and to 
rainfall. 
Inadequacy of piracy, to account for these changes. The first is 
the form that is found under normal erosion. By the cutting back 
of its own headwaters one stream captures the headwaters of 
another, thus diverting a greater or less portion of its drainage 
system. That such has taken place in this region is inconceivable. 
There is no evidence of a contest between rival streams for suprem- 
acy in this drainage area. There is no well defined divide, which 
is usually present in such an area, and, what is more to the point, 
the streams which now occupy this area could not have accom- 
plished the excavation of the present gorges, a task which the 
theory of piracy would assign to them. Since this is the case, we 
need not dwell on the other causes of piracy, a differentiation in 
the structure and tilt of the rocks, or a differentiation in the dis- 
tribution of rainfall over the area, neither of which has been opera- 
tive in this section of Ohio. 
Inadequacy of diastrophism, to accomplish these changes. Since 
diastrophism has been so strongly urged as the chief influence in 
the drainage diversions of an adjoining region, its operation in 
the Moot’s Run area might be anticipated. 
Imagine a mature drainage system, with a medium-sized 
stream occupying its basin, into which several low gradient 
tributaries flow; this fairly represents the old Alexandria River 
and its tributaries. Now imagine a gradual tilting of the land 
along a north and south axis in the neighborhood of Alexandria, 
a mild rise but sufficiently rapid to prevent the stream from main- 
taining its direction by degrading its bed. What change in drain- 
