178 J. D. Dana—The flood from the melting Glacier. 
ing cut exhibits at @ a portion of the previous deposit of fine 
sand, projecting up and enveloped in the coarse gravel that the 
tearing waters were bearing along down stream. 
Thus the great flood left its mark not only in the structure 
and degree of coarseness of the deposits along the water- 
courses, but also in denudations of the drift-covered surface. 
flowing waters often denuded the surface deeply and left the 
else the broad bed of the flooded stream. 
es, whe 
only by such a flood. Both Mill River and West River val- 
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geet 
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