828 THK GEOGRAPHICAL SIGNIFICANCE OF FLOODS, 



the much moister eastern division of the State, the streams being 

 of the same age. 



C. Shoreline Studies. 



The ordinary heavy gale is unable to use the weapons of the 

 great storm of the century. Beneath the cliffs lie these great 

 storm-relics, unaffected by the ordinary storm-wave; in fact they 

 actually protect the cliff against the buffets of these lesser storm- 

 waves. Thus, to the unobservant, the strength of the grand 

 visitation is itself an evidence of flood-wave incompetency. Let, 

 however, the requisite velocity be again forthcoming and the 

 inertia of the flood-debris is once more overcome; the giant 

 recommences work; the rock-shelf undergoes corrasion; and 

 great sand-barriers are thrown up in spots removed from cutting 

 curves. But with the departure of the great gale its working 

 grade becomes too flat for smaller subsequent storm-currents to 

 work along, and aggradation of these flood-contours ensues, 



D. The Penejylain. 



The peneplain is formed, approximately, at sea-level. However 

 great the initial vertical relief, the streams make an early 

 attempt to reach baselevel. In the cafion stage, many basins 

 are formed actually below baselevel; with progressive reduction 

 of land-surface — all other conditions remaining constant — the 

 gravitative stream-thrusts become less. In extreme old age the 

 streams have no action below baselevel, and the peneplain con- 

 sists of a central system of very low undulating surfaces associated 

 with wide plains showing a very gentle fall to main baselevel. 



Summary. 



An examination of the flood-channel contours of ordinary 

 streams reveals many interesting and significant features. 

 Trenches with straight sides and terminating headward in basin- 

 shaped contours are of common occunence; the floors also of 

 tributary streams are slightly hung above the base of the main 

 stream, while the absence of spurs and alignment of banks or 

 miniature bordering cliffs is pronounced. Basins also with 



