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Show 97 of ( pediment qediment ) ( brought broilght ) ( into hito ) the canyon section , and their height ( above aboye ) the normal ( water vater ) ( surface sia-face siaface ) ( indi hidir ) cates that such deposits could have been ( laid hilid ) down only during the most extreme floods . All ordinary floods cut these banks rather than add to ( tlieir their ) height . It seems evident , therefore , that these enormous flats or , in reality , bars , many of ( which Nrhich ) contain from ( 1 I ) to 5 million cubic yards , are the result of extreme floods and that except for side cutting and surface erosion they are fairly ( perma perma- perma ) ¬ nent for long periods of time . Their ( presence pTesence ) may . also be explained as a result of a change in flow ( conditions conditioiis ) resulting from changes in climate . In the canyon . sections we therefore have ( three tliree ) ( degrees degTeqs ) of permanency : ( Pirst First ) , the bed of the ( low-flow lowflow ) channel of ( which wbich ) ( the -the the ) crossing bars are a part which , to speak accu - ( rately Tately ) , is constantly shifting as the result of a ( rear rear- rear ) ( rangement angement ) of the finer materials of which it is made up and of the ( constant coustant ) addition of material brought into the section both in suspension and as bed load . Second the sand bars which lie ( from froni ) ( 1 I ) to 5 feet , above the water at ( low-flow lowflow ) stages and which are fairly permanent for periods between ( ordinary ordinaxy ) ( high-water highwater ) stages . ( Snch Ruch ) minor changes as take place consist of the gradual cutting ( and ancl ) ( sloughing slouglii-ng slougliing ) off along the edges and changes in ( surface SUTface ) ( config colifig- colifig ) uration due to wind . Third , the ( large laTge ) ( willow-covered willowcovered ) ( flats flat ) ( wliich -which which ) are ( permanent permanelit ) for long ( periods p9riods ) between exceptionally ( high bigh ) floods except for spasmodic cutting along their |