Annual report ..[bulletins and circulars] . s, for anything thattends to check the currentmakes it drop some of thesediment that it carries(Fig. 83). Yonder is an oldtree stump with its crookedroots caught fast on thebottom ; the mid-streamcurrent rushes against itonly to be thrown back in aboiling eddy and the waterssplit in twain and flow by oneither side with their cur-rent somewhat the rear of the stump isa region of quiet waterwhere the brook is build-ing up a pile of on, the banks of thebrook are low and here thewaters no longer remain inthe channel, but overflo
Annual report ..[bulletins and circulars] . s, for anything thattends to check the currentmakes it drop some of thesediment that it carries(Fig. 83). Yonder is an oldtree stump with its crookedroots caught fast on thebottom ; the mid-streamcurrent rushes against itonly to be thrown back in aboiling eddy and the waterssplit in twain and flow by oneither side with their cur-rent somewhat the rear of the stump isa region of quiet waterwhere the brook is build-ing up a pile of on, the banks of thebrook are low and here thewaters no longer remain inthe channel, but overflowthe low land spreading outon either side in a broadsheet. The increased friction of this larger area reduces the cur-rent and again we see the brook laying down some of its sand and gravel deposited here is spread out in a flat plain called2i flood plain because it is built up when the stream is in flood. Itis on the large flood plains of rivers that many of our richestfarm lands occur. These receive a fresh coating of soil mixed. 83.—A pile of brook debris depositedby the checking of the current 125 with fragments of vegetable matter each spring when the streamis in flood, and thus grow deeper and richer year by year. Theflood plains of the Mississippi and the Nile are notable examplesof this important form of stream deposit. And now let us make one more rainy day observation beforegoing back to our warm, dry homes. Just ahead on the otherside of that clump of alders and willows lies the pond into whichthe brook flows and where its current is so checked that it givesup almost all of its burden of sediment. Close to the shore ithas dropped its heaviest fragments while the sand and clay havebeen carried farther out,each to be dropped in itsturn, carefully assorted asto size and weight. Hereyou can see that the streamhas partly filled this end ofthe pond and is now send-ing its divided current outover the deposit which ithas made in a series ofbranching rivulets. This
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherithac, bookyear1899
