. Shore processes and shoreline development . l. While it seems to thewriter that as a general proposition this assumption is untenable,we may temporarily grant its reasonableness for sake of argument,providing it refers to a youthfully or maturely dissected landmass. As the land wears lower and the streams become moresluggish, the latter will bring to the sea a decreasing amount ofsediment, an increasing proportion of which will be carried insuspension and so will be borne out to deep water withoutpausing in the vicinity of the shores. The forces of marineerosion and transportation will event
. Shore processes and shoreline development . l. While it seems to thewriter that as a general proposition this assumption is untenable,we may temporarily grant its reasonableness for sake of argument,providing it refers to a youthfully or maturely dissected landmass. As the land wears lower and the streams become moresluggish, the latter will bring to the sea a decreasing amount ofsediment, an increasing proportion of which will be carried insuspension and so will be borne out to deep water withoutpausing in the vicinity of the shores. The forces of marineerosion and transportation will eventually remove the depositswhich impeded wave attack during an earlier part of the fluvialcycle of land dissection, and once more the relentless encroach-ment of the sea will be manifest. Under the assumption leastfavorable to wave erosion, therefore, the progress of marineplanation cannot be stopped by river-brought sediment. Itcan only be delayed. Deltas may be built seaward against the VALIDITY OF THE THEORY OF A MARINE CYCLE 241 Plate Photo by S. TF. of monadnock iii Plate XXIX, showing effects of marine erosion. 242 DEVELOPMENT OF THE SHORE PROFILE weves for a time, and help to keep parts of the shoreline young;late-mature coasts are delta-free. The direct effects of river sediments in preventing cliff erosionhave been exaggerated, as intimated in the foregoing the mouth of many rivers it is perfectly apparent that theriver deposits are directly shielding the cliffs from wave active clifRng is going on along many other coasts in spiteof the fact that numerous streams enter the sea through valleysopening in the face of the cliffs; while long stretches of coasthave enormous accumulations of beach deposits demonstrably notof fluvial origin. When we come to consider the deposits in theoffshore zone, however, it is probable that greater importancemust attach to stream-brought sediments, and that indirectlythey may play an important ro
Size: 1358px × 1840px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisheretcetc, bookyear191
