374 



GEOLOGY. 



Topography of shallow-water deposits. — The shallow-water deposits 

 have, on the whole, a rather plane surface, though there are some notable 

 departures from flatness. The steep slopes of the delta fronts and of 

 wave-built terraces have already been spoken of. Barriers often shut 

 in depressions, and the disposition of the material deposited is some- 

 times uneven, owing to shore and tidal currents. The result is that the 

 surface of the shallow-water deposits is often affected by low elevations 



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Fig. 329. — Irregularities of topography of shallow-water deposits. The depths of the 

 water are shown in fathoms. (Chart of C. and G. Surv.) 



and by shallow depressions. The elevations and depressions may be 

 elongate, circular, or irregular in form. These general facts are shown 

 in Figs. 319, 320, and 329. This topography is sometimes preserved 

 bn newly emerged lands, as at various points on the Coastal Plain of 

 the United States. 



