. Maryland geological survey . led with fresh or brackish-water marshes (Plate XX). In the upperportions of their courses the valleys are being eroded. In the lowerportions they are being filled. A glance at the map (Plate I) will serveto confirm the opinion which has been held for a long time, namely, thatthe riversof the Coastal Plain of Maryland have been drowned alongtheir lower courses, or, in other words, have been transformed intoestuaries by the subsidence of the region. The filling of these valleys hastaken place toward the heads of these estuaries (Plate XIX, Fig. 1).The headwaters o
. Maryland geological survey . led with fresh or brackish-water marshes (Plate XX). In the upperportions of their courses the valleys are being eroded. In the lowerportions they are being filled. A glance at the map (Plate I) will serveto confirm the opinion which has been held for a long time, namely, thatthe riversof the Coastal Plain of Maryland have been drowned alongtheir lower courses, or, in other words, have been transformed intoestuaries by the subsidence of the region. The filling of these valleys hastaken place toward the heads of these estuaries (Plate XIX, Fig. 1).The headwaters of these Eecent valleys are being extended inland towardthe divide with great rapidity. Many of the tributary streams occupy the reentrant valleys describedabove. The more energetic have succeeded in carrying out all of theancient floor which formerly covered these valleys and formed a portionof the various terraces. Others have left mere remnants of these valley MARYLAND GEOLOGICAL SURVEY. PLIOCENE AND PLEISTOCENE, PLATE FlG. I.—VIEW SHOWING SUNDERLAND-WICOMICO SCARP, WICOMICO surface in fore-ground, HUNTING CREEK VALLEY, CALVERT COUNTY.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectpaleont, bookyear1901
