. Maryland geological survey. delta deposits were identifiedin all the principal rivers of the Middle Atlantic slope and were foundparticularly well developed in the valleys of the Potomac, Susquehanna,and Delaware. Due to the presence of these huge boulders, whichwere evidently ice-borne and indicated a climate much colder than existsto-day in the same region, as well as to the fact that the Columbia, whentraced northward, was found to pass under the terminal moraine, McGeeconcluded that it was Quaternary in age and belonged to the earlierglacial advance. These beds, since their deposition, h
. Maryland geological survey. delta deposits were identifiedin all the principal rivers of the Middle Atlantic slope and were foundparticularly well developed in the valleys of the Potomac, Susquehanna,and Delaware. Due to the presence of these huge boulders, whichwere evidently ice-borne and indicated a climate much colder than existsto-day in the same region, as well as to the fact that the Columbia, whentraced northward, was found to pass under the terminal moraine, McGeeconcluded that it was Quaternary in age and belonged to the earlierglacial advance. These beds, since their deposition, have been raised andtilted so that they now lie higher in the regions to the north than they dofarther south. Their present elevation was found to be about 500 feeton the upper Susquehanna and 245 feet at its mouth; 400 feet on theupper Delaware; 145 feet on the Potomac; 125 feet on the Rappahanrnock; 100 feet on the James, and 75 feet on the Eoanoke. McGee also MARYLAND GEOLOGICAL SURVEY. PLIOCENE AND PLEISTOCENE, PLATE Fig. i.—view from Baltimore and ohio railroad bridge, Susquehanna river,looking east, showing sky-line of lafayette surface on the highlands of elkneck, cecil county.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectpaleont, bookyear1901
