. Maryland geological survey . hroughout the region as a whole there are distinguishable two typesof descent between the Lafayette and Sunderland terraces. The one typeis confined to the Piedmont Plateau, the other to the Coastal Plain, or, MARYLAND GEOLOGICAL SURVEY 69 in other words, when the Lafayette terrace lies on the Piedmont Plateauand the Sunderland terrace rests beneath it either on the Piedmont orclose to its eastern border, the descent from one surface to the other isusually considerable and is accomplished by a topography of low, subdued,rolling hills which pass down from the Lafa
. Maryland geological survey . hroughout the region as a whole there are distinguishable two typesof descent between the Lafayette and Sunderland terraces. The one typeis confined to the Piedmont Plateau, the other to the Coastal Plain, or, MARYLAND GEOLOGICAL SURVEY 69 in other words, when the Lafayette terrace lies on the Piedmont Plateauand the Sunderland terrace rests beneath it either on the Piedmont orclose to its eastern border, the descent from one surface to the other isusually considerable and is accomplished by a topography of low, subdued,rolling hills which pass down from the Lafayette terrace, occupyingsuccessively lower and lower areas until they finally blend with the surfaceof the Sunderland terrace beneath. This type of descent may be seenalong the eastern border of the Piedmont Plateau between Cecil countyand the District of Columbia (Fig. 3). The other type of descent isfound wherever the Lafayette and Sunderland terraces approach each lafayette forMat,on LAFAYETTE-SUNDERLAND SCARP PIEDMONT TYPE. SUNDERLAND FORMATION Fig. 3.—Diagram showing Piedmont type of Lafayette-Sunderland scarp. other in the Coastal Plain. It may be described, as suggested above, asbeing an abrupt descent resembling a wave-cut cliff which has since beenmodified to a greater or less extent by subaerial erosion (Fig. 4). Thebest localities for observing this type are to be found at Congress Heightsjust south of the Anacostia river in the District of Columbia, near Bryan-town and Aquasco in Charles county, and at Charlotte Hall in St. Maryscounty (Plate V). Two only of these localities need be described. AtCongress Heights the surface of the Lafayette terrace lies at an elevationof about 260 feet and that of the Sunderland at about 200. The descentbetween the two is accomplished by a cliff which is one of the most con-spicuous features of the region and, in fact, of the entire Coastal , as one stands on the unbroken Sunderland surface facing east, he 70 THE PLIOCE
Size: 2643px × 946px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectpaleont, bookyear1901
