. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. XIX.] TRANSVERSE VALLEYS. 361 sand, and sometimes, also, the gault, crop out. This steep declivity, is the great escarpment of the chalk before mentioned, which overhangs a valley excavated chiefly out of the argillaceous or marly bed, termed Gault (No. 3). The escarpment is continuous along the southern ter- mination of the North Downs, and may be traced from the sea, at Folkestone, westward to Guildford and the neighborhood of Petersfield, and from thence to the te
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. XIX.] TRANSVERSE VALLEYS. 361 sand, and sometimes, also, the gault, crop out. This steep declivity, is the great escarpment of the chalk before mentioned, which overhangs a valley excavated chiefly out of the argillaceous or marly bed, termed Gault (No. 3). The escarpment is continuous along the southern ter- mination of the North Downs, and may be traced from the sea, at Folkestone, westward to Guildford and the neighborhood of Petersfield, and from thence to the termination of the South Downs at Beachy Head. In this precipice or steep slope the strata are cut off abruptly, and it is evident that they must originally have extended farther. In the wood-cut (fig. 358, p. 360), part of the escarpment of the South Downs is faithfully represented, where the denudation at the base of the declivity has been somewhat more extensive than usual, in conse- quence of the upper and lower greensand being formed of very inco- herent materials, the former, indeed, being extremely thin and almost wanting. The geologist cannot fail to recognize in this view the exact likeness of a sea-cliff; and if he turns and looks in an opposite direction, or eastward, towards Beachy Head (see fig. 359), he will see the same line Fig. Chalk escarpment, as seen hill above Steyning, Sussex. The castle and village of Bramber in the foreground. of heights prolonged. Even those who are not accustomed to specu- late on the former changes which the surface has undergone may fancy the broad and level plain to resemble the flat sands which were laid dry by the receding tide, and the different projecting masses of chalk to be the headlands of a coast which separated the different bays from each other. Occasionally in the North Downs sand-pipes are intersected in the slope of the escarpment, and have been regarded by some geologists as more modern than the slope; in
Size: 2701px × 925px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1868
