Penny Blood: Serial Sensation and Working-Class Entertainment — page 236: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

CH. XVII. | EXPLAINED. 219 advantage, that it brings the phenomena of faulting, that other form in which the disturbances of the ‘earth’s crust are manifested, into harmony with those of compression, attributing both to the same ultimate cause. The reader is however re- quested not to consider the suggestions last offered, regarding the cause of compression, to rest on so firm a foundation as the results arrived at concerning the existence of a fluid sub- stratum, and of the characteristic duplex shape of the corrugations formed in the crust by compression, let the causes of it be what they may. We will now trace somewhat further than was done in the tenth chapter, the results of denudation and of additional com- pression upon an elevated tract constituted thus, and compare them with natural appearances. It is evident that, as the upper and exposed part of the chain is degraded, the equili- brium will be roughly speaking restored by the whole mass being lifted up, so that the part above the effective level of the fluid should hold approximately the same ratio as before, that of c—p : p, to the part below it. Consequently, before a mountain chain can be completely levelled down, not only must the originally elevated portion be degraded, but the crust beneath must also be lifted up and brought under the influence of the denuding agents, possibly down to the neutral zone, and the whole of the material so removed converted into sediment, and transferred to some lower level’. * -1 To determine to how great a depth denudation might be ex- pected to expose the crust, suppose that A is the crust of a corru- gation, and B the bottom of the corresponding protuberance, Z the place of the neutral zone; and let X be the point that is ultimately brought to the surface by denudation. We have concluded that, AZ=2AB, and ZB=3AB. Now if X is ultimately brought to the surface, B will at the same time be brought to the lower mean level. Hence AB=ce. L [| my And therefore AX=AB-—c=32AB+3AB-ce =AZ+#(AB-— 5c) ; | —Z AX —-AZ=}(AB — 5c). COLA @ NOO (CO)