Penny Blood: Serial Sensation and Working-Class Entertainment — page 68: what you’re looking at

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

CH. V. | ELEVATIONS AND DEPRESSIONS. 5I should have been a level surface, and that it is at present what we see it to be. Another point to which the reader’s attention is requested is that no assumption whatever has been hitherto made either as to the amount of contraction or of compression, except that the latter is small compared to the dimensions of the area com- pressed. The rude diagrams, which have been used in proving our equation, are not supposed to represent any thing in nature. This appears to be the proper place for considering the manner in which the results of the deposition of sediment over a limited area would enter our equation. Geologists believe thick deposits to have been accumulated upon sinking areas, and attribute the subsidence of the area to the weight of the deposit itself. If rocks, liquid or plastic from heat or any other cause, come within a moderate distance of the surface this is possible, and many instances both among ancient strata and modern river deposits seem to be explicable on no other hypothesis. But the displacement of such plastic matter from beneath the new deposit must cause the rise of an equal volume somewhere else, so that if the terms of our equation were in any way affected (which would depend upon whether the effect extended below the datum level) it would be by an addition to the tenm > (8), and a consequent equal addition to 2(a), and their sum would be zero. So that, as already intimated, our equation will in- clude any such effect of denudation and the resulting deposition. _ Such an action as has been just referred to would produce a slight amount of crumpling in the strata. but only a very slight one, unless the new deposit sunk through some subjacent strata, and pressed them sideways out of its way; as the Author has shown to have happened in the contorted drift of Norfolk’. But it is only possible for this to have happened where the de- posit produced a very much greater pressure upon the area which it occupies, than the rocks displaced by it did; that is when it is very much thicker than they were. And it is clearly impossible that it should elevate any displaced strata to a greater altitude 1 “*Geol. Mag.,” Vol. v. p. 550. 4— 2, GONG oOo SS (CO)