Penny Blood: Serial Sensation and Working-Class Entertainment — page 237: what you’re looking at

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

220 GEOLOGICAL MOVEMENTS (cH. XVII. It is not however necessary to suppose that the roots of the elevated tract ever at any one time bore this proportion of p : «—p to the whole volume which has ultimately been denuded away; for this would not be the case unless the compression and accompanying elevation were due to a single effort. For if, after a part had been denuded off, and the roots of the mountain had been concurrently lifted up, a second period of compression had ensued, the neutral zone would then have had its position along a lower line of ‘particles, and the depression produced might not have been so great at the second as at the first effort. The same may be said of a third, or of any subsequent effort. In fact, according to the ordinary reasoning of the method of limits, we may, by diminishing the intervals and increasing their number, pass to the case of a continuous movement of elevation, growing less and less until it ceased altogether; denudation going on all the while at a greater rate than, except at first, material was brought up for it to act upon. If the tract were now to become free from farther com- pression, the sequence of events we have sketched out would be terminated by its being reduced in thickness approximately to the normal thickness of the crust in its neighbourhood. But its internal structure, as exhibited in sections, would betray the results of the treatment to which it had of old been sub- jected. It would form a nearly level tract, consisting of the lower parts of the folds of highly contorted rocks, which had been subjected to the action of a temperature probably above the critical temperature of water, and to great pressure. The sediment, which had been transferred from the tract thus denuded down, would some of it have probably been spread over low lying land, and some of it have gone out to sea, and formed marine deposits not very far from the shore. Hence if AB<ic AX<AZ that is the neutral zone will not be brought to the surface unless 4B> de. But AB is about 11 times the height of the mountain. Therefore the height of the mountain must have been ;',c, or say 10 miles, before denudation commenced, in order that the neutral zone should come to the surface. COMIC OOOKS.EO