Penny Blood: Serial Sensation and Working-Class Entertainment — page 218: what you’re looking at

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

cu. xv.] COMPRESSION AND VOLCANIC ACTION. 201 that Prof. Nordenskidld does not make any reference to such injection of fluid rock into the earth’s crust. The ice upon a sheet of water that has been much skated on, after a few days’ frost assumes an appearance very much akin to that of a moderately disturbed area of the earth’s crust. This no doubt arises from the cracks which are formed, and by day are filled with water, which during the night freezes and expands, ridging up the ice on both sides of them. The trans- ference of sediment from one locality to another has an effect analogous to the irregular distribution of load by the skaters’ movements, and produces cracks opening upwards from below, carrying out the analogy. But besides the unequal pressure caused by local deposits of sediment, which must tend to crack the crust from below upwards, the mere contraction of sedimentary rocks, when they sink by becoming overloaded into hotter depths, and there become metamorphosed and assume a denser character, must cause them to crack during the process, It is to the opening of cracks from below that we now venture to attribute the sequence of operations which result in the corrugation of tracts of the earth’s surface. It necessarily follows that this action is the con- sequence of changing conditions, and is to be looked for where sediment is being deposited, and sedimentary rocks are becoming metamorphosed as along the shores of continents, rather than beneath the quiescent depths of the profound oceans, where the conditions are more fixed and changeless. Thus we are again led to regard compression as a continental phenomenon. Prof. James Hall, Dr Sterry Hunt, Prof. Joseph LeConte and other American geologists connect the exhibition of compression of the crust with those regions of the earth’s surface where thick sedimentary deposits have been previously laid down. Thus they conceive the corrugation of the Appallachian chain to have been a consequence of the extremely thick series of deposits of nearly the same age, of which that range consists. In the lecture already quoted’, Dr Sterry Hunt thus makes reference to a former publication by himself’: “The effects of heat and 1 p. 94. 2 ** American Journal of Science and Art,’’ May, 1861 (II., xxxr. 411). CONNEC OOO @ (CO)