Penny Blood: Serial Sensation and Working-Class Entertainment — page 230: what you’re looking at

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

CH. XvI.] ON FAULTING. 213 horizontal compression would be effected by faulting. The features produced by this kind of movement would therefore be superimposed upon the features previously or subsequently determined by compression and consequent corrugation. The blocks into which the strata were cut up would on the whole follow the “lie” of the country as previously or con- vomitantly determined by the forces of compression, a general law thus lucidly enounced by Prof. Green: “We find that we can account for the observed facts only on one supposition, and that is, that the rocks have been folded into a serves of troughs and arches, or thrown into domes and basins. This is the great general law which governs everywhere the arrangement of the disturbed portions of the earth’s crust. Faulting, or violent contortion and inversion, often complicate and obscure this structure and interfere with its symmetry, but never to such an extent as to prevent its being recognised as the great leading 1 99 feature in the arrangement of the rocks’. Faults occur of very different extent of throw, varying from a few inches to many fathoms, or even miles. In Captain Dutton’s “Geology of the High Plateaus of Utah” we read of displacements by faulting of 5,500, 1,800, 12,000, 4,000, and 7,000 feet. Prof. Bonney tells us that the perhaps largest known fault in the world is in the Appalachian Chain, where, on opposite sides of a crack over which a man can stride, beds are brought together that were once 20,000 feet apart’. It is of course possible that a fault may cut quite through the earth’s crust, and indeed where the throw 1s so great as to be measured by several thousand feet, as in some of the larger faults referred to, 1t 1s scarcely conceivable that it should not do so, if our estimate of about 25 miles for the thickness of the crust is correct. If however the fault originate in a fissure formed by the contraction of the strata near the surface, and they settle together as the fissure extends downwards, thus forming wedge-shaped blocks, broader at the top than the 1 «Geology for Students and General Readers,”’ 1876, p. 374. 2 Chap. 11. $ ‘¢‘ Manuals of Elementary Science. Geology.” §.P.C.K. 1874, p. 43. GONG oOo SS (CO)