We learn with surprise that an earthquake shock in distant San Francisco or in the inhospitable regions of Turkestan has recorded itself through the delicately-poised recorder at Helwan, long before the dire news of destruction has flashed along the telegraph wire to the same destination. There is a realization of the instability of the earth’s crust, in spite of the solidarity of its component parts, but though the sudden shocks bring home this truth, it is not so readily grasped that day by day and hour by hour parts of the earth’s crust are slowly rising and others sinking, offering stern problems to the dwellers on the shores where these changes are most markedly taking place. On the eastern shores of England, towns and forests are being submerged beneath the relentless advance of the sea; on the coasts of the Scandinavian peninsula, etc., on the other hand, beaches formerly beneath the sea now stand high above the influence of its waves, and in Egypt coral-reefs which once grew beneath the waters of the Red Sea rise in places to over two hundred metres above it in bold hills or steep-sided terraces. Though possibly of far greater importance and significance than the sudden convulsions which have left so deep an impression on the mind of man, these movements are nevertheless so imperceptible that they arouse little attention. A second type of deformation is noted where heavy masses of one rock rest on other and softer materials. The underlying beds are then often compressed and contorted; clays, for instance, are drawn out into thinner laminæ, giving rise to shales, while the massive rocks above either slip on the surface of the lower ones, if these be impermeable, and so permit of a water-layer forming along the junction, or else descend by sheer weight, producing a confused area of mixed materials in front of the still unshattered cliffs. Examples of this nature abound in Egypt wherever the Eocene limestones rest on the Cretaceous clays; on the railway from Armant to Matana the resulting effects are well observed near Shagab. Here in the main cliff the massive limestones are seen resting on the soft bluish clays, while in front is a wilderness of low hills in which limestones and clays are mixed, broken and contorted. But while these deformations may be irregular and local, there remain greater pressure-effects which have been regional in character, and by whose agency the solid rocks have been folded in the most remarkable manner, strata once horizontal being thrown into arches, or anticlines, and basin-like curves, or synclines. The importance of these changes cannot be over-estimated, and some of the marked features of Egyptian scenery depend directly on these effects. Reference has already been made to the slope of the Pyramid plateau, but the character of Egypt in far broader outline depends on the results of these pressures and the foldings so produced. A glance at the map suffices to show that