Page:Cliff Castles and Cave Dwellings of Europe.djvu/24

 Crimea it reaches into Syria, and may be traced as far as the shores of the sea of Aral in Central Asia.

The chalk is not throughout alike in texture; hard beds alternate with others that are soft—beds with flints like plum-cake, and beds without, like white Spanish bread.

We are accustomed in England to chalk in rolling downs, except where bitten into by the sea, but elsewhere it is riven, and presents cliffs, and these cliffs are not at all like that of Shakespeare at Dover, but overhang, where hard beds alternate with others that are friable. These latter are corroded by the weather, and leave the more compact projecting like the roofs of penthouses. They are furrowed horizontally, licked smooth by the wind and rain. Not only so, but the chalk cliffs are riddled with caves, that are ancient water-courses. The rain falling on the surface is drunk by the thirsty soil, and it sinks till, finding where the chalk is tender, it forms a channel and flows as a subterranean rill, spouts forth on the face of the crags, till sinking still lower, it finds an exit at the bottom of the cliff, when it leaves its ancient conduit high and dry.

But before the chalk was tossed aloft there had been an earlier upheaval from the depths of the ocean, that of the Jurassic limestone. This was built up by coral insects working indefatigably through long ages, piling up their structures, as the sea-bottom slowly sank, straining ever higher, till at length their building was crushed together and projected on high, to form elevated plateaux, as the Causses of Quercy, and Alpine ranges, as the Dolomites of Brixen. But in the uplifting of this deposit, as it was inelastic, the strain split it in every direction, and down the rifts thus formed danced the torrents from higher granitic and schistous ranges, forming the gorges of the Tarn, the Ardêche, the Herault, the Gaves, and the Timée, in France.