Or again, you might find that your town's pebbles and boulders came out of a pit of clay, in which they were stuck, without any order or bedding, like plums and raisins in a pudding. This clay goes usually by the name of boulder-clay. You would see such near any town in Cheshire and Lancashire; or along Leith shore, near Edinburgh; or, to give one more instance out of hundreds, along the coast at Scarborough. If you walk along the shore southward of that town, you will see, in the gullies of the cliff, great beds of sticky clay, stuffed full of bits of every rock between the Lake mountains and Scarborough, from rounded pebbles of most ancient rock down to great angular fragments of ironstone and coal. There, as elsewhere, the great majority of the pebbles have nothing to do with the rock on which the clay happens to lie, but have come, some of them, from places many miles away. Now if we find spread over a low land pebbles composed of rocks which are only found in certain high lands, is it not an act of common sense to say--These pebbles have come from the highlands? And if the pebbles are rounded, while the rocks like them in the highlands always break off in angular shapes, is it not, again, an act of mere common sense to say--These pebbles were once angular, and have been rubbed round, either in getting hither or before they started hither? Does all this seem to you mere truism, my dear reader? If so, I am sincerely glad to hear it. It was not so very long ago that such arguments would have been considered not only no truisms, but not even common sense. But to return, let us take, as an example, a sample of these boulder clay pebbles from the neighbourhood of Liverpool and Birkenhead, made by Mr. De Rance, the government geological surveyor: Granite, greenstone, felspar porphyry, felstone, quartz rock (all igneous rocks, that is, either formed by, or altered by volcanic heat, and almost all found in the Lake mountains), 37 per cent. Silurian grits (the common stones of the Lake mountains deposited by water), 43 per cent. Ironstone, 1 per cent. Carboniferous limestone, 5 per cent. Permian or Triassic sandstones, i.e. rocks immediately round Liverpool, 12 per cent.