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You know the gravel-pit itself; and all the upper soils and gravels, which are spread over the length and breadth of the country to the north. There is a third world.

Let us take them one by one.

First, the chalk.

The chalk-hills rise much higher than the surrounding country; but you must not therefore suppose that they were made after it, and laid on the top of it. That guess would be true, if you went south- east from here toward the Hind Head. The chalk lies on the top of the sands of Crooksbury Hill, and the clays of Holt Forest; but it dips underneath the sands of Shapley Heath, and the clays of Dogmersfield, and reappears from underneath them again at Reading.

Thus you at Odiham stand on the edge of a chalk basin; of what was once a sea, or estuary, with shores of chalk, which begins at the foot of the High Clere Hills, and runs eastward, widening as it goes, past London, into the Eastern Sea. Everywhere under this great basin is the floor of chalk, covered with clays and sands, which, for certain reasons, are called by geologists Tertiary strata.

But what has this to do with a gravel-pit?

This first. That all the flints in this pit have come out of the chalk. They are coloured, most of them, with iron, which has turned them brown; but they are exactly the same flints as those gray ones in the chalk-pit on the other side of the town.

How do I know that?

I think our own eyes will prove it: they are the same shapes, and of the same substance; but as a still surer proof, we find exactly the same fossils in them; sponges, choanites (which were something like our modern sea-anemones), corals, and “shepherds’ crowns” as the boys call the fossil sea-urchins. The species of all these, and of other fossils, in the chalk-pit and in the gravel-pit, are absolutely identical. The natural conclusion is, then, that the gravel has been formed from the washings of the chalk. The white lime of the chalk has been carried away in water by some flood or floods; the heavier flints have been left behind.

Stop now one moment, and think. You all know how very few flints there are in the chalk-pit, in proportion to the mass of chalk. You all know what vast gravel-beds cover the country to the north, and often to the thickness of many feet. Try and conceive, then, what a much more vast mass of chalk must have been washed away, to leave that vast mass of gravel behind it.–Conceive? It is past conception. I will but give you two hints as to its probable size.

The chalk to the eastward, between here and Farnham, is a far narrower and shallower band than anywhere else in England. Its narrowest point is, I believe, beneath the bishop’s palace at Farnham, where it may be a hundred feet thick, instead of several hundred, as it usually is in other parts of England. The cause of this is, that the whole of the upper chalk has been washed away, to form the gravel-beds to the north and east of us.

Again. Some of you may have been on the Hind Head or on Leith Hill, and have looked southward over the glorious prospect of the rich Weald, spread out five hundred feet below–a sight to make an Englishman proud of his native land. Now, the mass of chalk which has been carried away began behind you, at the Hogsback, and the line of chalk-hills which runs to Boxhill, and stretched hundreds of feet above your head as you stand on Hind Head or Leith Hill, right over the old Weald of Sussex to the chalk of the South Downs. And out of the scourings of that vast mass of chalk was our gravel-pit made.