London - Edward Rutherfurd [2]
THE RIVER
Many times since the Earth was young, the place had lain under the sea.
Four hundred million years ago, when the continents were arranged in a quite different configuration, the island formed part of a small promontory on the north-western edge of a vast, shapeless landmass. The promontory, which jutted out in a lonely fashion into the great world ocean, was desolate. No eye, save that of God, beheld it. No creature moved upon the land; no birds rose in the sky, nor were there even fish in the sea.
At this remote time, in the south-eastern corner of the promontory, a departing sea left behind a bare terrain of thick, dark slate. Silent and empty it lay, like the surface of some undiscovered planet, the grey rock interrupted here and there only by shallow pools of water. Under this layer of slate, deep in the Earth, pressures still more ancient had raised up a gently shelving ridge some two thousand feet high, which lay across the landscape like a huge breakwater.
And thus the place long remained, grey and silent, as unknown as the endless blankness before birth.
In the eight geological periods that followed, during which the continents moved, most of Earth’s mountain ranges were formed, and life gradually evolved, no movements of the Earth disturbed the place where the slate ridge lay. But seas came and departed from it many times. Some of these were cold, some warm. Each remained there for many millions of years. And always they deposited sediments hundreds of feet thick, so that at last the slate ridge, high though it was, became covered, smoothed over and buried deep below, with scarcely a hint that it existed.
As life on Earth began to burgeon, as plants covered its surface and its waters teemed with creatures, the planet began to add further layers formed from this new, organic life it had brought into being. One great sea that departed about the time of the extinction of the dinosaurs, let fall such a prodigious quantity of detritus from its fish and plankton that the resulting chalk would cover much of southern England and northern France to a depth of some three hundred feet.
And so it was that a new landscape came into being, above the place where the ancient ridge lay buried.
It was a different shape entirely. Here as other seas came and went, and huge river systems from the interior drained out through this corner of the promontory, the chalk covering became shaped into a broad and shallow valley some twenty miles across, with ridges to north and south, and opening out in a huge V towards the east. From these various inundations came further deposits of gravels and sands, and one, a tropical sea, left a thick layer of soft deposit down the centre of the valley, which would one day be known as London clay. These floodings and withdrawals also caused these later deposits to be formed into new, somewhat lesser ridges within the great chalk V.
Such was the place that was to be London, about a million years ago.
Of Man, there was still no sign. For a million years ago, although he walked upon two legs, his skull was still like that of an ape. And before he appeared, one great process had to begin.
The ice ages.
It was not the forming of frozen layers upon the Earth that altered the land, but their ending. Each time the ice began to melt, the ice-filled rivers began to churn and the stupendous glaciers, like slow-moving, geological bulldozers, gouged out valleys, stripped hills, and washed down the gravel that filled the riverbeds created by their waters.
In all the advances to date, the little north-western promontory of the great Eurasian landmass had been only partly covered by the ice. At its greatest extent, the ice wall ended just along the northern edge of the long chalk V. But when it did reach this far, about half a million years ago, it had one significant result.
At this time, a great river flowed eastwards from the centre of the promontory