We have already in the first chapter considered this important question under the guidance of Professor T. G. Bonney, F.R.S. Let us sum up the conclusions, and from his facts try to picture the site of London before the city was built.
Here we have before us, first, a city of great antiquity and importance; beside it a smaller city, practically absorbed in the greater, but, as I shall presently prove, the more ancient; thirdly, certain suburbs which in course of time grew up and clustered round the city wall, and are now also practically part of the city; lastly, a collection of villages and hamlets which, by reason of their proximity to the city, have grown into cities which anywhere else would be accounted great, rich, and powerful. The area over which we have to conduct our survey is of irregular shape, its boundaries following those of the electoral districts. It includes Wormwood Scrubbs on the west and Plaistow on the east. It reaches from Hampstead in the north to Penge and Streatham in the south. Roughly speaking, it is an area seventeen miles in breadth from east to west, and eleven from north to south. There runs through it from west to east, dividing the area into two unequal parts, a broad river, pursuing a serpentine course of loops and bends, winding curves and straight reaches; a tidal river which, but for the embankments and wharves which line it on each side, would overflow at every high tide into the streets and lanes abutting on it. Streams run into the river from the north and from the south: these we will treat separately. At present they are, with one or two exceptions, all covered over and hidden.
Remove from this area every house, road, bridge, and all cultivated ground, every trace of occupation by man. What do we find? First, a broad marsh. In the marsh there are here and there low-lying islets raised a foot or two above high tide; they are covered with rushes, reeds, brambles, and coarse sedge; some of them are deltas of small affluents caused by the deposit of branches, leaves, and earth brought down by the stream and gradually accumulating till an island has been formed; some are islands formed in the shallows of the river by the same process. These islands are the haunt of innumerable wild birds. The river, which now runs between strong and high embankments, ran through this vast marsh. The marsh extended from Fulham at least, to go no farther west, as far as Greenwich, to go no farther east; from west to east it was in some places two miles and a half broad. The map shows that the marsh included those districts which are now called Fulham, West Kensington, Pimlico, Battersea, Kennington, Lambeth, Stockwell, Southwark, Newington, Bermondsey, Rotherhithe, Deptford, Blackwall, Wapping, Poplar, the Isle of Dogs. In other words, the half at least of modern London is built upon this marsh. At high tide the whole of this vast expanse was covered with water, forming exactly such a lovely lake as one may now see, standing at the water-gate of Porchester Castle and looking across the upper stretches of Portsmouth harbour, or as one may see from any point in Poole harbour when the tide is high. It was a lake bright and clear; here and there lay the islets, green in summer, brown in winter; there were wild duck, wild geese, herons, and a thousand other birds flying over it in myriads with never-ending cries. At low tide the marsh was black mud, and on a day cloudy and overcast a dreary and desolate place. How came a city to be founded on a marsh? That we shall presently understand.