If you draw a straight line from 'Stanegate,' close to the end of Westminster Bridge, as far as the beginning of the Old Kent Road, you will understand the lie of the causeway. And this causeway, understand, was the very first interference of the hand of man with the marshes south of the Thames. It was a way across the marsh: not an embankment against the river, but a way. It did not keep out the tide which flowed in on the other side--the Battersea side: it was simply a way across the marsh. For a long time--we cannot tell how long--it remained the principal way of communication for the trade of Britain between the north and the south, the midland and the south, the eastern counties and the south. [Illustration: Causeway across Southwark Marsh.] Consider, next, the site of London, as it appeared to the merchants crossing the causeway. They saw, in the centuries of which no trace or memory remains, when they turned their eyes northward, first a level of mud, sprinkled with little eyots of reed and coarse grass, then the broad river, and beyond the river two streams, one fuller than the other, each in its own valley--that of the Walbrook was 132 feet wide at the present site of the Mansion House--falling into the river; a low cliff ran along the north bank, leaving stretches of marsh, as on the south, but, where these streams ran into the Thames, approaching close to the river, and actually overhanging it. On the river they saw numerous coracles, with fishermen catching salmon and every kind of fish in their nets. No river in the world was more plentifully stocked with fish; overhead flew screaming innumerable birds--geese, ducks, herne--which the trappers trapped, snared, shot with sling and stone by the thousand. On those cliffs overhanging the river, the travellers by the causeway saw the huts of the fisherfolk. Then, perhaps, they remembered the plenty of the markets of Thorney; the abundance of birds, the vast quantities of fish offered on those stalls. Those who were curious connected the coracles on the river and the birds that flew up from the lowlands with these markets; they saw that London--'the place or fort over the Lake'--was the settlement which furnished Thorney with a good part of her supplies. And this I verily believe to have been the real origin and cause of London. It was first settled by the humble folk who came here for the purpose of catching fish and trapping birds for the market of Thorney. This is a suggestion only; it will be set aside, most certainly, by those who are not pleased with the upsetting of old theories. To those who are able to realise the ancient condition of things and all it means, the suggestion will be received, I am convinced, as more than a theory: it will be regarded and accepted as a discovery.