Читать книгу Walking in London. Park, heath and waterside - 25 walks in London's green spaces онлайн

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The north bank was more favourable than the south as three little hills, now Ludgate Hill, Tower Hill and Cornhill, each rising barely 15 metres from the river, afforded some protection against flooding and perhaps some relief from insect life, which is why London’s core is where it is. To gain some idea of what the territory must have been like, look at the marshes around Tollesbury, just south of Colchester, a warren of mud, channels and islands through which progress is difficult to this day.

Then, as now, the Thames, rising 215 miles away in the Cotswold hills, drains much of south-east England, and is the longest river entirely within England. For the last quarter of its length, it runs across a flat plain of clay laid down around 50 million years ago and so specific of its type that it is known as London Clay. Bricks made from it are yellow, and easy to distinguish throughout the capital. But for agriculture London Clay mostly gives rise to poor, alkaline soils, and in prehistoric times the flood plain supported fishing and rough pasture but little in the way of crops.