Imagine yourself in a sand-pit in Stoke Newington in the 1860's. Around you are the four sides of the pit. The diagram shows three of these sides opened out. At the bottom are the horizontal strata neatly laid down by water. Above is an irregular mass of contorted drift. This is from the Ice Age.
The drift was not laid down by water, but by moving ice or frozen mud from the north.
It has ploughed through the land and, in some cases, pushed underneath the Floor.
Over long periods, the sea rose and fell. When it rose, the Thames and Lea valleys became marshy and flooded. Layers of material were deposited in the calm waters. Brickearth too was blown from the Continent and settled through the shallow water to form level deposits (layers B-M). In the Ice Ages, the glacier sheets pushed south, crushing everything in their paths. They stopped just north of Stamford Hill and large parts of the Palaeolithic floor are undamaged.
Besides the confusion caused by the drift, the cold caused other disturbances. On the edges of ice sheets, the cold penetrates deeply, shrinking and shattering the top few feet of soil. These periglacial (near a glacier) conditions are called crytourbation and have further split and distorted the section at 0.
The Upper Contorted Drift seals off all the relics of the Palaeolithic age. Man appears to have retreated in front of the advancing drift and cold. There is no evidence that Palaeolithic people ever returned.
|The Palaeolithic Hackney Brook