For the past few weeks I have been busy processing wild clay.
Like most of Essex, my garden has clay soil. I was recently digging fairly deeply to level off a sloping area, and realised that if I dug deeply enough I would come to a layer of pure clay. In fact I found that the top soil went down about 6-12 inches, then there was around 12-18 inches of very clayey soil, then there was just yellow clay.
According to my research this is either the Claygate Beds which lie on top of the London Clay or boulder clay left behind by the Anglian ice sheet. Apparently a lot of the clay in this area were produced in the Eocene period, which was about 56 to 33.9 million years ago. I find this quite exciting, when I'm making my pots with the stuff!
If there are any geologists reading this who could explain the origins more fully, I would love to hear from them.