I took this photo of the excavations for the new house in Somerton Road at the end of May. This view of the soil is no longer visible.

The point is this: there was a layer of darker material in the soil, about 6 feet below the previous surface and just above the level of Somerton Road. Can someone tell me - was that a layer of Street's famous blue lias? It was not thick. I can think only in feet and inches, really, and I'd say it was about 9 inches thick.