Ham lies within the London Basin and its London clay bedrock.

For the scales investigated, results suggested that hydraulic conductivity, K, is independent of scale for relatively thick till and clay bedrock deposits.

Usually a brickworks is located on a clay bedrock (the most common material from which bricks are made), often with a quarry for clay on site.

Such areas are generally to the south of Southwell where the clay bedrock plateau made up of Mercia Mudstone is dissected by a number of streams, forming steep sided, wooded valleys.