Many of the buildings in the town are built directly on to natural rock or have foundations cut into the rock. As a result there may be very little archaeological deposit or impression in overlying sediments.
This is particularly apparent towards the rise of the High Street known as the Rock. A C17th timber framed cottage is built on a stone plinth set on the sandstone. Similarly, buildings demolished on the site of the shopping precinct had rock-cut cellars. This would seem to be typical building practice from the C17th onwards, and perhaps earlier, using timber-framing and later brick, for the main structure.