In this subsoil, evidence of Colonial period buildings still exist. Several buildings have been identified at London Town which date from this period. Carpenters built the earth fast structures upon wooden posts which were sunk three to four feet into the ground. Discolorations in the clay subsoil are the identifiable remains of these support posts. Archaeologists locate and outline these structures by mapping post holes.
Archaeological evidence is used to determine the kind of structure that once stood on the site.