Close to the inner margin of the King's Ditch at Cambridge, which until quite recently was the only ditch known to exist, excavations were lately made for the foundations of Messrs. Fosters' new bank. The ditch which runs along Hobson Street was only just touched, but there was at this spot a large quantity of sand and gravel. This had apparently been thrown out of the ditch, which here skirted the edge of an extensive gravel bed. No water passed through this dry subsoil from any side, and the area was soon built over, so that no rain fell into it. These were, therefore, conditions very favourable for the preservation of perishable materials