Tallis, John (1839). A comprehensive gazetteer of Gravesend with its environs being a complete guide for visitors...to which is added a general directory of Gravesend and illustrations on steel. London: John Tallis. ASINBX88036852. Known as the Tallis Directory
Orr, William (London: 1847) Summer Excursions in the County of Kent along the River Thames and Medway, quoted in Barnard, Derek (1999) One Leg in the Water.Archived 12 March 2007 at the Wayback Machine Accessed 2007-30-01Barnard's article includes a diagram of the tunnel with the railway suspended above it.
Orr, William (London: 1847) Summer Excursions in the County of Kent along the River Thames and Medway, quoted in Barnard, Derek (1999) One Leg in the Water.Archived 12 March 2007 at the Wayback Machine Accessed 2007-30-01Barnard's article includes a diagram of the tunnel with the railway suspended above it.