Blisworth Limestone Formation today in the seas off the Bahamas (Kirkaldy p. 59). Much of it also contains marine shells, notably of oyster. Subsequently, the site was submerged less deeply so that the overlying Blisworth Clay was deposited in brackish conditions. (Gallois p. 20) The stratum is known as Blisworth Limestone because it was first studied at Blisworth in Northamptonshire when the Blisworth tunnel was being dug for what is now called the Grand Union Canal. The tunnel finally opened in 1805. Blisworth limestone is a generally thin but widely spread deposit in eastern England. It becomes thicker as one progresses southward from
Bruce Tunnel Bruce Tunnel The Bruce Tunnel is on the summit pound of the Kennet and Avon Canal between Wootton Top Lock and Crofton Locks in Wiltshire, England. This is the only tunnel on the canal and it is 502 yards (459 m) long. It is named after Thomas Brudenell-Bruce, 1st Earl of Ailesbury (1729–1814), the local landowner, who, when the canal was being built, would not allow a deep cutting through his land, and insisted on a tunnel instead. At the eastern end of the tunnel is a plaque commemorating its construction: The tunnel has red brick portals, capped with Bath