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 Savernake Forest which is open to the public with footpaths, drives and picnic sites, hence the tunnel is also sometimes known as the Savernake Tunnel. The main Paddington to Penzance 'Berks and Hants' railway line crosses the tunnel diagonally; both portals can be seen from the windows of passing trains with the canal running close to the railway at each end. 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