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
Sapperton Canal Tunnel Sapperton Canal Tunnel The Sapperton Canal Tunnel is a tunnel on the Thames and Severn Canal near Cirencester in Gloucestershire, England. With a length of 3,817 yards it was the longest canal tunnel, and the longest tunnel of any kind, in England from 1789 to 1811. Although the Thames and Severn Canal was authorised by an Act of Parliament on 17 April 1783, the details of the tunnel had not been worked out, and arguments about its size continued for two or three months. Boats on the Severn were trows and were wide, while those on the Thames were Thames