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
Dudley Tunnel Dudley Tunnel Dudley Tunnel is a canal tunnel on the Dudley Canal Line No 1, England. At about long, it is now the second longest canal tunnel on the UK canal network today. (Standedge Tunnel is the longest, at , and the Higham and Strood tunnel is now rail only). However, since the Dudley Tunnel is not continuous this status is sometimes questioned: (the main tunnel is , Lord Ward's tunnel is and Castle Mill basin is ). In 1959 the British Transport Commission sought to close the tunnel but this led to an Inland Waterways Association-organised massed protest cruise