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
Netherton Tunnel Branch Canal Netherton Tunnel Branch Canal Netherton Tunnel Branch Canal, in the English West Midlands, is part of the Birmingham Canal Navigations, (BCN). It was constructed at a 453–foot elevation, the Wednesbury or Birmingham level; it has no locks. The total length of the branch canal is and the canal tunnel is long. Netherton Tunnel was the last canal tunnel to be built in Britain during the Canal Age. The first sod was turned by the Lord Ward on 31 December 1855 and the canal opened on 20 August 1858, providing a waterway connection between the Black Country towns of Netherton and