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 Tividale Aqueduct. The northern mouth of the tunnel is near Dudley Road West, close to Tipton's border with Oldbury. An air-vent stands in the middle of Aston Road; another stands between two houses in Regent Road, both in the Tividale Hall estate near Dudley. The southern mouth of the tunnel is in Warrens Hall Park on the border of Dudley and Rowley Regis - the Bumble Hole and Cobb's Engine House are nearby. The Bumble Hole is a landscaped man made lake on the site of a former clay pit. The Dudley No. 2 Canal and the Boshboil Canal Arm