History of Northwich were looking for coal, but instead discovered rock salt, in the grounds of the family home, Marbury Hall, to the north of Northwich. Soon salt mining started again. This mining area is now known as Dairy House Meadow. By 1732 the River Weaver was improved from Frodsham Bridge to Winsford Bridge and eventually allowed vessels up to to travel up to Northwich Bridge. This allowed salt to be transported by boat rather than cart. The Trent and Mersey Canal, opened in 1775, passed to the north of Northwich because of objections from the trustees of the Weaver Navigation. However, the
Blue John (mineral) Blue John (mineral) Blue John (also known as Derbyshire Spar) is a semi-precious mineral, a form of fluorite with bands of a purple-blue or yellowish colour. In the UK it is found only at Blue John Cavern and Treak Cliff Cavern at Castleton in Derbyshire. During the 19th century, it was mined for its ornamental value, and mining continues on a small scale. Deposits of fluorite have been recently found in China with colouring and banding similar to the classic Blue John stone. The most common explanation for the name is that it derives from the French "bleu-jaune", meaning 'blue-yellow'.