The salt industry of Cheshire may be divided into three periods, viz.: the natural brine period, the rock-salt period, and the prepared brine period. From Saxon times up to the last quarter of the seventeenth century the manufacture of white salt from brine had been continued without interruption, but the output had never been large. In 1675 the production of the three “Wiches” was returned at 20,000 tons, and all the evidence shows that the total annual make had never exceeded 30,000 tons. In 1670, rock-salt was discovered in the county, and for the next hundred years, although brine continued to be worked, rock-salt mining was the chief producing industry. With the collapse of the mines, the salt proprietors turned once more to the brine supply, upon which Cheshire has since risen to its present commercial eminence as one of the great salt-making centres of the world. In 1670, a rock of natural salt was discovered on the Marbury Estate, about one mile north of Northwich, by one John Jackson, of Halton, who was engaged at the time in “searching for coals on behalf of the Lord of the Soil (or Manor, I should say), William Marbury, of Marbury, Esquire.” The event was communicated to the Royal Society by Mr. Adam Martindale in a letter dated 12th December, 1670. He added that the liquid issuing from the rock was “a vigorous sharp brine beyond any of the springs made use of in our salt works,” and, being asked by the Royal Society to visit the place and send a further report, he subsequently wrote: “The rock of salt, by the relation of the workmen, is between 33 and 34 yards distant from the surface of the earth, about 30 whereof are already digged and they hope to be at the Flagg which covers the salt rock about three weeks hence.... That piece of natural salt which the instrument brought up (divers saw it, a pure ore) was as hard as alum and as pure.” The records of the rock-salt mining period are singularly incomplete, inexact, and disappointing. It is not known for certain which was the first mine sunk after the discovery of the salt-bed in 1670. It may have been the one which is described as “very near to a small brook which drains Marbury Mere and joins the Witton Brook, near the Buttevant Bridge on the Marbury Estate.” Or it may have been another early mine which was situated “close to a small runnel or gutter which runs into this small brook near the Dairy House Farm but passes across the land of Mr. Lyons and over the old Marston mine.” If the curious inquirer is not yet satisfied with these conjectures, he is further informed that there is yet another subsidence of an old mine, “close to the Forge Lane or road leading to Budworth across the Fields, where the road branches off at the cottages and salt-works of Mr. Lyons’ property ... and this mine is probably the earliest sunk.”