The immense bodies of water in the neighbourhood of Northwich and Winsford, locally called “Flashes,” which cover a total area of many hundreds of acres, are the work of subsidences. The Flashes are not shallow swamps, but lakes varying in depth over many acres, from a few yards to 50 ft. The largest Flash, known as the Top of the Brook and resembling the letter =L= in shape, has a length in each arm of about half a mile, an average breadth of a quarter of a mile, and attains a depth of 150 ft. In an account of these subsidences, written in 1879, we read: “The whole of the surrounding district still sinks rapidly, and year by year the water covers more ground. The land subsides gradually here; but when we go a quarter of a mile to the north-east of the Top of the Brook, we come across a subsidence of a still more alarming character. Here the ground sinks bodily in immense masses to a great depth. A tiny brook or ditch that a child could skip across passed over flat fields some five years ago. Gradually the land began to sink, and cracks opened in the surface right across the course of the brook. The water went down the crevices. The land immediately sank more rapidly; huge cracks, wide enough for a man to slip down, formed, and very soon a district extending fully one thousand feet in length by as many in breadth, sank rapidly to a depth of forty or fifty feet in the centre, and was filled up to a certain height with water, which covered the hedges and trees. At times cracks opened in the bottom of this lake, and the whole of the water rushing rapidly below, caused still more extensive sinking.”