FLAG or SLATE STONE, common in Northumberland and some of the neighbouring counties, is called by some the Carlisle flag. Its strata are very thick; but they sometimes separate into laminae of about half an inch thick, and the workmen seldom attempt to split it any thinner: the upper strata, however, grow gradually thinner. The bottom ones are so thick, that they cannot be made use of for slates; but are used for tanners vats, the pavements of floors, and cisterns for water.