In the course of searching for flınt ımplements in South Devon and Cornwall my attention has continually been drawn to notched and perforated pieces of slate—a notch and perforation occurring in combination in some specimens. At first I did not pay much attention to these slates, thınking that perhaps the notches had been caused through the piece having come into contact with an agricultural implement of some sort, and that possibly the perforations had been made by a fork, or else that they were pieces of roofing slate containing the hole through which the nail, originally securing the slate to a roof, had passed. After a time I determined to collect and study the specimens carefully, the result being that I soon found myself greatly interested, for it became evident that my first impressions were not correct, and that the notches and perforations were not accidental but clearly intentional. At the same time I was at a loss to understand their meaning and application.