The Sunday Stone of the Oxford Museum

This is a large stone taken from a colliery-drain, and is remarkable in that it constitutes a perfect calendar of Sundays and holidays.

The stone is composed of carbonate of lime. When the miners were at work, the water running through the drain left a deposit colored black by coal-dust; but when they were not at work, the water ran down clear, and left a white deposit. In time these black and white layers made a stone of considerable thickness, which constitutes quite a calendar.

Each day of work has left a black streak, which is followed by a white streak left during the night. Wide white streaks mark the Sundays and other holidays, and from this circumstance the stone is called "The Sunday Stone."