E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A primitive almanac or calendar, originally made of a clog, or log of wood, with four faces or parallelograms, the sharp edge of each face or side was divided by notches into three months, every week being marked by a big notch. The face left of the notched edge contained the saints days, the festivals, the phases of the moon, and so on in Runic characters, whence the clog was also called a Runic staff. These curiosities are not uncommon, and specimens may be seen in the British Museum, the Bodleian (Oxford), the Ashmolean Museum, St. Johns (Cambridge), the Cheetham Library (Manchester), and other places both at home and abroad.