The Mark degrees are of British origin, and have no connection with the Hautes Grades of the Continent. To according with Grand Lodge of Mark Master Masons constitution , Jewel of The Order is " Keystone with silver Lewis". //////////////////////////////////////////////////////// LEWIS http://www.standrew518.co.uk/home.htm This technical word has several explanations. 1. An instrument in Operative Masonry. It is an iron cramp or clamp which is inserted in a cavity prepared for that purpose in any large stone, so as to give attachment to a pulley and hook whereby the stone may be conveniently raised to any height and deposited in its proper position. It is well described by Gibson,in the British Archeologia (volume x, page 127), but he is in error in attributing its invention to a French architect in the time of Louis XIV and its name to that monarch- The contrivance was known to the Romans, and several taken from old ruins are now in the Vatican. In the ruins of Whitby Abbey, in England, which was founded by Oswy, King of Northumberland, in 658, large stones were discovered, with the necessary excavation for the insertion of a lewis. The word is most probably derived from the old French levis, any contrivance for lifting. The modern French call the instrument a louve. ////////////////////////////////////////////////////////////////////////////////////////// In U.S.A. and Canada keystone represent Royal Arch.