FEUDAL FRANCE. Blois, anonymous Silver Denier, 12th to 13th Century, 21mm, 1.1g, obverse; stylised head facing right, reverse; + BLESIS CATRO, large cross. D'Avant-1689, Roberts-5056, F
References;
Faustin Poey D’Avant, Monnaies Féodales de France , Graz, 1961.
James N. Roberts, The Silver Coins of Medieval France (476-1610 AD) , South Salem 1996.