Spanish Colonies. (Rio De Oro). 1910. Registered envelope to France bearing Rio de Oro Yvert 49, 25c indigo, Yvert 58, 10c on 10c orange/brown and Yvert 60, 15c on 4p turquoise tied by Rio de Oro date stamp with m/s 'Registered' and Paris arrival on reverse. Very rare item from this small Spanish Colony to France.