Salt Silver
Kennett, in Parochial Antiquities of the year 1363, has the following: " Salt-Sylver is One penny paid at the Feast of St. Martin, by the servile Tenants to their Lord, as a commutation for the service of carrying their Lord's Salt from the Market to his Lardar. "
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)