[A_Brandybuck]

Beat you. ;-)

PoME, On Translation:
Similarly farthing has been used for the four divisions of the Shire, because the Hobbit word tharni was an old word for 'quarter' seldom used in ordinary language, where the word for 'quarter' was tharantin 'fourth part'. In Gondor tharni was used for a silver coin, the fourth part of the castar (in Noldorin the canath or fourth part of the mirian).

But I cannot find a reference to the suggested equivalence to the silver pennies of Eriador.