help Identify a coin.

Hi I recently inherited a coin dated 1780 the writing on it is as follows BURG - C0 -TYR 1780 X ARCHID - AVSR - DUX On the othe side R- IMP -HU - BO -REG M THERESIAD - G under the bust of a woman two letter s-f-. Can anyone help with what this is and where it comes from... Thanks