Frank:
I'm pretty sure you have a "State Copper" from the State of Sonora, Hermosillo, Mexico issued between 1832 and 1836. The size should be 21 mm, the same size as a US nickel. First, orient the coin (obverse side) so that the "D" (in D SONORA) is in almost the 3 o'clock position. Between two cornucopias is an arrow with its piont up. The obverse legend reads: EST D SORORA UNA CUART. On the reverse is a radiant Liberty Cap. The reverse legend reads: A DE (date) L S HERMOSILLO. The edge is diagonally milled.
Don....