I am trying to find out the origin of this bronze coin. It was found by my mother while metal detecting in Australia, close to Sydney. It was unearthed from the side of the Paramata River in a very old part of town. Can anyone help me identify this coin? I'm going to try and attach images, shot beside a USA Quarter for comparison. The coin is quite heavy, more thick than a quarter. Any help identifying this coin would be most appreciated.