Hi I found a pretty worn coin (my first!) using my new metal detector. The diameter of the coin is 21mm and features the outline of Britannia and what I think is a date starting with 18 underneath her. I cant make out the next two numbers. The other side of the coin is completely worn. I'm guessing because the state of the coin is pretty bad, you can allow for another 1mm to add to the diameter making it 22mm - Now, I have absolutely no coin knowledge so have been doing some searching online and everything seems to point to a young head copper farthing 1838 - 1860. But from what I have read the date is on the obverse side which confuses me as I am fairly sure i can read 18## underneath Britannia. I've tried to take a photo of the date but you just cant see it on the pc screen - it is so faint, but im convinced its not the rose and thistle. Is there a rare farthing from this period where the date is on the obverse side? Can anybody help? Many thanks Dan