my money is still on colonial of some sort. There is so many variations it may take some work to pinpoint. Have you soaked it in some olive oil yet? That may help bring out some of the writing and help with the ID.
Thanks for the help and comments....The coin was about 5 inches deep (halfpenny) and the Large Cent about 3 inches down...Fertilizer just kills these coins....Last year found a 1777 Reale at the same fields...I will post a pic of that coin...