Listen you two, I don't claim to know everything, I did get a giggle when I seen you both comment that new stuff was in your old spots.
Have you ever heard of the saying, "he's old as dirt"
If I had an old farm that I know was occupied by 1600's- 1700's farmers/migrant worker/pickers I would not let a few "modern coins" stop me from still hunting for that colonial stuff we all convent.
I remember a guy "who's name we shall not speak" used to find those "what he called (pesky Indians)" of course I don't know if he bought them on eBay or found them? He would leave them in the back of his pickup truck. I used to think, it must be nice to be able to find those poor little Indians and just throw them around like trash. Haaa, lol I'm grateful when I find them, merc's, wheats, toasted wheat whatever. I'm just saying, beauty is in the eye of the beholder. Early in my quest to find things I was looking for that magic honey hole, a couple of them were full of "modern coins" My point, in case your wondering, is just because you find something made in the mid 1800's does not mean there is not earlier stuff hiding under that and for myself, I'm grateful for any keepers.