Until I read this thread I had forgotten all about this incident. Many years ago we had a heavy rain, 5 inches in an hour, Newly seeded rye, just out of the ground, was washed badly. Eight inch trenches were cut everywhere. The next spring after the mud and sloughs dried up the neighbours little girl discovered a load of arrowheads that would have made Indy-Anna Jones happy. Spread out next to each other they covered almost half the kitchen table, (probably an area two feet by two). No idea what ever happened to them.
We speculated that maybe it was an indian campsite and that there had been a war at that spot at one time. The biggest ditch leading down to the slough started at a spot where we have had to be careful for many years not to get stuck in as it can be very wet at times. I have seen water run out of it all summer a couple of times. It is located on top of a hill where the view to the east is unlimited, to the south is six miles, to the west is thirty, and to the north 20 to 40. Great place to call a home with a view.