I found a site in a local park that was the gathering point for settlers heading north in the early 1800's, its about 2 acres square and mostly short grass...I did some detecting around a couple of really old trees in the area..Right at the base of 1 tree I found pieces of broken glass , a strange looking copper ring about 8 inch's in diameter and broken pieces of blue pottery..These were all at 9 inches in the same hole...Theres not much trash in the field, should I hunt it in relic or coin mode?