Identifying "wild" grapes

I found some grapes growing in a state park near the foundation of an old hotel. I'm interested in what they may be. Does anyone have any good links?
What I know:
likely planted some time between 1850 and 1900 (in New England)
fruit is very dark
each is round and about 1/2" in diameter
large seed
PH of 3.0
Sugar of about 1.080
I have a mental image of the leaf shape. It's hard to describe, but it's a rather generic grape leaf shape.

Link in my sig relates to this.

Sometimes foundation soils can become pretty contaminated with lead paints and other dangerous chemicals. Probably most kinds could be taken up in the fruit. Any chance of it there? You could clip you a bunch of plant starters and bring home if you decide not to use the fruit from the foundation.

CampFireWine said:

Sometimes foundation soils can become pretty contaminated with lead paints and other dangerous chemicals. Probably most kinds could be taken up in the fruit. Any chance of it there? You could clip you a bunch of plant starters and bring home if you decide not to use the fruit from the foundation.

Click to expand...

I took all the fruit that was there and it was only enough to make 500ml. If it's any good I'll take a cutting in the spring. The plant is in a bad spot as trees are now blocking most of the light it once got.
I'm sure there is a possibility of some toxic building materials, but the building burned down more than 100 years ago, so hopefully most soluble poisons have washed down into the ground water by now. It was also by a stable, not the main building, so there was less stuff that could have been painted.

I don't know a good way of identifying wild fruit. I have a couple of books but they aren't very good for specifics.

I think I may have found something. They seem to match the grapes pictured on this site. Maybe they really are a wild variety... though I still doubt the placement was accidental.