Hiking in Wawayanda State Park, you cannot miss the massive remains of the iron furnace and the little village the surrounds it. It is a landmark and people often use it when giving directions. Built in 1846, it operated for 10 years and the ore was of such high quality it was used for train wheels. But cheaper Pennsylvania coal drew the smelting business away and now the stone furnace sits in the woods a testiment to history. North Jersey is full of rocks and you can often see the rust stains on them from the iron.