Around 190 million years ago, the Pioneer Valley area was a subtropical swamp inhabited by carnivorous, two-legged dinosaurs, and a large cluster of their footprints is preserved in situ on the west bank of the Connecticut River. The prints here, some 134 in all, represent three distinct species. It's a cool sight and just a two-minute walk from the road.
From Northampton, go south on Pleasant St/US 5 for about 5 miles. The small parking lot is on the left-hand side.