From their website: During the latest ice age, an unusual East/West fault exposed this ancient rock to ferocious waters from retreating glaciers. Recent mapping and surveying by the National Speleological Society determined that the resulting Stone Bridge appears to be the largest natural marble cave entrance in the East. It measures up to 180' wide and 62' high. A self-guided trail winds around waterfalls, potholes and deep pools. Trout Brook emerges into a gorge through several caves, some accessible on foot, others only with spelunking (cave exploring) gear.
One of the more peculiar names, turns out, Peter Pan's Peephole looks like a girlie part...wink wink.
This is turtle rock, center of the photo, just below the upper railing is the head of the turtle jutting out of his shell.
They offer fun exploration for the little kids, too.