One of the interesting geologic features at the park is a large glacial erratic called Patterson's Pellet. It's a dramatic feature along Millbrook Mountain Carriage Road where it's perched atop the cliffs above Palmaghatt Ravine.
Here's a picture from the backside (I climbed a short distance down to a ledge). Another foot or two to the left and the erratic would never have lasted atop the cliff.
Here's a bad self-portrait (I was hiking alone) by placing the camera on the ground (and into the Sun!). As you can see, the rock is about 6 x 6 feet in size.
Here's a picture of Patterson's Pellet from the other side of Palmaghatt Ravine (a place called Kempton Ledge on Castle Point Carriage Road).