There are quite a number of boulders off the Rock Circuit Trail in the Hemlock Pool vicinity within the Middlesex Fells. It has the same type of rock as at Black and White Rocks just across the Fellsway to the east. There are also quite a number of boulders in the Boojum Rock vicinity.

Check out a map. Find Hemlock Pool in the Middlesex Fells (southwest of MWRA Reservoir). Find where Hemlock Pool Path intersects with Rock Circuit Trail. Head east along Rock Circuit Trail. Just a few minutes of walking brings you to a couple boulders just off the trail to the left. Walk a few dozen more feet down the path and there is a very nice boulder with at least two great problems.