This is pretty large low angle slab in the Northeast corner of the reservation. The rock is high quality Cape Ann granite. Although a large area, the angle is so low that the climbing is barely fifth class.
This would be a great place for taking younger kids climbing for the the first time though.
Park on Bray St. at the lot near the mini-crag, and then walk in keeping to the left. The path should lead up over bridge and along a ridge that runs roughly parallel to Concord St. The large slab heads down to the right. The ridge is a pretty well-defined feature (and should be obvious) is near by.
This slab is certainly pretty low grade. Marty's dog onsight, free soloed one of the routes, but it is certainly a fun location if you are new to soloing to get your head solid. Nice clean, sunny, longgg slab.