The other known quarry was near the Keep Homestead and shown on the 1857 map. Also, there may have been another below the Chicopee Mtn on the Gagne property - there are several large granite blocks, suggesting human crafting.
Also of some interest is the Rock House, which is not a house, but a natural ledge resembling a house. This is fairly close to the Flynt Quarry and could have been part of that operation.