Roadside attraction - Tewksbury split boulder from Rt 495

I noticed a split boulder (next to the highway) with a wide gap and three blocks of stone, with even spaces in between, placed so as to span the gap. Check it out: if you are driving north on Rt 495 and have passed the Rt 38 exit to Tewksbury then this rock is on the right before the Trull Rd overpass. I have been glancing at this rock, in passing, for years. The other day I noticed it was a bit too structured and symmetric to dismiss and thought I would mention it here. No photo available though.