A stone chamber re-discovered: the "Harvard Cave"

I got a tip from reader "TJ" about a stone chamber he played in as a kid in Harvard, MA. They used to call it the "cave". So I followed his directions and located the chamber in someone's front yard. I snuck in to take some quick photos and found an amazing chamber. Afterwards I excitedly phoned my friend from Carlisle, went back to his house to pick him up, drove back to Harvard for a second look at the chamber. This time, with two of us talking and making noise, the landowner came out to see who was tresspassing. It turned out we were not teenagers drinking, so we did not get shouted at and, instead, had an interesting conversation about the chamber. It turns out this is the chamber Mavor and Dix call the "southern chamber", on pp. 283, 284 of Manitou:
This is a"post and lintel" style of construction with vertical walls, roofed over with large flat slabs. Also, this chamber goes around two right angle turns [and probably used to go around a left hand turn before the entrance], making it very similar to the Acton "Potato Cave", currently being restored in Acton [Click here].

Here is the view from outside:
You see the tumbled rocks about the entrance (according to the landowner this part used to be the chamber entrance but it was destroyed by archeologists from Boston -- [College or University?]). You see a small mound of dirt over the entrance and also a larger mound behind and to the right of it - this is the mound over the inner chamber. Here is a head on view of the entrance:
If you poke your head in you see a right hand turn.
If you go in and look around the corner, you see a long passageway going in deeper. When I first went in, it was too dark to see down the passage but my camera flash showed me enough to guess there was another room at the far end. Also the narrow passage ("only 16 inches wide" according to Mavor) discouraged me from trying to fit my girth down it. The passage is perhaps 10 feet long.
Later on when I came back, my friend from Carlisle went all the way in. He had a flashlight and took pictures of the interior, which have not yet arrived via email. He saw a bat hanging from the roof. While he was in there and I was watching from the entrance he was about a foot lower than I was - so there appears to be significant soil buildup inside this chamber. But with loose cannon archeologists [aka -pot hunters with credentials] mucking about, all bets are off. The thing is, according to the landowner, the archeologists found Indian artifacts inside the chamber. That's news I don't think Mavor and Dix mentioned. It is also the kind of thing which rarely checks out.

This chamber is located in a what looks like a sand pit - and the landowner said that sand and gravel had been quarried there. This is at the very top of a brook and wetland that hasn't quite started yet but flows away in a southerly direction. The views outward from the chamber entrance are solstice aligned, however you would be in the pitch dark with nothing to look at, if you are in the innermost chamber. With the way the book Manitou is pre-occupied with alignments and sky watching it was surely a puzzle to the authors how this chamber might have been used - deep underground with no view of the sky possible, with three corners and long passages blocking any kind of line-of-site. I am going to go out on a limb here and state my suspicion that thes right hand turns (same with the Acton Potato Cave) have to do with audible phenomena rather than visual ones. I cannot back that up at all and want to finish with the thought that we know noting about these interesting structures. This Harvard one and the one in Acton are unique, in my limited experience. People who have visited more chambers could let me know about this. Surely some real archeology and publications ought to be done here. Luckily, the landowner is very interested in this wonderful structure and perhaps some more studies will be done in the future, and done more carefully.

One more comment about Manitou. I should re-read the pages on Nashoba carefully but it looks like the authors are trying to establish that the "northern" chamber, at the north end of Oak Hill, is in relation to this Harvard "southern" chamber. I don't think so. They are in different styles, the solstice alignment of the Harvard chamber only holds if you are at the entrance looking outward, not in the inner chamber. Also the Harvard chamber is not, in fact, at the southern end of Oak Hill but, several major hills distant from it. If related to anything, this Harvard "cave" is related to the Potato Cave in Acton. Still in Nashoba but part of a not quite so tidy story as given in Manitou.