I first visited this hill with Bruce McAleer who had visited it before. A central gully divides the hill into an eastern and western piece, and we explored the lower flat area on the southern side of the eastern piece of the hill. This is an area of dense concentration of rock piles, as dense or denser than anywhere else I have been. You can see the piles from the parking lot turnout on Crockett Rd between the hill and the lake. I read online that the lake was called the lake beneath the "Great Hill" by the Nipmuc people of the area. So the hill must have been a bit special to them and perhaps the large number of rock piles reflects that. We only explored a small portion of that lower flatter area to the south of the hill and I would be surprised if there were not hundreds of other piles further south and along those brooks.My exploration strategy has changed in the last year or so. I used to look where hills met water. If you go back an read how I was thinking about things (see here) the low flat areas did not even get a mention. But starting with Woodbridge Rd in Carlisle (see here) and thereafter, I started looking at where low flat areas (rather than hills) meet water because that is where one version of the Wachusett Tradition shows up - the version with rectangular chambered mounds and sometimes tails. What this change in strategy really means is: hunting more persistently along the edges of water - especially headwaters of brooks; and not spending as much time exploring hilltops. So...
I parked off Crockett Rd and headed up the southeast side of the hill. I wanted to check around the summit and then spend time circling the gully that divides the hill in two. The large number of rock piles on the lower southern slopes quickly died out, and the steep rocky hill side above was pretty barren of man made features. At the top of the eastern summit, I did a little zigzag to check the southwestern facing upper slopes, then proceeded down the northwestern side of the eastern slope, getting down to the top part of the central gully. There I headed south following a trail along the eastern side of the gully. There was one rock pile there at the top of the gully:
After that I saw nothing on the eastern side of the gully till I got to bottom, where there is a dam crossed by the path. I crossed to the western side there and started exploring along the sides of the brook that drains from the gully. I wanted to stay back a little from the water, thinking that is best for hunting Wachusett Tradition mounds, and soon saw this looming through the woods:
Another view:
[I have looked at several pictures of this mound (and the video) and come away with the impression that there is a lower wider structure built on the grade and a higher more vertical structure built on top of it. the pile is basically rectangular with a very deep central hollow. ]. A last look:
As usual with large rectangular "Wachusett" mounds, there are always smaller outlying rock piles. I can never decide if these are part of the original site architecture, or might have been added later. But I focused on whether there were other large mounds in there. I found 3 or 4 candidates. Like this:
and this:
None of these was as well preserved as the first one but it is clear this is a mound complex not too different from sites in Groton (Blood Rd) and Fitchburg (Falulah Brook).These mounds were on the western side of the brook on slopes a few yards above the water. We are now on the low flatter slopes south of the western piece of Peppercorn Hill. Above the mounds there was a flat plateau and a road through the woods. There were several piles on the plateau, perhaps marker piles. This one was caught my eye because it is so circular:
It looks out over the valley of the brook. There were also five or so piles up there 
and several rocks and rock-on-rocks:
These are all enjoying a view to the east with that piece of Peppercorn Hill as the horizon.I went south a bit. Here is an interesting example of a split-wedged rock, larger than usual:
Closeup of the wedge:
(Ironically, these "split-wedged rocks" are compelling examples of a completely impractical activity - hardy Yankee farmers are in no way implicated.).After poking around some more, I headed back north following the edge of the brook. (This brook becomes Mill River which become the Charles River. So we are talking about the very highest headwaters of the Charles River. This erases any theories about these rectangular mounds being a northern Mass phenomenon. Here they are south of the Mass Pike.) I crossed back over the dam to the eastern side of the gully and then headed south back towards my car.
There were also several examples of smaller rectangular mounds. Not sure whether to count these as mounds "with hollows" or as outliers.
and
Look at how this pile is beautifully placed at one of the springs that gives rise to the Charles River.
After that I went back to my car. Bruce may recall the armchair we found last time (click here). I passed it and today, little more than 5 years later, it is just rusting springs and no chair. At the time we interpreted this chair as an example of the continued sacredness of the spot and its continued use by modern Indians. Given how quickly the chair fell apart, it must have been quite fresh when we first saw it. I believe there were Nipmuc using this site in the last 20 years.I could not resist photo'ing some the piles on the way out:
I found more sites further south and west one time (see here) and you can see by looking at the map that there are plenty of other areas to explore around Peppercorn Hill. I want to get to that wetland at the very top of the map fragment (left of center at top) and low flat areas south of the eastern piece of the hill are quite extensive and, I am sure, full of rock piles.
