Wall near Purgatory Falls

We’ve got Purgatory Brook as a border between the southern NH towns of Mont Vernon and Lyndeborough.  It has gushed and dribbled there for the last dozen or so millennia since the big ice melted… long enough to carve the “Devil’s Footprint” and “Devil’s Beanpot”.  The place is overgrown now, but it was once a big feature for Mont Vernon, summer residence of many 1800’s families looking to escape the city heat without being too far away for daddy to visit on weekends…  The summer folk are long gone, and so are most of the farms, trees have reclaimed much of the land once again.  It is not hard to imagine what the Native Americans must have seen back when they came to the area, making it a part of their culture and tradition.

In another post, Southern NH Rock Piles, I describe a series of stone piles and huge wall located to the east of the Purgatory Brook attractions.  In this post, I will feature more details about the wall and its topography.


Big Wall near Purgatory Falls

A lumpy pencil mark shows the current edge of the woods (on the south side of the mark) and old orchard (to the north).  Dark cloud shapes indicate the locations of the biggest rock piles.  Several of these have depressions.  There are many low, round piles, too many to record with this rough sketch.  Depressions in the wall are marked with red.  The other marked features are pictured in  Southern NH Rock Piles blog post.  I think it is interesting that the wall narrows to a single rock thickness where ever it comes into contact with water.

Here are some other details about the wall…


Evidence of a very old tree, possibly a boundary marker

On the current Mont Vernon Tax map, the wall is a boundary.  In this picture, a very large (and very weathered) stump is located on the western end of the wall.  It may have been a boundary marking tree in its day.

It is not easy to decipher the terrain from the following photos.  Except that none of the existing trees are very old.  I suspect they were logged to maintain the view from the main farmhouse up the hill.  I also suspect that these areas may have been used for pasture.  But I doubt they were plowed because they are laced with boulders, a few as big as cars, most  bigger than a man could move without a friend or two and a pair of oxen.  While the orchard at the top of the hill also has some boulders, and protrusions of bedrock, it is more level and smooth than what is pictured here.  Whoever brought these sizable rocks to this east/west line did not have an easy path to haul them on.

The wall transitions from thick to thin in several places.    The next photos show an east and a west view of the second section of wide wall as it goes from left to right on the map.  The north side of the wall looks almost ramp like, while the south side is nicely faced (like the pictures above).  To the east of the ramp, there is a bulge on the north side.

There are many depressions in this wall.  A few are very well defined.  In the picture below, my back pack sits in one.  The rocks are beautifully faced to the left of it.  (To the right, entropy has been at work).  While this wall is a mess in a lot of places, its these surviving hints of its former glory that lead me to believe that it was far more intentionally stacked than a couple of farm boys unloading a wagon of stones would have bothered with.


Back Pack placed in wall depression. 

Now for a few examples of the crystal rocks placed near depressions.

Lastly, (for this posting anyway) I would like to address the idea that these depressions and possible “vents” (as seen in the picture below) were created in some sort of effort allow for water to drain off or through the structure.  When do rocks stacked on rocks drainage? It occurs naturally because of all the gaps that form when one surface does not match the next… Unless they are topped/covered with dirt or a good set of leaves, water will find its way through, just try and stop it!  In my yard I have taken advantage of this feature and created stone pallets for my woodpiles.  The bottom most wood may get wet during a storm, but the water drains away quickly and allows it to season, no depressions or vents necessary.


Possible vents on the south side of the wall.  Depressions behind them. A half buried glacial erratic lurks further up the hill.

OLYMPUS DIGITAL CAMERAWood pile stacked on rock pile.  Excellent drainage.  No depressions or ventilations needed.

This wall has certainly played a part in European farming practices, but I would argue that it was created before they ever came to this area currently known as Mont Vernon.  Those wise old Yankees took advantage of its existence.  Perhaps they were the ones that built the single rock wide parts of the wall.   It has been suggested that this is a burial wall.  The fertile Souhegan River valley is not far from here, I’ve wondered if baskets of corn could have been stored there, with the heavy rocks keeping (at least the larger) corn eating animals away…

What do you think?