Friday, June 5, 2015

Caves of Brownsville - A peek inside

Today we continue our look at the series of caves that once stood behind the main street of Brownsville, Minnesota. I went down on a marvelous early spring day after getting an invite from the local historical society who now own the two caves we will visit today.

The entrances are similar and right next to each other, so I will just show one of them.  Note the later cement additions.  It is possible that the backs of the buildings were in fact a few feet away from the cliff face.  I did not see much evidence of any modification of the cliff face to accept beams or metal pegs.

On the other hand, the foundation stones seen up above may have been the back wall of the building - both of these appear to have been pre Civil War hotels - and the caves may have been directly accessed through the ground floor.  Note also that the doorway here is too narrow to be practical as a brewery cave.

This cave has a rectangular shape and a slightly arched roof.  The latter had a thin coat of plaster on it but this has fallen off in places.  The plaster would have reduced the fall of sand and debris from the roof.  You could tolerate this with beer kegs perhaps.  But if the hotel kept produce, meat, wine etc in cold storage those might be commodities less tolerant of a little grit.

The other cave was smaller and somewhat crudely made.  The historical society has not yet cleaned out all the old stuff, hence the beauty parlor chair in the foreground!  Incidentally, this part of Minnesota is known for its orchards and these caves were used for apple storage until fairly recently.

It was fun to spend a bit of time investigating the caves in detail.  I am always interested in clues as to how these caves were made and why they had certain design features.   Consider the vent holes that most caves have, whether they stored beer or other temperature sensitive commodities.  The vents can sometimes extend upwards a very great distance but are invariably seen to be perfectly round. Nobody could shinny up a chimney that narrow while carving such a perfect hole.  I have long suspected that some sort of auger system must be used, basically a big drill bit to which one could add extra segments as the boring progressed.  And after years of search I finally found evidence.

Note the central divot and the circular grooves further out?  This looks like spot where the vent driller was placed, turned a few times and then moved further back in the cave where a shaft was then drilled to the surface.

Here is another interesting feature, one that appears to be specific to non brewery caves:

Nicely cut ledges for setting goods on.  I have seen something a bit similar in the Wolf brewery caves in Stillwater, but in general this sort of thing would be useless when the main goal was keg storage.

As to how the caves were formed, they appear to have just been chiseled out with pick axes.  St. Peter sandstone is easy to work with when fresh.  After exposure to air it firms up rock solid. This next picture shows pick axe marks.  Note that they are small and round near the ceiling, then turn into longer and angled grooves further down.  That is the reality of how one would swing a pick axe.  Near the ceiling you have no room for a downward swing.  I am surprised that the lower marks do not show a decided "right hander" orientation.

I close with a mystery.  In some caves you see  mysterious holes drilled into the sides of the cave walls.  Some are solo, others as below are in lines.  A single hole here and there might be a test drilling to see that the stone is solid. But an array of them is odd.  I have no compelling theory for it. Not yet anyway.

These caves are locked but the local historical society folks are very friendly.  If you are interested in this and in other history of this scenic part of the world I suggest you get in touch with them.

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