Monday, April 23, 2012

Excavation Ends

With nice cool weather returning for a brief spell, the opportunity to finish the dig couldn't be passed up!  The trench around the central stone is now complete, yielding no artifacts.  The image below is looking Northeast, w/ the central stone and a trench around it to a depth of approximately 1 foot.

The question posed in my last posting, regarding the presence of chert in the dig was resolved with a message from Jack Ray, Center of Archaeological Research, Missouri State University.  An extract of his kind assistance is shown below:

...chert occurs as redeposited cobbles in the Pennsylvanian sandstone.
Most of the chert is Burlington chert that was eroded from the older
Burlington-Keokuk Formation (345-310 million years ago) and redeposited by
the ancient river system during Pennsylvanian times (310-280 m.y.a.). In
some locations, the redeposited chert pebbles and cobbles (ancient gravel
bar deposits) may be abundant.

When still locked in place in the bedrock, the chert cobbles comprise a
conglomerate, but when the encompassing sandstone bedrock erodes away, it
releases the chert cobbles which become part of the surrounding regolith (or

I don't know if you have a copy of my chert book (see attached), but I
discuss this type of redeposited chert (I call Warner chert) on pages
295-299. Pictures of redeposited Burlington chert cobbles up to head-size
are pictured in Figures 9.8-9.11. Thus, it is not at all unusual to find
remnant fragments of insoluble Burlington chert in areas where the
Pennsylvanian sandstone has been eroded away, releasing some of the
inclusive chert cobbles.
 The book referred to in his message is Ozarks Chipped-Stone Resources: A Guide to the
Identification, Distribution, and Prehistoric Use of Cherts and Other Siliceous Raw Materials, Jack H. Ray, Missouri State University.

Pictures of the two pieces of chert in question are shown below.  Although the pictures are not definitive, an examination with a magnifier did not reveal any flaking on either sample.

So my last gasp at finding something Native American connected to Cairn #5 has proven to be futile.  The rational conclusion of the research and field work to this point is that our array of cairns was likely created in historic times.  The purpose(s) and builders is still a total mystery.  However, since the probable builders were of a culture with written history, it is reasonable that a dedicated search will reveal some answers.

The search continues...

Sunday, April 22, 2012

Dig Progress Report #4

Still nothing significant found.  An apparent false alarm was raised last week when two chert chips were found in the trench being dug around the central stone.  At first I thought I could see signs of working on both, but with more magnification and light on the subjects, it ain't so.

The two little chips are shown on the south edge of the central stone, with a trench about 12" below the stone's top surface.  I'm rather perplexed how they found their way here, buried a few inches below the grade level, under a man-made rock pile.  Underneath is about 30 feet of sandstone, capping limestone.  Sandstone is not known to harbor chert.

How was the chert transported to this locale?

The above image shows the context of the central stone nearest the shovel and the second stone that extends nearly to the outer periphery of the cairn on the south side.

The present extent of the trench is shown above, circling about half of the central stone.  The plan is to complete the trench all the way around the central stone.  If nothing else turns up, the dig will be considered complete and an alternative solution will have to be sought to solve the mystery of these rock piles!

Sunday, April 8, 2012

Dig Progress Report #3

No big finds, thus far.  The major effort continues to be around the central stone, on the chance that artifacts have fallen off it.  The ring around the stone is now exposing 4 to 8" of the central stone.  Today was the first encounter of clay-like soil, much lighter in color than the leaf litter encountered up to this point.  The north side has been excavated the most, which is where the clay was found.

A second stone of the same approximate size has been identified in the SE quadrant.  A portion of which extends to the edge of the original structure.  This stone remains to be cleared of the overburden of cobbles.

Sorting the removed debris with 1/4" screen has yielded chips of sandstone, but nothing else.  No chert at all has been noted.  If there is any pottery shards, they are smaller than 1/4"!

A positive development is the interest of a local historian scholar, who has previously visited the site.  She is inclined to think the cairns are prehistoric, in the absence of any historic record that she can find.  She reports a lead on another cairn group recently identified, about 20 miles north of our site.  At least it is something else to investigate for a possible connection.

Tuesday, April 3, 2012

Dig Progress Report #2

With the threat of rain today, I made an early start hoping to find something significant.  The only discovery today is the large center stone on which one might expect to find an artifacts that would have been left.  I found nothing, not even anything that that I could identify as burn residue.

Some sample photos of the project follows:

 Set up by Day 3.  Overburden rocks stacked in the background.

 Starting view on Cairn#5

 First day's efforts

 Day 2

 Day 3

 Day 3 w/ center stone revealed

The only volunteer to show up and totally useless, except for company!

The plan is to continue excavation around the center stone in the hope of discovering some artifacts in a lower level.  As best as I can tell, the jumble of rocks continue below the center stone, but for how far is unknown.