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.The book referred to in his message is Ozarks Chipped-Stone Resources: A Guide to the
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.
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...