Figure #1-1a. Two loose rocks (i.e., stones), both dolomite (i.e., dolostone), that were found in rubble in the wash of Lake Michigan at Gros Cap, Mackinac County, Michigan. The larger one (top) was found by Caroline B. Cheeseman; the smaller one (bottom), by Krista D. Brown. Background is 7-wale corduoroy. For additional information about their sizes, see Fig. #1-1b. 

OCCURRENCE

PATTERNS ON THESE STONES

Figure #1-2a. Features within each of the circles and ovals appear NOT to resemble forms known to be natural. (Photo by Caroline Cheeseman.)

Figure #1-2c. Close-up to show a few of the diverse edges of the "incised" lines.

[To date, no archaeologist or glyphologist has looked at the specimens ...  In the future, I hope to find one, preferably more than one, to examine (etc.) these stones.]

    Internet Searches (by image & keywords, individually and in combination) –

[An aside: Several images of each of the following examples are available on the internet. No particular reference for any of the examples seems to be more appropriate than several others. Consequently, with one exception, citations are not given in the following paragraph.] 

          No ancient patterns or parts thereof were found that appear to be more than roughly similar to those on the Gros Cap specimens. The following are a few of the obvious differences between the patterns on the Gros Cap specimens and those on glyph-bearing stones that were among the "hits" that resulted from the searches: Rosetta stone (dated 196 BCE) -- its characters are fairly well defined and well aligned.  Runestones (dated 1st to 12th centuries A.D.) – none of their patterns or even relatively small parts of those patterns resemble closely the patterns on the Gros Cap stones. Early Sumerian Cuneiform (dated 8,000-3,000 BC) -- some of these patterns, whether "etched" or "engraved" into rock or, like later cuneiform forms, pressed into clay, include features that do roughly resemble the patterned surfaces on the Gros Cap specimens (see 123RF).  Nicaraguan "petroglyphs" (dated as 300 BCE) – a few of the "glyph(s)" that adorn the loose volcanic stones, on the grounds of and within the El Ceibo Museum, Ometpep (on an island in Lake Nicaragua), has characters (scale not given!) the shapes of which roughly resemble some of those on the larger Gros Cap specimen.

    An "Off the wall" hypothesis for the larger specimen

          The immediate answer to the "each line or ‘character’ ...” alternative appears to be "NO!" -- This opinion is based largely on characteristics of the lines (See Figs. #1-2b & #1-2c) and also, in the larger specimen, the presence of so much repetition. [Granted, the pre-weathered and eroded surface may have exhibited characteristics, now weathered and eroded away, that would have indicated otherwise.  Also, even using only the currently available surface, any imaginative story teller (I think of my Grandfather Vincent and his reputation along this line) could, and probably would, come up with one or more interesting "translations"(!!), BUT should one even consider this latter possibility(?).]

[An Aside:   In any case: 1. even if the pattern was made to represent some thing/body [and] 2. if it also was, as concluded herein, man-made, this stone cannot be designated a mimetolith! Rather, it would be an artifact! -- This is so because the pattern that resembles something else is apparently NOT a product of a natural processes – i.e., it seems that it was “scored” or whatever by one or more human before it was eroded and weathered to give it its current appearance!?]

Questions, Questions, QUESTIONS ! ! !

  References Cited

Possible Help??:

I have contacted: Jacob Dahl, fellow of Wolfson College, Oxford and director of the Ancient World Research Cluster.  But NO response to date

             &          John O'Shea at the University of Michigan (email sent 21 Jan 2016).    But NO response to date

           Holey stones are said to have been used as anvils to crack acorns and nuts (e.g., Gray & Pape, 2016 & Fig. #2-1).  This recorded use, plus the fact that several of these stones occur near my current residence, led to preparation of this report, which consists largely of a review of pertinent literature and a summary of data and my conclusions that relate to the origin of holes in the holey stones of the Gros Cap, Michigan, area. The literature review, especially that relating to origins suggested for the formation of the holes in these rock, differs from that usually  given in reports  in that  it  includes -- indeed , so-to-speak, emphasizes -- "hypotheses" recorded by  non-scientists on  internet web sites. 

  

                                Figure #2-1. Nuts have long been cracked by humans and other primates by using stones as both the anvils upon which the nuts were
                                      placed and the hammers used to strike, and thus crack, them.  Stones similar to those shown in the above photographs are said also
                                      to have been used widely by Amerindians – e.g., the Ojibways and Hurons -- to remove the shells of acorns which they harvested 
                                      as a staple of their diets -- i.e., they ate the "meat" of acorns and extracted acorns' oils, which they used in cooking.  (e.g., Kuhnlein
                                      & Turner, 1991) 

Definition:  Holey stone, as used herein, is any naturally occurring stone (i.e., loose rock) with openings, typically at least roughly circular, into or through them.

This definition is strictly descriptive -- i.e., no origin (other than its being of natural occurrence), use, or any attribute of these stones is included or implied (see following paragraph.) In addition, this designation does not require any of the holes in a so-named stone to extend all the way through the stone; this is mentioned because the term has been so-restricted in some publications (e.g., Niagra, 2015 ). 

    Names given to specimens, which are illustrated and/or described in the literature (including internet entries), that closely resemble the Gros Cap specimens are referred to by many terms. Several of those designations, most of which are binomial (i.e., an adjective plus the word stone or rock) may be tabulated according to their usual connotations as follows:

   Shape important:  cupstone*I, holey stone, pitted cobble*I, ?Poculolith?*,

   Shape & use important:  anvil stone*I, nutting stone*I,

   Shape & origin important:  anvil stone*, cupstone*, holed stone*, nutting stone*, pitted cobble*, Poculolith*I

   Legend-related:  crick stone, faery (or fairy) stone, hag stone, hex stone, holy stone, mare stone (some only), Odin (or Odin’s) stone, Tafoni (tafone-singular), witch stone (or Witches amulet).

 
|Footnote|

The asterisks (*) indicate dual listing.  The hands (I) indicate stones the holes of which have been shown or believed to have been man-made (e.g., Davis, 2002).  Some of those so-called man-made holes, however, seem more likely to represent only modification of originally natural holes so they would better fill their desired function. [Indeed, an associated aspect about which I have often wondered is:  Do “concentrations” of  holey  stones, such as those at Gros Cap, indicate that these places were where a few or more people came together to use these stones?.

Gros Cap Stones: Four of the holey stones that were among onshore rubble or awash Lake Michigan near Gros Cap Road, Mackinac County, Michigan are shown in Fig. #2-2.  This location, at 45^o53'41.89"N - 84^o50'25.11"W (elevation of 581 feet), per Google Earth, is about a 0.25 mile southwest of the northern junction of Gros Cap Road and Route 2, which is approximately six miles(atcf) west-northwest of Saint Ignace, Michigan.

              Population-wise, these and other holey stones occurred or still occur sporadically among lithologically similar stones with similar sizes and shapes.  Number-wise, they made up well less than one per cent -- very likely well less than half of that. Other stones within the wash were a few igneous and metamorphic, large-cobble size stones, that apparently represent glacio-fluvial transport prior to their being incorporated into these lake shore deposits.
                 Each of these stones is a limestone or calcareous dolostone (= dolomite in most, especially early, literature).  All are probably of Silurian age (personal communication, Dan McGuire).  The longest dimension of these stones ranges from 5 to 8 inches (~12.5 to ~20 cm.).  Their roundness and sphericity ranges greatly:  All, however, are at least somewhat rounded and several, apparently reflecting their shapes when they were broken off their outcrops, are subprismoidal.
            The holes in the Gros Cap specimens have an apparently random distribution; roughly circular shapes perpendicular to their depths; and maximum diameters of ~ ¾ inch (~ 2 cm). The number, distribution, and relationship of the holes to the current shapes of the stones differs from specimen to specimen (see Fig. #2.2). The only constant seems to be the presence of virtually all of the holes on the two larger, relatively flat, parallel surfaces of the subprimoidal shaped stones; these are, of course, the surfaces upon which these stones would nearly always rest once transported by water.        

 

 Figure #2-2. Top, upper surfaces when found;  Bottom, lower surfaces when found.
  Each stone has been washed and brushed (plastic bristles).
 [An aside: The lower surfaces of three of these stones are fairly good mimetoliths, eh?!]  

Pre-2015 "Literature":   The following is a brief review of diverse origins that have been suggested, most by non-geologists, to account for the formation of the holes in stones that resemble the "holey stones: of the Gros Cap locality:

              1. Excavation by invertebrates –

                                A.“Rock-boring clams” – The inclusion of this designation in quotes, is used to distinguish boring from burrowing clams (see Stanley, 1970, p.8).  Rocks and stones with holes of similar shape and size as those shown in the included photographs have been reported to occur in numerous places here and there around the world, and many have been seen or concluded to have been formed by “rock-boring clams”  (e.g., those of the family Pholadidae – see, for example, [+++++see Frey(1975), Miller(2007), and Seilacher(2007)].  ß Although this origin seems best to fit the features of the Gros Cap holey stones, the fact that all recorded “rock-boring clams” live in marine or brackish environments is problematic so far as fitting the probable geological history of the holey stones of this area;  this matter is treated under the Problems/Questions subheading. <-- Considering range of these critters per Wilson and Palmer, 1988, IF holey stones are found in Mac Breccia, this “problem” disappears!

Dick:  The one feature I mentioned before to check is that pholad boreholes are not columns, i.e., having the same diameter from top to bottom, but rather they taper, being narrower at the top, and wider at the bottom as the clam grows.  Reed, virtually all of the holes in the Gros Cap specimens appear to have just the bottoms of such holes (or perhaps just the so-to-speak “starts” of such holes – indeed, this latter possibility  may be more likely, ESPECIALLY if the rocks were attacked after becoming loose;  I just do not know what strata were atop or below the strata in which the depressions occur.  I do, however, specimens with holes of different sized holes, be they the tops or bottoms of such boring activities.  So? ?

                                B. Other invertebrates – although other invertebrates (e.g., sea urchins and sponges +++++add others from refs on next line) are known to have bored holes in sediments and rocks [see Frey(1975), Miller(2007), and Seilacher(2007)], the only ones that I have seen indicated as responsible for the holes in holey stones, however, is “an ancient [otherwise unidentified] worm ‘tunneling through the mud – [with the ultimate result] worm tunnels!’” (Niagra, 2015). ß This possibility, which, among other things, would relate to soft sediment  that  was later  lithified, seems not to fit any but through-going holes, and even seems unlikely for them, at least those that are associated with holes, most of which are “dead ended” within their stone hosts. Noneless, one or more of the listed invertebrates, or perhaps others, cannot be completely ruled out as responsible for the holes in the Gros Cap specimens.                  2. Weathering – This suggested origin requires an originally pebble-bearing rock as the host rock and the holes to have been formed as the result of  a “popping out of  [those] pebbles.” -- “Eons of rolling … pushed around by glaciers and rivers … a lot can happen when stones roll; … pebbles lodged in the stone, and the pebbles popped out! … [of] softer areas within the stone which wore away quicker, leaving a hole” (Niagra, 2015). ß This suggestion, given in a narrative, seems to be a jumble, and least in part possibly given in jest(!?). In any case, the “popping out of pebbles” thus leaving the holes seems highly unlikely:  pebbles in calcareous rocks like these at Gros Cap are extremely rare, if indeed they have ever existed;  and, the nearly perfect circular shapes of the holes parallel to their length seems not to fit this possible mode of formation.  However, if this suggestion is extended to cover originally enclosed fossils rather than pebbles, this origin seems at least to warrant additional consideration.

                 2. Weathering – This suggested origin requires an originally pebble-bearing rock as the host rock and the holes to have been formed as the result of  a “popping out of  [those] pebbles.” -- “Eons of rolling … pushed around by glaciers and rivers … a lot can happen when stones roll; … pebbles lodged in the stone, and the pebbles popped out! … [of] softer areas within the stone which wore away quicker, leaving a hole” (Niagra, 2015). ß This suggestion, given in a narrative, seems to be a jumble, and least in part possibly given in jest(!?). In any case, the “popping out of pebbles” thus leaving the holes seems highly unlikely:  pebbles in calcareous rocks like these at Gros Cap are extremely rare, if indeed they have ever existed;  and, the nearly perfect circular shapes of the holes parallel to their length seems not to fit this possible mode of formation.  However, if this suggestion is extended to cover originally enclosed fossils rather than pebbles, this origin seems at least to warrant additional consideration.

              3. “Geological pothole effect” -- "These [holey stones] are created when the river current spins harder rocks that cut into softer rocks.  Over time, a long time we think, the harder rocks [may] drill [into or even] all the way through the softer rocks."  This origin, the designation in the heading mine, has been suggested for holey rocks/stones found in river (estuary) bars in western Alaska (Deneki Outdoors, 2014)  ß The size of the grain(s) that would have been required for such abrading, the conditions relating to the movements of the water, and length of time that those conditions would have had to have existed for such a genesis seems unlikely ever to have occurred.  Consider also the sizes and distribution of the holes in the specimens, both those from Gros Cap and those shown of similar stones from other localities.   

           4. Erosion by “surging water”  --   “… the many deep pores and holes are a result of the repeated surging of water on limestone across a long period.” (Hauser, 2014).   ß  No information is given, or seems likely to exist, that appears to support this suggested mode of formation.   

               5. Physical and/or chemical processes promoted by activities of humans or other primates -- This hypothesis has the holes formed as the result of countless impacts (i.e., poundings to crack acorns and/or nuts) with these stones functioning as the anvils.  The physical and/or chemical processes indicated to have been involved are abrasion and actions of solutions indicated to have been derived from the crushed acorns/nuts. Add citation ß This hypothesis seems unlikely for several reasons:  Granted, walnut shells, for example, are sometimes used as an abrasive, but only to polish such things as mortar;  [and] crushed acorns have been used as a source of tannin, which is acidic, but it is an extremely weak one.  In addition to have any effect, each hole would have had to have been a locus where an extremely large number of acorns/nuts were placed and cracked

          6. Seven “Wows, Hmmms, & Yikes”) – Most of the following “hypotheses” have merely been mentioned in narratives about holey stones the illustrations of which resemble the Gros Cap stones – i.e., their actual modes of formation are not or only briefly described, let alone discussed. Indeed, some of these suggested modes of formation seem hardly to warrant the following short descriptive characterizations; however, for so-to-speak a near-comprehensive coverage of possible modes of formation hypothesized, they follow:  A."created by predatory dinos. The holes in these rocks accommodate the claws cast from hollow rocks.  Boring clams didn't create the holes, but occupied them opportunistically...." (Culbreth, n.d.)   B.“All … are omarolluks, glacial erratics, or pebbles … [and] were made by a type of water erosion, whether liquid or solid.” (ibid.)   C.“The holes are from ground water seeping into the aquifers.” (ibid., a comment by J.Spencer)  D."wolly(sic) mammoths were the key.  There(sic) diet was such and their primitive kidneys such that their urine was extremely acidic ...pH of 3.4 is the estimate. ...  a squirt here then there .  When the acid urin(sic) hit an alkeline(sic) rock it began do(sic) dissolve the rock.  It was a quicky it made just a partial whole(sic) and you can figure the rest."  (Deneki Outdoors, 2014 -- comment by "grampus" dated 19 January 2015)   E.“These holes are usually formed by centuries of wave action and/or dripping water [acid rain?--RVD].” (Conjured Cardea. n.d.)  F.“The holes are the result of the repeated freezing of water which makes tiny fragmentations and turns a small crack into a fissure and eventually into a hole.” (H.Pringle, p.c. 9August2014 in Winder, 2015) – The shapes of the holes in these stones seem to negate this possible formation. Indeed, the characteristic shapes of the holes in the Gros Cap and similar stones (as shown in illustrations), seem to preclude most of the suggested origins for these holes. G. Holes are man-made mortars – descriptions and illustrations published by Eitam (2009), to which my attention was directed as a possible origin, seem actually to vitiate this possible origin for the Gros Cap stones and several others described and/or illustrated in the literature; nonetheless,  at least some of the Gros Cap and similar holey stones may very well have been used for the purposes attributed to the man-made mortar stones. Holes are man-made mortars – descriptions and illustrations published by Eitam (2009), to which my attention was directed as a possible origin, seem actually to vitiate this possible origin for the Gros Cap stones and several others described and/or illustrated in the literature;  however, at least some of these Gros Cap and similar holey stones may very well have been used for the purposes attributed to the man-made mortar stones. Holes are man-made mortars – descriptions and illustrations published by Eitam (2009), to which my attention was directed as a possible origin, seem actually to vitiate this possible origin for the Gros Cap stones and several others described and/or illustrated in the literature;  however, at least some of these Gros Cap and similar holey stones may very well have been used for the purposes attributed to the man-made mortar stones..  H.  IF any more such “hypotheses” are found,  add them here.
 

Problems/questions [[This whole section may become superfluous if similar stones are found in the Mac breccia!!! – but it may be worth summarizing the problem as a comment re possible post Michigan Basin fm of any such holes in rocks??!???]]:  What creature(s), if any, formed the holes in the Gros Cap stones?

      Although the configuration of the holes, the rocks they are in, etc. seem best to support their formation by some boring clam, this mode of formation appears to be difficult to correlate with the widely accepted geological history of the area and/or recorded biological/paleontological information (i.e., the marine vs. fresh-water environment for clams):  Evidence indicates that the holes were made after the sediment,which became the rock in which the holes occur, was buried, lithified, uplifted and exposed to weathering erosion, and transport; and that history appears to require formation of the holes when the stones derived from the resulting rock were in freshwater – i.e., freshwater clams with rock-boring capabilities/habits would be required.  ---  However, no freshwater clam known to have the capacity to bore such holes in rock has been recorded or is known by the malacologists or paleontologists whom I have contacted. [However, one paleontologist, who read this note in manuscript, did note: “I can’t find anything that says they [i.e., rock-boring clams] are only marine.”] <CHK some more experts!!  In addition, no other animal, either vertebrate or invertebrate, known to bore holes such as these has apparently been recorded. In any case, even if any such freshwater “rock-boring clams” or other possibly responsible animals were responsible for the holes, additional questions arise -- Two examples are:  1. When did they appear(?) – Although it was long believed that “Boring pelecypods have a range of Jurassic to Holocene.” (Boardman et al., 1987, p.392),  Miller (2007, p.362) reports that boring bivalves go back to the Ordovician (find original article re this – apparently by Wilson and Palmer, 1988. If the Gros Cap specimens were formed by rock-boring clams, the presence of similar holey stones within the mid-Devonian Mackinac Breccia, which includes fragments of proved Silurian rock, seems at least to support , the later report.  [[[ [and]  2. Is there any evidence other than possibly the holey stones that such clams ever lived in this region(?) OR in any area with a similar history of former environments?  < CHK!! – Perhaps it only needs to be said that there is no pertinent information – at least none that I have found in the literature to date?) ]]]?)  <<<--will need rewrite if no holey stones are found in Mac Breccia!!! 

Dick:  That is probably the best way to put it.  Fresh-water clams do go back as far as the Middle Devonian, according to Boardman.  Boardman also said “some infaunal pelecypods bore into hard substrates, including rock, coral, and wood” but he doesn’t say how far back that goes.

In any case :

       As already mentioned, the holes seem to have been made in the rock since it was lithified -- i.e., since its parent sediment was turned into rock.  And, at least some of the holes seem almost certainly to have been formed after fragments of the rock had been broken loose from their original strata  – i.e., when both their originally top and bottom surfaces so-to-speak alternately became prone to attack. This is confirmed by the presence of similar holes on both sides of some of the subprismoidal stones -- see especially the specimen that is second from the left in the above photographs. ß IF this conclusion is correct, a possible history of the Gros Cap stones in which the holes occur would probably have included the following steps, which, by the way, are consistent with the widely accepted geological history of the region:  Deposition of the parent sediment during the Silurian [[ß  Is any of it of early and middle Devonian age?? – if so, change the text AND the following datesà]]  (i.e., ~415 to 445 million years BP); lithification of that sediment;  relatively deep burial; uplift and exposure of these rocks to the elements (perhaps more than once  --  note pre upper Devonian karst period, formation of Mackinac Breccia, etc. and hypothesized deltaic upper Devonian;  “for good” exposure, perhaps before or near the end of the Paleozoic – i.e., ~150 my B.P. [but what of Jurassic – is it marine or non-marine??; and whichever, is it restricted to middle of basin(?)] ; -- in any case, certainly before the Pleistocene - ~2 my B.P. -- Can preceding be summarized as in following parenthetical …??  (probably near the end of the Paleozoic (i.e., ~150 my B.P.), and certainly before the Pleistocene (~2 my B.P.)   --------

Dick:  Probably summarize it as you’ve done in parentheses.  As we discussed, I don’t know how far back rock-boring clams go.  The Treatise has the Subfamily Pholadinae only going back to the Cretaceous (p. N707).  Of course, these could be Pleistocene-Holocene fresh-water boring clams, if fresh-water boring clams exits.

??!! Check to see if any holey rocks occur as pieces in the Mackinac breccia !!!!!!  IF they do, that would make formation of holes pre-collapse (i.e., pre- upper Devonian);  on the other hand, if no holey rock fragments are found in breccia, that would PERMISSIVELY lend strength to  formation of the holes in post-marine MiBasin time -- i.e., the holes would have likely been formed in freshwater.

     IF, however, holey stones are found in the breccia, that will require several  Major changes in above text!!  And It will even:(!!): raise additional questions such as:  Were any of the described and similar specimens wxed out of the breccia(?) -- Very likely, YES!!     When(?)  & Were the conditions when the caves, karst, etc. that existed when the source rock/debris of the breccias were formed and accumulated such that the included holey stones had already been subjected to non-marine environments and processes(?),      OR, perhaps they would have been formed in marine conditions BUT, if by rock-boring clams, that would extend their range back to pre-late Devonian!!!  , etc. Qre this last item, statements would then be appropriate re  fact that dates so far as information given in the Treatise… suggests that boring clams, although known to have lived in locations here and there the world over, have not been recorded in strata older than Mesozoic  -- ((The one noted as questionably Carboniferous seems to have been a burrower rather than a boring clam.))  BUT  all of that more likely indicates that I am unlikely to find any holey stones in the Mackinac Breccia;  nonetheless, I SHALL SEARCH!!! & and make a point to note that such as been done with whatever the results are  AND, it also would be worth at least mentioning that the refs from Reed do indeed  indicate that the holes were formed no earlier than mid-Mesozoic – i.e., when the northern part of MI Basin was no longer (or later) under marine or even brackish waters. etc.  Whatever, e, all of this could lead to some so-to-speak convoluted possible histories of these rocks/stones and even of at least this part of the Michigan Basin, … .

 
--------)    with consequent freeing of portions of the rock from their outcrops, and transport of those fragments by various agents in diverse environments. Part of that transport appears to have been within an environment where at least some of the loose fragments – i.e., stones – were turned over, probably more than once, by, for example, breaking waves, so diverse surfaces of those loose rocks were subjected to attack by whatever critter/process made the holes, IF they were so-formed. [[It is at least of passing interest that the Gros Cap stones are currently in such an environment, and this could be construed to indicate a relatively recent date for the formation of the holes. It would seem, however, that the only way this could be proved unequivocally would be to find such boring in process or indicated by the presence of, for example, some remains of the boring agent within one or more of these holes; on the other hand, one could also argue the lack of any such remains s within any of the holes would hardly be expected when the amount of weathering and erosion the holey stones of this area have undergone recently, and are, in fact, still undergoing .]]  Dick:  Yes, this all needs to be written, rewritten, after you’ve had a chance to look for more rocks this spring as we discussed on the phone.  Thmain thing to check is whether these ‘borings’ are symmetrical or tapered as I mentioned above.  If they are tapered, then they probably are from pholads and a more detailed analysis needs to be made as to whether there are freshwater boring clams, their geologic range, etc., and what is known in the literature.  It certainly seems not much is known about them, from the little bit of diggings I’ve done.   

The following aside may not be needed or need revision IF holey stones are found in the Mackinac Breccia!!! [An aside: If the holes in these stones were formed by any animal, the holes would be ichnofossils – i.e., “trace fossils.”  However, unlike more typical ichnofossils, these were apparently made much later than the rocks in which they occur.  That is to say, rocks which are more than [400,ßrevision to be needed?!!] my old contain ichnofossils made by life forms that lived as recently as the last few thousand, or perhaps only the last few hundreds, of years. Consequently, these ichnofossils, and perhaps others of this general nature would not have the same value – e.g., for dating their host rock – as most fossils do.]

 
Conclusions given the above sections of this entry should not be construed to indicate that I think all holey rocks have been formed when, where,  . . . or by the processes indicated as likely to obtain for those described in this “report.”

ALSO NOTEWORTHY: 

               1. Roughly similar stones have been recorded from several regions the world over.  Numerous photos, locations where these stones have been found, etc. are available on-line;  search – using, for example, ”holey stones” -- Google Images.

      One relatively nearby occurrence includes photographs of a few of these stones that were "gathered on the beaches along the north shore of Lake Superior near Grand Marais, Minnesota" (Still Blog, 2012).

                 2. Re when the holes of some of these stones may have been used as anvils, see those found in Adams County, Ohio and recorded as so-used;  this uses is recorded as "Dating to the Late Archaic period (ca. 8000-1000 B.C.)." (Gray & Pape, 2016).  See also Figure #2-1:  This photograph was setup in 2015 A.D.;  it should not be construed to indicate this use either to be or not to be current.

                3. Holey stones have long found roles in the Arts and Crafts.  Examples of these uses include such diverse things as the highly prized Scholar’s stones, decorative stones for aquariums and terrariums, worry and “good luck” stones,  parts of jewelry (especially pendants, but also as parts of wrist and ankle bracelets), and as clock faces and wind chimes.
                    The “Taihu rock”; a particularly interesting “Scholar Stone,” which is referred to as a natural sculpture, is now in the Art Gallery of New South Wales in Sydney, Australia. – Hauser (2014) notes in her remarks about that stone: “Chinese developed a complex connoisseurship of such phenomena … [This rock is a] fine example of the sort of aesthetically pleasing stone that came to feature in gardens (and paintings of gardens) during the Tang Dynasty [628-907]. … Large stones … were meant for gardens; smaller ones, known as ‘scholar’s stones’, would sit on desks as an aid to contemplation.”
                         Some so-called holey stones (etc.) in the marketplace have been manufactured.  Examples are those replicated by some silicone; and, some of them have had their surfaces plastered by a mixture consisting largely of crushed rock (Holey…, 2016).  It seems that most of these “holey stones” sold for use in aquariums and terrariums.

                4. Holey Stones have, as one might suspect, attracted a rather large following among people who associate minerals, rocks, etc. with, for example, healing (of both physical and mental conditions), enhancement of meditation, etc., etc.  Indeed, some advocates ascribe all sorts of attributes to these stones; and, of course, marketeers have extolled these claims and, for example, repeated diverse versions of the myths about these stones in releases about them in their brochures and other solicitations.   

ACKNOWLEDGMENTS:  Krista D. Brown helped collect some of the described and studied specimens. [Jessica M. Winder provided an opinion.] Reed Wicander, Kurt R. and Richard S. Dietrich read and criticized different drafts of the manuscript, and Dr. Wicander also supplied not otherwise readily available literature.  David D. Ginsburg formatted the cited references.  I gratefully acknowledge these contributions.    

REFERENCES CITED

Boardman, R.S. (senior editor), A.H. Cheetham and A.J. Rowell (editors). 1987.  Fossil Invertebrates. Palo Alto(California): Blackwell Scientific Publications:

       Conjured Cardea.   n.d.   “Hag Stone-Holy Stone-Fairy Stone-Witch Stone-Protection from the Evil Eye, Nightmares, Spirits, Misfortune-Key to the Faerie Realm”.  <http://conjuredcardea.indiemade.com/product/hag-stone-holy-stone-fairy-stone-witch-stone-protection-evil-eye-nightmares-spirits-misfortu>.
Internet; accessed  2 January 2016.

         Culbreth, Steve.  n.d.  Forensic Paleo biology: holey rock of Texas.  Dinosaur Home:
< http://www.dinosaurhome.com/forensic-paleo-biology-holey-rock-of-texas-806.html>.  Internet; accessed 14 November 2015.

Davis, A.B.  2002.  “Cupstones of Adair County, MO”. Missouri Folklore Society.  < http://missourifolkloresociety.truman.edu/cupstones.htm>. Internet; accessed 14 January 2016

Deneki Outdoors.   2014.  “Holey Rocks”.   <https://www.deneki.com/2014/12/holey-rocks/>.    Internet; accessed 18 November 2015.

          Dietrich, R.V.  2015.  Uses of Stones: Pebbles, cobbles and boulders. <http://stoneplus.cst.cmich.edu/stones/index.htm>. Internet; accessed 31 January 2015

       Eitam, David. 2009.  Late Epipalaeolithic rock-cut installations and groundstone tools in the Southern Levant: Methodology and Classification system. .Paléorient, 35, no.1:77-104. <http://www.persee.fr/doc/paleo_0153-9345_2009_num_35_1_5279>.    Internet; accessed 10 January 2016.

          Frey, R.W.(editor).  1975. The study of trace fossils: A synthesis of principles, problems, and procedures in ichnology. New York, …: Springer-Verlag.

Gray & Pape.  2016.  “How Do You Crack a Nut?”.  <http://graypape.com/how-do-you-crack-a-nut/>.    Internet; accessed 31 January 2015.

          Hauser, Kitty.   2014.  Nature is the artist… .  The Weekend Australian. 20 December 2014. Canberra: <http://m.theaustralian.com.au/arts/review/nature-is-the-artist-with-chinese-scholars-stones-at-art-gallery-of-nsw/story-fn9n8gph-1227159723045>.  Internet; accessed 14 November 2015.

         “Holey Rock Background”.  2016.  Your Fish Stuff.   <http://www.yourfishstuff.com/holey-rock-background>.    Internet; accessed 14 January 2016.

          Kuhnlein, H.V. and N.J.Turner.  1991.  Traditional plant foods of Canadian indigenous peoples: Nutrition, botany and use. (Volume 8 of “Food and nutrition in History and Anthropology).  Gordon and Breach Science Publishers: The Netherlands  (1996, second printing).   (“Oaks”:199-201)
<https://books.google.com/books?id=fPDErXqH8YYC&pg=PA200&lpg=PA200&dq=Ojibways+use+of+acorns&source=bl&ots=wG1m1PB0Ki&sig=55FuaywNKYz_ZoGc3EZgnWNClkA&hl=en&sa=X&ved=0ahUKEwjRqtCL_IjKAhXGYyYKHYiZCIAQ6AEIKDAC#v=onepage&q=Ojibways%20use%20of%20acorns&f=false>.  Internet; accessed 1 January 2016. 

   Miller, William, III (editor).  2007. Trace fossils: Concepts, problems, prospects. Amsterdam,…   :Elsevier.

>>>>   Moore, R.C. 1969. Treatise on Invertebrate Paleontology, Part N: Mollusca 6, Bivalvia, vol.2??. Boulder(Colorado):Geological Society of America 
  Does above citation need to be changed??

          Niagra, Kandra.   2015.   Holey Stones. Wee Peeple Doll Construction. < http://www.weepeeple.com/drawer/holeystonespage.htm>.  Smithville, Texas, September 2015.   Internet; accessed 1 January 2016.

            Seilacher, Adolf.  2007. Trace fossil analysis. Berlin, …:Springer-Verlag.  226p.

Stanley, S. M.  1970.  Relation of shell form to life habits of the Bivalvia (Mollusca). Geological Society of America, Memoir 125. Boulder (Colorado): Geol. Soc. America

Still Blog.   2012.  “collection of rocks with small holes”.  <http://stillblog.net/collection-of-rocks-with-small-holes/>.  Internet; accessed 10 November 2015.

Towrie, Sigurd.  n.d. “The Odin Stone”. Orkneyjar. <http;//www.orkneyjar.com/history/odinstone/>. Accessed 31 December 2015.

Wilson,… and … Palmer.  1988. Which one??

Winder, J.M.  2013.  Jessica's Nature Blog.  <https://natureinfocus.wordpress.com/>.  Internet; accessed 7 January 2016.

---

   Is Pacific Biological Station, British Columbia  worth a contact?? To see, for example, if they know of freshwater rock-boring clams …

 What about --  I believe there is a similarly directed group at U of Cal at Santa Barbara. 

  Also, what about archaeology departments – e.g., of Truman University (Missouri)?? 
-----
D, Try to find the site where the areas of these are shown on a map of British Isles. --  If found, can be cited in  ALSO NOTEWORTHY:  #

REREAD!>>  Davis, A.B.  2002.  <http://missourifolkloresociety.truman.edu/cupstones.htm>. AND  SEE ALSO SEVERAL ARTICLES IN References given at end of article.
--------------------------------
The following designations for holey stones, though not English, may warrant mention??:  men-an-tol, an-cloc consanta (drilled stones).  BUT, probably not -- they apparently apply only to larger (e.g., =/> monument-size), stones with one or more holes, and the holes are widely thought to have been man-made.

LITERATURE INFO to check/use:

 
Frey, R.W.(editor).  1975. The study of trace fossils: A synthesis of principles, problems, and procedures in ichnology. New York, …: Springer-Verlag.

P188 – mentions other borers:  “Bivalves, polychaetes, sipunculids, and other groups bore terrigenous rocks … and galatheid crabs excavate …”

P192 -- “Separate groups can produce very similar borings.”     Note that some  paleontologists  refer to this as bioerosion.

  RVD.  Conclude that with no more information that is apparently discernable from these specimens, which among other things have been wxed and eroded,  it seems prudent to conclude that these borings are of uncertain origin. ALSO, although it seems that perhaps the composition of the substrate might be of value, to date I have found no correlations known or recorded seem to provide any useful criteria. In any case, my study was not directed to determining what animal bored it, whether they were bored by abrasion – i.e., mechanically – or chemically, etc. or even the environments, etc.  In formation relating to these kinds of considerations  have been recorded in several publications – e.g., Frey( Warme part – i.e., does this book consist of pubs of people listed atop some of the pages rather than Frey himself?? See top of pages ??   -----.   Instead, not being a paleontologist, my efforts and recording of such are provided merely to show, describe, question – particularly hypotheses suggested on the internet – many by non-scientists – to try to account for the possible origin and time of origin of the stones at Gros cap.  Some of the basic information given here may be of value so far as getting an sappropriate paleontologist interested in  investigating the Gros Cap specimens thoroughly. – These specimens can be made available for any such study. <>         

There are several other invertebrates –e.g., sponges, barnacles,   that apparently excavate holes in rocks and/or other things such as shells and coral – several are listed, a few examples are illustrated  in Frey, -- See above!           In any case, the macroborings  illustrated that seem to resemble most closely those of the Gros Cap specimens are attributed to bivalves.  

 I should try to get and read  Kobluk et al. (1978) and perhaps Palmer 1982 –both referred to by Miller¸ who also directs attention to two other articles to see:  Taylor and Wilson (2003)  and Bromley (2004) <<-- REALLY TRY TO GET THESE LAST TWO!!!

 Much from this one is above it in remarks I put there.  

Seilacher, Adolf.  2007. Trace fossil analysis. Berlin, …:Springer-Verlag.

Borers:   crabs, clams,  worms  techniques of burrowing are given – I am NOT interested in them unless dealing with patterns that result from those techniques.

--The diagrams are okay,    BUT   This is one of those places -- And I think such is for many things (e.g., rocks) often more misleading than helpful!! --  that I think photo matching might be a better tool (!).
 

Wilson and Palmer. 1988 - Search on Google, using Wilson,… and …Palmer. 1988  will, I think, get to one to the info needed;  then Search within for Corallidomus and Ordovician.   IF not available on line, I need to get the article.
 
Following is copy from PDF of Miller, p.362:  

"The earliest bivalve boring is the Ordovician P,etroxestes, which was produced by Corallidomus, a facultative boring clam (Wilson and Palmer, 1988)"

  Question: were holes are in wood or rock or unconsolidated sediment?? – probably not wood considering date!!!!!!
  

---

D:  Things to do/consider/rewrite IF:
  1.Search for these stones in Mac Breccia. 

 2. If any are found, Consider when holes were bored – e.g.,

           a.during sedimentation – not likely with holes in both tops and bottoms of strata/stones

           b.post lithification!!!  Post breaking of layers off so they could be attacked on exposed surfaces!  SO –

 3.What were conditions from then to time they were incorporated into the Mac Breccia??  -- Note, for example, conditions (non-marine, even continental -- needed for karst topog, widely thought necessary for fm of the breccia.  ((Such might require, and at least would be a good place to mention the fresh- vs marine- water habitat info for boring clams)) [[AND, IF holey stones are not found in breccia, be sure to note that that absence does NOT necessarily preclude some being there at other places -- my sampling will be somewhat limited because of lack of outcrops, difficulty in getting to some of those known to exist, ... !!]]  ALSO, if not there, mention likelihood that post Mac breccia formation(time) the area was apparently under terrestrial or near such conditions at least much of time --- e.g., next overlying rock is the Engadine fm., widely considered to be of deltaic/estuarian/… deposition, etc., etc.    

---

 

#3. Stone "Circle" near Gamble Lake, Mackinac Co., Michigan.

DRAFT as of late 2014

      

           WHAT??.  This "structure" is an example of accumulations of stones with similar upland locations within the area.  Each of these stone piles is considered to be an ancient artifact by the local people who know them well.   In addition, some of these people have indicated their beliefs that the piles were likely made by, for example, neolithic "stone-age" aborigines, Celtic Druids, Vikings or pre-Columbian Native American Indians.  Whomever, it seems safe only to say that these "structures" were made after the last removal of glacial ice from the area, which was about 11,000 years ago. 
               The geographical locations and interrelations of most of these accumulations of stones are frequently cited to support the hypothesis that they are meaningful artifacts -- i.e., they are not just stones that were put where they are in order to clear the land. In support of this aspect of the hypothesis, it is indeed quite evident that the land surrounding this accumulation of stones would have never been cleared for, for example, farming (see the map), and, indeed, there are several stones that I believe would have been removed and become part of this group had that been the purpose.  In addition, it seems noteworthy that this structure is on what would have an island in during the so-called Algonquin and  Nipissing stages of the Great Lakes.  And, if only a few or no trees etc. were present, nearby areas of the lower-level Lakes Chippewa and Stanley as well as of the more recent, and current, Lakes Michigan and Huron could have been seen from this location. 
               One professional archaeologist is said to have looked at this group of stones and suggested that this structure represents a "post-American Civil War lime kiln."  Nothing that I have seen or been able find nearby seems to support that suggestion.  The only other suggestion that I have heard is that it may have been a place where fires were built to heat maple sap to make syrup.  Consequently, the given heading seems appropriate until the origin(s) and use(s) of this and other accumulations of stones in similar settings are proved.
              For the record: The outside "circumferance" of this roughly circular structure is approximately 55 feet; the "diameters" range from about 16 to 20 feet;  the inside diameter ranges from approximately 6 to 8 feet;  the height of the wall, the top of which is roughly horizontal, ranges from about 3½ to 4½ feet above the surrounding uneven ground-level;  the "floor" of the central part is about 1½ feet above the "average" surrounding ground-level.  The constituent stones are largely "limestone" rubble but "hard-rock" boulders are also included -- see close-ups.  That is to say, both stones from the rubble of fairly nearby formations and stones transported from Ontario by glacial ice during the last "Ice Age" are included.  This makeup, of course, is one of the criteria that establishes the date of creation of the structure as post-the most recent "Ice Age" glaciation.
             The topography of the nearby area led to my thinking of this structure it as analogous to a multi-jeweled pendant on a dowager's breast --see the section of the topographic map area that is included.  As might be expected, other people who are familiar with these relationships have alternative interpretations.

---

                      “Though they [i.e., A-tents] form only a minor structural and topographic feature, they are rather unusual
                          and the interest attaching to them is out of all proportions to their size and frequency.”             (H.P. Cushing , 1910)

INTRODUCTION

An A-tent, previously only mentioned in an obscure publication (Dietrich, 2008, p.61) and apparent modifications of a nearby A-tent, which was first recorded more than a century ago (Cushing et al, 1910, p.115) are described. Questions and comments that arose as these descriptions were recorded are noted.

DESCRIPTIONS

   INFORMATION COMMON TO BOTH A-TENTs.

PETROGRAPHY of the Potsdam Sandstone within the area is described by Buddington (1934, p.179) and Dietrich (1957, p.101). The strata involved are silica-cemented sandstone the sand of which consists of 99-plus per cent medium- to coarse-grained quartz sand.  A few lamellae consist largely of hematite-coated grains.  The strata involved in these two A-tents are similar.

STRATIGRAPHIC POSITION.  The stratigraphic relations and information about the variable thicknesses of the Cambro-Ordovician Potsdam Sandstone of the area are described by Cushing (1916, p.32 et seq.).

DATE OF FORMATION.  A post last glaciation of the area date for the formation of these A-tents is indicated by the presence of the glacial striae and chatter marks on the upper surfaces and the absence of such features on the other , surfaces of the blocks of these structures. [[??>> Because basic assumptions upon which such "blanket" names as Nebraskan and Wisconsinan have subsequently been concluded to lack their originally assigned application, none of these names is used in this note. <<??]]

    HADLOCK A-TENT.  This previously undescribed structure is called the Hadlock A-tent in this note.  Edwin C. Hadlock (d), then owner of the field in which the structure occurs, directed my attention to it in 2007, when he was taxiing me within the area during a geological reconnaissance study of the Hammond township (Dietrich, 2008) .

BETTER PHOTO to come!!!! 

  This A-tent (see Fig. 5 #1) is located a few meters west of Route 37, 1.8 miles north of Hammond village.  It consists of two, continuous sections, each of which has a virtually straight axis;  the strikes of these axes differ by ~!0 degrees.  Dimensions and descriptions follow:

 Location:  across Route 7 from the junction of Hadlock Road (i.e., at ~ 44°28'22"N; 75°40'58"W;     elevation ~341ft.MSL).  [This A-tent is ~ 5.4 miles, northeast the Cushing A-tent.}

 Strike of axes:  Southern part – N35E; 

   Northern part – N25E  (i.e., 35º  and  25º, respectively)

Height of apex above level of surrounding surface: up to ~1m. ( = ~3 ft.)

            Length of structure:  Total of two segments -- 53m. ( = ~175 ft.)  

                                      Southern part –     m. ( =  ~X ft.)  

  Northern part –     m. ( =  ~X ft.)  

Width of structure:  4.6 m . ( = ~15 ft.)    [[ <chk are both parts of same width? AND  THIS needs more measurements and explanation.  ]]

             Sizes of blocks:

                                     Southern part – Largest: 0.75  x 1.65 x 0.23 m = ~ 0.28 meters³  weight?       ( = ~  2½  x  5½   x  ¾  ft. =  ~ 10¼ feet³ )  

                                                                                      (delete this one? -- One of smaller ones: yy x yy x yy)  

                                     Northern part -- Largest: 2.3  x 4.4  x 0.2 m  ( ~  2  meters ³)  weight?      ( = ~  7½  x 14½  x  2/3   ft.  ( ~ 72.5 feet³ )        .                   

                                                                                      (delete this one?? -- One of smaller ones: yy x yy x yy

                     1.   chk >>(if none, say so)>.   Glacial striae and percussion marks are on original, neay horizontal tops of blocks but NOT on their other surfaces.

                     2.  The “cross joints” -- i.e., the broken surfaces of the blocks that are at a high angle to the axis of each of the two segments of thIs structure are approximately perpendicular to their respective axis.   

                     3. The block on one side of the axis of each segment overlaps its  opposing block. AND, with exceptions, each overlapping block adjacent to a block that is overlapped from the other side of the axis (Fig. 5-#2;  cf. Cushing et al.,1910,Fig.10, p.116). << D:– give photo to show and label as Mortise and Tennon arrangement.; 

                     4.  Really look at junction area, and describe here.   Get photos of “junction" area IF POSSIBLE!

                     5.  ( IF exposed, MEASURE STRIKEs and DIPs OF NEARBY JOINTS!!;  IF not, perhaps(??) cite diagram in Brier Hill report. )

  This A-tent (see Fig. 5 #2) is about 3.9 miles southsouthwest of Hammond village – i.e., about 1.8 miles south of Chippewa Bay.  Dimensions and descriptions, along with comments about modifications it has undergone during the last hundred years, follow:

            Location:  southwest of Webster Road, ca. 0.15 mi. from its junction with Callaboga Road  (i.e., at ~ 44°24'51"N; 75°45'25"W; elevation ~361ft.MSL).   [And, as already noted, this A-tent is ~ 5.4 miles, southwest the Hadlock A-tent.}

               THIS FIRST ONE, IN PARTICULAR NEEDS RECHECKING!!!!!

            Strike of apex: N.72E  [per Cushing: N.28W]   respectively -- 72º  and  152º  

Height of central part of apex above surrounding surface:  ~ 1.8 m. ( = ~ 6 ft.)  [per Cushing: about 12 ft.]

Length of structure:   ~ 41 m. ( = ~ 45 yds)  [per Cushing: 40 yds]

Width of structure (i.e., between edges of blocks on opposing sides):  ~13m. ( = ~ 14 yds/~ 42 ft.)                       THIS needs more measurements and explanation.

DELETE FOLLOWING?? One of smaller ones.  ~3.5’ x 3.5’ x 0.5’

                     1.   As already mentioned, glacial striae and sporadic chatter marks are on the original tops of blocks but NOT on their other surfaces.  

                     2.  The “cross joints” -- i.e., broken surfaces of the blocks that are at a high angle to the axis of this structure -- are approximately perpendicular to the axis.

                     3. Only a few of the broken surfaces that so-to-speak define the axis of the structure overlap as indicated by Cushing (Cushing et al.,.1910 - p.116, Fig.10) -- instead, nearly all of the blocks that are on the northwestern side of the apex overlap the blocks on the southeastern side -- (see photos Calaboga 8&9).  However, considering the fact that Cushing's indicated height of the apex is significantly greater than it is now (2007), the following question and comments seem noteworthy;  they possibly explain this possible discrepancy in Cushing’s and the recent observations.  Have the blocks moved outward from the axis  -- i.e., undergone post-formation partial collapse? since Cushing mapped the structure in the early 1900s? -- One or more of the following activities may, in fact quite likely, have occurred and would support an affirmative response:  a. Trees have grown in the axial since Cushing's observations -- (see Fig.  Calboga 9). (Tree wedging – e.g., see Dietrich (1957, p.21, Plate 6) -- provides permissive support so far as their having a causative role for such movements of the blocks.)   b. The surrounding, nearly flat bedrock is exposed on the southeastern side of the structure whereas the other side is covered by soil.  (Slipping atop the exposed rock, possibly enhanced by seasonal ice buildup would tend to be away from the apex;  this would result in the apparent change in height and possibly also the apparent differences in the character of the overlapping relationships along the crest of the structure.

                     4.  (Measure/record Strikes & Dips of  nearby Joints! ) 

ORIGINS

The two A-tents may have similar or different origins; this is true so far as both the pre-formation conditions of the rocks and/or the causative triggers (see COMMENTS …).  No origin has been or is herein suggested for the Hadlock A-tent.  Several comments about the possible origin of the Cushing A-tent are in the literature (e.g., Cushing in Cushing et al, 1910;  Twidale and Bourne, 2005;   Jacobi et al., 2007).

Two considerations indicate that only a comment ( i.e., NO conclusion) about the an origin should be given in this note  --  1. No data (i.e., values) relating directly to the stress -- internal/residual/compressive -- of the sandstone of either of these structures or the surrounding rocks are available.  [and]  2. Two seemingly significant references-- i.e. Dames and Moore, 1974 and Smith, 1977 -- that pertain directly to the Cushing and other nearby A-tents have been unavailable, even via ILL. 

The comment is:  Changes of conditions -- for example those that accompanied deglaciation and/or post-last glaciation isostatic rebound -- may have had major roles in both the buildup of internal stresses and their release, which may have been abetted by “triggers,” that caused buckling and formation of these A-tents

((That comment is based largely on impressions gained from   a. data recorded in this note;  b. a review of the vast literature relating to A-tents and the pertinent tectonic domain of the region;  [and]  c. considerations relating to Lowry’s (1959) and my (1961) investigations of the Mt. Airy “granite” and subsequently determined residual tress information obtained for that rock by overcoring procedures employed by the U.S. Bureau of Mines personnel, which were concluded to be conditions “ripe” for formation of additional buckles at the quarry.

          ((To elaborate, the following thoughts have arisen in my mind several times since I again saw the Cushing A-tent and had my attention directed to the Hadlock A-tent: 

((The axes of these A-tents have different strikes; in fact, the Hadlock structure has a bipartite, albeit continuous, axis -- the two parts of which have different strikes.  And, none of these strikes appears to fit into a pattern or correlate with the current regional – granted, less than well-established – regional tectonic/stress pattern. 

((The structures were formed after the last glaciation -- i.e., after the load of glacial ice, plus or minus debris, was removed -- and during the subsequent, still on-going, isostatic rebound.

((The so-called “trigger,” could have been instantaneous or have been a "slow-trigger" -- i.e., a gradual change in the position and condition of the rock until a critical condition was exceeded.  Two examples might be only the removal of the removal of the glacial ice and its load and/or when subsequent isostatic rebound reached a critical level – i.e., where a release of the compressive stresses within the rock occurred and one result was formation of one or more  A-tents. 

((--- Of course, no stress measurements for rocks of either A-tent or of nearby equivalent strata are known, and cannot be determined for the time of formation of these A-tents.  However, if current measurements of the internal stresses of the rocks of these structures and of the surrounding rocks are made, possibly those data could be programmed to give a model whereby one could at least determine their approximate previous conditions and even how these A-tents were formed, whther with or without a trigger per se or even with a “slow trigger.”  -- See paragraph XX in the following Comments and Questions section.))

 Model

As I typed the above comment plus, which some readers may consider a conclusion, two old “saws” came to mind:  “Fools rush in where wise men fear to tread.”  and  “There’s no fool like an old fool” (I am 92 years old).

It seems prudent to preface the following paragraphs with a disclaimer:  Because of my lack of access to some of the publications I should review, I urge readers to insert So far as I know before each of the following paragraphs.

   The first five paragraphs relate to the possibility that burial beneath thick glacial ice had a role in the formation of these A-tents.

          No A-tent in this region has been recorded as having been formed before the last glacial epoch.   Does this mean none was formed?   OR  Were such A-tents, if formed, disrupted and their parts moved and thus not recognized as such?  --  So far as the first question, three things may have precluded their earlier formation:  1. Strata susceptible to disruption and formation of A-tents may not have been at or near enough to the surface where they could form.  2. During earlier glacial and interglacial epochs the strata were not buried deep enough to gain an internal stress condition required for the release and formation of A-tents.  3. Whatever the depth of burial by the glacial ice (etc.) and the resulting condition of the the strata, the subsequent rebound was insufficient to change the environment where such would happen during earlier interglacial periods.  And, of course, some combination of these possibilities plus other things might have been effective controls.  In any case, IF either the second or third possibilities prevailed, they would have implications so far as reconstructing the Pleistocene history of the region.

          To continue that line of thought:  Was the glacial ice plus its load during the last glaciation of this region thicker, and thus heavier, than that of earlier glaciations?  If it was, the downward depression of the Potsdam Sandstone that constitute these A-tents would have been buried deeper than during preceding glaciations, compressional stresses built up within the buried rocks could have been greater, and consequently the post-glacial isostatic rebound, which is still occurring, would have caused those rocks to have undergone greater changes than those to which the rocks had been subjected in response to earlier glaciation and rebound “cycles.”  In addition, the current bedrock surface may not have been at or even near the surface before the last glaciation.   [Along this line, what is really known about the thicknesses of the last continental glacier within the region and of earlier Pleistocene ice sheets that covered the region?  Are dates indicating their longevities really indicative? Even if they are, is there any known correlation between durations of continental glaciations and their thicknesses(?), of the amount of erosion they caused(?),  ...?    Is the distance that the different glacial ice sheets extended southward related to their "up-stream" thicknesses?   Does the size and distance of travel of erratic boulders during any given glaciation have a relationship to the thickness of the glacial ice(?) to the speed of movement of the ice and its load(?), to the amount of erosion caused by any given glaciation(?) …

         Could fatigue have been involved?  -- That is, is it possible that more than one depression (for this region, multiple periods of glaciation) and rebound had a role, or perhaps was even required, for the formation of the A-tents in these rocks.  [This question is prompted by changes and effects known to be involved in breaking, for example, metal sheets, rods, etc. – i.e., those that break only after having been bent and straightened several times.]

        Could the occurrence of these A-tents indicate that the strata involved were only finally thinned enough by, for example, the last period of glacial abrasion, to the point that they could no longer retain their integrity – i.e., to the point they could be bent and broken to relieve the residual stresses within them .  [If this was a control, it seems likely that it must have been only a subsidiary control;   among other things, the thicknesses of the strata involved in the Hadlock and the Cushing A-tents differ markedly, AND several extensive areas with thinner, apparently similar Potsdam Sandstone strata as exposed bedrock with no A-tents occur within the area.]

         Are more A-tents likely to be found with the area?  This possibility came to mind because of an inquiry of a geologist who read this manuscript and reminded me that both A.F. Buddington, who mapped the area, and I, who lived in the area for many years and mapped an adjacent quadrangle, were basically hard-rock petrologists, and consequently may have had our minds on other things as we passed the Hadlock A-tent.  --   I feel sure that "Budd" did not see it, or he would have told me;  I know that I did see it  even though I drove past it  hundreds, if not thousands, of times.  I first saw it when the landowner took me to see it in 2007, more than 65 years after I first drove past it IF it was there.  [The "IF ..." is based on the possibility that it was formed sometime between about 1952 and 2006.  I shall continue to question people who might have information that would preclude or support this possibility.]

   The following comments include a maxim, a wonder, and “triggers”.

            A-tents can only form where a sufficiently large "open space" is present in direct contact with or relatively close to their constituent rock formation -- i.e., a space into which the rock can "burst."   Therefore, the presence of an A-tent can serve the same role as an unconformity so far as interpreting geological history.        

            One wonders if the fact that the Hammond A-tents are on so-to-speak high areas had any effect on their formation. – The Cushing A-tent is on a “high” between the St. Lawrence River and Chippewa Creek valleys; the Hadlock A-tent is on the "high" between the Chippewa Creek and Black Lake valleys.

      TRIGGERS:  

             DETonations – Nearby blasting could change conditions, perhaps only by slightly jarring, a rock in its near-critical condition and thus trigger formation of an A-tent. Time of its formation appears to preclude this possibility for the Cushing A-tent, but perhaps not for the Hadlock structure.

   EARthquakes – These, like detonations, may cause and/or be the result of the formation of A-tents such either, neither, or both of the A-tents considered in this note, and also of other A-tents. A recent example is one that formed near Menominee, Michigan in 2010.

  ENCircled  …… – This, apparently “far out” possibility came to mind during the 2014-15 winter when I observed the formation of an A-tent like structure formed of surficial and near suface ice in a bay near the northern shore of Lake Michigan.  It appears to have formed when a volume of “buttressed” ice had expanded to the point that it became too large for the confined space that it occupied. Granted, that feature apparently formed as a consequence of the expansion that occurs when water is frozen to ice within a confined space. And, rocks tend to have their volumes reduced, albeit only slightly, when cooled but what about rocks that have high porosities (and permeabilities) when they are saturated??

           METeorite impact – A true trigger, and it seems possibly a cause, wherever a meteorite might impact rock, the condition of which was at a critical state so far as becoming an A-tent.  Along this line, it might be worthwhile to search for meteorites in the vicinity of A-tents!?!?  AND, If it is possible to search within the open-space beneath the blocks of an A-tent, one should also look for shear cones (see Lowry, 1959, p.1; and Dietrich, 2008, cover 3).  What about the guy who gave me the latter??  Contact him through Donna/Nancy? – I need to know if that one was made by man-imposed percussion or if perhaps there is an A-tent where he found it !

  SHEeting of, for example, underlying granite -- Could sheeting of an underlying formation, whatever its cause, act as a direct "trigger"(?). or perhaps so act indirecty by furnishing open places into which water could get and freeze and expand?     [So far as the two A-tents described in this note, it seems quite possible that granite that exhibits sheeting is beneath the sandstone of the Cushing A-tent, and the identity of the rock beneath the sandstone of the Hadlock A-tent may be the same, but is less predictable. To date I have found no pertinentt well driller's data.]

          THErmal insolation (Would it be better to call this a condition??  As a possible trigger, this one is of special interest to me for two particular reasons:  1. This possible trigger reminds me of one of my favorite phrases in geological “literature,” one I first found in the early 1950s – i.e., “horizontal expansion of superficial strata, consequent on postglacial amelioration of climate“ (Gilbert, 1887). [and] 2. It  reminds me of the great timess Wally Lowy and I and our students spent at the Mount Airy "granite" quarry -- i.e., when we were repeatedly reminded of  the seasonal concentration of formation of the “bulges” there. 

          MIScellaneous  1. Could the existance of post-glacial Lake Iroquois, which covered this area, have had any role in the formation of these structures?

                                  2. Could permafrost had any role?

                     Frontispiece        This fieldstone faced building was originally built as a country schoolhouse.   Considering the
                                                  roles such buildings have had in the lives of so many of us, AND having several family members
                                                  -- my grandmothers, my mother, an aunt, two cousins, my wife, my two sons and my daughter --
                                                  who were or still are active teachers led my choosing this building for this position.   

R.V. Dietrich © 2015
Updated March 9, 2012