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Re: Corrections & concerns re Paluxy tracks
On Wednesday B. Aarons wrote that in his letter to an NBC station he wrote:
>>The supposed "mantracks" near Glen Rose, Texas are due to:
>> 1. Forgeries
>> 2. Erosion of dinosaur tracks
>> 3. Vague prints made by dinosaurs in the underlying substrate a
>> few inches below the surface they walked on. When these are
>> exposed to our view they look like questionable prints.
As many Dinosaurs list members know frommy previous posts, I have worked
and written extensively on the Glen Rose tracks and the "man track"
controversy, and was instrumental in prompting most human track advocates to
"backtrack" from their claims. However, some misconceptions still circulate
among both mainstream workers and creationists on this topic, and in view of
Aarons's remarks, I would like to clarify some additional points, as well as
address some concerns in regards to comments by Joel Sabal on the Paluxy
Aaron is correct in his first two points but not the third. His point
three describes what are often called "underprints." This phenomena does
occur but is not responsible for any of the publicized human prints near Glen
Rose. Nor is a typical tridactyl dinosaur track likely to yield a humanlike
shape in an underprint, but rather a less distinct version of the large three
toes (unless one digit were more impressed than the others, which can happen
but again, was not the case in any of the Glen Rose claims).
Aarons may have misunderstood from reports by me or others references to
infillings of Glen Rose tracks with underprints (they are not the same
thing). Allow me to explain. The most common source of "man track" claims
are actually elongate, metatarsal (or metapdial) theropod tracks whose digits
are subdued by erosion, mud-collapse, infilling, or a combination of factors.
In such cases the metatarsal segment is less subdued than the digits (because
of its larger and wider shape) and thefore often takes on a superficialy
humanlike appearance when the digits are indistinct (except for the large
size--hence the "giant man tracks").
On the most famous "man track" site (the "Taylor Site") the dinosaurian
digits are primarily subdued by a combination of mud-collapse and infilling.
The track depressions alone are now largely infilled (without the surrounding
substrate being covered by the same material). The infilling material is of
a somewhat different color and texture from the surrounding substrate; indeed
when the tracks are well cleaned the color and texture distinctions further
clarify the boundaries of the original track depressions, including the
dinsoaurian digit marks, to the chagrin of those who once called the tracks
human (often without cleaning the surface well).
The tracks could have become infilled (without the entire bed being now
covered with the same material) in at least two different ways. One is that
the infilling material that settled into the depressios before a third
sediment buried the entire works, or alternatively, when an overlying later
was scoured off the trackbed except for the track depressions that housed and
protected the infilling. At any rate, the tracks there are currently
infilled with a sediment that does not cover the rest of the bed. This is
not the same as underprinting, in which the entire track surface under
examination remains covered with another layer, obscuring print details. It
is possible that underprints of metatarsal dinosaur tracks would leave a
human like shape, but again, I have not seen this in Glen Rose. The important
point (sometimes misunderstood by both mainstream and creationist workers) is
that the humanlike shapes are not due to just poorly preserved or
underprinted examples of normal digitigrade dinosaur tracks, but rather are
forms of elongate, metatarsal theropod tracks whose digits are subdued by
infilling, mud-collapse, or a combination of factors. It is the metapodial
segment, not the digits, which ends up taking on the human-like shape.
Also, it should be noted that although carvings are often mentioned first
in critiques of the Glen Rose tracks, they actually have played a relatively
minor role in the controversy. Indistinct metatarsal theropod tracks are the
most common "man track" pheonomena (accounting for over half of the
publicized claims). Next most common are erosional markings (often
selectively highlighted to encourage human shapes, followed by ambiguous (and
occassionally doctored) markings of uncertain origin, and finally several
carvings--most on loose slanbs of rock.
I apologize to those who have heard much of this before, but since we
have had some new members (including Aarons), and the NBC show ressurected
the human track issue, I though these clarifications would be beneficial.
I also want to announce that I have just completed a Web site containing
several articles on the Paluxy "man track" controversy, including one that
specifically addresses the claims in the NBC program last Sunday. The
If you have any problems, comments, or suggestions regarding with the
site, please let me know.
I also want to address the following comment by Joel Sabel:
>I attended an AAPG national conference in Dallas in 1981. One of the field
>trips was to the Glen Rose site. The trip leader, a prof from UT as I
>recall, demonstrated how they were partially eroded and/or partially formed
>tracks. He pried up a track and we were able to see the cross section
>sediment patterns. Imagine if you will, a bird-like foot of of a swimming
>dino which barely reaches the soft bottom of a body of water. What do you
>get? The imprint of the center toe looking something like (only if you
>squint really hard and lots of beer helps) a human foot print. At that time
>(summer of '81) a religious organization was financing the excavation and
>related research as an effort to demonstrate creationism was a testable
>theory like evolution. I remember reading some time thereafter (months to a
>few years) that the project was abandoned and the group admited they were
>NOT human tracks.
>The lesson here is that it's hard to kill a myth...
Joel is right that it is hard to kill a myth. This unfortunately applies not
only to the human track claims, but some favorite mainstream explanations of
them. :) One of these is the "center toe" explantion mentioned above. This
has been advanced dozens of times in many mainstream publications, based (I
believe) on initial speculations by Wann Langston. There are examples from
other areas of central digits often being more impressed than the side
digits. The problem is, such "middle toe" tracks are not common in Glen Rose
(where the three major digits are typically impressed to approximately equal
depth), and do not account for any of the publicized human track claims.
The middle-toe concept was often advanced as an explanation for the most
famous creationist man track site: the Taylor Site, which have been
conclusively been shown to be largely infilled, metatarsal dinosaur tracks,
not middle digit impressions. It is disappointing to me that the middle toe
notion is still being suggested (especially by a field trip leader) long
after detailed explanations of the various man track sites have been
published. (I would be grateful if you could try to find out who this was,
so that I may forward to him some information).
Last, I was surprised to read that a track had been "pried up" to view
the subsurface features. The tracks in Glen Rose are a limited and
immportant resource. While as many know I strongly favor access to fossil
sites, when it comes to tracks, their removal or damage should be avoided
unless it is done in a justified and legal preservational messure. Besides
spoiling a track sequence for others, damaging or removing tracks at Glen
Rose or most other track sites is illegal.
Thank you very much.
Glen J. Kuban