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I don't recall if there
was a color difference between the layers. Memory (being what it is these
days) seems to think it was about the same and my non-professional,
non-geological impression was these layers were probably laid down by yearly
flooding of the river (Virgin River), which
is nearby.
The tail-drag imprint was
very faint and if the volunteer at the site hadn't pointed it out I would have
missed it. I did take a picture but looking at it now, I can't pick out
where the drag is. Once again, relying on memory, I remember these as
being slightly sickle shaped... one bent to the left, the other to the right as
if the tail were in motion assisting the animals balance rather than a straight
drag that might infer prey being dragged (as suggested as a possibility
elsewhere).
I seem to recall the list
now allows attachments (if not, forgive me), so I've attached a photo of the
"drumstick" imprint. Don't get too excited about the visible "claw".
Someone there thought it would be nice to have it for the tourists and made it
out of cement. Since these are natural casts of the imprint, the
claw would actually be pointed the wrong way had it been
real.
If I figure out where the
tail drag picture is, I'll attach it in another email.
PB
----- Original Message -----
Sent: Monday, June 25, 2001 2:49 PM
Subject: Re: POLITICALLY INCORRECT UTAH
DINOSAURS!
Phil
Brunette described:
"...There are some very well preserved tracks and it appears to have been a
site that the dino's visited often since there are multiple layers of
impressions suggesting yearly visits.... or migrations
perhaps?"
It
might be interesting to do a study to try and determine whether the several
substrate levels where the dinosaurs walked have even the slightest of color
difference -- as contrasts with layers in between -- that might suggest the
specific time of year in which the deduced migrations might have
occurred. For example, in some palro-environments it it has been
speculated that layers laid down in winter tend to be somewhat darker, perhaps
due to deposition of vegetable matter now visible as a carbon residue.
Did
anyone notice color differences where the track-bearing substrates are visible
in cross-section? If so, did the tracks tend to predominate in
darker or lighter layers?
Phil further
commented:
"Of
the 100s of footprints ranging...from several inches to about 18 inches...
there were only two spots which might be tail drag. They appear on one
trackway cluster (many foot imprints of multiple animals) and within approx 8
feet of each other. Maybe one animal with a broken tail or injured
leg?"
Phil
(or others who have been there), did you notice whether the possible tail drag
marks occur along the approximately central line of a trackway? If so,
the tail drag explanation becomes a lot more convincing, regardless of whether
it was due to injury, sinking into mud, or whatever. If not, then all
bets are off.
Ray
Stanford
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