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David Marjanovich, in response to my post of last night,
asked:
"Do you have a figure on
that?"
David, I'm unsure what you are
asking. Do you mean a digital image of the Newark Supergroup slab which
shows impressions resembling those in Gierlinski's paper? If so, no; but I
could produce one. Of course, we are not allowed to post such documents to
this list, but I could send you, personally, a jpeg of it if you're
interested.
David stated as a closing
thought:
"The feather impressions from the squatting
Condor look indeed like the impressions in question..."
If, in fact, there were 'dino-birds'
205 to 210 million years ago (as is the age of the trace discussed in
Gierlinski's paper), it seems hardly reasonable to expect their
feather (or, more reasonably 'proto-feather') covering to produce an impression
resembling that made by a squatting condor from our age. In view of the
impressions abundantly present on my Newark Supergroup example, which are
of identical character to those on AC 1/7, and clearly produced by
something other than a couchant dinosaur (and most plausibly make by wind or
water-drifting vegetation), and considering the fact that Paul Olsen has
examined Ac 1/7 first-hand and with a very experienced eye and
completely rejected the feather-impression interpretation (as has
Newark Supergroup track expert Donald Baird), it may be best to let a 'dead
bird' rest.
Oh, but how delightful it would be to many
of us if Gierlinski were right, and Olsen, Baird, and I were wrong. With
that kind of evidential deposit in the contrary 'hypothesis 'bank', even
the "Feducciaries" might well be forced to switch investment
brokers. :) (Sorry, I couldn't resist.)
But, let's keep on looking cautiously and
with cool heads. Other ichnites could have clearer, more diagnostic
stories to tell.
Ray Stanford
"You know my method. It is founded
upon the observance of trifles" -- Sherlock Holmes in THE BOSCOMBE VALLEY
MYSTERY
----- Original Message -----
Sent: Saturday, January 13, 2001 6:01
AM
Subject: Re: Not so new papers
David Marjanovic referred to:
"Gerard Gierlinski: Feather-like Impressions in a
Theropod Resting Trace from the Lower Jurassic of
Massachusetts"...
Several years ago when I first came
across this paper, I was thrilled at the thought that a Theropod had left
impressions of down or feathers that are preserved from the early
Jurassic. I held this enthusiasm for Gierlinksi's interpretation of
the dinosaur body impressions for several years, even after I met Dr. Paul
Olsen, probably the world's most experienced researcher on tracks from the
Newark Supergroup, in Philadelphia at Dinofest '98. When I brought up
the subject of Gierliski's paper, to Olsen, he told me that he has studied
the ichnite carefully and that the shapes interpreted by Gierlinski as
probable feather or down impressions definitely are NOT any such
thing. He had examined them very carefully and at
length.
:.-(
Frankly, at the time I was a bit taken
aback and even slightly offended. Olsen, I felt, was just too
skeptical and most likely wrong. Being the outspoken person
that I am, I flatly told him so!
Within the next year, however, a friend
brought some Newark Supergroup dinosaur ichnites to my home. One of
them -- much to my astonishment -- was covered with (all around, and any and
everywhere beyond, a theropod footprint) precisely (yes, identical in every
characteristic) the kind of traces that Gierlinski interprets as probable
feather or down-like imprints. What is clear, however, is that these
are not impressions made by a body covering of any sort. To my eye,
the most probably cause was some type of plant material having been dragged
across the wet or damp, very fine-grained substrate by action of shallow
water, wind, or both.
Do you have a figure of
that?
Now I have no doubt -- having seen this
(and the slab in now in my collection) -- that Paul Olsen's interpretation
of Hitchcock's item AC1/7 is the correct one, and Gierlinski's is
incorrect. After all, Olsen -- unlike Gierlinski -- has spent many
years (beginning in his youth) studying Newark Supergroup ichnites, and his
experienced opinion should carry considerable weight in evaluating
Gierlinski's paper.
Of course, I would be delighted
to be provided with evidence that both Dr. Olsen and I are wrong, but because of what I have now seen (the
Newark Supergroup ichnite now in my collection) it seems well advised to
stick with the more conservative interpretation of AC
1/7.
The feather impressions from the
squatting condor look indeed like the impressions in
question...
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