>Interestingly, on the cover of the AAPG tabloid, a year ago or so was a
>striking photo of a section of Navajo Sandstone Jurassic). In the photo
>was a man standing against a cliff of the sandstone, aand the legend
>declared this to be the desert sands of the Navajo. But directly behind
>the man, and obvious to any viewer were prominent dewatering strcutures not
>likely to be found in desert dunes! We wrote a letter to the editor
>pointing this out, but for some strange reason, they chose not to print it.
>
Unfortunately, I quit saving the AAPG explorer about 2 years ago. Now I
regret it. I remember that photo but a water escape structure might not be
unexpected given certain environments which are found in the Navajo.
"Recent work shows that the Navajo is indeed a classic
desert sand dune deposit. Locally, however, can be found
evidence for small oases or playa lakes represented by
distinctive thin layers of grayish limestone that often contain
reveal tracks. Although rare, the Navajo has also yielded
skeletal remains of crocodilians (a small primitive Protosuchus-
like crocodilian), mammal-like reptiles known as trytylodonts,
and dinosaurs including the chicken-sized theropod Segisaurus and
the small prosauropod Ammosaurus."~Martin Lockley and Adrian P.
Hunt, Dinosaur Tracks, (New York: Columbia University Press,
1995), p. 130
Escape structures in the playa deposits would not be unexpected.
glenn
Adam, Apes, and Anthropology: Finding the Soul of Fossil Man
and
Foundation, Fall and Flood
http://www.isource.net/~grmorton/dmd.htm