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Our in depth
site survey continues with the first half of Site 3, along the
Highway 260 trail - The Sinkhole trail. Starting with site one
where the outcrop starts, each section is about 80 - 120 paces
long. Each section is divided into two zones, zone 1 for the
first half and zone 2 for the second half. This was done because
of the huge variations in the preservation and fauna along each
section. Here is a map of the locations examined so far and those
to come. Exact GPS coordinates were taken of each location, which
usually started and ended with an easily found landmark such
as a wash or huge boulder or stump.
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Click
this thumbnail for the larger size. The parking area for the
trail is at bottom, and the sites are marked with pins. Site
3 is marked and is the start of this survey, and extends halfway
to site 4 marker. Again, this site is one of the best for micro
fossils in Arizona, but few if any larger fossils can be found
here. It takes a lot of work to collect the promising rocks,
haul them out and spend days or weeks in the acid bath. Then
there is the hours sorting under the microscope, then photos
and identification. |
What was found
at this site was far less quantities of fossils than any other
site surveyed so far. Preservation for most fossils was poor
and many of the specimens fell apart or were so crystallized
that they were unusable. However - several exciting finds
found here and no where else were obtained and one very special
fossil in particular - a trilobite glabella, the most complete
one we have ever found at this outcrop was pulled out of the
acid fines. More on that later.
As far as what
was found in a one gallon zip lock bag of rock, this list highlights
the best preserved specimens:
1. A small amount of Urchin material
2. Plenty of poorly persevered Branching Bryozoans
3. Serpulid Worm domiciles (Chonetes)
4. Dozens of nice Scaphopods
5. Two species of Ostracods
6. Hordes of both superbly and poorly preserved Gastropods
7. Several excellent Bellerophontid Gastropods
8. Trilobite bits including a mostly complete glabella and two pygidiums
9. Many tiny Bivalves including a superb assortment of winged clams
10. Half a dozen Straparollus gastropod juveniles and sub adults
11. And finally, two partial Brachiopods (other than productids)
And here is what was NOT found that had been at other sites along the trail:
1. No Sponges or sponge roots
2. No solitary rugose corals
3. Not a single crinoid ossicle
4. No quartz crystals or metallic pieces
5. No Nautiloids
6. Finally, NO productid spines or parts.
For a site so poor
in fossils, it made up for quantity and quality with a good variety.
It may be that the upcoming zone 2 is the start of a really rich
location. Well see.
The
Fossil Photos.
A few words on
how these photos were taken. Using an Amscope stereo microscope,
one or two dozen shots of each subject were taken with the focus
shifted a bit between shots. The focus stacking software Picolay
was used to combine the images to obtain one frame of fully sharp
focus. Thousands of frames are treated in this manner and the
final images of the Fort Apache micro fossils you see here are
the results of a huge amount of work! Enjoy.
Trilobites:
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Phillipsia
sp. For only
a gallon of rock, half a dozen or so pieces of the single species
of trilobite we have found at this site were collected. The upper
left is a free cheek with eye cutout, on the right is a partial
pygidium. Below are trilobite doublures - the rim around the
body. Other pieces shown below are even more interesting! |
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Phillipsia
sp. A superbly
preserved pygidium! Still, not enough to identify the trilobite
other than it is of the Genus Phillipsia. One more piece is missing... |
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Phillipsia
sp. And this
is the final piece of the puzzle. After thousands of pounds of
rock, this is only the second and by far the best glabella we
have found. It is smooth with a crenulated rim, and about twice
the size of the pygidium central extension for comparison. |
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The
completed cephalon, pygidium fitted onto a trilobite of very
similar appearance, Phillipsia Perocidens. Identifying Permian
trilobites is not easy. Most specimens are fragmentary with critical
pieces missing. Whole ones are exceedingly rare. The quest continues!
Until we find better more complete specimens, this one will get
this identification: "Phillipsia sp. c.f. Phillipsia Perocidens".
(c.f. is a paleontology nomenclature term meaning "closely
following".) |
Ostracods:
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More
ostracods than in the previous section, dominated by the ear
shaped translucent straw colored types. Also seen are the oval
clam shell types which were quite rare here. |
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Two
nice specimens, on the left is a top view showing the shell ornamentation
and general shape. On the right is one that is both halves still
intact standing on edge showing the separate parts. They are
quite thick for shier size! |
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This
second type of ostracod is more bean shaped and bears no ornamentation
on the shell. You can see the line between halves on the right
one. |
Brachiopods:
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Pseudodielasma
sp. Very rare
indeed are normal brachiopods in the Fort Apache. This is only
the second or third time we have ever found any at all. This
is a top view of both specimens, the left one mostly complete. |
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Pseudodielasma
sp. Underside,
showing that the left one has a pedicle opening and thus this
is the Pedicle valve. |
Chonetids
(Serpulids)
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Only
three serpulid tubes were found. The back is totally flat and
are normally glued to plant surfaces. |
Scaphopods:
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Plagioglypta
canna. A nice
selection of small scaphopods, both adults and juveniles. Both
ribbed and smooth types seen here, and the small ones at the
bottom are teleoconchs from juveniles. |
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Plagioglypta
canna. A very
nice specimen showing the horizontally ribbed juvenile teleoconch
on the left is gradiating to the smooth section to the right
of the adult shell. When the adult phase is reached, the teleoconch
breaks off and this then is the water outlet for feeding from
the larger open end where the animal resides normally buried
in the mud. |
Bryozoans:
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Small
bryozoans that are either branching or encrusting spines and
shells were found. Most had terrible preservation and were nearly
smooth or crystallized on the outside. Here are a few with the
holes clearly seen. A head of a pin for scale is shown. |
Echinoderms
(Urchins)
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Echinocrinus
sp. Few urchin
parts were found. Here a few spines and an ambulacral plate is
seen. No spine plates or water vascular plates were found. |
Straparollus
Gastropods:
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Straparollus
Kaibabensis. The
number of Straparollus parts is increasing as we go east along
the outcrop. Here are some juveniles and mid size pieces. Several
larger pieces showing the adult ornamentation on the coils were
found as well. |
Gastropods:
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Large numbers
of gastropods were found, but half were so badly preserved from
over silicification, or erosion. This rock is more carbonate
than other sites and the silicified fossils within were far less
detailed. This pile of shells here is the total sum of what I
pulled out of the gallon of rock.
Now lets detail
the different types. Identifications are from Winters monograph
GSA 89.
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Cinnamon
Buns - Apachella
prodontia sp., Tall
spired - Worthenia
arizonensis sp. |
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Apachella
translirata sp. These
were never seen before and Winters had identified them from several
he had found in the Smithsonian survey. |
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Genus
and species indet. Only
one of these beauties found. And it was quite a bit larger than
most gastropods. |
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Genus
and species indet. We
found lots of these deeply incised cones, very distinctive. |
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Apachella
prodontia. More
examples of this very common gastropod. |
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Genus
and species indet. This
and the next gastropod are way too generic looking for even Winters
to identify. |
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Genus
and species indet. Very
generic. |
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Genus
and species indet. Not
even listed in Winters descriptions, this one appears frequently
in selected outcrops. It is a gorgeous tall spire and can be
found in very small sizes as seen here. The nail head on the
right is actually the point of a straight pin. |
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Goniasma
terebra sp. A
few of these stunning ribbed specimens were found with intricate
details. |
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Goniasma
terebra sp. |
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Goniasma
sp. The shape
of these reminds me of a bee hive. |
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Tiny
tall spired gastropods, and the small juveniles of unknown species
sitting on a penny. |
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Tall
spired gastropods next to the head of a pin. |
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Knightites
modestus. With
part of the shell missing allowing us to see the coils inside.
It is almost like a ball or sphere. |
Bivalves
(Clams)
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Most
of the material from the acid fines were ground up bivalves.
Few whole ones were found, but there were surprises! More than
any other site so far, the winged clams made a good showing and
some of the specimens were amazing. |
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Parallelodon
anaklastum. The
gorgeous winged clams. This site so far has more of these than
any other. It was always a surprise to find these gems mixed
in with the hash, most were broken and the wings chipped. Here
several perfect specimens were to be had. What a great find! |
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Palaeonucula
levatiformis. The
most common clam found, many of them worn. Some are sub millimeter
sized. |
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Bakevellia
sulcata. The
OTHER winged clam. The deeply incised groove is diagnostic. |
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Palaeonucula
levatiformis. The
most common clam found, bottom view. |
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Astartella
subquandrata. Less
common but unique in shape. Less worn specimens here have nice
surface grooves. |
Bellerophontids
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Bellerophon
sp. Top view
showing dorsal ridge characteristic of the genus. |
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Bellerophon
sp. Same specimen
on its side showing the almost cephalopod like appearance. Bellerophontids
are somewhere in between gastropods and monoplacophorans. In
other words - They are very primitive gastropods with their planispiral
coiling. |
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