Placoderm Outcrop in the

Payson Area

Devonian Marting Formation,

Basal brackish water member 
Bothriolepis sp. Note the large ridge plate on the back. The Y shaped pieces between the eyes is also seen here.
Updated 5/5/14

The earliest known jawed armored fish in North America come from the Devonian. These primitive fish, known as Placoderms (Bothriolepis) occupied fresh, brackish and marine environments during that time dominated by bottom and mid level ecological niches. Placoderms were covered by dense bony armored plates, articulated with joint lines to allow limited movement. This dense covering allowed many of the species to be preserved in the fossil record as collections of both articulated and disarticulated plates, known informally as "Fish Plates" amongst paleontologists. Recently, we rediscovered the long lost Arthrodirian Sandstone named by Stoyanow in 1936, at a location north of Payson and here we describe additional exploration of that locality in early May of 2014.

Note: Because of the extreme rarity of this site and value to the professional paleontological community, the exact location of this locality will remain protected.

Parked at the wash on a very rough road.
Large garden hose sized Paleophycus trace fossils are very abundant in the layers near the fish beds
  The Stoyanow "Red Arthrodire Beds" really are stained red and have a high sand content that is also very ruddy in color
  More large trace fossils, most likely from crustaceans like crayfish or shrimp
  Beds of trace fossils
  First find, a big slab with a dorsal medial plate which would have been on its ridged back
  large upright slab of trace fossils
  An entire collection of larger fish plates! They are moslty hollows where the bone left an impression, but a large number of them also have the complete bone inside them too.
  Large six inch plate
  One of the best large blocks of fish material I found was this beast, packed with fish plates and bone
  Close up of the variety of pieces. Everything here is over 350 million years old.
This is an unusual bone, I suspect it is either the top or bottom of the skull near the jaw.
  A large number of plates have a patterned texture on thier exteriors
  One of the largest plates I found this day on the left edge you can see some of the original bone, nearly 3/4 of an inch thick!
  Close up of that large bone plate, serrations on edges.
  Very peculiar star pattern on this plate, I had never seen this before
  2 inch fish armor plates
  On the way back up the creek bottom, I took a better shot of the unusual bone
  The really sandy beds had the large trace fossils in them and represent a marine delta enviornment with a brackish water mix. Here is a side view of the sandy laters in the dolomite.
  A prize find - not only does this slab contain a nice plate in the center, it shows preserved mud cracks indications of subareal exposure. Perhaps a mud flat on the edge of the sea delta.
  close up of the fan shaped plate on the mud crack slab
  A big slab with literally thousands of pieces of fish material ground up into little fragments. Im seeing the beach here...
  Close up 1
  Close up 2
  Multi colored bone about a quarter of an inch thick on the big slab.
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