In the Payson Area, Northern Arizona

Lowermost member of the Tonto Group 
Updated 8/15/10
The Tapeats Sandstone is a lower middle Cambrian aged sedimentary sequence of conglomerates, coarse and fine sands down to nearly shale like facies. It represents a near shore to tidal flat deposit from 510 million years ago which covered the Payson area, Mogollon Rim and Grand Canyon areas in Arizona. Trace fossils are scarce, but when present give a unique window to a very ancient biome in which the dominant life forms were trilobites, a full range of extremely primitive arthropods, inarticulated brachs, hydrozoans, eocrinoids and other soft bodied forms that only were preserved as their traces on the sea bottom. The Tapeats was host to the same biota as the more famous Burgess Shale in Canada, Here in the Payson Area, we have two biogenic facies - the Skolithos facies and the Cruziana facies for trace fossils. Most of the trace fossils in the Payson area are various worm burrows and tubes, and we have as of yet never found a trilobite trackway here.
NOTE: click the smaller thumbnails below for a larger version Field Appearance
  Here is the outcrop at the East Verde River, just north of Payson. The sandstone layers sit on top of 1.8 billion year old Precambrian granite which decomposes to a coarse gravel through out the Payson area. Therefore there is a huge 1.2 Billion year disconformity here. Our house sits on the Tapeats as well, and while a few fossils are present, we have plenty of sedimentary structures. I always wanted to live near a beach...
Cruziana Facies - Deeper Water
  Diagram of the far from shore sand facies also found in the Payson area. We primarily have #8, Arenicolites fossils from this facies, which are a U tube worm burrow with no spreiten. (Former burrow position lines). We have also found a fossil not shown here, Bergauria - Sea anenome suction cup marks near the Verde River outcrops. We have yet to find Cruziana in Payson.
  Arenicolites, side view. Formerly called "Corrophiodes", this name has been reserved for an extant fish and is no longer used. Look carefully here, and you can see on the left side the U tube shape of the burrow.
  Arenicolites, Here are how most fossils are found, this is the very bottom of the U tube burrow, and looks like a curved slit in the mud. Many times the sandstones split like shales and show the layers that were below the surface as well.
  Arenicolites, surface view. Here are the paired holes that define what the mud surface would have looked like for this U tube worm burrow. The animal stayed in its burrow for its entire life and fed on the particles of food suspended in the water as it passed by.
  Arenicolites, as above found near out home near the Airport. Many U tube slits cover this specimen and shows the crowding that is encountered in many areas from this rich biome.
  Arenicolites, side view. Another view here of the actual U tube that the animal occupied during its filter feeding life style.
  Unknown Arthropod trackway. This was a fairly large animal, like a large crustacean or bottom crawling arthropod. We have never found anything like this ever.
Skolithos Facies - Near shore and Tidal Flats
  Diagram of the Skolithos facies. While I have yet to see Diplocraterion here, we have found both Skolithos and Monocraterion.
  Monocraterion. Straight vertical burrow, with funnel shaped opening. One can debate the purpose of the funnel, one possibility is the animal moved around in circles gathering food from the surface and rubbed a funnel in the top. Or perhaps the animal had feeding tentacles which needed a larger opening to emerge. The mystery of trace fossils!
  Monocraterion - close up. Found near the Airport.
  Skolithos Linearis - Side view of many small straight burrows that go into the sediment vertically. The picture below reveals the density throughout this rock.
  Skolithos Linearis - Top view. Same specimen as above. Every bump on the surface is the entrance to a vertical burrow. The density can be quite high in some areas. This was a worm with tentacles that fed on particles in the water currents by filter feeding.
  Skolithos Linearis -Larger animals. One of several species present in the Payson area.
  Skolithos Linearis - Side View same specimen.
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