Fossils from the Permian

Hermit Shale in the

Sedona/Oak Creek Area
Updated 2/25/07

 The middle Permian terrestrial formations in central Arizona, the Mogollon Rim area and within the walls of the Grand Canyon represent a massive mud flat with many braided flu vial channels on the edge of the sea that produced the Fort Apache Limestone and some of the marine deposits in the Supai Group in the Grand Canyon. In the Sedona and Village of Oak Creek area in central Arizona this group of formations is called the Schnebly Hill formation and consists of four members. The lower most is the Hermit Shale itself which in numerous localities we find locally abundant plant hash, conifer material, calamities, and sedimentary structures such as mud cracks, wave ripples and cross bedding. Also occasionally found are reptile tracks and track ways, the smallest are lizard sized reptiles, and the largest are huge mammal like reptile prints from such dramatic creatures such as the sail backed reptile - Dimetrodon. The remaining upper layers are in order, the Bell Rock member which is shale and sandstones, The Fort Apache Limestone which is marine, and the cap rock on many buttes is both the Fort Apache or the upper Schnebly Hill sandstones - the Sycamore Pass member.

On this expedition, we were joined by our good friend from Queensland Australia, Paul Tierney. We explored the lower slopes in the Hermit, and here you will find a photo pictorial of our trip and some of the fine fossils we found that day.

 Hiking back on many of the trails in the area, we found abundant trace fossils, and plant hash in many of the shale outcrops. In the background is the back of the view from Red Rock Crossing.
 Dawn and Paul at one of the river cut outcrops far off the main road. Here at this site were plenty of sedimentary structures in the ancient Permian rock such as wave ripples, rain drop impressions from a single event in time. There was a huge fossil log here as well up on the cliff perhaps a huge calamities or Walchia trunk still in life position.
 At a road cut off the beaten path, we found many of the shales were crossed with mud cracks criss crossed with fossil centipede track ways, mesichnium. We also found a huge pair of pelycosaur manus (front foot) impressions.
 This is our site we call "Insect Hill", because at one time I found some beetle track ways in the shales near the top. Now a days, we fine mostly huge conifer fronts - Walchia, reptile track ways, and some plant hash. Paul is here examining the eroding shales.
 With so many shales to ponder, you can spend a great deal of time on each outcrop looking through mostly blank unfossilferous material. Then, without warning you will come across a beautiful conifer front, or fern. Dawn is planning here assault on one such outcrop.
 Paul had about as much fun climbing around on the shale beds as actually finding the plant fossils contained within! Here we found some very nice calamities stems, roots and branches.
 In many areas, splitting shales is mandatory. Many of the slabs that are fossiliferous on the outside also contain fresh material within. Paul shows off his cleaving skills here, and extracts a perfect specimen!
 The Author (me) after I had just found a three inch diameter calamities trunk, and the rock mold it came out of.
Here are two specimens of the fern Pecopteris, one of the most common plant fossils we found that day. Preservation is usually not in great detail, but large slabs of four foot frond sprays have been found by us on earlier trips to this area.
 Better preservation of the leaves of Pecopteris, this one from a locality where we found numerous track impressions of mammal like reptiles.
 Bark impressions of either a Lycopod or Walchia. Small diamond shaped patterns appear on close examination.
 Typically, we find small pieces of Walchia fronds, here one twig from a frond shows the small needles this early conifer possessed.
 Here are some of the numerous stems, roots and trunks we find in the Hermit of calamities (horse tail). Some of the trunks are up to 10 inches or more in diameter! In the center here is a 2 inch diameter trunk section, with the ribs visible, and around it roots and branch like pieces.
 Tooling marks are very common in the Hermit. These can be thought of as "branch drag marks" at the bottom of a muddy stream. While some of the impressions in this slab are trace fossils, most are linear and are produced by debris.
 Large slabs of worm burrows appear also in the Hermit. This one was found very near the location of the first picture at the top of this page, in a dry creek. This is similar to Paleophycus, but represents a terrestrial organism such as a feeding trace of a large worm like creature.
 This slab, about 10 inches across from near Insect Hill. The footprints of a small reptile can be seen here, which walked this mud flat some 280 million years ago, and looks nearly as fresh as the day it was made. The toe pads on the ends may help us identify the family of the track maker.
 Close up of the footprints on the slab above showing a manus and pes impression.
 Huge Pelycosaur prints, both probably manus impressions. You can tell something very significant here, that the huge animal walked upright without its legs splayed, since the tracks are right next to each other. One could also argue that the front feet were splayed and rear more erect to produce a front and back track impression. Either way, such a track pair is typical Pelycosaur, but not Dimetrodon.
 On the left is "Dimetropodus", the clawed track of the Dimetrodon. It is the only animal that produces such a track. The huge front foot claws dug deeply into the mud. This animal may have been a juvenile, the track is fairly small. On the right is another very interesting print from another reptile, Ill get to that in a minute.
 Dimetrodon was here. Over a quarter of a billion years ago to boot. The amazing claw impressions are the hallmark of this reptile.
A surprise on the same slab was this "Laoporis like" track, similar to what we find in the Permian Coconino sandstone, which is a bit younger in age. This one however appears to show skin impressions on the ball of the foot, and is a first for the many tracks we have found in the Hermit Shale.
 Also on the same slab we have the toe imprints of a mammal like reptile that we have found from time to time in the Hermit, five large toes dig into the mud with hints on more complete specimens of a larger foot impression that can be over 7 inches across.
 Mesichinium - Centipede Track ways. They look like bulldozer tracks seen arrowed on this slab. The track maker? On a prior trip to this same outcrop, we found a body impression of a centipede. Case closed!
 Finally, we reflect for a moment of some of the amazing yet very rare fossils we have explored in the Hermit Shale in the Sedona/Oak Creek area and consider that we have walked on the very muddy shores as the giant sail backed reptiles shared with the huge tree sized horsetails and amazing short spined conifers did, 285 million years before.
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