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Last weekend, we took our final trip up to the Ash Fork (Arizona) area for the year to explore the outcrops of the bright angel shale. this time however, our goal was to collect trace fossils and coralomorphs ( more on that later). While a small group worked for shales in the lower part of the formation, some of the more adventurous of us climbed the hill capped by the Muav limestone. We spent a few hours searching for Cambrian trace fossils - and we're not disappointed! meanwhile, down in the Shale pit they found many Coralomorph specimens, and of course hordes of trilobites. The Stevens Way locality near Ashfork consists of three facies, a lower green shale member with body fossils of trilobites and other marine fauna, and two upper members within walking distance which has a base of a yellow crumbly shale loaded with only trace fossils of low diversity capped by the third member, the Muav Limestone which here was non fossiliferous. When we scouted the middle member extensively, and found some well preserved trace fossils - Some being quite enigmatic! While the nearby Tapeats Sandstone consists of primarily the Skolithos and Cruziana ichnofacies, this deeper water shale seems to be a mix of Cruziana and Glossifungites ichnofacies components. Here is a photo pictorial of some of the more interesting trace fossils we have found at the second yellow shale facies Trilobite Tracks, Resting places Cruziana - Grazing traces as the trilobites plowed through the upper layers of sediment. Rusophycus - resting trace. Simple Tubular Feeding Traces Paleophycus sp. (Worm like sub surface miner) Bilobed Traces Left side - Isopodichnus (Shrimp/Arthropod) Aulichnites (Gastropods grazing) Cyano bacterial mat hard ground (AKA: Elephant skin) When an algal or bacterial mat grows on the surface of mud, it wrinkles the surface to form this type of pattern. Locomotion Traces These two slabs are very unusual, we believe them to be a mollusk of some type pulling its way along the surface hard ground. Protovirgularia sp. Well, thats if for now. Many of the specimens are still being cleaned up, as they were attached to thick green glauconitic mud. And about those Coralomorphs? Ah, thats the next write up....

Hi all, Here is the LAST report on the truly amazing fossils we have found at the SW (Stevens Way, Ashfork) locality in the Bright Angel Shale, far south of the Grand Canyon. These were listed by us for years as "problematica" or "mystery sponges" and since then, a coordinated effort by the members of the museum (Mesa) and a bit of direction on the literature by Piranha here at this forum has illuminated the dark path to identifying these elusive animals. Never heard of a "Coralomorph"? Neither did we up until this past few months. In fact, we found many Cambrian researchers had not either. I am posting this here so all can see and enjoy yet another amazing Cambrian animal most of us have been unaware of. Only a few localities exist in the US, and a handful in the entire world. First, we have produced a extensive graphics filled write up on my web site here: http://www.schursastrophotography.com/paleo/Fossilfotos-4h.html However, Ill post a few images from this write up here to whet your interest! General field appearance in the green shales on the surface of a coralomorph at 10x: Side view of a fragment of the vase shaped animal laying on its side: 20x view of another surface impression. The bundles of tubes go down into the shale layers several centimeters. 10x side view with calices visible. Coralomorphs are very similar in appearance to a very primitive tabulate coral. But 10x smaller and they have to partitions in the tubes. The fragments are radial pieces of the compete animal. Our first reconstruction of the complete fragments looked like this: Finally, my attempt to show what the animal would have looked like in its live state. They were about the size of a tennis ball for our specimens. Again - Take look at our write up and there are many more images, graphics and information on how we found and finally identified these enigmatic animals. http://www.schursastrophotography.com/paleo/Fossilfotos-4h.html

HI all, Here is the last piece of the trilobites write up from our "SW Site" (Stevens Way, Ashfork, Az.) featuring the interesting pygidiums of the Zacanthoides Walapai trilobites we found in huge abundance in the Bright Angel shale. Ill post a few nice shots here, and at the end a link to the full (monstrous) write up on our paleo web site. Thanks for looking! The most common fossil found in the green shales at our SH locality are trilobite pygidiums for the Zacanthoides Walapai species. They are joined by assorted cranidiums, thorax and rib segments, and hordes of hyolithids, and a very rare coralomorph. Generally low diversity such as this site suggests has been attributed to a stressed environment, with perhaps low food sources, aggressive wave action, or an influx of fresh water from the nearby deltas. This was a shallow sea outbound from the deposits known as the Tapeats Sandstone which marked shore, delta and beach deposits. Combined with the deeper water Muav Limestone, this trio of formations is known as the Tonto Group. All three can be found outside the Grand Canyon to the south in small limited areas such as here, yielding an opportunity to explore the paleo fauna without hiking miles and thousands of feet into the Grand Canyon. A few images that are special: The full write up can be found here: http://www.schursastrophotography.com/paleo/Fossilfotos-4f.html

Greetings all, Another big project just completed, our photo survey of nearly every Hyalithid we found at our SW locality near Ashfork Arizona in the lower middle Cambrian Bright Angel shale. Me and my wife have been working on this project for several months now, getting all the specimens cleaned, prepared and photographed. The shale is greenish in color due to glauconite and is fine grained, preserving many of the finest details in the specimens. This contrasts greatly to the southern extension (in Arizona) of the BAS known as the "Abrigo Formation" which leaves much to be desired for the quality of preservation. Fortunately, the age of the BAS is about 5 MY older than the famous Burgess Shale, and many of the faunal elements are identical or very similar. The hyolithids here are "Hyolithes sp." same as the Burgess, but lack the curved extensions known as "Helens" which normally protrude out the sides of the conchs. In fact we looked extensively for these features, but they were not present even in the best preserved specimens. Apparently, not all Hyolithids had them. Here are a few images from this survey, and I would encourage you to take a look at our main web page summary of this study which can be found here: http://www.schursastrophotography.com/paleo/Fossilfotos-4e.html Selected hyolithids images from the survey: Thanks for looking, this was indeed a very illuminating project for us! Glad to share this with all of you!

Hi all, Now here's a tough one! As you may know, we have been extensively documenting many of our finds from a new locality in the middle Cambrian Bright Angel shale of northern Arizona, and have found superb preservation on molts of hordes of rare Zacanthoides trilobites. But - besides the hyalithids and occasional inarticulate brach, we find something very peculiar. Both mixed in with the trilobite beds and in a bed all their own about a few inches lower, we find this fossil, best described as "bundles of tubes" in quite an abundance. I have lots of photos we took under magnification, and our guess as to what this may have looked like which Ill post here. We have had a number of professional paleontologists look at these, and they just threw their arms up in the air. So here is what we know at this point after examining hundreds of specimens: 1. We never find solitary tubes 2. 90% of them are preserved upright in life position 3. 10% are found laying on thier sides with the trilobites so they cant be rhizomes or burrows. 4. Length varies from 1 - 3cm and goes through multiple layers of shale vertically. 5. No internal septa, tabulae or partitions, or branching. 6. Some have a tapered profile 7. cross sections are hexagonal in center, round on edges 8. separate tubes are .5 - 1mm dia 9. no sponge spicules seen at any magnification, and no osculum. Ok, so here are some shots with the microscope: 1. Cross sections at 10x 2. Side views paralell to bedding plane 3. Our best interpretation of what the animal may have looked like so far (dont laugh - Im no paleo artist!) Now I dont want to steer you into any conclusions, but our thoughts are a colonial hydrozoan or cnidarian, or some kind of strange holdfast or anchor for an animal. I dont think an algae or sea weed would have polygonal structures like this. Any thoughts on this will be greatly appreciated!

Greetings everyone, Finally finished our write up on the section illustrating images of the thorax components we found of the rare lower middle cambrian trilobite Zacanthoides walapai at our unique site south of the Grand Canyon near Ashfork. Although we wished for more complete specimens, a scan of the literature shows that most finds are very fragmentary on this species, and to be able to illustrate some additional specimens in good detail was sheer pleasure for us! We have found only 3 or 4 other localities outside the Canyon of Bright Angel Shale, and this is the ONLY one with Zacanthoides. Thank you all again for your interest and past comments on our work in the BAS, and we hope to keep posting more images in the future. http://www.schursastrophotography.com/paleo/Fossilfotos-4d.html

HI all, Here is the latest installment in this extensive series on the Bright Angel Shale of northern Arizona. We have spent many months taking thousands of images of lower middle cambrian fossils (5my older than the Burgess) and in this new upload we have posted nearly 500 new images of the cephalon and associated parts such as the cranidium, free cheeks, hypostomes, etc. of the trilobite Zacanthoides walapai. This is an extremely primitive trilobite and there are few if any images in the literature on this stunning arthropod. This most certainly is the largest collection of images of this species ever presented. We hope you will enjoy this series as much as we did putting it together. There is so much more to come on this topic. So let the Cambrian excitement begin! http://www.schursastrophotography.com/paleo/Fossilfotos-4c.html

HI all, As we work through the thousands of slabs of Bright Angel shale from the last few expeditions, I thought Id post for fun some of the more fossil packed slabs we pulled out of the outcrop. Trilobites overlapping trilobites! They are all one dominant type - Zacanthoides Walapai, and are typically molts. Trilobites are not common here in Arizona, but if you get into the right layers.... http://www.schursastrophotography.com/paleo/Fossilfotos-4b.html Arizona Chris Paleo Web site: http://www.schursastrophotography.com/fossiladventures.html

Hello all, We have a locality far south of the Grand canyon that has a small isolated outcrop of Middle Cambrian Bright Angel Shale. Besides hordes of trace fossils, there appear to be about two types of trilobites here. Mostly molts, we have a few whole ones. The one we identified was Zacanthoides sp. but this second one has us perplexed. Take a look at the image here Im attaching, it shows the small 2cm original specimen, then a mirrored image to try to show both halfs. Finally it shows the glabellas we find tons of that appear to be belong to this guy. Anything you can tell me that will put me in the right direction would be appreciated! We are new to this forum, it looks to be fantastic. I would love to share my decades of Arizona fossil hunting experiences with all of you! Chris

Hello all, As promised we are just starting to post the huge photo pictorial of our recent work in the Bright Angel Shale south of the Grand canyon in Arizona. I have over a thousand images that go with this write up, however for now Ive posted the starting page and the first photo page - Key fossils. Most paleontologist are led to believe that the Lower Middle Cambrian Bright Angel Shale can only be found in the depths of the Grand Canyon National Park, and therefore is not open to collecting for the general public. After much research spanning years pouring over old - and nearly unobtainable geologic maps, professional papers and Bulletins, we found that this is not the case. There are half a dozen small areas far outside the Canyon (south), and isolated outcrops in the Juniper Mountains in Northern Arizona. We spent over a year finding and evaluating these outcrops - when accessible, and found two in particular that were highly fossiliferous. Besides hordes of Cambrian trace fossils, we found a plentiful but low diversity of fauna similar to the Burgess Shale in British Columbia, and the Chengjiang Fauna in China. Phylums include at least half a dozen species of Trilobites, Hyolithids, inarticulate Brachiopods, a colonial hydrozoan like animal, and trace fossils from arthropods, mollusks, and annelids. So here is the new photo pictorial page itself: http://www.schursastrophotography.com/paleo/Fossilfotos-4a.html And if you want to see the planned future pages, this will be the BAS jump off page: http://www.schursastrophotography.com/paleo/Fossilfotos-4.html Thanks for looking. We have so much more to write up at this point, but the material is very exciting to us! Arizona Chris