Return to the Down's Quarry

The Placerias Quarry outside of St. Johns, Arizona is one of the best known vertebrate fossil localities in the Chinle Formation. The nearby Downs Quarry is not as well known.  Named for the late Will Downs who worked in the area in the 1970s with the Museum of Arizona, the Downs Quarry is just a stones throw from the Placerias Quarry and possibly slightly higher stratigraphically.  Crews from the North Carolina State Museum and Appalachian State University have been working these two sites for five years now and are uncovering a lot of good material.  This is exciting as these quarries have produced a lot of incredible material in the past and seem to still be very productive.  Vince Schneider from the NCSM has a blog posted describing some of the work at the Downs Quarry, which you can read here.

More Photos from the Petrified Forest

I'm currently creating a database of all of our photos from the last decade of paleontological work at Petrified Forest National Park and am working through 2002. These photos were taken by Daniel Woody who was investigating the Sonsela Member of the Chinle Formmation and assisting with the paleontology work. I'm amazed how far the quality of digital photos have over the decade!

Phytosaur lower jaw in the Crystal Forest

Phytosaur quadrate bone in the Blue Mesa Member

Triassic Fieldwork in Utah

Randall Irmis of the Utah Museum of Natural History is posting about current fieldwork in the Triassic of Utah.  You can check out the first post here and check back for more to follow.

New Open Access Paper Publishing Field Notes from the 1932 Excavations at Trossingen, Germany

Schoch, R. R. 2011. Tracing Seemann’s dinosaur excavation in the Upper Triassic of Trossingen: his field notes and the present status of the material. Palaeodiversity 4: 245–282.

Abstract - The field notes of Reinhold Seemann, who conducted the 1932 dinosaur excavation at Trossingen, are published for the first time. An English translation of the whole text is also provided. Quarry maps and stratigraphic sections were redrawn and compared with new data gathered in ongoing excavations. Of the 65 finds listed by Seemann, only 21 have survived the Second World War (Plateosaurus: 18, Proganochelys: 3). This includes most of the well-preserved skeletons, which had been moved to safe places during the war. An overview of these finds and their present state is given for the first time. This reveals major differences in preservation of bones, and it adds to the knowledge of bone completeness classes at Trossingen. The missing finds were probably destroyed by fire in 1944, and there are no remains from these specimens left. In combination with the field notes and sketches, the new data on Seemann’s material may serve as a platform for future studies of and excavations at the Trossingen lagerstaette.

Visiting Triassic Park - Ischigualasto Parque Triasico in Argentina

Last month I was fortunate to be able to travel to Argentina for some research time and to attend and present at the Fourth Latin American Vertebrate Paleontology Conference in San Juan. Part of the meeting involved a field trip to the nearby Ischigualasto National Park which is famous for its exposures of Triassic rocks and for fossils of some of the earliest dinosaurs including Eoraptor and Herrerasaurus.  As I work at the other Triassic Park, Petrified Forest National Park in Arizona, I was really looking forward to this visit and it did not dissappoint. Below I've posted some photos highlighting my visit. 

 The visitors center includes mounts (below) and life reconstructions (above) of many of the animals found in Triassic strata in the park. There are also exhibits of actual bones.

 Outcrops of the Upper Triassic Ischigualasto Formation. The expanse of the exposures is incredible.

 Bones, the Ischigualasto is full of bones.

 Christian Sidor and Zhe-Xi Luo getting excited about a cynodont skull that Chris found.

 Another in-situ cynodont skull. They are extremely (and amazingly) common here.

 Rhynchosaur bones weathering out. Again, the amount of fossil material in the exposures is staggering. Amazingly rhynchosaurs and cynodonts are so common, they are usually not collected. Working in a formation (the Chinle) where these types of animals are relatively unknown, it was very difficult to leave this material behind.

The younger Los Colorados Formation above the Ischigualsto.

Ischigualsto Park and the Ischigualsto Formation are absolutely incredible and I hope to be able to return someday to make new discoveries.

Summer Fieldwork at PEFO pt. 2

Susan Drymala has another post up at The Forgotten Archosaurs. I like the photo of the seat belt restraining the fossil jacket.

Revisiting Our Summer of Fieldwork at PEFO

It's been a pretty slow week for Triassic-themed papers and events, and I'm pretty swamped trying to complete a couple of manuscripts as well as getting ready for upcoming meetings in Argentina and Las Vegas.

Luckily Susan Drymala is back up and blogging at the Forgotten Archosaurs and has an excellent new post on the beginning of our 2011 summer fieldwork. Please go check it out.

2011 Field Season at Petrified Forest National Park Officially Starts on Tuesday

This year I will have two student interns, newcomer Susan Drymala from the University of Maryland who some of you may know from her blog Crurotarsi:The Forgotten Archosaurs, and 2009 alumnus Rachel Guest.  I'm hoping we will hit the ground running this year so wish us luck. Our goal this year: try to find a bit more of Chindesaurus bryansmalli. I'm planning on blogging quite a bit on what we are doing so stay tuned.  It may be at this site or I may start a new site specifically for PEFO fieldwork.  I don't know yet.  I hope that Susan and Rachel have a blast and enjoy their time doing some intense paleontology at the park for the next 10 weeks or so.

1980s Ghost Ranch Coelophysis Quarry Excavations

Palaeoblog has posted photos from the early 1980s Carnegie Museum excavations of the Coelophysis Quarry at Ghost Ranch, New Mexico.  These are courtesy of Greg McDonald who served as the quarry chief.

April Fieldwork - 2011 - Petrified Forest National Park Area

In April, despite the high winds, I was fortunate enough to spend a couple of days with the local landowners exploring parcels in the expansion area of Petrified Forest National Park. These sites are a continuation of the area in the park locally known as the "Devils Playground", named by paleontologist Charles L. Camp in the early 1920s.

Incredible clast supported conglomerate in the upper Brown Sandstone (Sonsela Member, Chinle Formation), a rare facies for this unit but one that clearly shows deposition in good sized channels.

Isolated mesa and one of Charles Camp's documented fossil localities. These strata represent belong to the upper part of the Sonsela Member.

In-situ phytosaur snout fragment found by one of the local landowners.

The 'persistent red silcrete' horizon and upper Sonsela strata near the Devil's Playground.

Fallen blocks of the Brown Sandstone, this accumulation is named the "Storyteller Doll" by the local landowners, after a popular puebloan indian figure.

The Laws of Fieldwork

A group of us came up with these 'laws' a few years back after spending several seasons in the field at Petrified Forest National Park. They are a work in progress, but hopefully you will find them enjoyable and applicable.

THE LAWS OF FIELDWORK
Compiled by Sterling Nesbitt, Randy Irmis, Michelle Stocker, and Bill Parker

1. If you can’t find your tools, look under your butt.

2. What is said in the field stays in the field (unless you are out with the same people).

3. Always make it look like an accident.

4. If grass can grow on it, you can go on it (i.e. it is safe to climb up or down on).

5. No one really ever falls or slips, they are either doing pushups or looking closely at rocks or fossils.

6. Last one up at night must be the first one up in the morning.

7. If something catches your eye, you must examine it.

8. To work in the Chinle, you must love the Chinle (or else it will drive you crazy).

9. No matter how far from civilization you think you have hiked, you will always find some discarded bottle or can.

10. If you are not finding any bones, you can always eat a granola bar.

11. You always find the best stuff at the end of the last day of the season.

12. There is no “line” in the field*.

*Unfortunately this one was actually broken in 2005 by a student intern and much to our dismay.

"Old Paleontologists Never Die. Their Knees Just Give Out"

This is an excellent account of the joys and importance of field paleontology (and some of the luck involved) in an interview with one of the 'greats' in the field of vertebrate paleontology, Dr. Mary Dawson of the Carnegie Museum.

http://www.post-gazette.com/pg/11072/1131175-51.stm

This article also mentions why it is important to revisit your previous digs and look for the pieces you are missing, many times they are often turned up by further erosion. In 2006 Randall Irmis and I described a new species of phytosaur, Pseudopalatus jablonskiae. One of the crucial preserved portions of the specimen was its braincase, which is one of the best preserved Pseudopalatus braincases ever found and in this particular species gives clues of the phylogenetic relationships between Pseudopalatus and the earlier Smilosuchus.  Unfortunately, the specimen had been trampled and slowly kicked apart (it was located on a trail). Many of the fragments had been washed downslope and reburied. We were able to piece together the braincase but lacked the lower portion, the basicranium. 

In 2008 I revisited the site and found more fragments that had eroded out from the downslope area and one of these was the nearly complete basicranium! At some point I will have to prepare a redescription of the entire braincase of this very cool (and important) specimen,

Chinle Formation Scenes

The Petrified Forest/Owl Rock Member contact in the Little Painted Desert north of Winslow, Arizona

Tracking Charles L. Camp in the Blue Hills of Arizona

 As my longtime readers know one of my favorite aspects of paleontological research is redocumenting historic localities.  It is important to exactly relocate these sites in order to place them in our modern stratigraphic framework, thus the fossils collected from these sites add more data to our local biostratigraphy.  But I also just get the thrill of following in our predecessors footsteps, seeing the terrain as they saw it.  It simply makes their data more relevant and in a way much more easier to understand when you take a walk in their shoes (or boots).  

Last week it was off to the Blue Hills northeast of St. Johns, Arizona.  In 1923 and 1924 Charles Camp of the UCMP made significant vertebrate fossil collections from these localities, including the type specimen of the phytosaur Machaeroprosopus zunii.  The stratigraphic position of this specimen was in doubt because Camp had misinterpreted underlying Chinle Formation strata as belonging to the Moenkopi Formation. Jeff Martz and I had been interested in the stratigraphic position of this specimen for awhile so with old field notes and photos in hand, and with one of the main local landowners showing us the best way to access the badlands, we were on our way. 

We were successful in relocating the M. zunii quarry almost immediately. The two photos directly below are one taken by Camp in 1923 of the M. zunii excavation (courtesy of the UCMP) and me at the same spot in 2010.

More difficult to find was Camp's "meal pots" locality, a greenish mudstone and fine sandstone horizon that produced numerous microvertebrates including plates of the diminuative aetosaur Acaenasuchus geoffreyi and some of the oldest recovered elements of the pseudosuchian Revueltosaurus.  Camp's field notes were a little ambiguous regarding this site, but we were able to finally relocate it (see photo below).

Of course to round out our day, no trip to the Blue Hills would be complete without exploring "Calamites Hill", a site famous since the 1940s for producing upright specimens of Neocalamites (giant horsetails).  The photo below is of a partially excavated specimen, and the ridge we were on contained numerous in-situ specimens. 

What I am Currently Reading

I appear to be on an late 19th - early 20th century paleontology fieldwork kick right now regarding the books I am reading.  I just finished Paul Brinkman's "The Second Jurassic Dinosaur Rush" book, which I found to be an enjoyable history of collecting Jurassic dinosaurs from the western U.S. by several institutions.  At times I found it was difficult to follow the chronological order of the work being done, but overall the book is a solid offering of this important time in American vertebrate paleontology.  For more see Brian Switek's recent review.

I am now starting "Bone Hunters in Patagonia" following John Bell Hatcher's work collecting fossil vertebrates in South America during the Princeton University expeditions of 1896-1899.  This is supposedly an absolutely amazing narrative of an amazing collecting trip and I hope I enjoy it thoroughly because...

the next book in the stack is "Barnum Brown: the man who discovered Tyrannosaurus rex" by Lowell Dingus and Mark Norell.  Several colleagues have told me that this is an excellent book.  I had actually started reading this book earlier in the summer and was enjoying it immensely, but stopped to read Paul Brinkman's book when it came out.  Reading Paul's book got me very interested in John Bell Hatcher and thus I've found myself reading "Bone Hunters in Patagonia" before going back to the Barnum Brown book.  I hope I'm not making a mistake here.

Overall, from what I have seen so far these are three great books covering the work of many great American early paleontologists.

The Rock Point Member of the Chinle Formation in the Chinle Valley

On of the great things about this weekend was seeing the entire Chinle Formation type section.  H. E. Gregory divided the Chinle into four divisions A, B, C, D; which since that time have been given formal names.  A = Rock Point Member, B = Owl Rock Member, C = Petrified Forest Member (which in our modern usage also includes the Blue Mesa and Sonsela Members), and D = the lower red member (or Bluewater Creek).  We were able to see all of these divisions as well as the underlying Shinarump Member (which Gregory did not include in hs Chinle). We spent 4th of July evening looking at the Rock Point Member:

The type section of the Rock Point Member is the slope forming base of Little Round Rock.

Rock Point Member on the side of Round Rock.

Close-up of Rock Point strata on Round Rock.

Jeff Martz examining the Rock Point Member at Round Rock.

Photo from a little more than half way up the Rock Point section on Round Rock.  Valley below is the Owl Rock Member.  Note our vehicle to the bottom left of the photo.  These exposures are really high up.

The Owl Rock Member of the Chinle Formation in the Chinle Valley

The Owl Rock Member of the Chinle Formation is widely exposed in the Four Corners area of the western United States.  The unit is characterized by its variegated color scheme and prominent carbonate lenses. In the Chinle Valley the Owl Rock overlies the Petrified Forest Member and is overlain by the Rock Point Member.

Owl Rock Member (top) and the Petrified Forest Member (bottom) at Round Top Ridge.

Prominent carbonate lenses in the Owl Rock Member at Round Top Ridge.

Thick beds of carbonate in the very top of the Owl Rock Member at Round Rock.

Close-up of fallen blocks of the upper carbonate beds at Round Rock.

Contact between the top of the Owl Rock Member and the overlying Rock Point Member at Round Rock.

The Sonsela Member of the Chinle Formation in the Chinle Valley

This is how I spent my fourth of July, checking out Sonsela Member outcrops throughout the Chinle Valley:

Sonsela Member outcrops.  The Chuska Mountains in the background.

In-situ petrified log in the upper portion of the member.

Another log at the same horizon. Round Top Ridge (left) and Round Rock (right) in background, the Petrified Forest, Owl Rock, and Rock Point Members of the Chinle, and the Wingate Sandstone.

The Sonsela Member is predominantly a sandstone interval.

In-situ petrified log on cliff top.

View of a portion of the Chinle Valley from ledge south of Round Rock at the end of the day.  The Sonsela Member is the grey swath across the upper center of the photo, the red is the Petrified Forest Member.

The Many Farms Desmatosuchus Quarry

As part of our weekend in the Chinle Valley, Jeff, Steve, and I revisted the quarry near Many Farms Lake where the Museum of Northern Arizona collected a fairly complete skeleton of the aetosaur Desmatosuchus spurensis in 1999.  This specimen was the basis for my Masters thesis (Parker, 2003) and a subsequent paper describing this specimen and revising the genus (Parker, 2008).  I spent a lot of time in this place but had not visited since 2003.  The excavation pit is still visible, but is reclaiming nicely.  I took a few photos of the site and the surrounding area:

Jeff Martz examining ripple laminated sandstone near the quarry

Many Farms Desmatosuchus Quarry

Slightly different view of the quarry outcrop

Looking north from the quarry at the local Chinle units.  Blue Mesa Member in foreground, ridge is distance capped by Sonsela Member.

 REFERENCES

Parker, W. G. 2003. Description of a new specimen of Desmatosuchus haplocerus from the Late Triassic of Northern Arizona. Unpublished M. S. thesis, Northern Arizona University, Flagstaff, 315 p.

Parker, W. G. 2008. Description of new material of the aetosaur Desmatosuchus spurensis (Archosauria: Suchia) from the Chinle Formation of Arizona and a revision of the genus Desmatosuchus. PaleoBios 281–40.

 

The Shinarump Member (Chinle Formation) Near Many Farms Arizona

The are some pretty spectacular exposures of the base of the Chinle Formation in the Chinle Valley in Northeastern Arizona.  Jeff Martz, our friend Steve Clarke, and I spent the day yesterday exploring these outcrops and as Jeff often puts it "figuring shit out".  Here are a few photos from yesterdays work:

Shinarump Sandstone forming slot canyon east of Many Farms Lake

Close-up of canyon walls

South rim of Tezinie Canyon, east of Many Farms.

Close-up view of North rim of Tezinie Canyon