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.

PEFO Summer Fieldwork Parts 3 and 4

Susan has the rest of her summer exploits in the Chinle Formation up at The Forgotten Archosaurs (Parts three and four). Reading through makes me wish I was there ;). Isn't she glad that she wrote everything down?

90th Anniversary of Charles Camp Collecting at the Petrified Forest

Today marks the 90th anniversary of Charles Lewis Camp's first day collecting fossils in the Chinle Formation of what is now Petrified Forest National Park. Camp was a PhD student at Columbia University who was later hired by the Museum of Paleontology at the University of California at Berkeley, and on June 4th, 1921 he received a telegram from Museum Director Bruce Clark asking if he would be able to help out museum founder and benefactor Annie Alexander and her field partner Louise Kellogg who were collecting fossils in the Blue Forest east of Adamana, Arizona. The two woman had made significant finds of vertebrate fossils and needed assistance. Charles Camp arrived in Adamana on June 11 and joined the two women at their camp on June 12.

His field notebook for this day (which was also a Sunday) recounts his trip from New York to Adamana, notes that the exposures are of the Chinle Formation and Triassic in age, and visited the various fossil forests, including those in the Petrified Forest National Monument, which was then located to the south and much smaller than the present national park.

The paleontology of the park and the Chinle Formation owes much to the work of Charles Camp. It is an honor to follow in his footsteps and in the 90th anniversary of the his first work in the area, we will occassionally revisit his localities (many of which are known because of detailed notes and photos) on the same dates that he did. Paleontology is not done in a vacuum and we truly do see farther because we are "standing on the shoulder of giants". We should never forget the work our predecessors have done and honor it when we can.

The Basal Chinle Formation in Canyon DeChelly National Monument

The base of the Chinle Formation is well exposed in Canyon DeChelly National Monument just outside of Chinle, Arizona.  Here the Chinle fills paleovalleys incised into Permian-age rocks, in this case the aeolian DeChelly Sandstone.  The only trail accessible in the monument is the White House Trail, which leads down to abandoned ancient puebloan indian sites on the valley floor and in the canyon walls.  Thus, this trail is very popular with visitors to the monument; however, I'll bet that the majority of them miss this feature, a 'u'-shaped valey carved in the DeChelly Sandstone and filled with gravels of the Shinarump Member of the Chinle Formation.

The capping darker sandstone is the Triassic Shinarump Member of the Chinle Formation, and the buff sandstone is the Permian DeChelly. In the direct center of the photo is a dark patch in the buff.  This is a 50 foot deep gravel filled paleovalley cut into the DeChelly.  You can also trace it to the left and right in the photo.  Note the figure on the trail just to the left of the valley, and a figure under the tree just to the right.

Something looks very wrong with the photo above. This is the contact between the Triassic Shinarump (on the left and the Permian DeChelly (on the right). The contact between the two is vertical along the sides of the paleovalley. This is relatively flat lying strata. Pretty rare to see this.

One very cool aspect of a vertical contact (and unconformity) like this is that it is pretty obvious that the older unit (in this case the cross bedded sandstone) must have been fully lithified before the younger unit was deposited.  In this case the was a slot canyon in the DeChelly that was filled in in the Late Triassic.  Actually Triassic topography is visible here.  You can stand on the end and look inot where the canyon would have been about 220 million years ago.

Bill Mueller and his Field Notes on the Paleontology and Geology of the Dockum Group

I have had this link up on my sidebar since first starting this blog, but I would like to point out Bill Mueller's great Field Notes site to everyone who has not yet visited. Bill is a professional photographer and a staff member at The Museum at Texas Tech University in Lubbock, Texas and for years now he has been detailing his Late Triassic work in the Dockum Group of Texas at his fine arts website. The amount of material he and his field partner Gretchen routinely uncover is nothing short of astounding. I highly recommend his site to anyone interested in ongoing paleontological field work.

Chinle Silesaurid and the Importance of Field Notes

Adam Yates nailed it. The specimen is the proximal end of the right femur of a silesaurid (PEFO 34347) from the Upper Triassic Blue Mesa Member (Chinle Formation) of Arizona. This specimen is significant because it represents the only known unambiguous silesaurid element from the lower portion of the Chinle Formation and from Arizona. It demonstrates that silesaurids were a portion of the fauna at Petrified Forest National Park.

This specimen was discussed in more detail by Parker et al. (2006) and Nesbitt et al. (2007). It is identical to the proximal ends of the femora of Silesaurus opolensis (Carnian of Poland) and Eucoelophysis baldwini (Norian of New Mexico) and thus cannot be assigned to a specific genus although the age (Norian) and stratigraphic position (Chinle Formation) of the specimen would suggests that it is probably could represent Eucoelophysis rather than Silesaurus. However, until more material is found this cannot be considered. A key characteristic of the proximal end of the femur in Silesaurus, Eucoelophysis, and PEFO 34347 is that the element is triangular in proximal view and has a mediolaterally trending sulcus. Whereas this sulcus is present in other taxa, most notably the pseudosuchian Shuvosaurus, the femur of silesaurids differs in having a subrectangular femoral head in lateral view with a slightly offset head as in dinosaurs.

Now for the promised “interesting” (and frustrating) story regarding this specimen. This specimen was collected sometime in the late 1990s by an unknown individual who was part of a larger research project. It went unrecognized and was included in a large amount of material deemed unworthy of study and potentially to be disposed of. When going through this material to see if anything was salvageable I came across this specimen. Unfortunately, the exact spot where the specimen was collected was not recorded. There are no known field notes for the project and field tags contain minimal information, in this case just a vague geographical reference. This reference is enough to pinpoint the specimen to a small geographical area and limited stratigraphic level; however, it will be nearly impossible to find the rest of the specimen if it exists (and the break is clean, suggesting that more of the specimen was preserved and awaits discovery).

I cannot emphasize enough (and I stress this to, and require it from, all of my employees and interns) the importance of collecting and recording accurate field data on every specimen collected whether the specimen seems important or not. I don’t know how I would function without my past field notes when it comes to identifying and interpreting specific specimens. I have found when I get lax (because of time, weather, arrogance, etc..) I usually end of regretting not having a key piece of information regarding a specimen at some point. At the absolute minimum for EVERY specimen collected there should be GPS coordinates, a photograph of the site showing the surrounding landscape (most important), and a brief description of the sediments and stratigraphic position. Taphonomic notes are also extremely important and often forgotten. Bottom line, you cannot collect too much information. Anyone who has worked with older specimens when simply a stratigraphic unit and state were deemed sufficient information will understand. PEFO 34347 currently represents to earliest known silesaurid from North America, yet its provenance cannot be precisely determined and clarification regarding this specimen depends exclusively on luck. Was more of the specimen preserved? Is it still present and will we be able to stumble across it? I certainly hope so.

REFERENCES

Nesbitt, S.J., Irmis, R.B., and W.G. Parker. 2007. A critical re-evaluation of the Late Triassic dinosaur taxa of North America. Journal of Systematic Palaeontology 5:209-243.

Parker, W.G., Irmis, R.B., and S.J. Nesbitt. 2006. Review of the Late Triassic dinosaur record from Petrified Forest National Park, Arizona. Museum of Northern Arizona Bulletin 62:160-161.