Charles R. Newsom: Fossils

My fossil collecting hobby began when I took my first high school field trip to central Texas (Austin area). We collected shells from localities that I still consider among the best I have ever visited. During my college years I continued collecting in the cretaceous rocks around the University of Texas. These rocks are of upper cretaceous age and are full of well preserved fossil remains. Nearly every road cut in the city of Austin contains fossils of some kind. With this kind of material available, it is easy to see how one can quickly become an avid fossil collector. In my junior year I took a spring break trip to the northwest of Austin into the paleozoic rocks of Texas. Uncertain of whether we would find anything at all I was amazed that first morning to find that the gravel used to line the roads of the campgrounds were made up entirely of fossil "horn" corals. The rest of the trip was full of similar surprises. Once my undergraduate and graduate school course work was completed I moved to New Mexico (Los Alamos) which is a volcanic region surrounded by rocks of Pennsylvanian age. I collected large numbers of shells from these rocks. After 2 years I joined the rock and mineral club in Los Alamos and discovered that I was the resident fossil expert in the area, much to my surprise!

My fossil career took a brief breather when I went to France for a 3 year post-doctoral research job. Upon my return I got a job in California and commuted to Chicago and Los Alamos. Needless to say, my collecting resumed, but at a low level. A year later I joined the faculty at the University of Iowa. The fossils to be found in this area are mostly Devonian in age.

At a social gathering I ran into someone who know the whereabouts of my best friend (and fossil collecting buddy) during college. I called him up and we now regularly meet for trips during spring and christmas breaks.

My collection can be described as stratigraphic in nature, consisting of about 600 boxes of fossils, each labeled as to locality, age, member and formation when known. I also try to take photos and global position information for the more recent localities. I have recently acquired a digital camera and am revisiting many of my localities in order to photograph the exposures more carefully.

I have a few areas where I have tried to concentrate my collecting efforts. The easiest fossils to collect are those whose shells are made up of calcite. Many shells are made up of the more fragile aragonite. Calcite tends to remain long after all of the aragonite has dissolved away. The oysters, scallops and sea urchins (echinoids) tend to fall into this category.

Photo The first area of specialization includes the oysters of the genus Exogyra. The Exogyra are large beautiful clams (they don't resemble modern oysters at all) that can weigh up to several pounds. I have managed to collect about 90% of the North American species that are known to exist, including some rather rare species. The remaining species are so rare that only a few specimens have been found worldwide. The oldest known Exogyra is from the mountains of Chile and probably descended from the Gryphaeate oysters.

Photo The second area of interest are oysters of the genus Pycnodonte. The oldest cretaceous pycnodonte are quite small and nondescript. The larger ones weigh up to a pound and have rather interesting shapes. The most recent cretaceous pycnodonte in my collection is so variable in shape that it was named Pycnodonte mutabilis.

My friend specializes in the oyster genus Texigryphaea. By having collected with him, my Texigryphaea, Gryphaea, and Cubitostrea oyster collections are also in pretty good shape with all but a couple of species present from the Cubitostrea genus. I hope to display these remaining genera in the near future.

Photo The third area of interest are the scallops of the genus Chesapecten. I have had a bit more luck with the more common (when they are found) Chesapecten, and at the moment am missing only 1 species (C. monicae) of the dozen or so that are known at the present time. Only a couple of examples of this species has ever been found during the excavation of a nuclear power plant. Needless to say, access to this property is not possible.

Over the years I have also collected many sea urchins (echinoids) from the Devonian through the pleistocene ages. My collection is now sufficiently large that I have begun identifying some of the species. In addition, I have been lucky enough to find an interesting Devonian nautiloid in the genus Tylodiscoceras. It is possible that this is a new species and I hope to interest someone in publishing this information. It is also doubly interesting because a large 3 dimensional conularid is nicely preserved inside the living chamber of the nautiloid. I have also enjoyed collecting many species of Ordovician thru Devonian nautiloids in Iowa and Utah and Cretaceous nautiloids in Texas and other states. I have collected many of the more common Ordovician thru Devonian genera found in the midwest. The most recent interesting echinoid I have found is Nortonechinus stainbrooki. There are only 2 other specimens of this ultra-rare Devonian echinoid collected worldwide. The current (2) specimens that were found have been put into the University of Iowa repository and are awaiting preparation. Finally, during a recentlake draining, I was lucky enough to unearth a Devonian snail "trap door" (operculum) nestled against a large Straparollus snail. It is quite unusual to find the "trap door" associated with the fossil snail. It also is now in the repository along with my other donations.

I expect to continue collecting for many years in the future.

Fossil References

NMITA Neogene Marine Biota of Tropical America
Upper Cretaceous Bivalvia of Alabama by Andrew Rindsberg, Alabama Geological Survey

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By C. Newsom