Jack W. Kallmeyer, President, Cincinnati Dry Dredgers

Jack at the 75th Anniversary Meeting of the Dry Dredgers.
It has been my pleasure to be President of the Dry Dredgers since 1988. This group of amateur paleontologists in existence since April of 1942 just recently celebrated its 75th anniversary. Personally, I am a retired mechanical engineer but am now enjoying my work as an avocational paleontologist.

Part of what I do now is volunteer work at the Cincinnati Museum Center’s Geier Collections and Research Center. There I work in the Invertebrate Paleontological Collections as one of a number of assistants to the curator doing curating, cataloging, organizing and identifying specimens in the research collections. Working in the collections is educational and exciting but I also do my own research in paleontology.

My interests in paleontology have always been varied but one theme consistent throughout has been my desire to know more about a fossil than what the scientific name happens to be. A number of my projects, all based upon self-collected specimens, have ended up in publications in various journals of paleontology. My most recent published work concerned my discovery of a new species of crinoid (sea lily) in the Cincinnatian: Deepwater occurrence of a new Glyptocrinus (Crinoidea, Camerata) from the Late Ordovician of southwestern Ohio and northern Kentucky: revision of crinoid paleocommunity composition, Kallmeyer and Ausich, 2015, doi: 10.1017/jpa.2015.72.

Jack in search of Hebertella.

Although I have specialized in the fossil crinoids from this area for a long time, they are not my only interest. I am currently working with two professional paleontologists and another member of the Dry Dredgers at a site that preserves abundant Stromatoporoids (a kind of sponge with a hard skeleton during life). Just as I had done with my interest in crinoids, I had to learn about these creatures by reading and studying the available professional literature and by talking to professional paleontologists who study these animals. This particular group of animals has been problematic for years in that no one knew of any modern equivalents for comparison. Recently a modern group of sponges called sclerosponges has finally provided some basis for comparison. Although not the same as stromatoporoids, they are similar enough to help us understand the ancient forms.

My fascination with stromatoporoids in general is that they are poorly known. My particular study concerns those within a restricted range in a geologic formation known locally as the Elkhorn. The preservation of the stromatoporoids at this site is unique within the Upper Ordovician in this area in that they are silicified (preserved with silica replacing the original skeletal material) rather than the more common preservation in calcite. The preservation has also retained much of the original internal structure that is used to identify these animals to a specific species. Most stromatoporoids in the Upper Ordovician are preserved in calcite and the internal structures have been recrystallized into an amorphous featureless mass. Mamelons (rounded cone shaped protrusions) on the surface of the stromatoporoids in the study layer are almost completely worn flat. In the living animal, mamelons were the structures supporting flow of water and waste products out of the sponge.

An example stromatoporoid called Lebechia. The white scale bar on the left represents 10 mm and the black scale bar on the right represents 5 mm.

Study of this site and the stromatoporoids preserved there will ultimately reveal the environment in which they lived. The exposure is alternating shales/mudstones and limestone type layers that will tell us about the original water depth and water chemistry. The fossils we are studying have their bases on a siltstone layer. This layer is capped by a tan shale layer about 150mm thick that is itself capped by a dark gray 30mm thick shale. The tan shales represent influx of muds and clays from areas far to the east originating from storm surges. The dark gray material represents muds high in organic content.

Initial examination by professional paleontologist Carl Stock (University of Alabama) indicates that the stromatoporoids in these strata represent two different species and perhaps two different genera in the Family Labechiidae. Further study is required to answer many questions: what was the source for the silica that allowed silicification of the stromatoporoids; does the silicic preservation give clues to the original composition of the stromatoporoids (calcite or aragonite); what caused the nutrient rich dark gray layer to form; what set of conditions caused the erosion of the mamelons on the exterior of the stromatoporoids in this layer?

The discovery and publication of information or fauna that is new to science is one of my favorite parts of doing research. There is always a great sense of accomplishment when the field work and detective work of literature research comes together to answer some unresolved question. My advice to anyone interested in the earth sciences is to follow the path that drives your passion for learning. By doing this, regardless of your field, you will do your best work and derive the greatest sense of accomplishment.

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