Wooster Geologists

It was my privilege to join an Estonian-Polish-Chinese-American team interpreting partial soft-tissue preservation of the feeding devices of Silurian cornulitids, which are extinct Paleozoic organisms that constructed small conical, ribbed tubes. Cornulitids are very common sclerobionts (hard-substrate dwellers) in the Upper Ordovician Cincinnatian Group of Indiana, Kentucky and Ohio, so these are familiar fossils to Wooster geologists. Now we know a little bit more about their paleobiology. Our new paper can be downloaded here.

The top image is from Figure 3A of Vinn et al. (2026). It is Cornulites cf. cellulosus (HWR007a) showing a fully protracted likely lophophore (filter-feeding device). Scale bar is 5 mm.

Abstract.–Circular structures observed at the apertures of several Cornulites specimens from the earliest Silurian of China are interpreted as possible fossilized remains of a lophophore with a simple, ring-like morphology. These structures may represent partial preservation of the feeding apparatus, with the absence of tentacle preservation likely resulting from taphonomic processes. The preserved rim surrounding the circular structure likely reflects the thickness of the lophophore and its tentacles, while a neck-like extension visible in one specimen is interpreted as the basal region of the lophophore. Specimens displaying a partially extended lophophore suggest that Cornulites individuals may have been capable of retracting their lophophore entirely into the shell, between feeding episodes, although complete retraction remains speculative. These partial soft-­tissue remains support the classification of cornulitids as lophophorates. However, the available evidence remains insufficient to definitively resolve whether cornulitids are more closely related to bryozoans or phoronids. As the only shelled benthic fossils in the Huangshi deposits, cornulitids seemed to have been opportunistic organisms which were able to colonize and thrive in oxygen-deficient palaeoenvironments following the Late Ordovician mass extinction.

From Figure 4 of Vinn et al. (2026). Cornulites sp. (specimen HWR072a-1) interpreted as showing a partially retracted lophophore. Scale bar is 5 mm.

From Figure 5 of Vinn et al. (2026). Schematic line drawing of Cornulites cf. cellulosus (HWR007a) showing a fully protracted lophophore. Scale bar 5 mm.

Cornulitids are old friends to those Wooster geologists who studied Ordovician fossils in paleo courses. This is the genus Cornulites Schlotheim 1820, specifically Cornulites flexuosus (Hall 1847). It was found in the Whitewater Formation (Late Ordovician, Katian) during a College of Wooster field trip to southeastern Indiana (C/W-148; N 39.78722°, W 84.90166°).

I thank my international co-authors for inviting me to join this team.

Reference:

Vinn, O., Zong, R., Wilson, M.A., Liu, Y. and Zatoń, M. 2026. Partially preserved cornulitid feeding apparatuses from the lowest Silurian of South China support the lophophorate affinities of this enigmatic group. Lethaia https://doi.org/10.18261/let.59.3

Dr. Lyon’s class along with her TAs and in collaboration with the Wooster Art Museum’s director Dr. Marianne Wardle, significantly upgraded many of the fossil and mineral displays in Scovel Hall this past fall.

The classes hard work was revealed in an “opening” on the last day of Geoclub with students presenting their work to the Wooster Earth Scientists.

One of the formerly empty cases in the North entrance of Scovel Hall is now populated with new displays that are Ohio-centric.

Each of the geologic time periods is represented, and in this case, fossils from Ohio are keyed to each period are explained.

A detail of one of the cases and Ohio’s fossils.

Another new addition to Scovel Hall is a case on the first floor with examples of various modes of preservation and remarkable aesthetics in the setup with cards that offer explanations for each specimen.

Modes of preservation was a topic in much of the interpretive materials in the first floor case.

A detail from one of the shelves of the first – floor case.

Departmental technician, Nick Wiesenberg, painted over the not-so-nice pink color that was pervasive in our building, making this almost-three-story-wall shades of blue to provide an oceanic backdrop. Its great to see these displays each day and to see an increase in student, faculty, staff and visitors reading and interacting with the materials. Thank you Dr. Lyon, students and TAs from Paleoecology as well as the Wooster Art Museum and Nick for his support of this project.

Imagine a world with larch trees in the uplands and dawn redwoods in the flats, and bald cypress trees in the wetlands. This existed in the Eocene (~40 million years ago) when the world was warmer, the treeline was at higher latitudes and altitudes, and carbon dioxide in the atmosphere was more than two times Earth’s preindustrial levels. In fact, in the high Arctic where no trees can survive today, deciduous conifers were as lush in terms of carbon sequestration and bioproductivity as today’s rain forests.  Now, imagine a world that is sliding back into the greenhouse after millions of years of relative icehouse conditions.

How can we better understand the role of deciduous conifers in the biosphere and their utility in a warmer world. One “natural” experiment is to use dendroclimatology to infer the response of deciduous conifers to a warmer and wetter world. Secrest Arboretum in Wooster, Ohio has two species of larch trees (Siberian and European) as well as bald cypress and dawn redwood trees. These species are all exotic to Ohio and have been growing in the arboretum in some cases for over 100 years. How do they grow in their new homes? This is the subject of a new paper from the Wooster Tree Ring Lab published in Plants People and Planet.Dawn Redwoods from the Arboretum

The Weather station active in the Arboretum since the late 1800s provided the monthly climate records.

Here is the upshot of the work: Rising temperatures and wetter conditions in the Midcontinent of North America are influencing climate responses in trees. Dendroclimatological analyses of the four exotic deciduous conifer species from Secrest Arboretum, Northeast Ohio help identify past, present, and future climate-tree interactions. Analyses suggest that two larch species have changed their response to climate, whereas dawn redwoods and bald cypress trees are well suited for the present and future climate. This study elucidates tree responses to climate gleaned from a largely untapped source of tree growth in arboreta that can be more broadly applied at other sites as well as facilitate forest management decisions.

This effort included professors, staff and students at The College of Wooster as well as our collaborator and geo-ecologist Dr. Ben Gaglioti from the University of Alaska – Fairbanks. We thank Jason Veil (the curator of Ohio State University’s Secrest Arboretum) and its staff and volunteers for managing this amazing facility and for allowing us to sample the trees. We also acknowledge support of the National Science Foundation, Division of Earth Sciences, Grant/Award Numbers: EAR 2039939, GP-2023154.

Nigel Brush and colleagues have assembled a record of human history in the Walhonding Valley of Ohio (see map below). Along with Jeffrey Dilyard and others, Brush has worked in the region for decades  examining the history of human occupation throughout the Holocene in this part of Ohio. In this latest contribution Brush and colleagues (2025), along with Wooster geologists, has pieced together a story of hunting point technology, resource use, and climate change. A key question of this work focused on the technology of the lanceolate point (see figure below), which was widely used in the Great Plains for hunting bison early in the Holocene (late Paleoindian interval).  Why this same technology was used later in the Holocene about 4.4 to 4.0 ka (~4,400 to 4,000 years ago) in Ohio is a mystery given that bison were not thought to be plentiful. Perhaps the reason was, that during this time of known climate shifts (ie. the 4.2 ka event) bison migrated east into the region and residents adopted the lanceolate technology to exploit this change in resource. The dry conditions in the central plains during this time and expanded prairies into Ohio might explain the lanceolate workshops in the Walhonding River valley and the need for these points. This is one of the hypotheses that the authors put forth to explain the presence of these points in the Walhonding Valley and an idea that could be tested further.

The cover of the Archaeology of Eastern North America (AENA) – the points on the upper left (red background) pertain to the article showing the manufacture of the lanceolate points.  

Map showing the Walhonding River site at the confluence of the Mohican and Kokosing Rivers. The Cox South E-Site is crucial in this study. Downstream also shown are the Honey Run and McConnell sites, which also have documented lanceolate point workshops.

A next-step in this study might be to investigate the ~4.2 ka interval in lake cores from Northeast Ohio to better understand the environmental changes at this time. A strong candidate would be to recover and study that interval as recorded in the sediments of  Browns Lake in southern Wayne County where the other two other abrupt climate changes that define the Holocene are evident. The Younger Dryas (Shane and Anderson, 1993; Lyon et al., 2025) and the 8.2 ka event (Lutz et al., 2008) are well-documented in the lake, why not then the 4.2 ka event? Perhaps a student in Earth Sciences or Archaeology at Wooster will take this on as their Independent Study.

References:

Brush, N., Dilyard, J., Burks, J., Kardulias, P.N., Wiles, G. and Wiesenberg, N., 2025, The Cox South-E Site (33-CS-986): a Late Archaic Lanceolate Workshop in the Walhonding Valley, Coshocton County,Ohio, Archaeology of North America, 53: 129-162: ISSN 0360-1021.

Lutz, B., Wiles, G.C., Lowell, T.V., and Michaels, J., 2007, The 8200 abrupt climate change in Brown’s Lake, Northeast Ohio: Quaternary Research. 67, 292-296, doi:10.1016/j.yqres.2006.08.007.

Lyon, E. C., Wiles, G. C., Wilson, M. A., Lowell, T. V., & Diefendorf, A. F. A HIGH-RESOLUTION LAKE RECORD OF THE YOUNGER DRYAS FROM NORTHEASTERN OHIO. Geological Society of America Abstracts with Programs, 57(7), Abstract #7848.

Shane, L. C. K., and Anderson, K. H. (1993). Intensity, gradients and reversals in late glacial environmental change in east-central North America. Quaternary Science Reviews, 12(4), 307–320.

The global tree-ring community is racking up the papers investigating the utility of the relatively new proxy using blue intensity of annually-dated tree rings. This latest effort is a blue intensity investigation followup of a recent study on ring widths also led by Dr. Santosh Shah of Birbal Sahni Institute of Palaeosciences in Locknow, India. Blue intensity is a proxy that has added a new dimension to thermal histories across the globe including efforts at the The College of Wooster Tree Ring Lab. Shah et al. (2025) used cores extracted from three sites of the Western Himalayan Fir (Abies pindrow) from the Kashmir Valley.

Map from the study showing the location of the three tree-ring sites and the meteorological station (Srinager). The centrally-located Srinager climate station has records of precipitation and temperature spanning 1901-2024, one of the longest in the region.

A figure from the paper showing the beautiful images of earlywood (above) and latewood (below) blue light reflectance for individual rings from the Western Himalayan Fir (Abies pindrow). 

The upshot of the work is that time series of blue intensity values from the latewood of A.Pindrow are strongly correlated with monthly average and maximum temperature series  from nearby climate station (Srinager).  Ring-width are more strongly correlated with summer precipitation and thus blue intensity with its response to late summer temperatures promises to provide a new proxy for thermal histories for the region. These collaborations with Dr. Shah and colleagues have enriched our efforts at the Wooster Tree Ring Lab and we look forward to future efforts.