Flora and Fauna of the Pleistocene Oak Creek Formation Peat Deposits

Mikayla Walker, “Flora and Fauna of the Pleistocene Oak Creek Formation Peat Deposits”
Mentor: Scott Schaefer, Geosciences

Pleistocene Oak Creek Formation deposits dated to 45,000 to 35,000 years old are exposed at Sheridan Park in Cudahy, Wisconsin. Sediments from this formation include strata of ancient bog material known as peat which contains potentially identifiable flora and fauna that predate the last glacial advance. Leaves, twigs, seeds, and insect fragments recovered from the peat will help characterize the lesser-known paleoecology of this ecosystem essential to Wisconsin’s geological history. Samples of peat were processed by disaggregation to recover previously unaccounted for flora and fauna. Because this bog represents one of the earliest phases of the Oak Creek Formation, understanding its biota enhances the narrative and continuity of this fossil deposit for geoscience students. This field locality is frequented by regional underrepresented minority students; therefore, this research will provide a more complete and captivating narrative to further inspire future generations of scientists. 


  1. Mikayla,

    Excellent job. I’m interested in the stratigraphy and sedimentology of the bluff so it was helpful in learning more of what was growing in the bogs during an intraglacial. Mark Borucki might be an additional resource for you. He has gotten some new dates and has updated the stratigraphy from that site.

    John Isbell

  2. Excellent presentation, Mikayla! Great photos and well organized. I’m excited to see what you learn next.

  3. Great presentation, Mikayla! You explained everything so clearly, and the images were great. Was all this material collected from one stratigraphic level within the formation? Or multiple levels? I’m curious if you saw changes in the fossil assemblage over stratigraphic time.

  4. I appreciate the presentation including with a lot of figures. The presentation will be easy to be followed if an outline of the talk is provided. I am a bit confused with the information among background, methods and the results.A clear objective of the project will be also helpful for readers who are not familiar to the area.

    1. Thank you for your feedback! I agree that an outline would create a better flow for my presentation. Are there any specific questions you have regarding my background, methods, and results? The objective might have been less clear as this research was preliminary and it helped give me more direction for future research.

  5. I enjoyed the talk – lots of good information on the fossil material and comparable modern materials. I was curious if there are other peat levels that you could compare to this. Also, the presentation made it easy to follow along.

  6. Interesting presentation. I am wondering if this occurs at other locations around Milwaukee, or just at Sheridan Park. I have never heard of this sort of material showing up on the beaches before.

    By the way, it might be worth trying some DNA barcoding to identify the samples….if you can get DNA out of some of them. That could simplify identification.

  7. Very interesting presentation Mikayla, I really enjoyed the bit about the beetle elytra. It sounds really difficult to identify specimens when you have a list that’s over 30,000!

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