Mazon Creek Fossil Fauna

Eggs 

Shark Egg Cases

Within the taxonomic realm, Paleaeoxyris has had two lives: first within the flora, and now among the fauna. Its discovery some 175 years ago amidst plant material in the Mazon Creek concretions, coupled with its resemblance to a Weeping Willow or Ash leaf, prompted early researchers such as Leo Lesquereux (1880) to classify it as a plant. Similar specimens were placed in the genera Vetacapsula, Spiraxis, Fayolia, and Spirangium; species were then erected in these genera. Not all authorities agreed. By 1888, a paper stating these fossils to be "eggs of Elasmobranch fishes" had already been published. Opinions remained divided until the relationship between Palaeoxyris and modern forms of spiral shark egg capsules was demonstrated by Zidek (1976).

Palaeoxyris prendeli - Lesquereux, 1870

                  Palaeoxyris prendeli, Little Vermillion River, Georgetown, IL, Herrin Coal roof shale - K.Robitschek collection.
                               (The Energy Shale is slightly younger than the Francis Creek shale of the Mazon Creek area)
                                                     Palaeoxyris prendeli, Mazon River, Morris, IL - A.Young collection
                                                                 Palaeoxyris prendeli, Lauer Foundation collection
                                                                     Mazon River, Morris, IL - J.Wittry collection
                               Palaeoxyris prendeli, Pit 3, Wilmington, IL - K.Robitschek collection (photo by K.Robitschek)
                                                       Palaeoxyris prendeli, Pit 2, Wilmington, IL - A.Young collection
                                                     Palaeoxyris prendeli, Pit 2, Wilmington, IL - A.Young collection
                      Palaeoxyris prendeli, one half seen in two views, found open at Pit 3, Wilmington, IL - A.Young collection
                                                                        Palaeoxyris prendeli - R.Rock collection
     Above and left: Pit 2, Wilmington, IL - A.Young collection
                                                                      J.Wittry collection
                      Chicago Academy of Sciences collection
                                                   Palaeoxyris prendeli, Milwaukee Public Museum collection VP377853
                                          Palaeoxyris prendeli - Lauer Foundation collection (positive and negative halves)
                  Pit 11, Braidwood, IL - A.Young collection
                Pit 2, Wilmington, IL - A.Young collection
                 Palaeoxyris prendeli, one half seen in two views, found open in the Mazon River, Morris, IL - A.Young collection
                                                Palaeoxyris prendeli - Milwaukee Public Museum collection VP377850.1

Palaeoxyris helicteroides - Morris, 1840

                                              Palaeoxyris helicteroides, Milwaukee Public Museum collection VP377851.1
                                            Palaeoxyris helicteroides - R.Rock collection (positive and negative halves)

Palaeoxyris multiplicatum - Lesquereux, 1880

                Above and below: Palaeoxyris multiplicatum with Euproops danae, Pit 2, Wilmington, IL - K.Robitschek collection
                                                              Palaeoxyris multiplicatum - Lauer Foundation collection
                                                                     Palaeoxyris multiplicatum - R.Rock collection

Palaeoxyris lewisi - Zidek, 1976

                                      Above and below: Palaeoxyris lewisi - R.Rock collection (positive and negative halves)
                                                                       J.Wittry collection
      Palaeoxyris lewisi, Field Museum collection PF8960,
       Figure 160.2 The Mazon Creek Fossil Fauna 2012
                                                           Palaeoxyris lewisi, Milwaukee Public Museum VP377849
                                                                         Chicago Academy of Sciences collection

Palaeoxyris warei - Crookall, 1927

                                         Above and below: Palaeoxyris warei, Pit 11, Braidwood, IL - M.Angkuw collection
                                                        Palaeoxyris warei, Pit 2, Wilmington, IL - A.Young collection
                                                                   Palaeoxyris warei - R.Rock collection

Palaeoxyris carbonaria - (Stiehler) Schimper, 1869

     Palaeoxyris carbonaria, Mazon River, Morris, IL - J.Wittry
                                                            B.Morton collection
                    Palaeoxyris carbonaria, Knob Noster, Missouri - Field Museum collection (Knob Noster is thought to be the 
                        same age as Mazon Creek. This specimen shows excellent anatomical detail including the collarettes.)

Fayolia ellipticus - (Langford) Fisher et al., 2008

Vetacapsula cooperi - (Mackie) Crookall, 1928

Vetacapsula johnsoni - (Kidston) Crookall, 1928

Fish and Amphibian Eggs

Mazonova helmichnus - Godfrey, 1995

                                                              Mazonova helmichnus - Lauer Foundation collection
                                                                       Mazonova helmichnus - J.Wittry collection 
                                     Mazonova helmichnus, Milwaukee Public Museum collection VP940.1, P28720, and P28715.2
                                                                        Mazonova helmichnus - R.Rock collection
                         Mazonova helmichnus, tumbled and smoothed by the Mazon River, Morris, IL - P.Anderson collection