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 prendelli

                                    Palaeoxyris prendelli, K.Robitschek collection - Vermillion River, Herrin Coal roof shale
                                       (slightly younger than the Francis Creek shale of the Mazon Creek area)
                                                 Palaeoxyris prendelli, A.Young collection - Mazon River, Morris, Illinois
                                                                 Palaeoxyris prendelli, Lauer Foundation collection
                                                                      J.Wittry collection - Mazon River, Morris, IL
                                                        Palaeoxyris prendelli, A.Young collection - Wilmington, IL
                                                           Palaeoxyris prendelli, A.Young collection - Wilmington, IL
        A.Young collection - Wilmington, IL (left and above)
                                                                      J.Wittry collection
                  The Chicago Academy of Sciences collection
                                            Palaeoxyris prendelli, Milwaukee Public Museum collection - MPM VP377853
                                          Palaeoxyris prendelli, Lauer Foundation collection (positive and negative halves)
                  A.Young collection - Pit 11, Braidwood, IL
                    A.Young collection - Wilmington, IL
                                           Palaeoxyris prendelli, Milwaukee Public Museum collection - MPM VP377850.1

Palaeoxyris multiplicatum

                                   Palaeoxyris multiplicatum with Euproops danae, K.Robitschek collection - Wilmington, IL
                                                              Palaeoxyris multiplicatum, Lauer Foundation collection

Palaeoxyris lewisi

                                                                       J.Wittry collection
      Palaeoxyris lewisi, The Field Museum collection PF8960,
      Figure 160.2 The Mazon Creek Fossil Fauna 2012
                                                      Palaeoxyris lewisi, Milwaukee Public Museum - MPM VP377849
                                                                   The Chicago Academy of Sciences collection
                                            Palaeoxyris lewisi, Milwaukee Public Museum collection - MPM VP377851.1

Palaeoxyris sulcatus (or P. warei)

                                                    Palaeoxyris sulcatus, M.Angkuw collection - Pit 11, Braidwood, IL
                                                                           A.Young collection - Wilmington, IL

Palaeoxyris carbonaria

                             J.Wittry collection - Mazon River, Morris, IL
                                                                 B.Morton collection
             Palaeoxyris carbonaria, The Field Museum collection (Note: this complete specimen is from Knob Knoster, Missouri.
                               The same age as Mazon Creek, it shows excellent anatomical detail including the collarettes).

Fish and Amphibian Eggs

Mazonova helmichnus

                                                              Mazonova helmichnus, Lauer Foundation collection
                                                                       Mazonova helmichnus, J.Wittry collection 
                                     Mazonova helmichnus, Milwaukee Public Museum collection VP940.1, P28720, and P28715.2