Summary.mw-parser-output table.commons-file-information-table,.mw-parser-output.fileinfotpl-type-information{border:1px solid #a2a9b1;background-color:#f8f9fa;padding:5px;font-size:95%;border-spacing:2px;box-sizing:border-box;margin:0;width:100%}.mw-parser-output table.commons-file-information-table>tbody>tr,.mw-parser-output.fileinfotpl-type-information>tbody>tr{vertical-align:top}.mw-parser-output table.commons-file-information-table>tbody>tr>td,.mw-parser-output table.commons-file-information-table>tbody>tr>th,.mw-parser-output.fileinfotpl-type-information>tbody>tr>td,.mw-parser-output.fileinfotpl-type-information>tbody>tr>th{padding:4px}.mw-parser-output.fileinfo-paramfield{background:#ccf;text-align:right;padding-right:0.4em;width:15%;font-weight:bold}.mw-parser-output.commons-file-information-table+table.commons-file-information-table,.mw-parser-output.commons-file-information-table+div.commons-file-information-table>table{border-top:0;padding-top:0;margin-top:-8px}@media only screen and (max-width:719px){.mw-parser-output table.commons-file-information-table,.mw-parser-output.commons-file-information-table.fileinfotpl-type-information{border-spacing:0;padding:0;word-break:break-word;width:100%!important}.mw-parser-output.commons-file-information-table>tbody,.mw-parser-output.fileinfotpl-type-information>tbody{display:block}.mw-parser-output.commons-file-information-table>tbody>tr>td,.mw-parser-output.commons-file-information-table>tbody>tr>th,.mw-parser-output.fileinfotpl-type-information>tbody>tr>td,.mw-parser-output.fileinfotpl-type-information>tbody>tr>th{padding:0.2em 0.4em;text-align:left;text-align:start}.mw-parser-output.commons-file-information-table>tbody>tr,.mw-parser-output.fileinfotpl-type-information>tbody>tr{display:flex;flex-direction:column}.mw-parser-output.commons-file-information-table+table.commons-file-information-table,.mw-parser-output.commons-file-information-table+div.commons-file-information-table>table{margin-top:-1px}.mw-parser-output.fileinfo-paramfield{box-sizing:border-box;flex:1 0 100%;width:100%}} Description: Essexella asherae Foster, 1979 fossil jellyfish from the Pennsylvanian of Illinois, USA (concretion is 7.1 cm tall). One of the most remarkable soft-bodied fossil deposits (lagerstätten) on Earth is the Pennsylvanian-aged Mazon Creek Lagerstätte near Chicago, Illinois. In the Mazon Creek area, the Francis Creek Shale consists of concretionary gray shales. The Francis Creek concretions are composed of argillaceous ironstone, and can be fossiliferous or nonfossiliferous. The fossiliferous concretions contain land plants and terrestrial & marine animals, including nonmineralizing organisms. This is an Essexella asherae fossil jellyfish. Jellyfish are extremely rare in the fossil record. This is hardly surprising, considering they completely lack hard parts, and the tissues they do possess are gelatinous. The most abundant marine organisms in the Mazon Creek biota are jellyfish. Many Mazon Creek jellyfish specimens do not have many diagnostic features, and are affectionately referred to as “blobs” by local fossil collectors (“blob A”, “blob B”, “blob with character”, etc.). Essexella asherae jellyfish fossils consist of a bell and a relatively long skirt. Sometimes, well-defined tentacles extend below the level of the skirt, as in this specimen. Classification: Animalia, Cnidaria, Scyphozoa, Scyphomedusae Stratigraphy: Mazon Creek Lagerstätte, Francis Creek Shale Member, Carbondale Formation, Desmoinesian Stage (= Westphalian D), upper Middle Pennsylvanian Locality: coal mine dump pile near Essex, northern Illinois, USA Ode to a Blob (Rob Shula, 2002) Oh, lowly blob, Whose grave I did not rob. On the ground you sit So round and nicely split. Were you but a few, I'd bend to pick up you. But alas, you're not so rare. And although I wish I'd care, I left you lying there. Date: 13 October 2014, 15:05. Source:
Essexella asherae fossil jellyfish (Mazon Creek Lagerstatte, Francis Creek Shale, Middle Pennsylvanian; coal mine dump pile near Essex, northern Illinois, USA) 2. Author:
James St. John.