Scientists have found two specimens of a 444 million-year-old "inside-out" fossil with well-preserved soft tissue, according to a new study. Unlike most fossils, the creature's muscles and guts — but ...

Ediacara -- The Burgess Shale -- The Soom Shale -- The Hunsrück Slate -- The Rhynie Chert -- Mazon Creek -- Grès à Voltzia -- The Holzmaden Shale -- The Morrison Formation -- The Solnhofen Limestone - ...