fossilcrazy Posted September 12, 2011 Share Posted September 12, 2011 Some of the oldest Fish remains in North America can be found in the Colorado Ordovician Harding Sandstone and their discovery is credited to Charles Walcott. Limited mostly to scales, plates and teeth; very few articulated remains have been found. The material is neat looking under a microscope but does little for imagining what the Fish looked like. Examples of later Silurian Fish are much better represented. Here are some Fish that moved like Tadpoles because they had headshields with tails but no fins. Americaspis americana was discovered by Claypole but he had named it Paleoaspis. My specimens were collected in Pennsylvania. The outside of the shield has a "fingerprint" type pattern - Drawing by Dennison while the inside of the shield has indentation markings of internal organs - Drawing by Halstead My sketch of Americaspis americana modified from Claypole - In Devonian time the Placoderm Fish still had headshields and tails but started arms for primative fins. My specimen was not self-collected, it is from an old collection of a locality now protected as a UNESCO World Heritage Site (Miguasha, Quebec) The end of the Devonian marked the end of the Tadpole-like swimmers. 4 Link to comment Share on other sites More sharing options...
Auspex Posted September 12, 2011 Share Posted September 12, 2011 Another very informative post; thank you! The fossils are way cool too "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
RomanK Posted September 12, 2011 Share Posted September 12, 2011 I really like materials you posted, thank you. Regards, Roman. Roman http://s1143.photobu.../donbassfossil/ Link to comment Share on other sites More sharing options...
pleecan Posted September 12, 2011 Share Posted September 12, 2011 Wow Another great post John! Enjoy seeing these rare fossil fish.... PL Link to comment Share on other sites More sharing options...
Tachikoma_kun Posted September 12, 2011 Share Posted September 12, 2011 Wonderful collection and thanks for the detail! I remember seeing these in a dinosaur book I had as a child and being fascinated by them and their head shields Link to comment Share on other sites More sharing options...
flyguy784 Posted September 12, 2011 Share Posted September 12, 2011 Very cool and interesting. Thanks for filling us in. Link to comment Share on other sites More sharing options...
pleecan Posted September 12, 2011 Share Posted September 12, 2011 Now I know what to look for in Silurian rock! Thanks for the pictorial guide. Link to comment Share on other sites More sharing options...
Sinopaleus Posted September 12, 2011 Share Posted September 12, 2011 wowie. Link to comment Share on other sites More sharing options...
fossilcrazy Posted August 27, 2013 Author Share Posted August 27, 2013 Yet another message string I didn't see in my personal content. Link to comment Share on other sites More sharing options...
Fossildude19 Posted August 27, 2013 Share Posted August 27, 2013 Yet another message string I didn't see in my personal content. I believe, John, that the content gets "archived" after a year, so you don't see it unless you search for it by author and date using advanced search. Regards, Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
sseth Posted August 27, 2013 Share Posted August 27, 2013 Amazing fossils! _____________________________________ Seth www.fossilshack.com www.americanfossil.com www.fishdig.com Link to comment Share on other sites More sharing options...
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