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                       Asaphid
                            Trilobite Fossils    | 
                   
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                    | Family
                    Asaphidae Saint
                    Petersburg, Russia |  Family
                        Asaphidae Criner
                        Hills, Oklahoma  |  Family
                          Asaphidae  Wenlock
                          Shale, UK | Family 
                        Trinucleidae Blekos,
                        Morocco  | 
                   
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                    | Family 
                        Asaphidae Saint
                        Petersburg, Russia | gen 
                        et sp indet Jbel 
                        Bani, Morocco | Subfamily 
                        Ptyocepalinae Fillmore 
                        Formation, Utah | Family 
                        Asaphidae Walcott – Rust
                        Quarry, New York | 
                   
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                    | Family 
                        Trinucleidae Llanvirn 
                        Series, Wales | Family
                          Trinucleidae Czech
                          Republic | Family
                          Trinucleidae Ourzazate,
                          Morocco | Family
                          Asaphidae Saint
                          Petersburg, Russia | 
                  
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                    | Subfamily
                    Isotelinae   Ontario,
                    Canada | Family Trinucleidae Liberty Hall Shale, Virginia |  | 
                        
                        Saint
                            Pertersburg, Russia | 
                  
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                    | 
                        
                        OrdovicianSuborder Asaphidae
 Saint
                            Pertersburg, Russia | Asaphus
                            latusOrdovician
 Family Asaphidae
 Saint Petersburg, Russia
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                    |  |  |  | Asaphus
                              holmiOrdovician
 Family Asaphidae
 Saint Petersburg, Russia
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