| 
                                    
                                        gptkbp:instanceOf
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:geological_formation
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:characterizedBy
                                    
                                 | 
                                
                                    
                                        
                                            
                                            high sea levels
                                        
                                        
                                         
                                    
                                        
                                            
                                            diversification of marine life
                                        
                                        
                                         
                                    
                                        
                                            
                                            first appearance of coral reefs
                                        
                                        
                                         
                                    
                                        
                                            
                                            first land plants
                                        
                                        
                                         
                                    
                                        
                                            
                                            glaciation at end of period
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:climate
                                    
                                 | 
                                
                                    
                                        
                                            
                                            generally warm, cooling at end
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:continent
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Siberia
                                        
                                         
                                    
                                        
                                            gptkb:Baltica
                                        
                                         
                                    
                                        
                                            gptkb:Laurentia
                                        
                                         
                                    
                                        
                                            
                                            Gondwana dominant
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:dividedInto
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Middle_Ordovician
                                        
                                         
                                    
                                        
                                            gptkb:Early_Ordovician
                                        
                                         
                                    
                                        
                                            gptkb:Late_Ordovician
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:duration
                                    
                                 | 
                                
                                    
                                        
                                            
                                            about 41.6 million years
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:endDate
                                    
                                 | 
                                
                                    
                                        
                                            
                                            443.8 million years ago
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:followedBy
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Cambrian
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:lake
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Rheic_Ocean
                                        
                                         
                                    
                                        
                                            gptkb:Iapetus_Ocean
                                        
                                         
                                    
                                        
                                            gptkb:Paleo-Tethys_Ocean
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:namedAfter
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Ordovices
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:notableSite
                                    
                                 | 
                                
                                    
                                        
                                            
                                            brachiopods
                                        
                                        
                                         
                                    
                                        
                                            
                                            conodonts
                                        
                                        
                                         
                                    
                                        
                                            
                                            graptolites
                                        
                                        
                                         
                                    
                                        
                                            
                                            nautiloids
                                        
                                        
                                         
                                    
                                        
                                            
                                            trilobites
                                        
                                        
                                         
                                    
                                        
                                            
                                            early jawless fish
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:partOf
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Paleozoic_Era
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:precededBy
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Silurian
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:recognizedBy
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Charles_Lapworth
                                        
                                         
                                    
                                        
                                            
                                            1879
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:significantEvent
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Great_Ordovician_Biodiversification_Event
                                        
                                         
                                    
                                        
                                            gptkb:Ordovician-Silurian_extinction_event
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:startDate
                                    
                                 | 
                                
                                    
                                        
                                            
                                            485.4 million years ago
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:type
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Wales
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:bfsParent
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Kentucky_River_Palisades
                                        
                                         
                                    
                                        
                                            gptkb:Manhattan_schist
                                        
                                         
                                    
                                        
                                            gptkb:Tennessee_marble
                                        
                                         
                                    
                                        
                                            gptkb:Illinites
                                        
                                         
                                    
                                        
                                            gptkb:Parys_Mountain
                                        
                                         
                                    
                                        
                                            gptkb:West_Coast_Range
                                        
                                         
                                    
                                        
                                            gptkb:Cambrian
                                        
                                         
                                    
                                        
                                            gptkb:Charlevoix_impact_structure
                                        
                                         
                                    
                                        
                                            gptkb:Chazy_Fossil_Reef
                                        
                                         
                                    
                                        
                                            gptkb:Silurian
                                        
                                         
                                    
                                        
                                            gptkb:Southern_Uplands
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:bfsLayer
                                    
                                 | 
                                
                                    
                                        
                                            
                                            6
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        https://www.w3.org/2000/01/rdf-schema#label
                                    
                                 | 
                                
                                    
                                        
                                            
                                            Ordovician
                                        
                                        
                                         
                                    
                                 |