britishcolumbia burgessshale cambrian cambriangeologicperiod canada clay contingence(philosophie) contingency(philosophy) copperores evolución evolutie evolution extinction(biologie) extinction(biology) fossielen fossil fossiles fossilinvertebrates fossils geology histoire history influence invertebratefossils invertebrates invertébrésfossiles life naturalhistory ongewerveldedieren paleontologie paleontology paléontologie philosophie philosophy sandstone schalies slopes(soilmechanics) soilconsolidation stratigraphic yohonationalpark évolution