Notealso, inthisconnection, thatalongwithawonderfulpersistenceoftype, withchangeofspecies,genera, orders, etc., fromformationtoformation,, butthatthelinkofgenerationhasbeensundered? Why, onthehypothesisofindependentoriginations, werenotfailingspeciesrecreated,eitheridenticallyorwithadifference, inregionseminentlyadaptedtotheirwell-being? ,isshownbythefacilitywithwhichtheyhavethererunwildandenormouslymultiplied, , atthedawnofthepresentperiod,wild-horses—certainlyverymuchliketheexistinghorse—, whyweretheynotreproduced, when, afterthecolderinterveningera, thoseregionsbecameagaineminentlyadaptedtosuchanimals? Why, butbecause, bytheircompleteextinctioninSouthAmerica, thelineofdescentwasthereutterlybroken? Upontheordinaryhypothesis,thereisnoscientificexplanationpossibleofthisseriesoffacts, , "thesuccessionofthesametypesofstructurewithinthesameareasduringthelatergeologicalperiodsceasestobemysterious, andissimplyexplainedbyinheritance." Theircessationisfailureofissue.
Alongwiththeseconsiderationsthefact (alludedtoonpage98) shouldberememberedthat, asageneralthing, , andstillmoreoftheanimals, ofeachseparatecountryarepeculiartoit; and, asmostspeciesnowflourishoverthegravesoftheirby-gonerelativesofformerages, sotheynowdwellamongoraccessiblyneartheirkindredspecies.
