I assigned reasons why such links do not commonly occur at the present day under the circumstances apparently most favourable for their presence, namely, on an extensive and continuous area with graduated physical conditions.
Eman ditut arrazoiak azaltzeko zergatik ez diren gaur egun eskuarki ageri aipaturiko lokarriak, berak izateko zirkunstantzia faboragarrienetan ere, hau da, baldintza fisiko mailakatuak dituzten herrialde zabal eta etengabeetan ere.