Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/92

66 The most westerly chains of the Australian Cordilleras are the oldest, the most eastern the most recent. Tasmania forms a continuation of this system of folding. The reflected similarity with the South American Andes in the structure of the mountain systems is interesting, for there, on account of the position on the other side of the pole, the more easterly chains are the oldest. However, the most recent chains are absent in Australia. Suess found them again in New Zealand. To be sure the folding does not extend into the Tertiary in that country: “According to the view of most New Zealand geologists, the main folding of the Maorian mountain chains occurred in the period between the Jurassic and Cretaceous.” Previously it was totally covered by sea, until the folding first “converted the region of New Zealand into a land-mass.” The Upper Cretaceous and the Tertiary are mainly marginal and undisturbed. On South Island, Cretaceous deposits only occur on the east coast, not on the west coast, where a land connection must still be assumed in the Cretaceous. The breaking-away of the west coast followed in the Tertiary, “for Tertiary marine deposits are also found on it.” Finally, in the Upper Tertiary further but smaller folds, faults and overthrusts were formed which gave the mountains their present forms. All this can be explained by the displacement theory as due to the fact that New Zealand was formerly the eastern margin of the Australian Cordilleras. But when these chains were separated as island festoons, the folding processes ceased. The Upper Tertiary disturbances can very