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CORDILLERAN MESOZOIC REVOLUTION.
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Cretaceous Mesozoic time, followed by continental uplift and great denudation.

From the facts above cited certain conclusions seem to be warranted which may be presented in the form of hypotheses for future examination:

(1) The pre-Cretaceous Mesozoic revolution which has been freely recognized by nearly all Californian geologists was not limited to the western United States, but affected the entire extent of the Cordilleran belt from Alaska to South America.

(2) It is not clear that the revolution was strictly synchronous in all portions of the Cordilleran belt which have been affected. It may have been progressive, and have extended through the time from the close of the Triassic to the close of the Jurassic so as to obliterate the Jurassic seas earlier in some regions than in others.

(3) An essential feature of the revolution was the development of batholitic magmas which invaded the crust, replaced large portions of it, and eventually congealed as plutonic rock of a prevailingly rather acid character.

(4) The development of the batholite, or batholites, was followed or accompanied by continental uplift.

(5) The complex of invading granite and consequent metamorphics is analogous to that of the Archæan and indicates that the conditions which are commonly recognized as Archæan are not peculiar to rocks of that age.

By way of addendum to this brief note it should be remarked that the irruption of granite in South America did not wholly cease with the Mesozoic revolution. Farther south than the countries which have been mentioned, in the Cordillera of the Argentine Republic, Stelzner has shown that this phase of crustal development continued through into the Tertiary. After a narration and discussion of his facts he formulates the following conclusion:

"So mit bleibt denn nur noch die Annahme übrig, dass die als Granite, Syenite und Diorite zu bezeichnenden Andengesteine eruptive Gebilde sind, die theils nach der Jura- und Kreidezeit,
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