CORDILLERAN MESOZOIC RE VOL UTION. 585 



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 syn- 

 chronous 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 develop- 

 ment 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 meta- 

 morphics is analogous to that of the Archaean and indicates that 

 the conditions which are commonly recognized as Archaean 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 follow- 

 ing conclusion : 



"So mit bleibt denn nur noch die Annahme iibrig, dass die 

 als Granite, Syenite und Diorite zu bezeichnenden Andengesteine 

 eruptive Gebilde sind, die theils nach der Jura- und Kreidezeit, 



