28^ GEOLOUICAL SECTIONS THROUGH THE ANDES. [vol. Ixxvii. 



worse than strata verticallj^ npreared on end and some overfolds. 

 The igneous mtrusions were, however, on a grand scale, and it 

 looked as though it might be necessary to make a jDartial return to 

 hypotheses now out of date. Possible batholiths may have j^layed 

 a more important part than the opinions at present fashionable will 

 concede. 



The Al'THOE, said that, in the short time at his disposal, he had 

 only been able to give a very brief sketch of the geological features 

 of the section, and several of the points raised by the speakers were 

 dealt with more fully in the paper. He f ulh^ agreed Avitli Dr. Evans 

 that much of the evidence tended to show that the foldino" was 

 not contemporaneous throughout the length of the chain. In the 

 Jurassic rocks, for example, deposition appeared to have ceased 

 with the Lower Lias in the district now described ; farther south 

 it was continued into Bajocian times, while in the north of Cliile 

 beds of Oxfordian age were found. The transition of the fossili- 

 ferous Cretaceous limestones of the north into the g}' psiferous red 

 sandstones of the south was also a significant feature. 



In reply to Prof. Sollas, he said that the facts now recorded were 

 in no way opposed to the views that he had previoush'^ expressed, 

 as to the nature of the "processes which gave rise to the uplift of 

 the Andes. The great granite-mass of the Perene formed, with 

 the nepheline-sj^enites of the Inambari district, one of the jaws 

 of the vice that had compressed the transgressi\^e deposits of the 

 geosyncline. Fragments of the other jaw were to be found in 

 the similar granite of the coastal Cordillera. 



In conclusion, he reminded the Fellows of the debt of gratitude 

 which he owed to the late Mr. W. E. Balston, who had enabled 

 him to visit South America, and at the same time thanked them 

 for the kind reception given to his paper. 



[November 11th, 1921.] 



