THE 



QUARTERLY JOURNAL 



OF 



THE GEOLOGICAL SOCIETY OF LONDON. 



Vol. LXXVI 



FOR 1920. 



1. Geological Sections through the Andes of Perit and 

 Bolivia : II — From the Poet of Mollendo to the Inam- 

 bari River. By James Archibald Douglas, M.A., B.Sc, 

 F.G.S. (Bead February 4th, 1920.) 



[Plates I-VI.] 



Contents. 



Page 



I. Introduction 1 



II. Main Topographical Features of the Country included in 



the second section (Mollendo to the Inambari River) . . 4 



III. Geological Description of the Section from Mollendo to 



the Inambari River 7 



( 1 ) The Country between Mollendo and Arequipa 7 



(2) The Country between Arequipa and Puno 26 



(3) The Country between Tirapata and the Inambari River. 39 



IV. General Summary and Conclusions 52 



V. Bibliography ■ 58 



I. Introduction. 



In a formei- communication to this Society, published in April 

 1911, I described a geological section through the South American 

 Andes, from Arica on the Pacific coast of Northern Chile to the 

 Bolivian Yungas. 



The present paper, the publication of which has been long delayed 

 owing to the War, is a further contribution to the same series, the 



QJ.G.S. No. 301. b 



