166 TRANSACTIONS OF THE * [fEB. 15, 



The first paper of the evening was by F. C. Nicholas, on 

 " Explorations in the Gold Fields of Western Colombia." It 

 will appear in the School of Mines Quarterly for April, 1897. 

 The second paper of the evening was by Prof. R. E. Dodge, en- 

 titled " Recent Work in Phj'siography." Professor Dodge gave 

 a brief review of De Lapparent's " Le9ons en Geographic Phys- 

 ique ;" of Sir John Lubbock's " Scenery of Switzerland," and 

 of two recent papers by M. R. Campbell and C. F, Marbutt. 



The paper was discussed by the Secretary. 



The third paper of the evening was by Dr. A. A. Julien on 

 " The Sculpture and Sorting of Sands." It was discussed by 

 Professor Dodge and the Secretary. 



The Academy then adjourned. 



J. F. Kemp, 



Secretary. 



THE MOUNTAINS AND TERTIARY VALLEYS OF 

 EASTERN COLOMBIA. 



Read December 21, 1896. 



[With Plate XV.] 



By Francis Child Nicholas. 



In asking your attention to a series of explorations and stud- 

 ies in eastern Colombia, I do not come claiming great knowl- 

 edge as a geologist, or particular merit as an explorer ; but ta 

 tell of what I have actually seen, thinking that it may be of some 

 service. For, just as an able scientist, making researches in 

 an unknown country, may ask superficial information from any 

 who might be locally acquainted with the places to be explored, 

 so my notes, gathered by personal investigation, may presently 

 be of some service when abler minds begin to look about for in- 

 formation as they prepare to enter seriously on geological inves- 

 tigation in this part of South America. 



The striking features in the countr}^ of which I write are 

 these : The Sierra Nevada de Santa Marta mountains of crystal- 

 line formations, isolated and lying almost at right angles with 

 the general axis of the Andes; the Cretaceous system found 

 among the Andean ranges but a few miles distant ; and the low 



