174 TRANSACTIONS OF THE [feB. 15, 



ezuela border had, suddenly disappeared, during the earthquake, 

 and that not a soul was left alive. All had been swallowed by the 

 sea. It was only a little hamlet far aw^ay from any city, and at a 

 time when Caracas and Bogata were being shaken to their founda- 

 tions its loss was passed by unnoticed. Here there was then a 

 subsidence even in our times, and in earlier days such dis- 

 turbances were possibly more frequent, and slight depressions 

 could easily lead to irregular strata of sands and alluvium. From 

 Rio Uacha I went east, examining the countrj^ and found the 

 same conditions as alread}' described, and which seem to be 

 general to all the lowlands of this part of the world. These 

 lowlands extend to Cabo de Vela where a ridge of hills is found 

 gradually increasing in height in an irregular disconnected chain 

 till they reach the ranges of the Black Andes to the south. Be- 

 yond these hills the same alluvium is found in all the country 

 about Lake Maracaibo in Venezuela. At Cabo de Vela the hills 

 are of basic eruptive rocks, distinctly crj^stalline at some places, 

 at others they are of even texture, and these two merge into ir- 

 regular zones in which all components are mingled together. 

 This possibly indicates rapid cooling, and as they are not much 

 eroded, or broken by seismic action, which at an early period 

 must have been of great violence through all this section, I 

 think these ridges are of comparatively recent intrusion. I 

 noted the augite minerals and chlorite, and the rocks dolcrites, 

 and basalts, which later at places were amygdaloidal and had 

 seams and secondary infiltrations. 



The irregular nature of this formation, with its soft seams and 

 harder crystalline material makes these rocks particularly liable 

 to erosion by the sea, and steep precipices, isolated rocks among 

 the v/aves, and narrow fjords among the cliffs are common. Off 

 Cabo de Vela the sea is very deep and the precipices descend 

 directly into it, with scarcely any beach line, and at most places 

 there is not even standing room. 



This ended my explorations on the flat country and I next 

 turned my attention to the Sierra Nevada de Santa Marta moun- 

 tains. I landed at Dibulla, a little place on the north coast of 

 South America and, before proceeding to the mountains, made 

 an examination of the lowlands between them and the sea. These 

 are from four to twelve miles wide and are covered generally with 

 alluvium. There are dense jungles, swamps and open meadows. 

 Little could be noted on which to base calculations as to the 

 period in which this strip of land was formed, but it seems to 

 be the same as that of the other lowlands in this part of Co- 

 lombia, with perhaps beds of Cretaceous limestone, or even earlier 

 formations deposited by the action of the sea along the Sierra 

 Nevada mountains. 



