L. V. Dalton — Geology of Venezuela. 207 



Ana. A rock of similar type covers a wide area in the hills south of 

 Caracas, in the region of San Casimiro, apparently of Tertiary age, hut 

 this cannot at present be definitely stated. 



III. Tectonics. 



The main tectonic features of Venezuela are very simple. In the 

 south vp^e have the great Guayana massif, with, apparently, a general 

 east and west strike vaiying to east-north-east, and with a boundary 

 on the north side which is at right angles to the meridian. On the 

 left bank of the Orinoco there lies the great synclinal basin of 

 the Llanos, and beyond this again a continuous line of upheaval in the 

 Cordilleras of the Andes and of the coast ; here the strike changes, 

 becoming approximately east and west in the Caribbean Hills, and 

 north-east or north-north-east in the Andes, while in the intermediate 

 highlands the strike varies from point to point. Beyond this the 

 Maracaibo basin and the coastal plains of Coro represent a second 

 synclinal area, while north and west of these the Sierra of Perija, the 

 igneous masses of Goajira in Colombia, the granite and Cretaceous of 

 Paraguana and Curagao, and the metamorphics of Margarita, appear to 

 mark a second anticlinal line on the northern limits of Venezuela. It 

 will be seen that in general the structure-lines agree with the main 

 physical divisions of the country : the upward movement which 

 changed the Llanos region from a shallow partly-enclosed sea to broad 

 low-lying plains was probably part of that which, beginning in the 

 Middle Tertiary times, is still continuing to accentuate the folding of 

 the Andes and to raise the Maracaibo region. The subsidiary 

 movements and structure-lines have hardly been studied sufficiently to 

 afford data f6r a detailed account of them. 



IV. Earthquakes and Hot Spkings. 



While active volcanoes are entirely wanting in Venezuela, there is 

 little lack of those evidences of internal energy so often associated 

 with them. Earthquakes have been known in the northern part of 

 the country from the time of the earliest settlements ; thus Nueva 

 Cadiz (on Cubagua) was shaken and the fortress of Cumana 

 demolished in 1530, and thirteen years later the city on Cubagua was 

 utterly destroyed. Many shocks were experienced of greater or less 

 violence throughout the seventeenth and eighteenth centuries, but 

 perhaps the best known is that of March 26, 1812, when some 

 10,000 people perished in the destruction of Caracas. The great 

 earthquake in South America on August 13, 1868, was as severely 

 felt in Venezuela as anywhere, and the waters of some of the great 

 rivers were for a short time so much affected as to overflow their 

 banks. Great damage was done in the Andine towns in 1894, and in 

 Caracas in 1900, while shocks were experienced in the former region 

 during the author's visit in 1910; these were, however, unimportant 

 as regards effect. Venezxiela thus enjoys an \inenviable notoriety as 

 an earthquake country, but the shocks are remarkable for their linear 

 character, both as regards the area in which they occur and in their 

 effects, for practically no serious shocks have been experienced 

 outside the region of the Cordilleras. 



