ANCIENT SEA-SHORE. 





leading to tee great village of San Jose de Tisnao. 

 parsed the farms of Luque and Juncalito, to enter the 

 valleys which, on account of the bad road, and the blue 

 colour of the slates, bear the names of Malpaso and Pie- 

 dras Azules. 



This ground is the ancient shore of the great basin of 

 the steppes, and it furnishes an interesting subject of re- 

 search to the geologist. We there find trap-formations, pro- 

 bably more recent than the veins of diabasis near the town 

 of Caracas, which seem to belong to the rocks of igneous 

 formation. They are not long and narrow streams as in 

 Auvergne, but large sheets, streams that appear like real 

 strata. The lithoid masses here cover, if we may use the 

 expression, the shore of the ancient interior sea; everything 

 subject to destruction, such as the liquid dejections, and the 

 scoria} filled with bubbles, has been carried away. These 

 phenomena are particularly worthy of attention on account 

 of the close affinities observed between the phonolites and 

 the amygdaloids, which, containing pyroxenes and horn- 

 blende-griinsteins, form strata in a transition-slate. The 

 better to convey an idea of the whole situation and super- 

 position of these rocks, we will name the formations as they 

 occur in a profile drawn from north to south. 



"We find at first, in the Sierra de Mariara, which belongs 

 to the northern branch of the Cordillera of the coast, a 

 coarse-grained granite ; then, in the valleys of Aragua, on 

 the borders of the lake, and in the islands, it contains, as 

 in the southern branch of the chain of the coast, gneiss 

 and mica-slate. These last-named rocks are auriferous in 

 the Quebrada del Oro, near Guigue; and between Villa 

 de Cura and the Morros de San Juan, in the mountain of 

 Chacao. The gold is contained in pyrites, which are found 

 sometimes disseminated almost imperceptibly in the whole 

 mass of the gneiss,* and sometimes united in small veins 

 of quartz. Most of the torrents that traverse the moun- 

 tains bear along with them grains of gold. The poor in- 

 habitants of Villa de Cura and San Juan have sometimes 

 gained thirty piastres a-day by washing the sand ; but most 



* The four metals, which are found disseminated in the granite rocks, 

 as if they were of contemporaneous formation, are gold, tin, titanium, 

 rod cobalt. 



