74 ANCIENT SEA-SIIOEE. 
leading to tne great village of San Jose de Tisnao. "We 
passed the farina of Luque and Junealito, to enter the 
valleys which, on aceount 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 
scoriae 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 hom- 
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 Gluigue ; and between Villa 
de Cura and the Morros de San Juan, in the mountain of 
Clmcao. 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 
* Tile four metals, which are found disseminated in the granite rocks, 
as if they were of contemporaneous formation, are gold, tin, titanium, 
and cobalt. 
