EOCKS Ob' T1IE 1>LAIBS. 
185 
transition-slates,* and on tlie south it rests immediately on 
the granites of the Orinoco. We observed in it rounded 
fragments of quartz ( kieselschiefer ), and Lydian stone, 
cemented by an olive-brown ferruginous clay. The cement 
is sometimes of so bright a red that the people oi the 
country take it for cinnabar. W e met a Capuchin monk at 
9 a labozo, who was in vain attempting to extract mercury 
from this red sandstone. In the Mesa de Paja this rock con- 
tains strata of another quartzose sandstone, very fine-grained ; 
Wore to the south it contains masses of brown iron, and 
fragments of petrified trees of the monocoty ledonous family , 
but we did not see in it any shells. The red sandstone, 
called by the Llaneros, the stone of the reefs (piedra de 
arrecifes), is everywhere covered with a stratum of clay. 
This clay, dried and hardened in the sun, splits into separate 
Prismatic pieces with five or six sides. Does it belong to 
fhe trap-formation of Parapara? It becomes thicker, and 
wised with sand, as we approach the Rio Apuro; for near 
Calabozo it is one toise thick, near the mission ol Guayaval 
five toises, which may lead to the belief that the strata of 
* e d sandstone dips towards the south. We gathered in the 
Mesa de Pavones little nodules of blue iron-ore disseminated 
111 the clay. 
A dense whitish-gray limestone, with a smooth fracture, 
somewhat analogous to that of Caripe, and consequently 
to that of Jura, lies on the red sandstone between Tisnao 
and Calabozo.t In several other places, for instance in the 
^esa de San Diego, and between Ortiz and the Mesa de 
Taja,+ we above the limestone lamellar gypsum alter- 
nating with strata of marl. Considerable quantities of this 
fiypsum are sent to the city of Caracas, § which is situated 
a Widst primitive mountains. 
This gypsum generally forms only small beds, and is 
Wised with a great deal of fibrous gypsum. Is it of the 
* At Malpaso and Piedras Azules. 
+ Does this formation of secondary limestone of the Llanos contain 
|flena ? l t has been found in strata of black marl, at Barbacoa, between 
r ^xillo and Barquesimeto, north-west of the Llanos. 
+ Also near Cachipe and San Joacquim, in the Llanos of Barcelona. 
This trade is carried on at Parapara. A load of eight arrobas sell* 
acas lor twenty-four piastres. 
