SS8 
SAKDSIOIfE OP THE LLASOS. 
V. FEipATHic Sandstone op the Oeinoco. — Tlie 
gneiss-granite of tlie Sierra Pariine is covered in some few 
places (between tlie Encaramada and the strait of Baracuan 
and in the island of Guachaco), in its western part, with an 
ohve-brovTii sandstone, containing grains of quartz and fra"- 
ments ot felspar, joined by an extremely compact clayev 
cement. This cement, where it abounds, has a conchoidal 
fracture, and passes to jasper. It is crossed bv small i-eins 
of brown irou-ore, which separate into very thin plates or 
scales The presence of felspar seems to indicate that this 
small formation of sandstono (the sole secondary formation 
hitherto known in the Sierra Parime), belongs to red sand- 
stone or coal.* I hesitate to class it with the saiidatone of 
the Llanos, the relative antiquity of wliich appears to me to 
be less satisfactorily verified. 
VI. I OBVIATION OP THE SANDSTONE OP THE LeaNOS OP 
Cal.vbozo.— I arrange the various formations in the order 
which I fancied I could discern on the spot. The carbu- 
retted slate (thoiischiefer) of the peninsula of Arava connects 
tlie primitive roclcs of gneiss-granite and mieaslate-gneiss 
with the transition strata (blue and green slate dTorite 
serpeutmo mixed with amphibole, and granular grceuish-<rrev 
limestone) of Malpasso, Tiieutunemo, and Sail .luan. “Ou 
the south, the sandstone of the Llanos rests on this transi- 
tion strata ; it is destitute of shells, and composed, like the 
savaiinahs of Calabozo, of rounded fragments of quartz t 
kieselschiefcr, and Lydian stone, cemented by a ferriminous 
olive-brown clay. We there find fragments of wood in 
great part moiiocotyledonous, and masses of brown iron-ore. 
borne strata, as in the Mesa de Paja, present grains of very 
1 mnl intact crystals of feldspar are found in the tudle lianendt 
coal-sandstone of Ihunngia. I obscrreil in Me.tico a very singular a.'O'Io- 
meiated felspar ft, niiatioii, superposed upon (perhaps iiielosed inrred 
sandstone, near Guaiia.vuato. ' 
+ In Germany, sandstones vrliieh belong unquestionably to red sand- 
stone, contain a so (near M eiderstadt. In Thuringia) nodulL, and rounded 
flh ' P pudding-stone subordinate to the red 
sandstone of the Pyrenees, because the age of that sandstone destitute 
of coal may ho disputed. Layers of very large rounded nodules of 
sues a “ii^stone of Thuringia, and in Upp J 
