I Could Discover No Fragmentary Stratum (Grauwacke) Nor Kieselschiefer Nor Chiastolite.

The kieselschiefer belongs in those countries to a limestone formation.

I have seen fine specimens of the chiastolite (macle) which the Indians wore as amulets and which came from the Sierra Nevada de Merida. This substance is probably found in transition-slate, for MM. Rivero and Boussingault observed rocks of clay-slate at the height of 2120 toises, in the Paramo of Mucuchies, on going from Truxillo to Merida.* (* In Galicia, in Spain, I saw the thonschiefer containing chiastholite alternate with grauwacke; but the chiastolite unquestionably belongs also to rocks which all geologists have hitherto called primitive rocks, to mica-schists intercalated like layers in granite, and to an independent stratum of mica-slate.)

3. FORMATION OF SERPENTINE AND DIORITE (GREEN-STONE OF JUNCALITO.)

We have indicated above a layer of granitiferous serpentine inclosed in the gneiss of Buenavista, or perhaps superposed on that rock; we here find a real stratum of serpentine alternating with diorite, and extending from the ravine of Tucutunemo as far as Juncalito. Diorite forms the great mass of this stratum; it is of a dark green colour, granular, with small grains, and destitute of quartz; its mass is formed of small crystals of felspar intermixed with crystals of amphibole. This rock of diorite is covered at its surface, by the effect of decomposition, with a yellowish crust, like that of basalts and dolerites. Serpentine, of a dull olive-green and smooth fracture, mixed with bluish steatite and amphibole, presents, like almost all the co-ordinate formations of diorite and serpentine (in Silesia, at Fichtelgebirge, in the valley of Baigorry, in the Pyrenees, in the island of Cyprus and in the Copper Mountains of circumpolar America),* traces of copper. (* Franklin's Journey to the Polar Sea page 529.) Where the diorite, partly globular, approaches the green slate of Malpasso, real beds of green slate are found inclosed in diorite. The fine saussurite which we saw in the Upper Orinoco in the hands of the Indians, seems to indicate the existence of a soil of euphotide, superposed on gneiss-granite, or amphibolic slate, in the eastern part of the Sierra Parime.

4. GRANULAR AND MICACEOUS LIMESTONE OF THE MORROS OF SAN JUAN.

The Morros of San Juan rise like ruinous towers in a soil of diorite. They are formed of a cavernous greyish green limestone of crystalline texture, mixed with some spangles of mica, and are destitute of shells. We see in them masses of hardened clay, black, fissile, charged with iron, and covered with a crust, yellow from decomposition, like basalts and amphiboles. A compact limestone containing vestiges of shells adjoins this granular limestone of the Morros of San Juan which is hollow within. Probably on a further examination of the extraordinary strata between Villa de Cura and Ortiz, of which I had time only to collect some few specimens, many phenomena may be discovered analogous to those which Leopold von Buch has lately described in South Tyrol.

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