IIG 
THE BEDS or ALUM. 
the island, La Asuncion, the port of Pampatar, and the vil- 
lages of Puehlo de la Mar, Pueblo del Norte, and San Juan, 
belong to the second and most easterly of these groups. 
The western group, the Macanao, is almost entirely unin-_ 
habited. The isthmus that divides these large masses of 
mica-slate was scarcely visible ; its form appeared changed 
by the effect of the mirage, and wo recognized the inter- 
mediate part through which runs the Laguna Grrande, only 
by two small hills of a sugarloaf form, in the meridian of 
the Punta do Piedras. Nearer we look down on the small 
desert archipelago of the four Morros del Tunal, the Ca- 
ribbee, and the Lobos Islands. 
After much vain search we at length found, before we 
descended to the northern coast of the peninsula of Araya, 
in a ravine of very difficult access (Aroyo del Eobalo,) the 
mineral which had been shown to us at Cumana. The 
mica-slate changed suddenly inl o carburetted and shining 
clay-slate. It was an ampclite ; and the waters (for there 
are small springs in those parts, and some have recenth' 
been discovered near the village of Maniquarez) were im- 
■|)regnated with yellow oxide of iron, and had a styptic taste. 
Wc found the sides of the neighbouring rocks lined with 
capillary sulphate of alumina in effervescence ; and real 
beds, two inches thick, full of native alum, extending as 
far as the eye could reach in the clay slate. The alum is 
greyish white, somewhat dull on the surface, and of an 
almost glassy lustre internally. Its fracture is not fibrous, 
but imperfectly conchoidal. It is slightly translucent when 
its fragments are thin ; and has a sweetish and astringent 
taste, without any bitter mixture. When on the spot, I 
proposed to myself the question whether this alum, so pure, 
and filling beds in the clay-slate without leaving the smallest 
void, be of a formation contemporary with the rock, or 
whether it be of a recent, and in some sort secondary', 
origin, like the muriate of soda, found sometimes in small 
veins, where strongly concentrated springs traverse beds ot 
gypsum or clay. In these parts nothing seems to indicate 
a' process of formation likely to be renewed in our days. 
The slaty rock exhibits no open cleft ; and none is found 
parallel with the direction ot the slates. It may also be 
inquired, whether this aluminotis slate be a transition- 
