STRATA OF THE SIEBRA PARIME. 3C9 



of the sliore of Venezuela, and belongs exclusively to that Cor- 

 dillera and the group of the Parime mountains ; since it no- 

 where pierces the secondary and tertiary strata in the Llanos 

 or basin of the Lower Orinoco. Thence it results, that the 

 same formations do not constitute the region of plains and 

 that of mountains. 



If we may be allowed to judge of the structure of the whole 

 Sierra Parime, from the part which I examined in 6 of lon- 

 gitude, and 4 of latitude, we may believe it to be entirely 

 composed of gneiss-granite ; I saw some beds of greenstone 

 and amphibolic slate, but neither mica-slate, clay-slate, nor 

 banks of green limestone, although many phenomena render 

 the presence of mica-slate probable on the east of the May- 

 pures and in the chain of Pacaraina. The geological forma- 

 tion of the Parime group is consequently still more simple 

 than that of the Brazilian group, in which granites, gneiss, 

 and mica-slate, are covered with thonschiefer, chloritic quartz 

 (Itacolumite), grauwacke, and transition-limestone; but 

 those two groups exhibit in common the absence of a real 

 system of secondary rocks ; we find in both only some frag- 

 ments of sandstone or silicious conglomerate. In the littoral 

 Cordillera of Venezuela the granitic formations predominate ; 

 but they are wanting towards the east, and especially in the 

 southern chain, where we observe (in the missions of Caripe 

 and around the gulf of Cariaco) a great accumulation of 

 secondary and tertiary calcareous rocks. From the point 

 where the littoral Cordillera is linked with the Andes of New 

 Grenada (long. 71^), we observe first the granitic moun- 

 tains of Aroa and San Felipe, between the rivers Yaracui and 

 Tocuyo ; these granitic formations extend on the east of the 

 two coasts of the basin of the Valleys of Aragua, in the 

 northern chain, as far as Cape Codera ; and in the southern 

 as far as the mountains (altas savanas) of Ocumare. After 

 the remarkable interruption of the littoral Cordillera in the 

 province of Barcelona, granitic rocks begin to appear in 

 the island of Marguerita and in the isthmus of Araya, and 

 continue, perhaps, towards the Boca del Drago j but on the 

 east of the meridian of Cape Codera, the northern chain only 

 is granitic (of micaceous slate) ; the southern chain is 

 entirely composed of secondary limestone and sandstone. 



If, in the granitic series, here a very complex forma- 



2 B 



