832 
tion of the chalk-rocks of Jura, of Pap- 
penheim, La Mancha, Marteilles, Derby- 
fhire, and Suez, which have all been pro- 
duced at the fame time by precipitation. 
Of the three cordillerss of primitive 
mountains which traverfe South America 
from weit to eaft, rhe moft northern, that 
of Venezuela, is the higheit, but narrow- 
eft. ‘lhe real chain of the Andes extends 
from the large plain of Quito, through 
Popayan and Choco, to the weftcrn fide 
of the river Atrato, (or Rio San Juan,) 
between the vatley of Tatabé, in the 
provinces of Zitara and Biruguete, to- 
wards the ifthmus, where it forms a moun- 
tainous diftri&t of not more than two. or 
three hundred toifes in height on the bank 
of the Chagre. 
the cordillera on the coaft of Venezuela. 
Rows of mountains higher, but forming 
‘roups lefs regular, extend on the ealt fide 
of the Rio Atrato, under the name of the. 
Sierra de Abibé and. the Montes de Cau- 
ca, through the high favannahs of Jcolu 
towards Magdalen River and the province 
of St. Martha. ‘The cordillera of the 
coaft contracts itfelf like that of the Gulf 
of Mexico, approaches nearer to Cape 
Vela, and then proceeds firlt fiom fouth- 
fouth wef to north-north-eaft, and then 
from weft to eaft to the ridge of Paria, or 
rather to the Punta de la Galera in the 
‘Hand of Trinidad. Its greateft heightis 
found at that place whereit has the name 
of Sierra de Nevada deS:. Martha, in la- 
titude ro° 2’, and of Sierra Nevada de 
Merida, in latitu’e 8% 30’; the former is 
about 5000, the latter 5400 Spanifh ells, 
(varas) or 2350 toifes in height. The 
aramo de la Rofa and de Macuchi, and 
alfothe mountain of Merida, are continu- 
ally covered with fnow: boiling water, 
with hydrogenated fulphur, iffues from 
th<ir fides, and they exceed in height the 
Peak of Teneriff, and are, perhaps, equal 
to Mont Blanc, which has been more ac- 
curately meafured. Thefe coloffa] maffes 
and St. Martha ftand almoft infulated, 
being furrounded by few high ridges.— 
To the weft of Santa Fé, or as far as the 
Sierra of Zuindiv, no fnow-clad peaks 
are feen, and the Sierra Nevada de Meri- 
da ftands at the edge of the plain of Ca- 
raccas, which is fcarcely forty toifes above 
the level of the fea. Mont Blanc, which 
terminates the high ridge of the Alps, ex- 
hibits the fame phenomenon. The alti- 
tude cf the higheft mountains, however, 
is fo very {mali m proportion to the mag- 
nitude of the earth, that it would appear 
that very fmali local cautes cught to have 
accumulated more matter in thele points, 
From thele Andes ariles. 
Gerlogical Defeription of South Anerica ~ {April 14° 
That part of the cordillera of the coat 
which lies to the welt of Maracayabo= 
Sees, and joins.the .Andes, has large val. 
leys extending from north to fouth, fuch 
as that of Magdalena, of Cauca, of Saint 
George, of. Sinu,-and Atrato. They are 
very, long and narrow, but covered with 
wood, 
On the other hand, that part of the 
cordillera which extends frum’ Merida to 
Trinidad inclofes three valleys, lying eaft 
and weft, which fhew by certain figns, 
like, Bohemia, or the Haflithal of Swiffer- 
land, that they have formerly been lakes 
the water of which has evaperated or run 
off by opening for itfelf a paflage.- Thefe 
three valleys are-incloied by the two. pas! 
rallel rows'of mountains, into which the” 
cordilera of the coaft divides itfelf, from: 
Cape Vela.to Cape;Codera 3 the northern} 
row. is a continuation of, Saint Marthay, 
the fouthern a prolongation of: Sierras 
Nevada, de Merida. The. firit extends» 
through Burburuta, Rincen del. Diablo % - 
through the Sierras de> Mariara, theé- 
mountain Aguafnegras, Monte de Arilay 
and the Silla de Caracas,,-to Cape Codera., 
The fecond from three to four miles more 
to the fouth, extends through Guigni, La 
Palma, the high {ummits of Gusiraima, 
Tiara, Guiripa, and the Savana de Ocu- 
mare, as far as the mouths of the Tuy. 
Thefe two chains unite with two arms, 
which run from north to fouth, like, as it 
were, dykes, by- which thefe old lakes 
were confined withia their boundaries. 
Thefe dykes are, on the wefl, the moun- 
tains of Carora, Tonto, Saint Maria, 
Saint Philips, and Area; they feparate 
the Llanos de Monai from the valleys of 
Aragua: on the eait they are the naked 
fummits of Los Teques, Coquiza, Buena 
Vitta, and the Alcos de S$. Pedro, by 
which the valley of Aragua or the fources. 
ofthe Tuy (for there is only one valley 
between the bottom of Coquiza, or the 
Hacienda de Brifenno, to Valencia,) from 
the valiey of Caraccas. On the eatt, from 
Cape Codera, the greater part of the cor- 
dillera of the coaft of Venezuola was de- 
ftroyed and laid under water by the great 
cataftrophe which formed the Gulf of 
Mexico. The reft of it is diftinguifhed 
in the high mountain-peaks of the ifland 
of Margaretha, (Macanao and the Valle 
S. Juan,) and in the cordillera of the 
Ifthmus of Araya, which contains the mi- 
caceous {chiftous mountains of Manigu- 
ares, Chuparipari, Diitilador, Cerro- 
Grande, the mountain of St. Jofeph and 
of Paria: the remainder I have accurate. 
ly examined, and found in them the fame 
; ftructure, 
