4.24 Botanical Notices from Spain. 
to Villaharta and Cordoba. After a residence of a fortnight in 
this town, I again crossed the whole mountain-chain and went north- 
wards to Almadea in the Mancha, then turned back again into the 
province of Cordoba, and journeyed south-west through Hinojosa 
to the little mountain-town of Fuente Ovejuna, and from hence 
westwards to Estremadura, which however I very soon quitted to 
enter the province of Seville. From the mountain-town of Guadal- 
canal, I turned westwards, and journeyed through the most moun- 
tainous portion of the Sierra Morena to the little town of Aracena, 
only five leagues from the frontiers of Portugal, where the Sierra 
Morena divides into two principal branches, one of which follows the 
chief direction, and stretches away far into Portugal, and the other 
goes off in an almost southerly direction as far as the Atlantic, covers 
the greatest portion of the province of Huelva, and forms the left 
wall of the valley watered by the Guadiana. Through this southern 
and very broad branch, I journeyed from Aracena through Cerro and 
Villanueva de los Castillejos to the mouth of the Guadiana. 
The chief portion of the whole of the Sierra Morena consists of 
graywacke, which crops out in part as a compact rock, partly as 
graywacke schist, which takes an endless variety of forms according 
to its consistence and colour. In isolated spots this stone alternates 
with clay-schist, as at Almadea, where it forms the matrix of the 
celebrated quicksilver ores, and between Villaharta and Fuente Ove- 
juna, where recently very rich coal-mines have been discovered. 
This graywacke formation stretches from Murcia as far as Portugal 
and up to the Guadiana, is from four to six German miles in extent, 
and forms uniform, undulating, gently rounded mountains and 
ridges, which in a great portion of the chain scarcely attain the 
height of 3000 feet. Only in the most western portion, in the pro- 
vince of Huelva, in the environs of Aracena, this formation consists 
of rugged and loftier mountains, which may perhaps be from 83-4000 
feet high. Here the graywacke is in many places interrupted by a 
gneiss formation, which probably also constitutes the most northern 
chains of the western portion of the Sierra Morena, lying in Lower 
Estremadura, for this part is much more watered than the central and 
eastern part of the mountain-chain. .Along the southern foot of the 
Sierra Morena various other formations overlie the graywacke, namely 
in the east of Murcia, as far as the country of Carolina, a red, very soft 
and clayey sandstone, which forms long, horizontal, but steep ridges. 
To this is joined a large formation of red, very hard and fine Schle#f- 
stein, which covers the whole southern margin of the mountain- 
chain of Baylen as far as beyond Montoro, forms somewhat steep, 
cup-formed or pyramidal, but neither rocky nor lofty, mountains, 
and passes into a white sandstone, which extends from Cordoba 
westward to the foot of the Sierra Morena. In the central part of 
the Sierra Morena, that is to say in the province of Cordoba, an 
immense granite formation breaks through the graywacke, which 
however forms no isolated summits, but an immense undulating 
table-land sloping gently towards the north, and lying between the 
northern margin of the graywacke formation and the lofty mountain- 
