63 
cisely in those localities where the assistance of European 
workmen would be required, is of the greatest consideration. 
The small rains of Tarifa and of the valley of San Miguel are 
not of sufficient consequence to impede the continuation of 
the work during a considerable portion of the day. 
During the long sojourn of the Commission in the Isthmus, 
they had often to undergo hard and severe toils, and were 
frequently exposed to the most trying inclemencies of the 
weather, and yet neither themselves nor their numerous atten- 
dants experienced any illness - indicative of an unhealthy cli- 
mate. 
MINERALS. 
The geological collection will give a sufficiently clear idea 
of this department of the subject. Iron is found in abun- 
dance in many points of the Isthmus, and that of Tarifa espe- 
cially appears to be of excellent quality. As regards the 
precious metals, which made the department of Oajaca once 
so famous, there is a tradition still prevalent from the time of 
the conquest that the mountains of Mijcs and tiie upper 
Uspanapan contain very rich gold and silver mines. 
VEGETATION. 
The mangrove tree (rhizophora mangel) of sinister omen is 
not so common on the coasts of the Isthmus as on others of the 
Republic. In the southern division, it can only be found in 
the neighbourhood of San Francisco and of the Morro. 
In the peninsula of San Mateo and Santa Maria the most 
remarkable plants are the tamarind, the palm, and the cocoa- 
nut trees, besides which the ground is also covered with vege- 
tation. Three different species of the sensitive plant are here 
found in abundance, one of which attains to nearly a metre in 
height. 
The land to the nortli of the lower eastern lagoon, in which 
the Haciendas of San Dionisio and San Francisco are situated, 
appear clothed with a luxuriant vegetation somewhat resem- 
