HYDROGRAPHIC REPORTS. 
99 
As your instructions required likewise an exploration of the 
IJspanapa River, I repaired to Mina-titlan, and after equipping 
a canoe with the necessary men and provisions, left that place 
on the morning of the 7th of May, accompanied hj Mr. George 
E. Evans and Padre Rom ay. Establishing a base at Mina- 
titlan, a series of compass courses and distances were run to the 
mouth of the Uspanapa, in order to determine its relative posi- 
tion, and to connect the work with the surveys of the other par- 
ties. Entering the river, these operations were continued suc- 
cessively until reaching the Playa del Tigre, a point on the left 
bank, 45 miles from its confluence with the Coatzacoalcos, and 
beyond which it was impossible to go, without violating your 
instructions respecting our return to Mina-titlan by the 25th of 
May. Yet while it is to be regretted that the subsequent acts 
of the Mexican government, in reference to the grant of Don 
Jose de Garay (upon which all our surveys were necessarily 
predicated), precluded a renewal of the exploration of the Us- 
panapa to its head-waters, I have endeavored to add to the utility 
of the limited results obtained, by locating such of the elevated 
points as would prove valuable sites, and by designating the 
names and places of the most useful trees and plants, where 
they are particularly abundant. In addition to this, the charac- 
ter of the bottom has been carefully noted, in order to present 
at a glance such portions of the river as are susceptible of im- 
provement ; and embodied in the notes of the accompanying 
map are the water heights at various points, the usual rise and 
fall of tide, and the months of the rainy season. From these, 
it will be seen that as far as the reconnaissance extended, the 
IJspanapa is superior to the Coatzacoalcos, not only as regards 
the richness of its margins, but in its greater depth, and better 
chance of improvement. 
Among the tributaries to the Uspanapa are the following, viz., 
Arroyos Totuapa, Chichigapa, Mexcalapa, Francia, Naranjo, 
that of the Urgells, and the Tecuanapa. The first of these is an 
insignificant stream entering on the left bank of the river, one 
and three-quarter miles from its mouth, and draining the west- 
ern slope of a small clump of hillocks a short distance above. 
Nearly a mile further on is the island of Uspanapa, which is 
