18 
ENGINEERING REPORTS. 
stream in the driest part of the season gives one foot by twenty- 
five feet, with a very rapid current. The waters of the Ostuta are 
at least three times as abundant as those of the Chicapa. The 
elevated mountain peaks near the source of these streams are al- 
most constantly enveloped in clouds, which may account for their 
remarkably uniform flow of water throughout the entire year. 
Most of the rivers watering the southern slope have a com- 
paratively limited extent, and before reaching the plains present 
the character of mere mountain torrents. In the dry season 
many of the smaller ones become completely absorbed, or lose 
themselves in the sands of the plains ; even the Rio de los Per- 
ros, a stream of some magnitude in the rainy season, exhibits a 
dry channel below El Espinal for six months in the year, viz.,- 
from December to July ; while near the mountains it always 
carries a considerable volume of water. 
All of these streams, as they issue from the mountains, are 
remarkably pure and limpid, even in times of flood, thereby in- 
dicating the rocky nature of the districts which they drain. In 
their descent towards the plains they offer almost unlimited 
sources of water-power, which at many points may be made 
available for sawing lumber or for other purposes. 
The lagoons, which receive most of the drainage of the south- 
ern slope, extend a distance of nearly forty miles along the coast, 
and comprise an area of more than 200 square miles ; they are 
divided by a narrow peninsula of land into two principal divis- 
ions, known as the upper and lower lagoons. Though of con- 
siderable extent, they are generally shallow, and no doubt an- 
nually becoming more so from the sediment brought down by 
the numerous rivers which discharge into them. 
The bay of Yentosa is formed by an indentation in the coast, 
and the projection of the Cerro Moro on the west. The Tehuan- 
tepec River discharges itself near this point. The bay is par- 
tially sheltered from the north winds by low ranges of hills from 
three to four miles distant. A short distance to the westward 
are two similar indentations of the coast, known respectively 
as Salina Cruz and Salina del Marques.* 
* For a detailed description of Ventosa, vide page 104. 
