ENGINEERING KEPOKTS. 
71 
Should the best route be found through the hills of Xochiapa, 
via the Mesilla or the Nisi Conejo Pass and the Almoloya, a 
bridge over this stream would not be necessary, for as the road 
would cross near its source, there is seldom water enough to 
prevent fording with carnages. Besides, it has a good, hard, 
gravelly bottom. From the Eancho de Calderon over the plains 
to the summit of Chivela Pass, no difficulties whatever will be 
met with. 
The five bridges at the crossings of the Jumuapa, Sarabia, 
Malatengo, Los Perros, and Tehuantepec rivers may be built on 
strong timber bents. As the freshets are sudden and quickly 
subside, it will probably only be necessary to build the bridges 
across the main channels, in order to clear the highest water. 
They can thus be built with less spans than the railroad bridges. 
Prom the summit of Chivela Pass to the Pacific plains, at the 
Rancho de la Mar tar, is about six miles. Upon this distance the 
engineers of Senor Garay have already constructed about two 
miles of carriage-road, which was designed as a preliminary step 
to the accomplishment of his project. Between the end of this 
and Torrente Masahua, there is about two miles more of pretty 
difficult road to construct, being round the west end of the 
limestone mountain called " Cerro Prieto." 
From Torrente Masahua to the end of Cerro de laMartar, the car- 
riage route might be made to keep to the left of what is now called 
Rio Yerde, down to a point opposite the end of Cerrro de la 
Martar, and then recross this stream to the plains of the Pacific ; 
thence on nearly a direct line to San Geronimo, Comitancillo, 
to Tehuantepec and Yentosa. 
From the foregoing it may be inferred, that should the rail- 
road be ultimately located on the west side of the Coatzacoalcos 
River, and via Chivela Pass, the auxiliary road can be run in 
its immediate vicinity, nearly all the way from the Jaltepec to 
Yentosa. 
