44 
ENGINEERING EEPOETS. 
this, and for nearly the entire distance to the Jumuapa River, 
traverses a heavy rolling country, requiring for the construction 
of the road a considerable amount of excavation and embank- 
ment. The line passes the open plains above mentioned on the 
east, and is timbered for nearly the entire distance between the 
Sarabia and J umuapa rivers. The excavations on this portion 
of the route will be mostly in a gravelly clay. There is no rock 
at the surface, but in the beds of some of the creeks we find a 
soft argillaceous sandstone, and in one or two instances a con- 
glomerate or pudding-stone, united with a calcareous cement. 
At the points of crossing the Sarabia and Jumuapa rivers, 
we find the former elevated one hundred and fifty feet above 
the latter ; and in descending towards the Jumuapa, a grade of 
sixty feet per mile is required for a distance of nearly two miles. 
This latter stream can be passed with a bridge of one hundred 
and fifty feet span, with the same elevation as at the Sarabia. 
The foundations of the abutments will probably require piling, 
or other artificial support. 
We foiind some difficulty in selecting a good route for the 
road between the Jumuapa and Jaltepec rivers, owing to the 
irregular formation of the ground, and the fact that this portion 
of the country is entirely covered with a dense forest, which 
renders it difficult of observing its topography. The principal 
obstacle is found in crossing the summit of an elevated ridge, 
or chain of highlands, separating the valleys of the above- 
named streams. These highlands terminate at Suchil, on the 
east, and running nearly parallel with the Jaltepec Eiver, join 
the Cordillera to the west, their summits being distant from 
the Jaltepec from three to four miles, and elevated from 250 to 
600 feet above the stream. This main dividing ridge is inter- 
sected by a secondary ridge, extending from a point near Paso 
de la Puerta to the Rancho Amate, the crest of which is trav- 
ersed by a picadura throughout its entire length. There is 
also a road traversing the summit of the main dividing ridge, 
from its intersection with this picadura to Suchil. Of these 
roads, the former may be termed the Amate Picadura, and the 
latter the Suchil Picadura. 
From the summit the ground descends rapidly towards the 
