ENGINEERING REPORTS. 
45 
Jaltepec, in some cases leaving a considerable interval of bot- 
tom-lands on the south side of this river. Between the summit 
and the river-bottoms the surface is very rough, being traversed 
by a multitude of deep, narrow ravines, separated by sharp spurs 
from the main ridge. 
The general appearance of the country to the east of the 
Amate Picadura and southward of the summit, is nearly level. 
On a closer inspection, however, we find it traversed by numer- 
ous ravines and intervening ridges, having a general direction 
nearly east and west, or at right angles to the line of survey. 
The country to the west of this picadura is drained by two 
or three principal streams, having a southerly direction, and 
discharging into the Jumuapa, below the Paso de la Puerta. 
These streams are separated by high spurs or ridges, joining 
the summit ridge on the north, and extending a considerable 
distance to the south. The intervening valleys are narrow to- 
wards the summit, but gradually widen out as they approach 
the Jumuapa. 
In starting our survey northerly from this river we had the 
choice of two general routes ; one to the east of the Amate 
Picadura, and the other to the west, following up the valley of 
a large creek running nearly parallel with this road. With 
the limited knowledge we then had of the country, the latter 
appeared the more feasible route, as we could take advan- 
tage of two considerable creeks ; one discharging into the Ju- 
muapa, and the other into the Jaltepec, and having a general 
direction nearly coincident with the proposed line of survey. 
But after gaining the summit from the south with a maximum 
grade of sixty feet per mile, and but moderately heavy work, 
we found the descent towards the Jaltepec too rapid to be over- 
come without increasing the maximum grade, or involving a 
heavy expense. In the mean time we discovered a depression 
in the summit at a distance of one and a half miles to the east 
of our first line ; and finding this impracticable, we immediately 
commenced operations from the new summit, which proved, to 
be 120 feet lower than the first, and elevated but 200 feet 
above the Jumuapa river, and 260 feet above the Jaltepec. 
From this point to the crossing of the latter stream the line is 
