22 
ENGINEEEING EEPOETS. 
ISTueva, oi* the Calzadas, this being the channel through which 
the Coatzacoalcos receives the waters of the river Huasuntan, a 
considerable stream draining an extensive alluvial basin to the 
south of the Tuxtla range of mountains. This river also connects 
with the sea bj a narrow channel at La Barrilla. The strip of 
land intercepted between the river Tierra Nueva and the Gulf 
coast, and extending from the bar of the Coatzacoalcos to the 
Barrilla, near the base of Mt. Pelon, is made up on the Gulf 
side by sl chain of sand-hills, leaving a considerable margin of 
low land on the river side. These sand-hills are elevated from 
fifty to one hundred feet above tide-water, and border all this 
part of the coast. 
The banks of the river below Mina-titlan are very low and 
frequently flooded. The mouth of the Coatzacoalcos, the geo- 
graphical position of which has been given, is one hundred and 
fifteen miles west from the river Grijalva or Tobasco, and about 
one hundred and ten miles from Yera Cruz. Its width is about 
fifteen hundred feet, and its depth varies in different places. A 
transversal section of the river, over the bar, shows it to be 
slightly swelled in the middle and hollowed out towards the 
two banks of the river ; the hollow on the right forming the 
eastern, and the other the western pass. The greatest depth of 
the latter is close to the bank on which the fort is built. This 
pass is a straight channel, of easy entrance, and always the 
same, by reason of the nature of the material composing the 
bar. It has a width of three hundred and fifty feet and a 
depth of thirteen feet, which, however, is diminished to twelve 
and a half in the month of May. The tides are not strong on 
this part of the Mexican coast ; but in case of heavy northerly 
winds, the waters of the river are backed up, giving a sensible 
increase of depth on the bar. The eastern channel is about one 
hundred feet in width, and its depth varies from eleven to 
twelve feet. 
As soon as the bar is crossed, and the ascent of the river com- 
menced, it widens and deepens, and at seven miles from the 
Gulf the lead shows a depth of forty feet, which is preserved for 
some distance. The least depth in the channel below Mina- 
titlan is twelve feet, and this may be carried nearly to the island 
