march that could be selected led through mountain passes easily
defended. In fact, there were at that time but two roads from Vera Cruz
to the City of Mexico that could be taken by an army; one by Jalapa and
Perote, the other by Cordova and Orizaba, the two coming together on the
great plain which extends to the City of Mexico after the range of
mountains is passed.

It was very important to get the army away from Vera Cruz as soon as
possible, in order to avoid the yellow fever, or vomito, which usually
visits that city early in the year, and is very fatal to persons not
acclimated; but transportation, which was expected from the North, was
arriving very slowly. It was absolutely necessary to have enough to
supply the army to Jalapa, sixty-five miles in the interior and above
the fevers of the coast. At that point the country is fertile, and an
army of the size of General Scott's could subsist there for an
indefinite period. Not counting the sick, the weak and the garrisons
for the captured city and fort, the moving column was now less than ten
thousand strong. This force was composed of three divisions, under
Generals Twiggs, Patterson, and Worth. The importance of escaping the
vomito was so great that as soon as transportation enough could be got
together to move a division the advance was commenced. On the 8th of
April, Twiggs's division started for Jalapa. He was followed very soon
by Patterson, with his division. General Worth was to bring up the rear
with his command as soon as transportation enough was assembled to carry
six days' rations for his troops with the necessary ammunition and camp
and garrison equipage. It was the 13th of April before this division
left Vera Cruz.

The leading division ran against the enemy at Cerro Gordo, some fifty
miles west, on the road to Jalapa, and went into camp at Plan del Rio,