[Illustration: BATTLE OF MONTEREY GENERAL PLAN] The opportunities for defence were excellent. Lying encompassed--except on the north and east--with steep, high spurs of the Sierra Madre, where the Saltillo road and the small but swift Santa Catarina River debouched from Rinconada Pass, the city formed a sort of rectangle somewhat more than a mile in length from east to west and about nine squares wide at the broadest. Only a short distance from the western end rose high and steep foothills, and some of these were now crowned with redoubts. Along the southern side the river and its high, rough bank were almost a sufficient protection; but they were supplemented with fortified buildings and yard walls, barricades at the ends of the streets, and for about half the way a solid parapet.[11.15] The eastern part of the town was given special attention, for here entered the principal roads from the north. In the city proper nearly all the streets ran straight either at right angles or parallel, and in each of the central ones now rose a double line of overlapping barricades or breastworks of masonry, provided with embrasures and with ditches. Outside these a series of redoubts was constructed; and wherever the enemy seemed likely to come, the houses--almost always one story high--were loopholed and provided with ammunition. As they had been constructed very solidly of rubble-work, were protected with strong doors and iron-barred windows, and had flat roofs (_azoteas_) defended with sand-bags in addition to their stone parapets, they were veritable fortresses. At the heart of the town stood the cathedral with its elaborately carved façade, a chime in one spire and in the other a clock. This became the general magazine. In front of it was the main plaza, bounded on the western side by the prison; and beyond the prison lay the market square.[11.15] The north side of the town had even stronger protection. Within 12-pounder range of almost every part of the city stood a solid pile of masonry, twenty-five or thirty feet high, blackened by time. This was an unfinished cathedral; and, taking it as a donjon, Mejía's engineers threw round its columns and buttresses a quadrangular bastioned earthwork, intended for about thirty guns. The high parapet, eleven and a half feet thick, was faced on both sides with a soft gray tufa, in which cannon balls were expected to embed themselves. The ditch, though not wide enough and not completely excavated, was twelve feet deep. A garrison of four hundred with eight guns occupied the position; and although the two small magazines were not adequately protected against falling projectiles, and still other faults could be pointed out by an expert, this fort, commonly known as the citadel, was a powerful work, and, standing on a slight elevation, it could sweep the roads and the plain east and north of the town. A sort of telegraph enabled its commander, Colonel Uraga, to communicate with headquarters.[11.16]