The walls of the fortress which Cortes is represented to have constructed for his quarters, were next shown to us. Their height is about twenty feet--their width at the base about six or seven, decreasing towards the top. Some pronounce this the work of a more remote age, but the manner of its construction is sufficient evidence to the contrary. That it is a work of the Conqueror is a more reasonable conjecture, though even this is beset with difficulties. The time Cortes is said to have occupied the city of _Tescuco_, appears too short to have completed so huge a building: to this, however, it may be said, that he possessed ample means, with so many thousand Indians under his orders. But where was the necessity of raising such strong walls against adversaries so feeble, when, without so much severe labor, he might have defended himself equally well, and in the event of his being compelled to abandon it, he would have encountered less difficulty in recovering possession of it? Thence we proceeded some distance--the moon shone brightly--to see other remains of an ancient structure, but being unsuccessful in our search, we returned to the house of our kind friends, the Camperos. The town of _Tescuco_ now contains about 5,000 inhabitants--the houses are of one story only--with regular but unpaved streets, not very neat. Its modern mediocrity must contrast strongly with its ancient magnificence, if the early historians of Mexico are to be credited. During the revolution a ditch was dug around it, in order to repel the attacks of cavalry. It was assailed several times, and suffered some injury. It is by no means a pretty town, but is situated amid a pretty country, and supplied with good water. DEC. 26. We appointed to-day to visit the mountain of _Tescusingo_. Before setting out, we made another circuit about the town, and found on a wall in front of one of the churches, a circular stone, the circumference of which was curiously carved. Near the northwestern corner of the _Plaza_ is a well constructed arch of _tetzontli_, cemented with lime, which had been discovered in opening a ditch--the extent and purpose of it are alike unknown. We next visited the house of the Most Holy Trinity, La Casa de la Santissima Trinidad, to examine an arch of stone, said to have been taken from the ruins of the palace. Its figure is beautiful--the whole is well wrought--and would do credit to any edifice. If an antique, of which there seems very little doubt, it proves beyond any thing I have yet seen, the civilized state which the Indians of Mexico had attained prior to the conquest. The arch of three pieces, and four stones which support it, believed to have once formed a portal in the palace, are perfect. The latter now are the sides of an entrance to a stable, the arch lies neglected in the yard--two stones are wanting to complete the supports to the arch.