and sand which cover a great portion of the porphyritic trap and basalt composing the cordillera issued forth.
From my passing observations I should suppose that some of these craters have ejected water as well as fire; and particularly the cone which the traveller leaves to the right in traversing the ridge. It has evidently thrown its lavas on both directions; and report says, that one immense stream proceeding from it, or from a neighbouring cone of the Ajusco chain, may be traced down the successive steps of the table land to the very shore of the Pacific.
In process of time we reached the Cruz del Marques, a solid stone cross erected by Cortez, to indicate the bounds of the territory assigned to him by Montezuma.
The shade of the pine forest, which still clothes a great part of the upper region of the mountain, was grateful to us; at the same time that it was the most perilous part of our voyage, so far as the probability of our being robbed went. We passed, however, without molestation, retaining possession of our watches and purses, and the cherished opinion of our being invincible.
If, in quitting the valley of Mexico at daybreak, we had to complain of the cold, noon brought with it a degree of heat for which we were quite unprepared, and it grew in intensity as we descended the steep face of the mountain to the southward. The western slopes of the cordillera of Mexico are far more sudden and inclined than those on the side of the gulf, and the consequence is, that by the route we were now following, after a journey of a few hours' travel, you descend to a level, to reach which, on the opposite side, you must travel for several days.
We had not descended far upon the southwestern slope, before we descried the sea of broad and yellow plain, which here formed the second step of the table
- About 9,500 feet above the sea.