As we proceeded, one pile of volcanic hills after the other started into isolated prominence on our left, disentangling themselves from their neighbours, and from the more distant ranges, with which they had hitherto appeared to be connected. Cones, which from the roofs of the city had appeared to rise from one common ridge, we now discovered to be separated by broad strips of level marsh. I believe I forgot to mention among our excursions, one which we had made some time before, from the Hacienda San Antonio to the great group of volcanic hills beyond Mejicalzingo, which consists, as far as I could determine, of three truncated cones, rising progressively in bulk and height, one over the other, from the surface of the plain. On this occasion we had contrived to scramble up the steep sides of the lowest, consisting of abrupt slopes covered with rotten scoria, and gained the brink of the crater, which in its present state forms a smooth, grass-covered bowl, of about a mile in circumference.
After passing the Peñon Viejo, we approached the foot of the volcanic cone of the Ajotla; but then quitting the great calzada at Santa Martha, followed a track over the half-dried marshes at the southernmost extremity of Lake Tezcuco to the village of Santa Madalenda, on terra firma.
As we rode in front of the old church and dark group of Italian cypress of the village, and, turning northward, advanced over a hilly tract of country, spotted by herds of cattle and haciendas, towards Chapingo, the views increased in beauty and interest at every step. Popocatepetl, and its neighbour, now rose to the southward over the summits of the innumerable cones in the middle ground. Both were covered with snow to a far greater extent than on our arrival three weeks before; and even the Ajusco appeared sprinkled to a considerable extent. The whole breadth of the lake was now interposed between us and the city, and a most singular optical illusion was displayed from the effect of the mirage: the white edifices and coloured domes of the capital appearing afloat, like a fleet of snowy sails, upon the blue surface