214 MEXICO. 
south of the city of Mexico. Proceeding westward from the Capital, it was 
perceived again in Morelia, and it became so violent in the direction 
of Acapulco, that it destroyed houses, cracked the earth, and finally 
plunged into the sea, whose waves rose and swelled as under the influ- 
ence of a violent storm. During its continuance of nearly five min- 
utes, there were no meteoric phenomena worthy of note, no subterranean 
noise, and no perceptible change in the altitude of the barometer, in the 
city of Mexico. 
Standing on the summit of Popocatepetl and looking over the immense 
panorama — which now lay spread like a map at his feet — Mr. Von Gerolt 
compared his repeated examinations of the geology of the valley and of the 
adjoining departments, and he came to the conclusion, that both the volcano 
and the vale owe their origin and present condition to some violent erup- 
tion, by which the actual surface has been raised from the interior to its 
present level, through the primitive and transition rocks ; and that in the 
mining districts of the states of Puebla, Mexico and Michoacan, the rich 
veins, manifested in slaty formations, or in metallic porphyry, are but the 
trifling remains or islands, as it were, left rising above the plain, after the 
fiery deluge that swept over portions of our Continent. 
But (turning to the prospect around them, from the examination of the 
crater of that vast stack, which pours forth the smoke and vapors of the 
central fires, and acts, perhaps, as the great safety-valve of a large part 
of the New World,) the travellers speak of the immense picture that lay 
before them as indescribably sublime. 
The day was remarkably clear. Few clouds, and those very high in 
the air, appeared against the sky, which was almost black with the inten- 
sity of its azure ; and, as far as the eye could reach, in every direction, 
there was one uninterrupted waving of mountain, valley and plain, until 
(almost without a horizon) the earth and the sky blent in vapory blueness. 
In the midst of the eastern plain, the tall cone of Orizaba stood up in bold 
relief against the sky, with its snowy peak glittering like a point of flash- 
ing steel. Below them, near two thousand feet, lay the summit of Iztac- 
cihuatl, covered with snow, and exhibiting not the slightest evidence either 
of crater or volcanic action. 
After enjoying this splendid panorama as long as their enfeebled con- 
dition would allow them, erecting a flag-staff*, and making the sketch I 
have placed at the commencement of this letter ; — the travellers, at four 
o'clock, began a descent, which they describe as not the least difficult 
portion of their enterprise. If they complained of the toilsome slowness 
of climbing, they could now with equal justice complain of the dangerous 
swiftness of their return. The day was far advanced ; the cool wind 
of the evening had already frozen the surface that melted under the noon- 
day sun, and, passing over the sands and snows at a sharp angle, thev 
