which are still found, at an immense distance, covered with black, stony masses.
"These historical records, which we might, indeed, wish to see more complete, agree perfectly with what I learn from the mouths of the natives, fourteen years after the ascent of Antonio de Riaño.[1] To the questions whether ' the castle mountain' was seen to rise gradually for months or years, or whether it appeared from the very first as an elevated peak, no answer could be obtained.
"According to the tradition, the phenomena of small eruptions of water and mud, which were observed during the first days simultaneously with the incandescent scoriæ, are ascribed to the destruction of two brooks, which, springing on the western declivity of the mountain of Santa Ines, and consequently to the east of the Cerro de Cuiche, abundantly irrigated the cane-fields of the former Hacienda de San Pedro de Jorullo, and flowed onward far to the west to the Hacienda de la Presentacion. Near their origin, the point is still shown where they disappeared in a fissure, with their formerly cold waters, during the elevation of the eastern border of the Malpais. Running below the hornitos, they reappear, according to the general opinion of the people of the country, heated in two thermal springs. . . .
"In order to acquire a clear notion of the complicated outline and general form of the surface of the ground in which such remarkable upheavals have taken place, we must distinguish hypsometrically and morphologically:
"1. The position of the volcanic system of Jorullo in relation to the average level of the Mexican plateau. 2. The convexity of the Malpais, which is covered with thousands of hornitos. 3. The fissure upon which six large volcanic mountain-masses have arisen.
"On the western portion of the central Cordillera of Mexico, which strikes from south-southeast to north-northwest, the plain of the Playas de Jorullo, at an elevation of only 2,657 feet above the level of the Pacific, forms one of the horizontal mountain terraces which everywhere in the Cordilleras interrupt the line of inclination of the declivity, and consequently more or less impede the decrease of heat in the superposed strata of the atmosphere.
"On descending from the central plateau of Mexico (whose mean elevation is 7,460 feet) to the corn-fields of Valladolid de Michoacan, to the charming Lake of Pátzcuaro with the inhabited islet Janicho, and into the meadows around Santiago de Ario, which Bonpland and I found adorned with the dahlias, which have since become so well known, we have not descended more than nine hundred or a thousand feet.
- ↑ In 1803
