A WESTERN LAVA FIELD.
Lieutenant Ruffner describes one of the great lava outflows in the West in a way that serves to set before the reader the magnitude of the eruptions which have made America par excellence the volcanic continent. It is in New Mexico.
From the Conejos river, in Colorado, one continuous sheet of lava covers the face of the country to the south, for eighty miles unbroken; and then for fifty miles further is now exhibited in outlying areas and detached masses, separated from the main body by the exercise of the power of erosion through prolonged ages. One hundred and thirty miles in length, and perhaps thirty in breadth at its widest, the area of a principality lies swallowed up for ever. From craters existing probably in the San Antonio mountain and in the Ute Peak, near the boundary of Colorado, and possibly from other centres, this flood poured over the land. Reaching to the east, it was checked by the mountains of the Sangre de Cristo range; flowing to the west, the mountains and hills of the main divide, and the spur now between the Chama and the Rio Grande, limited its extent. To the south it was deflected westwardly by the spur of the mountains called the Picuris range, some fifteen miles south of Taos. Protected by this spur, we find the east bank of the Rio Grande for many miles free from the flux. Confined on the west by the slopes of the Jemez mountains, the breadth of the field is narrowed. But from the village of San Ildefonso to Pena Blanca, we find the lava on both sides of the Rio Grande, spreading to the east as far as the Santa Fé creek. Secondary centres in the Jemez mountains possibly contributed to this extension, but the main force of the eruptions was probably felt further to the north. However, in this vicinity the edges and extremity of the field have been reached, and there has been so much erosion in places since its deposition, that outlying masses, as in the bluffs to the west of San Felipe, alone remain. Throughout the whole region thus depicted, the lava field is the great and controlling element. The streams that have eaten their way through it with untold difficulty are found in narrow and deep cañons having no land for cultivation. A dangerous feat for man to descend these precipices, the passage by an animal of burden is almost impossible. The Rio Grande passes for eighty miles or more through its black abyss, with walls of seven or eight hundred feet in height, crowned with perpendicular cliffs of solid lava, two and three hundred feet high. Throughout the whole region there is no agriculture.