The letters Ws., Br., and Ht., are placed to distinguish the barometric measurements of Dr. Wislizenus, Oberbergrath Burkart, and my own. Wislizenus has appended to his valuable memoir three vertical sections of the surface of the ground: one from Santa Fé to Chihuahua by Passo del Norte; one from Chihuahua to Reynosa by Parras; and one from Fort Independence (a little to the east of the Confluence of the Missouri and the Kanzas River) to Santa Fé. The calculation is founded on daily corresponding observations of the barometer, made by Engelmann at St. Louis, and by Lilly at New Orleans. If we consider that the difference of latitude between Santa Fé and Mexico is 16° and that thus (apart from deviations from a straight line) the distance in the north and south direction is above 960 geographical miles, we are led to inquire whether there be in any other part of the whole globe a similar conformation of the Earth, equal in extent and elevation (between 5000 and 7000 French, or 5330 and 7460 English feet above the level of the sea) to the highland of which I have just given the levelling, and yet over which four-wheeled waggons can travel as they do from Mexico to Santa Fé. It is formed by the broad, undulating, flattened crest of the chain of the Mexican Andes, and is not the swelling of a valley between two mountain chains, as is the case in some other remarkable elevations of plain or undulating surface--in the Northern Hemisphere, in the “Great Basin” between the Rocky Mountains and the Sierra Nevada of California,--in the Southern Hemisphere, in the high plain of the lake of Titicaca, between the eastern and western chains of the Andes of Bolivia,--and in Asia, in the highlands of Thibet, between the Himalaya and the Kuen-lün. GENERAL SUMMARY OF THE CONTENTS OF THE FIRST VOLUME. _Preface to the First Edition_--p. vii. to p. ix. _Preface to the Second and Third Editions_--p. xi. to p. xv. _Note by the Translator_--p. xvii. _Steppes and Deserts_--p. 1 to p. 26. Coast chain and mountain valleys of Caraccas. Lake of Tacarigua. Contrast in respect to the luxuriance of vegetation between those districts and the treeless plains. The steppe regarded as the bottom of a Mediterranean Sea; broken strata a little higher than the rest of the plain called “banks.” General phenomena of extensive plains; the Heaths of Europe, the Pampas and Llanos of South America, the African Deserts, and the Steppes of Northern Asia. Different characters of the vegetable covering of the surface. Animal life. Pastoral nations, and their invasive migrations 1-6 Description of the South American plains and prairies--their extent and climate; the latter dependent on the outline of the coasts, and on the hypsometric conformation of the New Continent. Comparison with the plains and deserts of Africa 7-13