But the most singular and dubious relics of antiquity, are subteraneous or in excavations: these are in caves, mines, pits, &c.: while under ground are found trees, stumps, charcoal, ashes, shells, pavements, walls, houses, &c. that must have been buried by alluvions, diluvions or new formed soil. It has been surmised or ascertained that some may be antidiluvian: although those in deep alluvial soils, near streams, and connected with graves, may have been buried by men, or fluvial inundations. Mummies, skeletons and bones, with human apparel and implements have been found in caves, evidently buried there by human means, and not by floods. Human remains are but seldom if ever connected with the organic remains of the soil and caves, even of the latest geological date. 3. _Geography, Maps, &c._ The knowledge of the regions and localities inhabited by mankind, or where colonies are sent, empires founded, is needful to history, in order to understand and treat the events and migrations. The physical configuration of the land, the climates, plains, mountains and streams, have a great influence on civilization and communications. Physical geography is constant and invariable: while civil or ethnographical geography is constantly fluctuating in limits and names. If we had complete series of maps by chronological order upon America; we should find therein the materials for a comparative historical geography, and successive ethnography, showing the gradual revolutions of mankind. The old maps of America, those of Laet, the old geographers &c. are very valuable for this object. Many travellers in America, have given original maps, which furnish similar materials. I have chiefly used for Peru and Austral America, the maps of Laet, Acarete, D’Anville, Molina, Falkner, Cochrane, Wedel, the Jesuits, &c. Among the modern general maps, relating to South America, the Spanish maps of 1810 and 1822, the English of 1815, the French of 1830, the latest American of Tanner, &c. By those materials I have been able to trace and fix four periods of American geography, 2 ancient and 2 modern. I. Primitive geography of America. II. Ancient ditto, or between 1400 and 1500. III. Modern colonial geography. IV. Modern independent geography. I have formed Mpt. maps of the two first periods, which shall be published gradually, or in my Illustrations of the Ancient Geography of America. We have thousands of maps on the early geography of the Eastern Hemisphere, and no one as yet on the Western Hemisphere! to show the respective limits and positions of Ancient Empires, Nations, Cities, &c., except Clavigero’s map of Anahuac at the Spanish conquest, those of Hayti, Laet, &.c.