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MEXICAN ARCHÆOLOGY

may be considered a continuation of the Sierra Madre to the west and north. Campeche, Yucatan and the part of Guatemala excepted above, constitute a sort of annexe to the former, formed of limestone, low-lying, and of comparatively recent elevation from below the sea. Guatemala (including British Honduras) is an elevated plateau with its highest and steepest escarpment on the Pacific side, and sloping less abruptly and in irregular fashion towards the Atlantic. In the south is a volcanic system, giving rise to scenery of particular beauty, especially where it includes such highland lakes as that of Atitlan. The igneous range constitutes the main watershed, and consequently the only rivers of importance, the Usumacinta and Motagua, drain into the Atlantic, while in the low-lying region of Peten a number of lakes are found. In Honduras the mountain system decreases in elevation into hilly country, also with its principal slope towards the Atlantic, traversed in various directions by ridges branching off from the central plateau. The volcanic system extends from Guatemala along the Pacific coast. As in Mexico, climate corresponds with the degree of elevation, and in Guatemala the same three zones, tierra caliente, tierra templada and tierra fria, are found, with similar abrupt transitions from one to the other. In the lower country cacao vanilla, rubber, coconuts, bananas and palms grow freely, while the uplands are covered with oak and pine. The Atlantic side of Honduras produces a variety of valuable tropical timber, while the higher ground is on the whole more open than that of Guatemala, much of the vegetation being herbaceous and affording good grazing. The climate of Yucatan is purely tropical, and the rainfall is very heavy. Under such conditions, more favourable to vegetable than human existence, the country 1s thickly covered with forest which reappears as soon as cleared and renders exploration a matter of great difficulty, besides making the country very un-