This wealth of plant life is confined to the littoral and the coastal valleys, but the central valleys and the plateaux have, if not a varied flora, a considerable wealth of timber trees in every way superior to the flora inland in the same latitudes.
When the warmer interglacial periods recurred the polar and continental ice-caps melted and the sea-level became raised again - that is, there was submergence of the eroded plateaux formed as indicated above.
Devonian beds also lie upon the older rocks in the Matto Grosso and other provinces in the interior of Brazil, where they generally form plateaux of nearly horizontal strata.
Neveu-Lemaire, Les Lacs des hauts plateaux de l'Amerique du Sud (Paris, 1906); M.
(3) In the steppe the vegetation is that which prevails in similar soil from Central Asia to Algeria; but many of the arborescent plants that grow in the rockier and more irregular plateaux of western Asia, and especially of Persia, have been reported as missing.