Note 86 — Chapter VI · THE PLAIN OF THE PAMPAS

Outside the districts with quick and dead dunes, a frequent type of landscape on the Pampa is a plain thinly sown with very small lagoons, generally circular, between which develop a series of barely perceptible undulations. The inequality is at times so slight that one only notices it by the contrast between the vegetation of the lower and the higher ground. This type of landscape, which is especially seen in the district of Lincoln or of Nueve de Julio, is due to the action of the wind on a plain where the level of the underground water is near the surface. This level marks a limit below which æolian erosion does not take place: a sort of base-level. The periodic variations of level of the underground water reduce or enlarges the undulations of the surface.