GEOGRAPHY’S CONTRIBUTION 201 
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Figure 1. The Serra do Pereiro, rising abruptly out of the crystalline 
plain, eastern Ceara. Partially destroyed mature landscape of upland 
gives way to steep flanks of serra. 
sive patches of the once widespread sedimentary blanket have 
been left behind as tablelands on the resurrected erosion surface 
of the basement complex. More or less isolated massifs of resistant 
igneous and metamorphic rock also rise abruptly as mountains 
(serras) above the undulating plain (Figure 1). They represent 
remnants of a higher, even older, erosion surface or, in some cases, 
fault blocks. 
Broadly speaking, moisture decreases rapidly from east to 
west, hence the threefold, longitudinal division of the Nordeste in 
climato-botanical bands, recognizable when striking inland from, 
say, Recife or Joao Pessoa: (1) the so-called zona de mata, or 
forest zone, a humid coastal region; (2) a transition belt known as 
the agreste; and (3) the vast, drier backlands, or sertao, where 
precipitation, after reaching minimum values, picks up again 
toward the west. The area of more abundant and dependable 
rainfall, which parallels the eastern coastline, will not be of im- 
mediate interest in this discussion. 
In the section with which we are concerned, seasons are sharply 
defined by precipitation, not temperature: winter, so-called, 
