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E. C. HARDER AND R. T. CHAMBERLIN 



crumbles to pieces and the crystalline areas become lowlands. But 

 on account of comparatively recent uplifts, the granite areas of 

 central Minas Geraes are not yet reduced to plain conditions, though 

 they represent a state of advanced erosion. The hills are mostly 

 small and very numerous. They produce the peculiar knobby, 

 hummocky topography which characterizes so many areas of crys- 



FiG. II. — View toward the Serra do Caraga from the Morro do Seahara showing 

 the topography resulting from the unequal resistance of the formations; quartzite 

 ranges in the foreground and in the distance; Morro Agudo, a pyramidal peak of iron 

 ore, to the left of the center of the picture, and the billowy lowlands of granite beyond. 



talline rock within the tropics, and which has been aptly likened by 

 Eschwege to the billows of a rolling sea (Fig. ii). Wherever 

 erosion has become sluggish in these lowland areas, the rapid 

 disintegration of the crystalline rock has formed a very thick 

 covering of mantle rock which effectively conceals the solid rock 

 from view. 



