Bendrat — Notes on Region about Caieara, Venezuela. 447 



ure, after the streams have fallen during the dry season, it is 

 exceedingly plastic. But as soon as it becomes dehydrated it 

 turns extremely hard and becomes a clay ironstone, the lat- 

 erite of the sabana, the river banks and the cerros : the German 

 "zelliger Brauneisenstein." It is, however, not continuous 

 and is often replaced by a hard conglomerate cemented together 

 by iron oxides. This is the case at Caicara, where the lower 

 terrace on which the village is situated consists of the hard 

 conglomerate. Also the level at which the laterite occurs is 

 not uniform, and while at one point it may be seen to rise well 

 above the stream, it disappears at another point below the 

 level of the water. 



Not only along the Orinoco, but also inland on the plains of 

 the sabana, wherever the granites or gneisses emerge from the 

 younger deposits, even on the slopes of the cerros at consider- 

 able heights, irregular, limited patches of this clay ironstone 

 are found to fill to a greater or less extent the hollows in bed- 

 rock. 



The general appearance of this laterite deposit in the Llanos 

 of the Orinoco drainage basin, the sabana being only a " floral" 

 form of the Llano, has led Dr. S. Passarge, who saw similar 

 laterite formations in the Kalahari desert in southern Africa, 

 to suggest a possible extended period of laterite formation by 

 weathering from, perhaps, Tertiary time. 



This laterite deposit seems to determine the ground- water level 

 in the sabana, carrying ground water over its surface to the sides 

 and slopes of gullies, ravines and streams, as well as to the banks 

 of the Orinoco, or allowing these waters to accumulate in more 

 or less extended and comparatively shallow depressions, thus 

 acting as a hardpan and giving rise to the formation of the 

 " lagunas" which in turn, where partially drained or when dry- 

 ing up, to a certain extent during the dry season, may change 

 into " Potreros," swampy meadows, or into " Morichales," 

 swampy woods, in which the " Mauritia" palm is the character- 

 istic tree. Thus the laterite plays a not unimportant role in 

 the shaping of the features of the landscape. 



The Upper Llanos Beds. — The Upper Llanos deposits, 

 which, as a rule, un conformably overlie the laterite, wherever 

 they have not been removed by subsequent erosion, or corra- 

 sion, or both combined, may be said to consist of the following 

 three members : 



A whitish or yellowish clay, rich in iron, which exhibits cell 

 structure. 



Loams of various kinds. 



Sands of different fineness and color. 



Their relations to one another change with the locality and 

 so also does their respective horizon. ■ They constitute the 



