CHAPTER XXI 



GEOLOGY AND MINERALS 



THE petrology of Liberia is still very little known— almost 

 unknown would be the correct phrase. It is a land 

 which rises gradually from the sea coast, with a very 

 diversified surface of hill and valley till the open country of 

 the Mandingo Plateau is reached on the extreme north, where 

 the average altitude is about 2,500 feet above sea level. Nowhere, 

 so far as we know, is there any large extent of marsh in Liberia, 

 or any sheet of open water big enough to be styled a lake, 

 though during the rainy season — from May to October — a good 

 deal of the coast country is under water. The rivers have 

 tumultuous courses, strewn with rocks and cataracts, and, with the 

 exception of the St. Paul's and Cavalla Rivers, tidal influence does 

 not reach more than a few miles inland from their mouths. 



The petrology of the coast is to some extent hidden under 

 recent alluvium covered with mud, mangroves and pandanus, 

 or with a growth of dense forest or plantations. Much of the 

 surface of Liberia is Archaean, references to the " Miocene " 

 characteristics of its fauna and flora ^ not being intended to 

 convey for an instant the idea that there are any deposits of 

 so recent an age as the Miocene in its geology. The rocks 

 are mostly metamorphic, and include gneisses of various kinds, 



1 Meaning, of course, that there is much in the existing fauna and flora of 

 Liberia which suggests affinities with the fauna characteristic of France and 

 Germany in the Miocene age. 



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