The Pedras Negras of Pungo Aiidongo in Angola 25 



also often in Europe under similar cirumstances. However, all 

 these hues observed on land and in water, though the product 

 of true algoid vegetation, are mostly of short existence, and not 

 limited to definite periods ; they rarely, sometimes never, reappear 

 on the same spot, and, therefore, they must be looked upon as 

 ephemeral ajDpearances, which thus escape general observation, 

 and disappear without trace. 



Quite different is it with the colouring of the mountain rocks of 

 Pungo Andongo, because there this phenomenon has not only been 

 observed for centuries, recurring annually with a certain regu- 

 larity, but also with such intensity, extending on a large scale 

 over so wide a district, that it gives a definite character to the 

 physiognomy of the landscape, in which the fantastically shaped 

 huge mountain rocks, which project high above the level of the 

 green forest and fields, appear sometimes in their natural grey-red- 

 dish, or greyish-white aspect, at other times clothed in deep black, 

 rising towards the blue sky Hke the gigantic ruins of a bygone 

 Cyclopean town. 



At first glance it is evident that such colouring of rocks 

 caused by the smallest plants, and extending in a short time over 

 an immense district, cannot be the result of climatic influences 

 alone, but must also be dependent on the co-effect of other, 

 especially of topographical circumstances ; hence a short sketch of 

 the situation, the environs and the climate of Pungo Andongo, 

 with a few remarks on its vegetation, may here not be out of place. 

 Pungo Andongo, the chief place in the district of the same name, 

 includes a large portion of the upper river country of the great 

 River Cuanza, is situated in 90° 42' 14'' south lat., at a distance of 

 about 180 geographical miles from the Atlantic coast, and rises, 

 inclusive of the height of the surrounding mountains, to about 

 3800 feet above the level of the sea, picturesquely over- 

 towering the fertile pastures in the valley of the Cuanza * which 

 limits the district on the south, and which is 5 miles distant. 

 Opposite, on the left bank of the Cuanza, rise the mountain chains 

 of Libollo Alto, further east those of Hako and of other negro 

 countries, converging or diverging more or less with the river-bed. 

 Pungo Andongo, as well as the subordinate district belonging to 



• I write Cuanza not Quanza, the former being more in accordance with the 

 pronunciation and genius of the Bunda language, also because this mode of 

 writing has been adopted by the better Bunda grammarians. — Conf. Cannecatim. 

 Observ. grammat. sobre a liiigiia Bunda, p. 9. 



