i8 



keep to the north of the Mampon, Agogo, Kwahu and Akwapim ranges 

 of hills. In the east of the Colony it has supplanted the Guinea 

 Vegetation right down to the sea front. It is now steadily progressing 

 along the sea front in the shape of a wedge, ever widening behind, 

 and at the same time extending its thin end westwards. In this manner 

 it has progressed as far as Seccondee. Westwards of Seccondee it 

 cannot yet be said to be established, although many of its characteristic 

 denizens such as Borassus, Phcenix and Sanseveria are found as far as 

 Half Assinie along the sea front, and the latter two right to the western 

 frontier of the Colony. The extension of com and groundnut farms 

 between Seccondee and Half Assinie is causing the tall forest to con- 

 tract inland rapidly and so preparing for the conversion of this country 

 to the Sudanese Vegetation. 



As in the case of the Guinea Zone the soil may be sand or clay, 

 but there seems little doubt that the majority of the country has a 

 sandy soil covering. In many places, however, owing to the destruction 

 of the vegetation, the soil is completely removed, and there the bare 

 rock surface is exposed. This occurs sometimes as stretches of flat 

 rock over which it is extremely trying to walk during the heat of the 

 day, sometimes as prominent jagged rocks and scarps. Where the 

 vegetation exists there is found a black soil to the depth of a 

 few inches only, formed by the collection of vegetable ash from the 

 annual fires, and often described as " a rich black soil suitable for 

 the growth of cotton and similar agricultural crops." The removal of 

 the vegetation, however, quickly causes its dispersal by wind and 

 rain. 



The principal rock of this part of the country is sandstone. Where 

 this has been eroded, as on the hill tops, granite with quartz appears, 

 and the effect of the erosion is seen in the sandy accumulations in the 

 depressions and low valleys. Where this zone of vegetation occurs in 

 the south-east of the country detached outcrops of clay ironstone 

 occur, and here and elsewhere further north are occasionally found 

 schists and shales. 



The general rise of the country which has been indicated pre- 

 viously does not appear to be continued, and maximum heights of the 

 majority of the isolated hills are not recorded as being greater than 

 those of the principal divides of the country. It seems reasonable to 

 suppose that the northern part which embraces the Northern Terri- 

 tories and Northern Ashanti is a land surface reduced to a low relief 

 by erosion. This explains the exposed granite on the hill tops and 

 the alluvium in the depressions, the latter being constantly moved 

 on to the sea. 



Whereas the part of the Guinea Zone within the Gold Coast is that 

 of the rivers of the south and south-west, the part of the Sudanese 



