GEOGRAPHY OF USAGAEA. 



227 



ing a peninsula, the seaward declivities are the more 

 abrupt ; the landward faces are not only more elongated, 

 but they are also shortened in proportion as the plateau 

 into which they fall is higher than the mountain-plains 

 from which they rise. To enter, therefore, is more toil- 

 some than to return. 



From the mingling of lively colours, Usagara is de- 

 lightful to the eye, after the monotonous tracts of ver- 

 dure which pall upon the sight at Zanzibar and in the 

 river valleys. The subsoil, displayed in the deeper cuts 

 and ravines, is either of granite, greenstone, schiste, or a 

 coarse incipient sandstone, brown or green, and outcrop- 

 ping from the ground with strata steeply tilted up. In 

 the higher elevations, the soil varies in depth from a 

 few inches to thirty feet; it is often streaked with long 

 layers of pebbles, apparently water -rolled. The colour 

 is either an ochreish brick-red, sometimes micaceous, and 

 often tinted with oxide of iron ; or it is a dull grey, 

 the debris of comminuted felspar, which, like a mixture of 

 all the colours, appears dazzlingly white under the sun's 

 rays. The plains and depressions are of black earth, 

 which after a few showers becomes a grass-grown sheet 

 of mire, and in the dry season a deeply-cracked, stubbly 

 savannah. Where the elevations are veiled from base 

 to summit with a thin forest, the crops of the green- 

 stone and sandstone strata appear through a brown coat 

 of fertile humus, the decay of vegetable matter. A fos- 

 sil Bulimus was found about 3,000 feet above sea-level, 

 and large Achatinas, locally called Khowa, are scattered 

 over the surface. On the hill-sides, especially in the 

 lower slopes, are strewed and scattered erratic blocks and 

 boulders, and diminutive pieces of white, dingy-red, rusty- 

 pink, and yellow quartz, with large irregularly-shaped 

 fragments and small nodules of calcareous kunkur. Where 



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