ROCKY FORMATION OF THE COUNTRY. 211 



" The eastern ridge seems to bend in to the west at the part we have 

 crossed, and then trends away to the north-east, thereby approaching the east 

 coast. It is fringed on some parts by ranges of hills, but my observations 

 seem to show they are not of greater altitude than the flats of Linyanti. I 

 cannot hear of a hill on either ridge, hence the agricultural phrase I employ. 

 And if the space between the ridges is generally not broader than 600 miles, 

 instead of calling the continent basin-shaped, it may be proper to say that it 

 has a furrow in the middle, with an elevated ridge on each side, each about 

 150 or 200 miles broad, the land sloping on both sides thence to the sea. 



"I have referred to the clay-shale, or 'keel' formation, of which I got a 

 glance in the western ridge. In the eastern we have a number of igneous 

 rocks, with gneiss and mica-slate, all dipping westwards ; then large rounded 

 masses of granite, which appear to change the dip to the eastward. I bring 

 specimens of both classes of rocks along with me. Is this granite the cause 

 of elevation? 



" I shall refer to but one topic more. The ridges are both known to be 

 comparatively salubrious, closely resembling in this respect that most healthy 

 of healthy climates, the interior of Southern Africa, adjacent to the desert. 

 The grass is short ; one can walk on it without that high, fatiguing lift of the 

 foot necessary among the long tangled herbage of the valley. We saw 

 neither fountain nor marsh on it ; and, singularly enough, we noticed many of 

 the plants and trees which we had observed on the slopes of the western ridge. 



"If my opinion were of any weight, I would fain recommend all visitors 

 to the interior of Africa, whether for the advancement of scientific knowledge, 

 or for the purposes of trade or benevolence, to endeavour to ascertain whether 

 the elevated salubrious ridges mentioned are not prolonged farther north than my 

 inquiries extend, and whether sanatoria (health stations) may not be established 

 on them. At present I have the prospect of water-carriage up to the bottom of 

 the eastern ridge. If a quick passage can be effected thither during a healthy 

 part of the season, there is, I presume, a prospect of residence in localities 

 superior to those on the coast. Did the Niger expedition turn back when 

 near such a desirable position for its stricken and prostrate members ? 



" I have said that the hills which fringe the ridge on the east are not of 

 great altitude. They are all lower than the crest of the ridges, and bear 

 evident marks of having been subjected to denudation on a grand scale. 

 Many of the ranges show on their sides, in a magnified way, the exact 

 counterparts of mud-banks left by the tides. A coarse sandstone rock which 

 contains banks of shingle and pebbles, but no fossils, often exhibits circular 

 holes, identical with those made by round stones in rapids and water-falls. 

 They are from 3 to 4 feet broad at the brim ; wider internally, and 6 or 8 feet 

 deep. Some are convenient wells, others are filled with earth ; but there is 

 no agency now in operation in the heights in which they appear which could 



