Page:EB1911 - Volume 04.djvu/624

 still smaller Lakes Nakuro (5845 ft.) and Elmenteita (5860 ft.), followed in turn by that of Lakes and  (q.v.). Beyond Baringo the valley is drained north into Lake Sugota, in 2° N., some 35 m. long, while north of this lies the much larger (q.v.), the valley becoming here somewhat less defined.

On the west of the rift-valley the wall of cliffs is best marked between the equator and 1° S., where it is known as the Mau Escarpment, and about 1° N., where the Elgeyo Escarpment falls to a longitudinal valley separated from Lake Baringo by the ridge of Kamasia. Opposite Lake Naivasha the Mau Escarpment is over 8000 ft. high. Its crest is covered with a vast forest. To the south the woods become more open, and the plateau falls to an open country drained towards the Dogilani plains. On the west the cultivated districts of Sotik and Lumbwa, broken by wooded heights, fall towards Victoria Nyanza. The Mau plateau reaches a height of 9000 ft. on the equator, north of which is the somewhat lower Nandi country, well watered and partly forested. In the treeless plateau of Uasin Gishu, west of Elgeyo, the land again rises to a height of over 8000 ft., and to the west of this is the great mountain mass of (q.v.). East of Lake Rudolf and south of Lake Stefanie is a large waterless steppe, mainly volcanic in character, from which rise mountain ranges. The highest peak is Mount Kanjora, 6900 ft. high. South of this arid region, strewn with great lava stones, are the Rendile uplands, affording pasturage for thousands of camels. Running north-west and south-east between Lake Stefanie and the Daua tributary of the Juba is a mountain range with a steep escarpment towards the south. It is known as the Goro Escarpment, and at its eastern end it forms the boundary between the protectorate and Abyssinia. South-east of it the country is largely level bush covered plain, mainly waterless.

[Geology.—The geological formations of British East Africa occur in four regions possessing distinct physiographical features. The coast plain, narrow in the south and rising somewhat steeply, consists of recent rocks. The foot plateau which succeeds is composed of sedimentary rocks dating from Trias to Jurassic. The ancient plateau commencing at Taru extends to the borders of Kikuyu and is composed of ancient crystalline rocks on which immense quantities of volcanic rocks—post-Jurassic to Recent—have accumulated to form the volcanic plateau of Central East Africa.

The formations recognized are given in the following table:—

Archaean.—These rocks prevail in the districts of Taru, Nandi and throughout Ukamba. A course gneiss is the predominant rock, but is associated with garnetiferous mica-schists and much intrusive granite. Hornblende schists and beds of metamorphic limestone are rare. Cherty quartzites interbedded with mylonites occur on the flanks of the Nandi hills, but their age is not known.

Carboniferous?—From shales on the Sabaki river Dr Gregory obtained fish-scales and specimens of Palaeanodonta Fischeri.

Karroo.—The grits of Masara, near Rabai mission station and Mombasa, have yielded specimens of Glossopteris browniana var. indica, thus indicating their Karroo age.

Jurassic.—Shales and limestones of this age are well seen along the railway near Changamwe. They contain gigantic ammonites. According to Dr Waagen the ammonites show a striking analogy to forms from the Acanthicus zone of East India. Belemnites are plentiful.

Pleistocene.—These are feebly represented by some boulder beds on the higher slopes of Kilimanjaro and Kenya. They show that in Pleistocene times the glaciers of Kilimanjaro and Kenya extended much farther down the mountain slopes.

Recent.—The ancient and more modern lake deposits have so far yielded no mammalian or other organic remains of interest.

Igneous and Volcanic.—A belt of volcanic rocks, over 150,000 sq. m. in area, extends from beyond the southern to beyond the northern territorial limits. They belong to an older and a newer set. The older group commenced with a series of fissure eruptions along the site of the present rift-valley and parallel with it. From these fissures immense and repeated flows of lava spread over the Kapte and Laikipia plateaus. At about the same time, or a little later, Kenya and Kimawenzi, Elgon and Chibcharagnani were in eruption. The age of these volcanic outbursts cannot be more definitely stated than that they are post-Jurassic, and probably extended through Cretaceous into early Tertiary times. This great volcanic period was followed by the eruptions of Kibo and some of the larger volcanoes of the rift-valley. The flows from Kibo include nepheline and leucite basanite lavas rich in soda felspars. They bear a close resemblance to the Norwegian “Rhombenporphyrs.” The chain of volcanic cones along the northern lower slopes of Kilimanjaro, those of the Kyulu mountains, Donyo Longonot and numerous craters in the rift-valley region, are of a slightly more recent date. A few of the volcanoes in the latter region have only recently become extinct; a few may be only dormant. Donyo Buru still emits small quantities of steam, while Mount Teleki, in the neighbourhood of Lake Rudolf, was in eruption at the close of the 19th century.]

Climate, Flora and Fauna.—In its climate and vegetation British East Africa again shows an arrangement of zones parallel to the coast. The coast region is hot but is generally more healthy than the coast lands of other tropical countries, this being due to the constant breeze from the Indian Ocean and to the dryness of the soil. The rainfall on the coast is about 35 in. a year, the temperature tropical. The succeeding plains and the outer plateaus are more arid. Farther inland the highlands—in which term may be included all districts over 5000 ft. high—are very healthy, fever being almost unknown. The average temperature is about 66° F. in the cool season and 73° F. in the hot season. Over 7000 ft. the climate becomes distinctly colder and frosts are experienced. The average rainfall in the highlands is between 40 and 50 in. The country bordering Victoria Nyanza is typically tropical; the rainfall exceeds 60 in. in the year, and this region is quite unsuitable to Europeans. The hottest period throughout the protectorate is December to April, the coolest, July to September. The “greater rains” fall from March to June, the “smaller rains” in November and December. The rainfall is not, however, as regular as is usual in countries within the tropics, and severe droughts are occasionally experienced.

Inhabitants.—The white population is chiefly in the Kikuyu uplands, the rift-valley, and in the Kenya region. The whites are mostly agriculturists. There are also numbers of Indian settlers in the same districts. The African races include representatives of various stocks, as the country forms a borderland between the Negro and Hamitic peoples, and contains many tribes of doubtful affinities. The Bantu division of the negroes is represented chiefly in the south, the principal tribes being the Wakamba, Wakikuyu and Wanyika. By the north-east shores of Victoria Nyanza dwell the (q.v.), a race remarkable among the tribes of the protectorate for their nudity. Nilotic tribes, including the (q.v.), Lumbwa, Suk and Turkana, are found in the north-west. Of Hamitic strain are the (q.v.), a race of cattle-rearers speaking a Nilotic language, who occupy part of the uplands bordering on the eastern rift-valley. A branch of the Masai which has adopted the settled life of agriculturists is known as the Wakuafi. The Galla section of the Hamites is represented, among others, by Borani living