Chapter I: Physical Geography (1)

Introduction. Hydrographical systems; primary watersheds. The Niger: Lokoja and Mount Patti; Jebba and the Juju Rock; the rapids of the Niger. The Benue: the great plain of Muri; sandbanks. The Niger Provinces: the tableland of central Kabba; domes and inselberge; the plain of Ilorin; Borgu; Kontagora; typical scenery of crystalline and sedimentary regions; the plains of Nupe; the sandstone plateaux of the Niger. The Benue Provinces: Bassa and Nassarawa; the river belt of sandstones; the Karshi hills and the Abuja Rock; the central plain; the northern tableland; the plains of Muri; volcanic hills of the middle Benue; the Wase Rock; the Murchison hills; the plateau of southern Yola; the lower Gongola; volcanic craters and granite inselberge. The Central Provinces: Zungeru and the gorge of the Kaduna; the plains and hills of Zaria; the Bauchi plateau; the Ningi hills; Angass and Kanna; the eastern plains; the Gongola valley; the cliffs of Tongolan; the Kudu valley; the Gateri hills; Tangale and Waja; The Peak. The Northern Provinces: southern Bornu; the Bima hills; the Barbur volcanic plateau; the Tagum hills; eastern Bornu; firki land and blown sand; Lake Chad; the central plains of Bornu; the Kerri Kerri plateau; intersecting trench-like valleys; the plains of Katagum; Kano; Mounts Dala and Kogon Dutsi; Kazaure; Katsina; Sokoto; the Gulbin Kebbi; dallols and dissected sandstone plateaux.

The Protectorate of Northern Nigeria comprises an area of about 255,700 square miles, of which the greater part is enclosed within the obtuse angle formed by the Niger with its great tributary the Benue. The north- eastern corner is occupied by Lake Chad, whence irregular lines forming the northern and eastern boundaries between the Protectorate, the French Sudan and the Kameruns run west and south respectively to the Niger and the Benue. Within the oblique figure thus formed lie the provinces of Sokoto, Kano, Bornu, Bauchi, Zaria, Kontagora, Nupe, Nassarawa and portions of Muri and Yola. West of the Niger lie Borgu, Ilorin and Kabba, which adjoin Dahomey and Southern Nigeria, while south of the Benue lie Bassa and parts of Muri and Yola, marching with Southern Nigeria and the Kameruns. The administrative headquarters of the Protectorate are at present fixed at Zungeru on the Kaduna in western Zaria, while the subordinate headquarters of the fourteen provinces enumerated above are located respectively at Sokoto, Kano, Maidugari, Bauchi, Zaria, Kontagora, Bida, Keffi, Ibi, Yola, Kiama, Ilorin, Lokoja, and Dekina. Lokoja also, in addition to being the headquarters of Kabba province, is from its situation at the confluence of the Niger and the Benue the natural emporium of European commerce.

Many of the more striking physical features of the Protectorate are now comparatively well known. The Niger with its flat-topped sandstone hills, the Benue and the plains of Muri, the peaks of the Murchison Hills, Lake Chad, and the sands and swamps of Bornu, have become familiar from the writings of both early and recent explorers.[1] Equally striking, however, are the broad, flat-bottomed valleys of the north-west, in which diminutive streams now represent the mighty rivers of old; the rolling sandy plains of Hausaland[2] with their sluggish rivers, their isolated granite domes and groups of rounded hills; and the mysterious Bauchi plateau, the home of innumerable pagan tribes, whose precipitous walls on the south and west long marked the limit between the known and the unknown.

_Hydrographical Systems._ (Map. p. 4).

The Bauchi plateau, which rises to a height of 4,000 to 4,500 feet above the sea, is the hydrographical centre of the Protectorate. From it the rivers radiate north, south, east, and west; but while at first they flow in such diverse directions, they become ultimately included within one or other of the two great hydrographical systems, the Niger-Benue system and the Chad or Inland system. All the rivers leaving the plateau, with the exception of those flowing directly north, belong to the Niger-Benue system. The “primary watershed,” or dividing line between the two great hydrographical systems, runs from the neighbourhood of Daura on the northern frontier of the Protectorate south-westward between Katsina and Kano to the twelfth parallel. Thence it runs south-eastward to the latitude of Zaria, and then southward to the neighbourhood of Bukuru, on the summit of the plateau. From Bukuru it strikes approximately north-eastward to Kerri Kerri, and thence south-eastward to the Yola border in the neighbourhood of Mubi. Within the Chad system the only important river is the Yo, of which the rivers Hadeija, Katagum, Delimi, and Shidya form the headwaters. The Yedseram, the only other large river of Bornu, forms for some distance the boundary line between Nigeria and the northern territories of the Kameruns. In the west the primary watershed of the Niger system coincides approximately with the boundary of the Protectorate from the eleventh parallel to the neighbourhood of Aiedi on the eighth parallel, whence it runs eastward to Kabba, and thence southward through the Egbira and Kukuruku hills into Southern Nigeria. South of the Benue, the primary watershed runs through Southern Nigeria and the Kameruns entirely beyond the southern limit of the Protectorate.

_The Niger._

The Niger enters the Protectorate at Ilo in the north-west, and flows within the Protectorate for a distance of four hundred and fifty miles to Idah on the Southern Nigerian frontier. Its breadth varies in places from a few hundred yards in the dry season to several miles during the rains. The annual variation in depth may reach at Lokoja as much as thirty-five feet, and when in flood the river is navigable for small ocean-going steamers as far as Baro, the terminus of the Baro-Kano railway, and for light stern-wheelers as far as Bajibo, twenty miles north of Jebba. Its largest tributaries within the Protectorate join the Niger on the left, those on the right being comparatively short and unimportant. On the left are the Kebbi, Malenda, Kontagora, Kaduna, Bako, Gurara, and Benue; on the right the Wessa, Oli, Teshi, Awo, Oshin, Oyi, Oro, Kampi, Mimi, and Meadowbank. Of these the Gurara is navigable in flood for small stern-wheelers for a distance of thirty miles from the Niger, the Kaduna as far as Wushishi at the foot of the rapids, and the Kebbi as far as the confluence of the Jega river.

Primary Watersheds and River Systems.

MAP No. 1.

London. Macmillan & Co., Ltd.

_Face p._ 4.]

The alternation of narrow gorge and open plain is a striking feature of the Niger valley within the Protectorate. Where the channel is narrow and bounded by steep cliffs on either side the seasonal variation in level gives rise to comparatively little change in the aspect of the river. The blackened rocks in the river bed and the sandy stretches on either shore may be lost to view, but the flood is still confined within its walls of rock. It is where a plain tract intervenes in the course of the river that the contrast between the Niger in flood and the Niger at low water becomes particularly striking. The sandy bars and shallows which in the dry season present such obstacles to navigation, as well as the grassy banks and islands of alluvium with their terraced slopes of sand and clay, are buried during the rains under a flood, which may spread for miles over the plain on either side of the river.

At Idah the Niger narrows and flows swiftly between low cliffs of white sandstone which pass northward into stretches of wooded rising ground on either bank. Ten miles above Idah a group of flat-topped hills approach the right bank of the river, only to turn off abruptly inland in a line of buttresses six to seven hundred feet in height. Farther on, the low, flattened ridges on the left bank run out in a line of rounded hills: and beyond, the river broadens and a broken plain stretches inland to distant groups of lofty hills. Nearing Itobe Mount Purdy stands out, a solitary cone, in advance of the level-crested plateau beyond. From Itobe to Igbo the Niger flows through the most picturesque portion of its lower course.[3] The hills rapidly close in, the channel becomes narrow and rocky, lofty granite domes and rounded hills separated by narrow gloomy valleys rise up on either bank, and on the left the level crest of the plateau looms behind on the sky-line (Plate I, Fig. 1). Below Lokoja the river opens out, the hills die down on either side, and from the left bank a broken hummocky plain stretches inland to the base of the Bassa hills, while at Lokoja itself flat-topped Patti (Plate I, Fig. 2), with its projecting buttresses and the red roofs of the cantonment at its base, stands sentinel over the confluence of the Niger and the Benue (Plate II).

An extensive alluvial plain annually flooded during the rains stretches away to the Benue from the left bank of the Niger for long miles above Lokoja. The right bank is occupied more or less continuously by the worn escarpment of the plateau of which Mount Patti forms the southernmost extremity. Above Koton Karifi the hills reappear on the left bank, and for more than twenty miles the Niger flows between the broken walls of what has once been a magnificent river gorge. In places for considerable distances the flat-topped hills still rise up with precipitous slopes on either side in all their ancient grandeur. More frequently, however, the escarpments are rounded off and much eroded by lateral valleys, while at times they recede to a distance, and leave between themselves and the river a more or less extensive swampy plain, with here and there a flat- topped remnant of the once continuous plateau. Before Baro is reached, however, the plateau has disappeared on the right bank, and on the left is represented only by more or less isolated flat-topped fragments. The bend of the Niger at Egga and Kacha marks the eastward limit of an extensive alluvial flood plain, which includes the lower courses of the Kampi and the Bako, and stretches westward on the north bank as far as the Kaduna. On the south bank the pinnacle peaks of Egbom[4] tower high above the river, while a flattened ridge extends westward as far as Pategi. Beyond the Kaduna the Niger flows through a broad and shallow valley with extensive swampy plains on either hand, and only at Shonga on the right bank and at Rabba on the left does the river approach the rising ground which elsewhere bounds the valley in the distance.

At Jebba the hills close in on either side, and the Niger issues by a double channel from a picturesque gorge which extends northward as a deeply cut and rocky valley as far as Bussa, a distance of seventy-five miles. For eight hundred yards above Jebba the gorge is narrow and bounded by vertical walls of quartzite. The Juju Rock[5] and the other islands which interrupt the channel mount steeply from the river, the rapid current pours over sunken rocks which rise abruptly from the river bed, and mighty whirlpools bear witness to the depth of the water. Beyond Jebba the quartzite gives place to granite, the vertical walls become rounded, wooded slopes, the river broadens its rocky bed and flows in a narrow valley between two belts of broken hilly ground which lead up to the plains of Kontagora and Borgu, five hundred feet above the level of the river. In spite of the obstructions in the channel the river is navigable with caution for small stern-wheelers as far as Bajibo. Above Bajibo, however, navigation becomes precarious and dangerous even for native canoes. The current becomes more violent; rocks, cascades, and whirlpools more numerous, and small rapids more and more frequent, until above Leaba the Niger flows in a rocky gorge which leads to the base of the Great Rapid of Wuru.[6] Here the river is formed of two branches with a rocky island between. The fall of forty feet between the summit and foot of the rapid is distributed over some thirteen hundred yards of river, giving a slope of at least 1 in 100 and a current of from fifteen to eighteen miles an hour. In the rains the granite boulders are completely submerged under a seething flood, and even in the dry season the water is thrown up by the projecting rocks in sheets of foam, and the roar of the rapid is heard for long distances on either side.

A stretch of two and a half miles of comparatively smooth water, broken only by some small rapids and cascades, separates the Great Rapid of Wuru from the rapid of Patassi, which is composed of two sets of cascades, each twelve to fifteen feet in height and separated by a straight reach of some two hundred and eighty yards. Twenty miles farther on, the third important set of rapids is reached, the rapids of Garafiri, whose cascades and whirlpools occupy a stretch of about three miles between the villages of Garafiri and Malali. At Bussa, the scene of Park’s disaster, the channel is still much obstructed by projecting rocks and islands, and the small cascades and the rapid current still render navigation both difficult and dangerous. The right bank of the river is here formed of low, wooded rising ground, while on the left ranges of low hills rise in series one behind the other. Soon, however, the hills die down and the rocks disappear from the river bed, and at Warra the river is broad and smooth with an extensive flood plain on either side. From Warra to Ineku the Niger is formed of two branches, of which the more westerly preserves the calm aspect of the river at Warra, while the more easterly becomes again obstructed by rocks and rapids. Between Ineku and Yelwa the river is bounded by low, rounded hills covered with scanty forest, innumerable islands rise from the river bed supporting an abundant vegetation, while several sets of lesser rapids obstruct the channel. At Yelwa the banks become low and swampy, the hills begin to recede from the river, and five miles farther on, near the village of Sakassi, the last set of minor rapids occurs in the channel. Beyond Sakassi the whole aspect of the river changes, the channel becomes broad and sandy and obstructed by nothing more serious than sand bars. On the north bank a broad, swampy flood plain, with low rising ground in the distance, bounds the river as far as the mouth of the Kebbi, and from the Kebbi to the swamps of Ilo an open sandy plain stretches northward between the river and the base of the plateau. On the south bank the gently undulating plain which bounds the river stretches westward to the Dahomey border, broken only by some scattered groups of flat-topped hills.

_The Benue._

The Benue enters the Protectorate to the east of Yola, and after a course of nearly five hundred miles joins the Niger at Lokoja. Its principal tributaries are on the right bank the Gongola, Kudu, Wase, Simanka, Ankwe, Modu and Okwa; on the left bank the Faro, Ini, Mainarawa, Tarabba, Donga and Katsena. The Benue is navigable when in flood throughout its whole course for steamers of light draught. The Katsena is navigable as far as Katsena Allah, the Gongola as far as Nafada, and the Donga and Tarabba for considerable distances up stream.

In the matter of scenery the Benue presents a striking contrast to the Niger. There is on the Benue no picturesque alternation of narrow gorge and open plain; no rapids trouble its surface from Lokoja to the flat- topped hills of Yola, and even in the dry season it is only at long intervals that rocks are exposed in its sandy bed or in its steep banks of alluvium. The precipitous front of Mt. Patti and the level crest of the plateau on the right bank of the Niger are visible from the Benue for twenty miles above Lokoja, across the great alluvial plain which marks the confluence of the two mighty rivers. Above Mozum a range of flat-topped hills with occasional peaks follows the right bank for some distance, but soon turns inland and leaves a broken plain between the river and the base of the hills. A similar range, also separated from the river by a broken plain, runs parallel with the left bank a few miles inland. The escarpments of these ranges on either side of the river represent the walls of a broad flat-bottomed valley which is comparable in origin with the steep-sided gorge of the Niger above Lokoja. Here on the Benue, however, erosion has been more intense, and the hills have been cut farther back on either hand.

Above Umaisha a tract of broken country stretches eastward on the north bank and gives place in the neighbourhood of Loko to alluvial swamps in the foreground, with undulating sandy plains beyond. On the left bank, meanwhile, the hills approach the river at Amara and pass eastward into a hummocky plain, which is bounded to the south by a distant range of flat-topped hills. Above Loko the Doma Hills touch the river at Udeni on the right bank, but turn off abruptly inland with their low, buttressed slopes overlooking an extensive swampy plain which stretches eastward as far as Akwaneja. Beyond Akwaneja the right bank assumes a similar aspect to that of the left. The river is bounded by low, well-wooded banks, with here and there a projecting mass of sandstone, while a hummocky plain stretches inland on either side to distant rising ground. The volcanic tract above Abinsi introduces an agreeable change into the monotony of the scenery. The worn and weathered cones and banks of lava stand out picturesquely from the wooded plains, and on the river-side the black basalt and the yellow sand offer a pleasing contrast to the eye. Soon, however, the low banks resume their familiar aspect and a featureless plain spreads out on either hand. Nearing Ibi the right bank becomes low and swampy, and the great plain of Muri opens out beyond. From Ibi to Lau the channel is broad and sandy, and the river winds about amongst everchanging sand-bars and banks of alluvium. In the rains broad stretches are flooded on either side, and for long distances on the right bank the plain beyond becomes an almost impassable swamp, while on the left long tongues of marshland run up the tributary valleys. Far to the north the peaks of the Murchison Hills[7] tower high above the plain, while to the south the rock of Bantaji guards the swamps of the Donga.

PLATE I

Farther east, and especially between Numan and Yola, the river plain is traversed by a large number of anastomosing channels, which in many cases are only connected with the main stream during the rains, and in the dry season are cut off by sand-bars into strings of shallow pools and marshes. Alluvial mud covers the rocks for some miles inland, and while in the rains travel on foot is impossible and the villages are isolated one from another, in the dry season the ground shrinks and is broken everywhere by wide cracks. This alluvial plain is perfectly level, so that the small volcanic mounds, dotted here and there, which in a more varied country would be overlooked, form conspicuous landmarks. The most striking of these hillocks is Jeme Hill, below Numan, which stands on the river bank and can be seen for twenty miles around. (A. L.)

The Benue plain, which is so extensive in Muri province, contracts near Lau, and thence eastward it is limited on both sides by plateau areas which rise suddenly and steeply at distances of fifteen miles from the river. These masses of hills with their varying outlines introduce a pleasing change into the hitherto monotonous river journey, and contrast sharply with the river plain. Here the plain of the Benue is like a broad and shallow trench, bounded by sharply rising walls, whose height is small compared with the distance between. At the same time the height is considerable in itself, for the rise to the plateau is well over a thousand feet. (A. L.)

These hills running eastward parallel to the river are breached by the Gongola plain, about ten miles wide, entering from the north, and by the plain of the Ma-Ini and Maio Belwa entering from the south. Farther on the hills come in again. To the north they are rather scattered and detached, with long tabular outlines, or, as in the Bagele Hills, with terraced sides and abrupt scarps. On the other side, though flat-topped hills do occur, the outlines are usually more varied, while south of Yola rises the typical plateau of the Vere Hills—a solid mass fronting boldly outwards upon the surrounding plains with continuous rocky faces indented by a few deeply-cut and narrow valleys. Meanwhile the plain of the Benue with its flat and marshy character continues eastward beyond Yola and the Faro river into the German Kameruns. (A. L.)

Along the whole course of the Benue from Lokoja to Yola exposures of the underlying rocks are very infrequent, and this remark applies equally to the lower courses of the tributaries. The main trunks of the Benue system have long passed the stage at which they effected any appreciable erosion, and now serve only as the channels along which detrital material brought down by the head-waters is transported to the Niger. The finer portion of the material is carried in suspension, and is responsible for the covering of alluvial mud found over those parts of the river plain which are inundated during the annual rise. The coarser portion is rolled along the bottom and gives rise to the sandbanks. These are covered in flood, but for the other part of the year they are a constant feature of the river scenery. The stream, much lessened in volume, swings first to one side and then to the other of the wide river bed, with the broad sandbanks occupying the bends. (A. L.)

The sand is rather coarse, principally of clean grains of quartz and felspar, but at times with pebbles of vein quartz or occasionally of polished limonite. Typically, a spread of sand, many acres in extent and with its level surface only a few feet above the water, ends on the down-stream side in a slope which plunges into deep water at perhaps 40°. While the river is falling, the formation of these sandbanks can be well studied. The water, covering the sandbank by only a few inches, is seen to sweep grains of sand or occasional pebbles along over the level surface till they reach the end of the bank and roll down into deep water, thus helping to form the next lamina. In this way the sandbank is built up of successive laminæ inclined down stream at a steep angle to the horizontal, and wherever a bank is cut into by a change in the direction of the current the inclined lamination is beautifully displayed. The lamination is of course only a particular instance of the “current bedding” produced whenever detritus in process of deposition is subjected to currents of air or water, but it is important to understand that the oblique lamination of the sandbanks is brought about by the river currents, and not by the wind as has been supposed. Any slight rearrangement of the surface layers by wind is obliterated by the next rise of the river. (A. L.)

_The Niger Provinces.—Kabba, Ilorin, Borgu, Kontagora, Nupe._

The orographical structure of Kabba and Ilorin is somewhat complex. The primary watershed of the Niger basin which runs from Kabba to Aiedi and thence westward a few miles south of the Ilorin frontier, is not defined by any range of hills or mountains, but by the crest line of a lofty plain which, like a low, extended arch, slopes gently northward towards the Niger and southward towards the sea. In central Kabba the high plain assumes, to some extent, the character of a tableland, which is bounded to the north-east by the Lukke hills and the broken ground beyond the Mimi valley. To the east and south-east the tableland is abruptly limited by the worn escarpments of the Shokko Shokko, Agwede and Egbira hills, at whose base, 500 feet below, are spread out the broad, well- watered and well-wooded plains which stretch away eastward to the Niger, and of which passing glimpses are caught from the river below Itobe. To the south these undulating plains slope gently upward and inward from the Niger and lose themselves in the narrow valleys of the Kukuruku Hills.

Although such in brief is the orographical character of the major portion of Kabba and Ilorin, the actual conditions of the surface and the peculiar character of the scenery to some extent obscure the issue. In central Kabba the undulating surface of the tableland is in places densely wooded, in places covered with thin bush, in places open, grassy, and park-like with cultivation near the towns and villages, while above the plain at frequent intervals rise isolated rounded hills or groups of hills, or even short rocky ranges, which form secondary watersheds between the minor streams. Similarly, on the lower plains adjoining the Niger, the attention is arrested by the dome-shaped island mountains and picturesque clusters of rounded hills which rise abruptly into view. The full significance of this peculiar type of scenery can only be grasped when gazing from the summit of one of the isolated hills themselves, or from some favourable spot on the crest of the escarpment which separates the higher from the lower plains. Then all the minor irregularities disappear, and the level, wooded surface of the plain can be seen stretching up to and around and between the bases of the hills which rise like rocky islands from a verdant sea. The hills may be covered to the summit with angular _débris_ and scanty forest, or the lower slopes may be littered with exfoliation fragments, amongst which a few trees find a precarious footing, while the summit may be smooth and bare, with a few large boulders perched picturesquely in apparently impossible positions. The contours of the bare and treeless summits are frequently particularly graceful with beautiful domes and cupolas rising from gently-rounded slopes of granite or gneiss. In many cases a precipitous path leads to the village which caps the summit, while for long acres round the base the plain is cleared and cultivated. (Plate XVII.)[8]

The northern part of Kabba is more rugged, the population is more scanty and forest more abundant. The rocky valley of the Mimi is bounded to the north by the broken, hilly ground between Jakura and Akpara, which passes to the east and north under the flat-topped sandstone hills which fringe the Niger. The Jakpara Hills with their conical peaks upon rounded bases are landmarks for miles around. The white quartzite hills in the neighbourhood of Lukke alternate with belts of soft schists which support a luxuriant forest growth. Farther west by Moppa, Sanlu and Takete detached groups of granite hills rise upon an undulating plain. The thicker vegetation, however, obstructs the view, and it is only when the landscape is surveyed from the summit of one of the higher hills that the structure is seen to be very similar to that of southern Kabba. To the west, Ogga and Eri are set within a cluster of rocky hills, while to the north there is a comparatively rapid fall to the plains of the Kampi. Between the Kampi and the Niger a steep-sided range of sandstone hills capped by the pinnacle peaks of Egbom (p. 7) runs out westward in a succession of rounded ridges two hundred feet above the level of the river, and not until near Share is the river belt of sandstones again bounded by a low escarpment. The Shappa and Orissa Hills form the only prominent range in central Ilorin. The Shappa Hills are of granite, and many of the peaks are gracefully rounded and most picturesque, while the quartzites and gneisses of the Orissa hills give more rugged and irregular contours. West of the Orissa hills lies the great plain of Ilorin, thickly populated and well cultivated, in broad undulations trending generally north and south, with scattered inselberge and many kopjes of granite boulders, but with no conspicuous ranges or groups of hills. The Jebba hills, which extend southward for some distance towards Ilorin, pass westward into an extensive tract of hilly country, high lying, little known and largely uninhabited, which forms a natural boundary between Ilorin and Borgu.

The primary watershed of the Niger basin follows the frontier of the Protectorate more or less closely from the eighth parallel to the south of Ilorin as far as Okuta in the west of Borgu, whence it runs northward to the latitude of Nikki before turning off westward into Dahomey. With the watershed the high plains, along whose crest it runs, also swing round to the west of Borgu and fall off gently towards the Niger on the right, while along the river itself from Bussa to Jebba a narrow belt of broken country marks the transition from the high plains of Borgu to the gorge-like valley of the Niger.

Southern Borgu is one of the least inviting districts in the Protectorate. The rocks are concealed almost everywhere by recent alluvium or by surface ironstone,[9] which in places forms extensive platforms entirely bare of vegetation. Where rocks do emerge from the superficial accumulations they seldom form hills. The granite hills around Kiama are an exception to this rule, and along the western frontier a number of granite domes rise from two to three hundred feet high. These domes, however, are separated by wide stretches of country over which all geological processes seem to have come to a standstill. The drainage system is very poorly defined, and for the most part the water is carried off, not by stream courses with sand and boulders, but along shallow, soil-covered depressions in the plain. Such streams as there are dry up soon after the end of the rains, and the natives then resort largely to wells dug in the surface soil. The crests of the gentle undulations follow one another on the sky-line in endless succession, and the journey becomes monotonous in the extreme. The northern part of the province is diversified by a number of sandstone hills, and some swift, clear streams, fed from springs at the base of the hills, afford a welcome change to the jaded traveller. (A. L.)

In the provinces which lie to the east of the Niger the intimate relation which exists between the character of the scenery and the nature of the rocks becomes increasingly evident. In Kabba, Ilorin, and Borgu, where crystalline rocks of a granitic or gneissic character cover by far the larger part of the surface, the prevailing and most characteristic type of scenery is that of rolling sandy plains with isolated hills or groups of hills rising abruptly above the general level. On the other hand, where sedimentary rocks, such as sandstones and ironstones, cover the surface, as in the river belt of sandstones in Kabba and Ilorin, the characteristic type of scenery is that of steep- sided and flat-topped ranges and plateaux, with detached tabular and conical hills rising from the lower plains. Over the greater part of Kontagora province, to the north of the parallel of Kontagora itself, granites and gneisses form the surface rock. In the west, near N’gashki, a group of granite hills rises abruptly from the plain which stretches away to the east, with its surface diversified in typical fashion by occasional inselberge. A belt of slaty rocks much pierced by quartz veins runs along the left bank of the Niger from N’gashki to Yelwa, and gives rise to a stretch of broken country adjoining the river. The granites and quartzites in the lower valley of the Malenda river also give rise to much rough and stony country, which culminates in the quartzite hills of Maibirro. Beyond Jindani and Yelwa the plain reappears in a more typical character, and stretches northward as a gently undulating surface covered with deep, sandy drift, from which emerge at long intervals low, rounded, or rocky hummocks of granite or gneiss.

PLATE II

The country around Kotonkoro and to the south-west is extremely picturesque. Numerous domes of bare rock rise from a grassy park-like country. The plain around one of these domes passes imperceptibly into a gentle slope of sandy wash, which leads the eye up to the spring of the dome. As the path winds along, first one and then another of these domes engages the attention. On approaching Mahorro two of the highest hills have flattened summits and are found to be capped by about twenty feet of stratified ironstone. To the north-east of Kontagora these outliers are more numerous, though seldom of a sufficient size to mark on the map. The country is in consequence very rough and broken and the track becomes difficult and stony. The poor agricultural prospects, however, are compensated for by good iron ore, and the crude native furnaces soon come to be a familiar sight. When these outliers are finally left behind at Libo, a belt of very rough broken country has to be crossed before descending to the Kara river. (A. L.)

The town of Kontagora is set in an open undulating sandy plain, deeply covered with surface drift, which stretches eastward to Moriga and the Kara river, with its surface diversified by a few isolated sandstone hills near Kontagora and a group of granite hills at Beri. To the south of Kontagora begins the sedimentary series which stretches southward into Nupe province and westward to within a few miles of the Niger. The change in the nature of the surface rock is accompanied by corresponding changes in the character of the scenery. Here at first are the same rolling sandy plains, if possible more deeply covered with drift than before; but here are no turtlebacks or lofty domes of granite forming conspicuous features in the landscape, no rivers flowing over smooth surfaces of rock in valleys so shallow that they are almost indistinguishable from the plain. In place of these are low, flat-topped sandstone hills rising singly or in groups above the general level, and deep and narrow canyon-like valleys cut down, it may be, fifty or a hundred feet below the surface of the plain. A typical group of hills with their level summits of hard ferruginous grit and their slopes covered with rounded boulders of the same occurs at Madara, a few miles south of Kontagora, while at Kagara, Kaboji, and Sonko the streams run in typical canyon valleys, whose presence is unsuspected upon the plain until the chasm opens abruptly at one’s feet. The larger rivers flow in broad, trench-like valleys, with their steep and wooded slopes covered with rounded pebbles and boulders of ironstone and grit. To the west the plains pass into the belt of hilly ground which leads to the Niger valley, and which in its eastern portion shows the characteristic tabular outlines of the sedimentary series, and in the west, adjoining the river, the rugged irregular contours of broken crystalline hills.

The province of Nupe is somewhat unequally divided into two parts by the Kaduna river. With the exception of the quartzite and granite hills of Jebba and Kailema and the crystalline rocks of the eastern corner of the province between Badegi and the Gurara river, the entire surface is covered by sandstones, which are continuous with the sedimentary series of southern Kontagora. West of the Kaduna, however, the high plains become much dissected and broken up into extended tabular ridges and irregular plateau-like masses, with the tracks leading over a succession of low, well-wooded hills and shallow, flat-bottomed valleys bounded by rough and stony slopes. On either side of the Kaduna rise isolated tabular hills and short ranges separated by long stretches of open plain, while to the east of Bida there open out the great rolling sandy plains of Nupe, which extend from the Bako river to Badegi and southward to the bend of the Niger. Beyond Kacha the character of the landscape again changes: scattered hills and short ranges diversify the surface and coalesce southward into the extended flat-topped ranges and plateaux, whose wooded slopes dip steeply down to the narrow ledge of crystalline rock which fringes the Niger. In the north-eastern angle of the province beyond Badegi the sandstones give place imperceptibly to granites and gneiss. The sandy plains of Nupe are continued eastward, but their drift-covered surface presents now the characteristic features of a crystalline floor. Knobs and hummocks and low ridges of gneiss project here and there above the general level, while lofty groups of rounded granite hills, like those of Gaung, rise abruptly and picturesquely from the plain.

The sandstone plateaux which bound the Niger to the north of the Gurara river are continued southward as far as Koton Karifi, and pass eastward into Nassarawa as a dissected system of flat-topped and conical hills. To the south of the confluence of the Niger and the Benue, the scenery on the left bank of the Niger in Bassa province, as already described (p. 6) is that of a hummocky plain with groups of rounded hills in the foreground, backed and capped by lofty plateaux and conical hills. Such a type of scenery is readily explicable as that of a dissected sedimentary series resting upon an irregular crystalline floor of granite and gneiss.

_The Benue Provinces. Bassa, Nassarawa, Muri, and Yola._

With the exception of the narrow strip of crystalline rocks exposed along the Niger, the province of Bassa, so far as known, is entirely covered by the sedimentary series whose western and northern escarpments are visible respectively from the Niger and the Benue. These escarpments, however, which from a distance appear continuous, are found on nearer view to be much incised by river valleys which have been cut back for long distances into the high ground behind. A system of lofty, flat-topped and conical hills, extended ranges and plateau-like masses, separated by narrow, steep-sided valleys, has thus been dissected in the north and west out of the once continuous tableland. In the interior the relief lessens, and the surface of the tableland becomes broken up into a succession of tabular ranges and rounded ridges, separated by shallow valleys well cleared for cultivation. The hills are usually thickly wooded and the paths frequently rough and stony and covered with pebbles and broken fragments of ironstone. In the south the Akpoto country becomes in places particularly hilly and difficult, while the little known Munchi country in the east is said to open out into undulating park-like plains beyond the belt of forest which fringes the river.

For purposes of description the province of Nassarawa may be conveniently divided into three portions, the river belt of sandstones, the central crystalline plains and hills, and the northern tableland. The Gurara river forms the greater part of the western and northern boundary and drains all but the eastern portion of the elevated plains in the north. The river belt of sandstones between the Gurara and the Okwa in the west presents the characteristic and familiar scenery of a dissected sandstone tableland. Beyond the Okwa river the flat-topped hills and ranges die down into undulating sandy plains which stretch eastward as far as the Modu river, while the detached group of hills, which strikes inland from Udeni, is the last prominent tabular range on the lower Benue. Farther east, the low-lying plains stretch into the unexplored land of the Munchis, while to the north the trade route from Loko to Ibi leads over well wooded undulating plains deeply covered with sandy drift. The solid rock is frequently exposed in the beds of the larger rivers and streams which have cut their channels through the superficial accumulations; and here and there, as at Doma and Lafia, groups of low rounded sandstone hills and projecting hummocks of grit diversify the surface of the plain.

Central Nassarawa is, in the west, particularly broken and rugged. Around Gwombe and Gwagwada and as far east as Buga a mass of low rounded hills has been carved out of a series of soft micaceous schists. The rocks are much decomposed on the surface into red gritty earth which supports an abundant vegetation and in which the rivers and streams have cut deep and narrow channels. To the north these rounded hills pass into a tract of exceedingly difficult and broken country where precipitous hills of granite and gneiss, separated by narrow rocky valleys, rise to a height of two thousand feet above the sea. This mountainous tract, of which the Karshi hills are the northern prolongation, forms the secondary watershed between the river systems of the Gurara and the Okwa. Beyond the Karshi hills a lofty and rapidly undulating plain, in places rough and stony, and much diversified by inselberge (Plate IV, Fig. 1) and short ranges of granite hills, stretches north-westward towards Abuja. The Abuja Rock, a typical granite mount, streaked and channelled by the summer rains, is a far-famed local landmark and an object of superstitious veneration to the inhabitants of the surrounding country. (Plate III, Figs. 1 and 2.)

Eastward from Buga to Nassarawa extends a broken plain with hummocks of gneiss and detached groups of granite hills. At Kurudu, the Okwa river flows through a narrow picturesque gorge between two rounded granite hills, with the bare rock in the river bed honeycombed with potholes. Nassarawa itself is set in the midst of gently undulating park-like plains, well wooded and well cultivated, which extend northward as far as Keffi and are continuous southward with the sandy plains of the river belt. To the east they are limited by the rocky mass of the Anagoda hills and the broken hilly ground between Keffi and the Modu river. To the north of Keffi there opens out the great central plain of Nassarawa which extends from the neighbourhood of Abuja in the west to the Mada country in the east, and is limited northward by the worn escarpment of the northern tableland. Turtlebacks and kopjes of granite and broken hummocks of gneiss rise at intervals from the undulating surface of the plain, while the minor irregularities are obscured, as usual, by deep sandy drift. The larger rivers flow in broad sandy beds with long stretches of swampland on either hand, or, where the drift is thinner, in narrow rocky channels with belts of broken plain on either side from which the surface drift has been in large part removed.

PLATE III

Viewed from the central plain, the margin of the northern tableland is in places particularly picturesque. A well-marked, though much worn and rounded escarpment (Plate IV, Fig. 2), extends continuously from the neighbourhood of Kari in the west by way of Kukwi, Tatara, and Jaginde, to Darroro and Assab in the east, and the skyline is variously ornamented by domes, cupolas, conical peaks and perched blocks, with here and there, as beyond Darroro, a jagged wall of granite rising perpendicularly from the plain. The escarpment is steeper in the east than in the west, and beyond Kari it is lost in the broken hilly ground around Abuja, which falls in a succession of rocky steps to the plains of the Gurara. The tableland itself slopes gently towards the Gurara, and in the west, in the picturesque Gwari country, the numerous domes and turtlebacks of granite afford ideal sites for pagan villages. Parallel with the escarpment runs a narrow belt of broken country which represents the worn edge of the tableland, while to the north the undulating park-like plains, diversified by inselberge and groups of rounded hills, wrapped closely round with sandy drift, recall in every detail of scenery the central plain of Nassarawa below. A belt of broken rising ground, stretching northward from Jaginde, separates the Gurara system from the Kogin Kogom which drains the grassy plains of Morrua and issues behind Jaginde from a narrow rocky valley cut backward for a considerable distance into the plateau. The flat-topped granite massif of the Kagoro hills, whose precipitous wall forms the continuation of the escarpment from Darroro to Assab, projects also on the north above the plateau and overlooks the lofty undulating plains of Morrua and Akul which stretch away northward towards the Kaduna. Far away to the south of Darroro, the peaks of the Mada hills can be seen across a broken wooded plain: but this eastern portion of the province is as yet unknown and unexplored.

The great plain, which forms the major part of Muri province, extends from the base of the Murchison hills on the north to the frontier of the Protectorate on the south, and from the Ankwe river in the west to the Wurkum and Shebshi hills in the east. With the exception of the narrow margin of crystalline rock in the north-west which runs parallel with the Murchison hills, and the broader belt in the south between Takum and Bakundi, the plain possesses throughout a floor of sedimentary rock. The flat-topped hills, which are such a conspicuous feature of the scenery of the lower Benue and the Niger, are here, however, entirely wanting. The surface of the plain slopes gently towards the Benue from either side, and into it the tributary rivers have cut a succession of shallow swampy valleys separated by tracts of gentle rising ground, which run approximately at right angles to the Benue. The undulating plain thus produced is deeply covered with surface drift and relieved only by an occasional hummock of sandstone or grit. The thin forest, which usually covers the rising ground, gives place in the neighbourhood of the rivers to extensive stretches of open grass land, which, in the rains, become almost impassable swamps.

West of the Ankwe river the surface of the plain is more frequently broken by ridges of rock, and around Awe and on either side of the Benue to the south a number of worn volcanic cones are scattered over the plain. (Plate V, Fig. 1.) Similar volcanic hills project above the surface on the northern margin of the plain between Yelua and Wase. The Wase Rock[10] itself, a pillar of trachyte, is a landmark for miles around. (Plate V, Fig. 2.) At Namu, also, in the north-west of the province, and at Bantaji on the Donga to the south of the Benue, solitary hills of similar origin form striking features in the landscape. Turtlebacks and kopjes of granite boulders are found only on the margins of the plain where the floor is crystalline. In the north- west the narrow belt of hummocky crystalline ground, with its inselberge and groups of granite hills, is limited by the domes and pinnacles of the little known Murchison hills,[11] while in the south the undulating plains which stretch along the frontier of the Protectorate from the Katsena river to the Tarabba present all the characteristic features of a crystalline floor. In the north-east of the province, between Bashar and Jeb-jeb, the plains stretch northward up the Kudu valley but are limited to the east by the Ligri, Wurkum, and Jenoe hills, whose steep and rocky sandstone slopes become in places quite rugged and picturesque. The Kwana and Mumuye hills, which bound the plain to the south of the Benue, are largely granitic and present the usual rounded contours, while the foothills of the Shebshi range are of quartzite and gneiss and give rise to more rugged and irregular outlines.

The Mumuye and Shebshi hills are portions of an extensive tract of hilly country which stretches into German territory and which occupies the southern part of Yola province.[12] The western boundary of this tract runs almost northward, past Jalingu and Kwana, as if to approach the Benue at Lau, but instead turns sharply at right angles. Running eastward from near Kwana there is a practically continuous wall of rock, and at Bamga a steep and almost precipitous climb brings the traveller from Lau to Yola on to the rim of the plateau area. From this position he looks out over the Benue plain several hundred feet below. The river is far away to the north, while beyond that again, just discernible on a clear day, is the further wall of hills stretching continuously from the Wurkum country to the Gongola. Turning south, he sees the tumbled Shebshi hills as a faint silhouette in the distance, while in the foreground, slightly below him, stretch sandy uplands with a gentle eastward slope. The track drops down upon the uplands and then proceeds just within the rim of the plateau towards Yola. For the first day this rim is made up of a chain of rounded hills. Then a number of sandstone outliers arrests the attention. (Plate VI, Fig 1.) The sandstone is massive and breaks down along vertical faces. The fallen blocks, in assuming their position of rest, smooth off the irregularities of the granite base, and from the truncated cones thus produced, the cliff- sided outliers rise and dominate the landscape, like great fortresses. From this point the plateau descends gently to the plain of the Maio Belwa and Ma-ini rivers. (A. L.)

Opposite Lau the hilly ground to the north has similar outlines to those of the crystalline plateau to the south. Farther east, behind Wuduku, its appearance changes and the hills are composed of sandstone. Here the ridge seems to be a bold escarpment limiting the unknown Yam-yam country in precipitous cliffs, but with a dip slope to the south which plunges down below the marshy levels of the Benue. Further eastward again there is another change and the outlines of the hills become regular and flat. Where the plain of the Gongola enters the Benue valley, they turn at right angles and run northward parallel to the river. At the angle which separates the two plains the mass is seen from a distance to be made up of horizontal beds, with seven or eight terraces on its sides. These hills, which run up to the west of Kombo, are still, however, unentered and unexplored. (A. L.)

The plain of the lower Gongola is a repetition of the Benue plain on a somewhat smaller scale. The floor of the trench is about ten miles wide and the height of the walls perhaps a thousand feet. On travelling up the Gongola, Kwaba hill is conspicuous two or three days before it is actually reached. It is a massive hill of granite with numerous satellites, of which some are of granite while others are outliers of horizontal sandstones, bounded by vertical cliffs. The successive beds are exposed in their sides like string-courses of masonry, the Gongola outliers differing in this respect from those of southern Yola, which have been carved out of unbedded sandstones. (A. L.)

The plateau of the Vere hills has been already mentioned (p. 14). It is completely separated from the Karin mountains, Alantika mountains, and other hilly ground to the south by broad and level plains. The essential feature of the scenery is the contrast between the plain and the plateau masses. They rise up from one to two thousand feet higher than the plain, with no transitional foothills or slopes. The base is concealed by sandy wash, and at intervals streams, issuing from the plateau by narrow ravines, trench down through the compacted wash to form steep- sided nullahs. (A. L.)

Opposite to the Vere hills and across the Benue stand the Bagele hills. A little further north is the Hossere Furo. Both groups are of sandstone, rising up from the smooth grassy plain. The rise, however, is not immediate, as it is in the Vere hills, but through basal slopes and foothills toward the higher summits. North-eastern Yola consists of a high-level plain, elevated considerably above the plain of the Benue, but passing into it more gradually than do the plateaux to the south. There is, however, one step of about 200 feet running eastward from Song to the frontier, while the belt of country twenty miles broad to the north of it forms rather a curious contrast to the remainder of north- eastern Yola. Possibly there has been a slight local uplift. Granite is seen over almost the whole surface breaking down into coarse sand and giving rise to a hummocky country difficult to travel. The variations in level are only small, and taken as a whole it is still a plain, but the breaking down of the granite is going on actively over the whole surface. Parallel to this country and almost in alignment with it, is an interesting string of craters and flows of basalt. (Plate VI, Fig. 2, VII, Figs. 1, 2.) The eastern extremity of this line appears to be at Song, but westward it extends across the Mboi hills into the Yungeru country, to what distance is not yet known. The remainder of north- eastern Yola, with its rocky islets set in extensive thinly wooded plains, is similar in character to that of so many other parts of the Protectorate. Some of the inselberge, especially in the Kilba hills (Plate VIII, Fig. 1.), afford excellent examples of exfoliation. (A. L.)

_The Central Provinces.—Zaria and Bauchi._