Chapter XIV: Appendix: II

THE PALÆONTOLOGY OF THE UPPER CRETACEOUS DEPOSITS OF NORTHERN NIGERIA

By HENRY WOODS, M.A., _University Lecturer in Palæozoology, Cambridge_

The fossils collected by Dr. J. D. Falconer and Mr. A. Longbottom from the Upper Cretaceous deposits of Northern Nigeria include Fishes, Ammonites, Gasteropods, and Lamellibranchs. The localities from which these fossils were obtained are: Awe, Deba Habe, Jibaru, Gongila,[196] Gulani, Kumberi, Kunini, and Reme. At present the number of species which can be identified is comparatively small, but the collection is sufficient to show that under more favourable conditions a large and important fauna could probably be obtained from the deposits of this region.

Teeth, vertebræ, &c., of fishes were collected at Kumberi and Jibaru, and have been examined by Dr. A. S. Woodward who identifies them as _Gigantichthys_, a genus which is known from the Chalk of Egypt and the Sahara.[197] Ammonites have been found at Gongila, Reme, Kunini, and Kumberi, and they show that the deposits are of Turonian age—probably Lower Turonian. The Ammonites belong to the genera _Vascoceras_, _Mammites_ (_Pseudaspidoceras_), and _Hoplitoides_. _Vascoceras_ is confined to the Turonian. _Pseudaspidoceras_ is mainly of Turonian age. The species of _Hoplitoides_ belongs to the section of that genus which occurs in Turonian deposits. The species of _Vascoceras_ and _Mammites_ (_Pseudaspidoceras_) found in Nigeria are closely allied to forms which occur in the Lower Turonian of Northern Africa and the Iberian peninsula.

The larger number of the Gasteropods and Lamellibranchs were found at Awe, but no Ammonites were obtained at that locality; these fossils, so far as they can be identified, do not give any definite evidence that the deposit at Awe is of earlier age than the Turonian.

At Deba Habe _Ostrea (Exogyra) olisiponensis_, Sharpe, is abundant and is the only fossil obtained at that place. In Portugal that species occurs in both Turonian and Cenomanian deposits. In Nigeria it has also been found at Gongila, where the Turonian _Hoplitoides_ occurs. So that it is probable that the deposit at Deba Habe is of the same age as the one at Gongila.

At Gulani _Ostrea prælonga_, Sharpe, is abundant, but no other fossil was found at that locality. In Portugal _O. prælonga_ occurs in the Bellasian—an horizon which is believed to come between the Aptian and the Cenomanian. The same species is found at a similar level in Tunis and Algeria. The occurrence of this one species can, I think, hardly be taken as sufficient evidence that the deposit at Gulani is of Bellasian age, since it is not unlikely that, as is the case with _O. (Exogyra) olisiponensis_, this form may recur at later horizons when a favourable facies of deposit again appears.

At present, then, we can state that the deposits in which Ammonites occur are of Turonian age, and that there is not sufficient evidence to show that beds of earlier age are represented.

The fauna of the Turonian deposits of Northern Nigeria resembles closely that found in beds of similar age in Portugal, Tunis, and Algeria. This is shown especially by the Ammonites and oysters. At present the genus _Vascoceras_ is known only from Portugal, Spain, Algeria, Tunis, Egypt, Nigeria and Brazil. _Hoplitoides_ occurs in Algeria, Tunis, Nigeria, the Kameruns, and probably in Egypt. The species of _Pseudaspidoceras_ found in Nigeria is allied to forms found in Portugal, Tunis and Brazil. The oysters likewise belong to species characteristic of Northern Africa and South-western Europe, and one of them has also been found as far south as Angola. The Ammonites also show, as Pervinquière has already pointed out is the case in Tunis, that the fauna is related to that found in the Upper Cretaceous of Brazil.

Amongst other places in West Africa, Cretaceous deposits have been found in the Kameruns, and are regarded by Solger as of Upper Turonian and Lower Senonian age, but by Harbort[198] they are referred to the Emscherian (Lower Senonian). They certainly appear to be of later date than the Nigerian deposits with which they are connected chiefly by the presence of _Hoplitoides_.

Until the fauna of the Nigerian Cretaceous is more completely known any further discussion of its relationship to the faunas of other areas must be postponed.

The list on the following page shows the distribution of the species found in Nigeria, and is followed by palæontological notes and descriptions of some of the species.

--------------------+----+-----+--------+-------+--------+-------+----- |Awe.|Deba |Gongila.|Gulani.|Kumberi.|Kunini.|Reme. | |Habe.| | | | | --------------------+----+-----+--------+-------+--------+-------+----- _Nuculana_, sp. | | | | | * | | | | | | | | | _Trigonoarca_, sp. | * | | | | | | | | | | | | | _Trigonia_, sp. | * | | | | | | | | | | | | | _Modiola_, sp. | * | | | | | | | | | | | | | _Pecten (Neithea) | * | | | | | | quinquecostatus_, | | | | | | | Sow. | | | | | | | | | | | | | | _Lima (Mantellum)_, | * | | | | | | sp. | | | | | | | | | | | | | | _Ostrea prælonga_, | | | | * | | | Sharpe | | | | | | | | | | | | | | „ _(Exogyra) | | * | * | | | | olisiponensis_, | | | | | | | Sharpe | | | | | | | | | | | | | | _Gervillia | * | | | | | | (Pseudoptera)_, sp. | | | | | | | | | | | | | | _Astarte awensis_, | * | | | | | | sp. nov. | | | | | | | | | | | | | | _Lucina_, sp. | | | | | * | | | | | | | | | _Cardium_, sp. | * | | | | | | | | | | | | | _Corbula_, sp. | * | | | | | | | | | | | | | _Pseudomelania_, sp.| * | | | | | | | | | | | | | _Turritella_, sp. | | | | | * | | | | | | | | | _Semifusus | * | | | | | | africanus_, sp. nov.| | | | | | | | | | | | | | _Vascoceras | | | | | | * | * nigeriensis_, sp. | | | | | | | nov. | | | | | | | | | | | | | | „ | | | * | | | | _gongilensis_, sp. | | | | | | | nov. | | | | | | | | | | | | | | _Mammites | | | * | | | | (Pseudaspidoceras)_,| | | | | | | sp. | | | | | | | | | | | | | | _Hoplitoides | | | * | | | | nigeriensis_, sp. | | | | | | | nov. | | | | | | | | | | | | | | „ sp. | | | | | | | * | | | | | | | _Gigantichthys_, sp.| | | | | * | | --------------------+----+-----+--------+-------+--------+-------+-----

LAMELLIBRANCHIA.

NUCULANA, sp.

Plate XIX., Fig. 4.

An internal cast resembles in form _N. Mariæ_ (d’Orbigny), but in the absence of the shell the species cannot be identified.

_Locality._—Kumberi.

TRIGONOARCA, sp.

Plate XIX., Figs. 1–3.

Several specimens of _Trigonoarca_ were found, but are not sufficiently well-preserved for specific identification. In general form they resemble some examples of _T. trichinopolitensis_ (Forbes)[199] from the Trichinopoli Beds of Southern India.

_Locality._—Awe.

TRIGONIA, sp.

Two specimens of a species belonging to the Scabræ section of _Trigonia_ are in the collection, but are not sufficiently well-preserved for identification.

_Locality._—Awe.

MODIOLA, sp.

Examples of a small form of _Modiola_ occur at Awe.

PECTEN (NEITHEA) QUINQUECOSTATUS, Sowerby.

Three specimens with the shell preserved were found at Awe.

LIMA (MANTELLUM), sp.

An imperfect specimen from Awe resembles _Lima (Mantellum) gaultina_, Woods.[200]

OSTREA PRÆLONGA, Sharpe.

Plate XIX., Figs. 5–8.

1850. _Ostræa prælonga_, D. Sharpe, _Quart. Journ. Geol. Soc._, VI., p. 187, Pl. XX., Fig. 4.

1869. _Ostrea prælonga_, H. Coquand, _Mon. Ostrea. Terr. Crét._, p. 169, Pl. LXVI., Figs. 1, 2.

1890. _Ostrea prælonga_, A. Peron, _Moll. Foss. Terr. Crét. Tunisie_, p. 110, Pl. XXIII., Figs. 1–6.

_Remarks._—About twenty more or less perfect specimens of an _Ostrea_, agreeing closely with _O. prælonga_, Sharpe, were found. _O. pentagruelis_, Coquand,[201] is considered by Peron to be only a very old individual of _O. prælonga_.

This species occurs in the Bellasian of Portugal. In Algeria and Tunis it is characteristic of beds which occur below the Cenomanian, and are referred by Peron to the Upper Albian.

_Locality._—Gulani.

OSTREA (EXOGYRA) OLISIPONENSIS, Sharpe.

Plate XX., Figs. 1–3.

1850. _Exogyra olisiponensis_, D. Sharpe, _Quart. Journ. Geol. Soc._, VI., p. 185, Pl. XIX., Figs. 1, 2.

1862. _Ostrea Overwegi_, H. Coquand, _Géol. pal. rég. sud. prov. Constantine_, p. 226, Pl. XIX., Figs. 1–6.

1862. _Ostrea Coquandi_, Julien, in Coquand, _ibid._, p. 324, Pl. XXXIII., Figs. 10–12.

1869. _Ostrea olisiponensis_, H. Coquand, _Mon. Ostrea. Terr. Crét._, p. 125, Pl. XLV., Figs. 1–7.

1869. _Ostrea Overwegi_, Coquand, _ibid._, p. 140, Pl. XLIV., Figs. 1–9; Pl. XLVI., Figs. 14, 15.

1873. _Ostrea olisiponensis_, L. Lartet, _Ann. Sci. géol._, Vol. III., p. 59, Pl. XI., Fig. 1.

1882. _Exogyra olisiponensis_, G. Seguenza, _Atti d. R. Accad. dei Lincei_, Ser. 3; _Mem. Scien. Fis. Math._, Vol. XII., p. 180, Pl. XVII., Fig. 2.

1882. _Exogyra oxyntas_, Seguenza, _ibid._, p. 178, Pl. XVIII., Fig. 1.

1888. _Ostrea olisiponensis_, P. Choffat, _Mém. Soc. Phys. et d’hist. nat. de Genève_, XXX., 2, p. 95.

1891. _Ostrea olisiponensis_, A. Peron, _Moll. Foss. Terr. Crét. Tunisie_, p. 114, Pl. XXIII., Figs. 14–18.

1902. _Ostrea (Exogyra) olisiponensis_, P. Choffat, _Faune Crét. Portugal_, Vol. I., Ser. 4, p. 166, Pl. VI., Figs. 17–19.

1903. _Ostrea olisiponensis_, R. Fortau, _Bull. Instit. Égypt._, Ser. 4, Vol. IV., p. 283, Figs. 3–5.

1905. _Ostrea (Exogyra) olisiponensis_, P. Choffat, _Géol. Col. Portug. d’Afrique. II, Nouvelles données sur la zone littorale d’Angola_, p. 44, Pl. I., Figs. 4, 5.

_Remarks._—This species is represented by numerous examples, in a few of which the surfaces of the shell are well-preserved and show a few coarse ribs. Sharpe and other writers have noted the great variability in the ribbing of this species. The Nigerian specimens agree with the varieties which possess only a few ribs. Peron, Choffat, and Fortau have discussed fully the affinities and synonymy of _O. (Exogyra) olisiponensis_. This species is common in Northern Africa and Portugal; it occurs in the Cenomanian of Algeria, Tunis, Egypt, and Palestine; in Portugal it is found in both the Upper and Lower Turonian, as well as in the Cenomanian, wherever the deposits are of the marly facies. South of Nigeria this species has been discovered in the province of Angola.

_Localities._—Deba Habe and Gongila.

GERVILLIA (PSEUDOPTERA), sp.

Plate XX., Figs. 4–6.

There are several internal casts resembling in form _G. (Pseudoptera) anomala_ (Sowerby),[202] but there is no evidence to show whether radial ribs were present on the shell or not, and the species cannot be determined at present.

Specimens from the Cenomanian of the neighbourhood of Tebessa (Algeria) have been identified with Sowerby’s species by Coquand,[203] and Peron[204] states that it is abundant and well-preserved at that locality.

_Locality._—Awe.

ASTARTE AWENSIS, sp. nov.

Plate XX., Fig. 7.

_Description._—Shell rather small, moderately convex, with the postero- dorsal part somewhat compressed, outline subquadrate or subtriangular, very inequilateral. Anterior margin slightly concave; ventral margin convex; posterior margin short, truncated, forming an obtuse angle with the long, slightly convex postero-dorsal margin. Umbones pointed, rather prominent. Lunule large, ovate, smooth, with a sharp edge. Escutcheon large, deep, with a sharp edge. Ornamentation consists of about fourteen broad, prominent concentric ribs, which are marked by fine concentric lines. Length, 8·25; height, 7 mm.

_Affinities._—In the character of its ornamentation _A. awensis_ resembles several small species of _Astarte_ found in the Cretaceous rocks. It is more inequilateral, more elongate, and has the posterior margin more distinctly truncated than in _A. subsimilis_, J. Böhm.[205] In similar respects it differs from _A. griesbachi_, Woods,[206] from Pondoland.

_Remarks._—Numerous casts of this species occur in ferruginous nodules.

_Locality._—Awe.

LUCINA, sp.

Plate XX., Figs. 8, 9.

_Description._—Shell nearly orbicular, convex, slightly inequivalve; height and length nearly equal. Anterior and ventral margins rounded; posterior margin truncated, forming an obtuse angle with the straight or slightly convex postero-dorsal margin. Umbones rather prominent. Ornamentation consists of regular, concentric lamellar ribs separated by broad, flat interspaces which are marked by fine, concentric lines. Length, 11 mm.; height, 11·5 mm.

_Affinities._—In general form, and in the character of its ornamentation, this species resembles one of the varieties of _Lucina fallax_, Forbes, described by Stoliczka[207] from the Utatúr Group, but the umbones are more prominent, and the postero-dorsal angle is more distinct. It also resembles _L. saharica_, Quaas,[208] and some forms of _L. subnummismalis_, d’Orbigny.[209]

_Locality._—Kumberi.

CARDIUM, sp.

Plate XX., Fig. 10.

In the possession of numerous radial ribs and in the general form of the shell, some internal casts resemble _Cardium cenomanense_, d’Orbigny,[210] but the valves are less convex.

_Locality._—Awe.

CORBULA, sp.

Specimens of _Corbula_ resemble _C. elegans_, Sowerby,[211] in the character of their ornamentation, but the posterior part of the shell is more produced.

_Locality._—Awe.

GASTEROPODA.

PSEUDOMELANIA, sp.

Plate XXI., Fig. 1.

Several specimens of a small gasteropod resemble _Pseudomelania Pallaryi_, Peron and Fortau,[212] from the Cenomanian of Egypt, but they are of much smaller size, being from 8 to 13 mm. long. The surface of the shell is smooth, except for slightly curved growth-lines, and, on the base, spiral grooves.

_Locality._—Awe.

TURRITELLA, sp.

Plate XXI., Fig. 2.

A species of _Turritella_ resembles _T. Choffati_, Thomas and Peron,[213] from the Turonian of Tunis. The anterior part of each whorl is bent at an angle with the large flattened posterior part, and the ornamentation consists of four strong spiral ribs, one of which occurs at the angle, giving the appearance of a carina. On the later whorls the ribs become granular or tubercular. The ribs are much coarser than in _T. Choffati_.

_Locality._—Kumberi.

SEMIFUSUS AFRICANUS, sp. nov.

Plate XXI., Figs. 3–5.

_Description._—Shell subfusiform. Spire shorter than the last whorl, consisting of about five whorls. Whorls carinate, the carina being more or less distinctly nodular. Posterior part of the whorls flattened, much larger than the anterior part in the spire. Anterior part of last whorl convex. Ornamentation consists of narrow spiral ribs with flat interspaces crossed by growth-lines; on the later whorls the ribs become divided up into rows of elongated tubercles.

_Remarks._—This species, which is represented by several imperfect specimens, shows some resemblance to _Lagena nodulosa_, Stoliczka,[214] and _L. secans_, Stoliczka,[215] from the Ariyalúr Group, and also to _Serrifusus dakotensis_ var. _vancouverensis_, Whiteaves,[216] but possesses one carina only.

_Locality._—Awe.

CEPHALOPODA.

_Genus_—VASCOCERAS, P. Choffat.

(_Faune Crét. Portugal_, I., 1898, p. 51.)

VASCOCERAS NIGERIENSIS, sp. nov.

Plate XXI., Fig. 6; Plate XXII., Figs. 2, 3.

_Description._—Shell inflated, rounded, subglobose. Whorls thick, largely embracing; umbilicus deep, rather more than a third of the diameter of the shell, with nearly vertical walls, the umbilical margin subcarinate, without tubercles. Flanks curving gradually from the umbilical margin and not limited from the rounded periphery. Surface of shell with growth-rings.

Sutures: Saddles large, broad, and low; external saddle unsymmetrically divided and with small minor divisions; first lateral smaller than the external saddle, more rounded, less divided, with the outer margin sloping and the inner margin nearly perpendicular; second lateral saddle broad, only slightly divided. External lobe deeper than the first lateral lobe; the latter is small with one main division; second lateral lobe smaller, with two points.

(1) (2)

Diameter 88 93 mm.

Thickness 58 54

Height of last whorl 37 34

Width of umbilicus 30 33

(1) Reme. (2) Kunini.

_Affinities._—This species resembles the thicker forms of _V. durandi_ (Peron and Thomas),[217] but the walls of the umbilicus are steeper, the umbilical margin is without tubercles, and the external and first lateral saddles are broader and not so high. In general form, and in the absence of tubercles at the umbilical margin, _V. nigeriensis_ resembles _V. amierensis_, Choffat,[218] but the whorls embrace to a larger extent, and their sides are less flattened; there are also some differences in the suture. In the form of the umbilicus, and in the breadth of the saddles, this species resembles _V. harttiformis_, Choffat,[219] but the shell is much less thick. Another similar form but with a thicker shell, is _V. hartti_, Hyatt,[220] from Brazil.

_Localities._—Reme and Kunini.

VASCOCERAS GONGILENSIS, sp. nov.

Plate XXI., Fig. 7; Plate XXII., Fig. 1.

_Description._—Shell moderately inflated. Umbilicus less than a quarter of the diameter of the shell, with vertical walls and subcarinate margin. Flanks somewhat compressed. Periphery flattened. Inner whorls with strong ribs on the flanks and prominent tubercles at the umbilical margin and at the limit of the flanks and periphery; on the last whorl the ribs and tubercles gradually become obsolete.

Sutures: External saddle broad, subquadrate, with small divisions; first lateral saddle broad, rounded, divided unsymmetrically by a small lobe; second lateral saddle subquadrate; one small auxiliary saddle on the flanks. External lobe deep and larger than the first lateral lobe, which has only small divisions; second lateral lobe small, its lower margin with pointed divisions.

Diameter 108 mm.

Thickness 57 „

Height of last whorl 52 „

Width of umbilicus 24 „

_Affinities._—This species resembles _V. subconciliatum_, Choffat,[221] from the Turonian of Portugal, but the ribs and tubercles become obsolete at an earlier stage, the umbilicus is smaller, the divisions in the external saddle are less deep, the first and second lateral saddles are more rounded, and the first lateral lobe is narrower. _V. gongilensis_ also resembles some forms of _V. cauvini_, Chudeau.[222]

_Locality._—Gongila.

_Genus_—MAMMITES, Laube and Bruder.

(_Palæontographica_, XXXIII., 1887, p. 229.)

_Sub-genus_—PSEUDASPIDOCERAS, Hyatt.

(“Pseudoceratites of the Cretaceous,” _U. S. Geol. Surv. Mon._, XLIV.,
1903, p. 106.)

MAMMITES (PSEUDASPIDOCERAS), sp.

Plate XXIII., Figs. 1, 2.

In the collection there is one specimen of _Mammites (Pseudaspidoceras)_; it resembles the form figured by Choffat[223] under the name _Acanthoceras_ (?), cf. _Footeanus_ (Stol.), from the Turonian of Portugal, but differs in having a smaller umbilicus and less distinct siphonal tubercles. The sutures are not shown in the specimen from Nigeria.

The Portuguese form differs from _A. footeanus_, Stoliczka,[224] by the absence of secondary ribs on the siphonal region of the inner whorls, and by the forward inclination of the ribs between the lateral tubercles and the siphonal tubercles.

Other allied species are _M. (Pseudaspidoceras) salmuriensis_ (Courtiller) var. _byzacenica_, Pervinquière,[225] from the Lower Turonian of Tunis, and _M. (Pseudaspidoceras) Pedroanus_ (White),[226] from Brazil.

_Locality._—Gongila.

_Genus_—HOPLITOIDES, A. von Kœnen.

(“Nachtrag Foss. Unter. Kreide Mungo in Kamerun,” _Abhandl. d. k. Gesellsch. d. Wiss. Göttingen, Math.-Phys. Kl., N.F._ Band 1, 1898, p. 53. Emended F. Solger, _Foss. Mungokreide in Kamerun_, 1904, p. 127; L. Pervinquière, _Études Pal. Tunis, I. Ceph._, 1907, p. 215.)

HOPLITOIDES NIGERIENSIS, sp. nov.

Plate XXIII., Fig. 3; Plate XXIV., Figs. 1–5. Text-figure 1.

_Description._—Shell discoidal, compressed, with truncated periphery. Whorls largely embracing, with the flanks slightly or moderately convex, the greatest convexity being at a short distance from the umbilical margin. Umbilicus small, or very small, about one-seventh of the diameter of the shell, its sides nearly perpendicular. Periphery usually rather broad, bounded on each side by a prominent rounded carina; the prominence of the siphuncle gives rise to a median rounded ridge between which and the carinas the shell is concave.

In fully-grown individuals the shell is smooth, but in smaller examples the flanks bear a few strong, rounded ribs, which curve slightly forwards near the periphery; the larger ribs start from the umbilical margin, and one or two smaller ribs may be intercalated on the flanks. Where the ribs join the carina the latter may become more or less distinctly tuberculate. Usually the ribs become obsolete when the shell reaches a diameter of about 50 mm., but occasionally they persist on larger individuals.

Sutures: External saddle broad, rather low, with a variable number of small divisions. First and second lateral saddles similar to, but distinctly smaller than the external saddle; each has usually some small divisions, but in some cases these are absent, and the saddle is then rounded. One or two auxiliary saddles may occur. External lobe deep, sometimes nearly as wide as the space between the two carinæ. First lateral lobe usually rather narrower and not so deep as the external lobe, with more or less numerous small divisions. The second lateral lobe is similar to, but smaller than the last.

(1) (2) (3) (4) (5) (6) (7) (8)

Diameter 110 95 84 67 68 62 57 44 mm.

Thickness 47 42 34 28 28 27 28 20 „

Height of last whorl 61 49 45 37 38 38 34 25 „

Width of umbilicus 15 15 10 10 7 6·5 8 6 „

(1–8) From Gongila.

_Affinities._—This species appears to belong to the bicarinate group of _Hoplitoides_. In general form it resembles _H. munieri_, Pervinquière,[227] from the Lower Turonian of Tunis, but the whorls, are thicker, the flattened periphery is broader and shows a distinct siphuncular ridge. The sutures are similar to those of _H. munieri_, but are symmetrically placed, and the first lateral lobe is relatively narrow. The ribbing of the smaller specimens is similar to that of _Hoplites ingens_, v. Kœnen em. Solger.[228]

In general form, _H. nigeriensis_ is similar to _Heterotissotia neoceratoides_, Peron,[229] from the Lower Senonian of Algeria and the Upper Turonian of Tunis. Both possess a broad, flattened periphery with a keel on each side and a prominent siphuncular ridge, but in _H. neoceratoides_ the ribs are retained to a later stage. The figures given of the suture of Peron’s species are not satisfactory, and I am indebted to Dr. L. Pervinquière for comparing figures of the sutures of _Hoplitoides nigeriensis_ with the type of _Heterotissotia neoceratoides_ which is now in the Sorbonne. Dr. Pervinquière states that the differences in the suture are too great to allow of these two species being referred to the same genus.

_Remarks._—The sutures of _Hoplitoides nigeriensis_ vary considerably in appearance on account of the difference in the number and size of the small divisions of the saddles. A somewhat similar variation is seen in the sutures of _H. ingens_, v. Kœnen, em. Solger, and _H. munieri_, Solger. Variations also occur in the thickness of the whorls, the breadth of the periphery, the size of the umbilicus, and the period at which the ribs become obsolete. In one specimen, which is less thick than the other, the siphuncular ridge is absent.

This species is represented by numerous specimens, all of which are internal casts or have only a small portion of the shell preserved, and in nearly all cases the sutures are clearly exposed.

_Locality._—Gongila.[230]

PLATE XIX

T. A. Brock, del.

(The figures are of natural size unless the amount of enlargement is stated).

FIGS. 1–3. _Trigonoarca_, sp. Awe. 1, right valve; 2, dorsal view of the same; 3, hinge of left valve. (Page 276.)

„ 4. _Nuculana_, sp. Kumberi. Internal cast of left valve. × 1½. (Page 276.)

„ 5–8. _Ostrea prælonga_, Sharpe. Gulani. 5, right valve; 6, 8, right valves with umbo of left valves; 7, left valve. (Page 277.)]

PLATE XX

T. A. Brock, del.

FIGS. 1–3. _Ostrea (Exogyra) olisiponensis_, Sharpe. Deba Habe. Left valves. (Page 277.)

„ 4–6. _Gervillia (Pseudoptera)_, sp. Awe. Internal casts. 4, 5, left valves; 6, right valve. (Page 278).

„ 7. _Astarte awensis_, sp. nov. Awe. Right valve, drawn from a wax impression of an external cast, × 1½. (Page 279.)

„ 8, 9. _Lucina_, sp. Kumberi. 8, right valve; 9, dorsal view of the same, × 1½. (Page 279.)

„ 10. _Cardium_, sp. Awe. Internal cast of right valve. The marginal part of the valve is imperfect. (Page 280.)]

PLATE XXI

T. A. Brock, del.

FIGS. 1. _Pseudomelania_, sp. Awe. × 1½. (Page 280.)

„ 2. _Turritella_, sp. Kumberi. × 1½. (Page 281.)

„ 3–5. _Semifusus africanus_, sp. nov. Awe. 3, drawn from a wax impression of an external cast; 4, portion of the ornamentation of 5, × 6. (Page 281.)

„ 6. _Vascoceras nigeriensis_, sp. nov. Reme. (Page 281.)

„ 7. _Vascoceras gongilensis_, sp. nov. Gongila. Internal cast. (Page 282.)]

PLATE XXII

T. A. Brock, del.

FIGS. 1._Vascoceras gongilensis_, sp. nov. Gongila. Siphonal view of Fig. 7, Plate XXI. (Page 282).

„ 2, 3. _Vascoceras nigeriensis_, sp. nov. Kunini. Two views of the same specimen. (Page 281.)]

PLATE XXIII

T. A. Brock, del.

FIGS. 1, 2. _Mammites (Pseudaspidoceras)_, sp. Gongila. Two views of the same specimen. (Page 283.)

„ 3. _Hoplitoides nigeriensis_, sp. nov. Gongila. (Page 284.)]

PLATE XXIV

T. A. Brock, del.

FIGS. 1–5. _Hoplitoides nigeriensis_, sp. nov. Gongila. 1, siphonal view of Fig. 3, Plate XXIII; 4, siphonal view of Fig. 3. (Page 284.)]

[Footnote 196: The occurrence of Turonian fossils at this locality has been recorded by G. C. Crick, _Geogr. Journ._, Vol. XXIV., 1904, p. 522, footnote 1.]

[Footnote 197: Dames, _Sitzungsber. Ges. nat. Freunde, Berlin_, 1887, pp. 69, 137.]

[Footnote 198: Guillemain and Harbort, “Profil der Kreideschicht. am Mungo,” _Abhandl. d. k. preuss. geol. Landesanst. N.F._, Heft 62, 1909, p. 405.]

[Footnote 199: Stoliczka, _Cret. Fauna S. India_, 1871, p. 353, Pl. XVIII., Figs. 12, 14; Pl. XIX., Figs. 2, 3; Pl. XX., Figs. 2, 8, 9, 10.]

[Footnote 200: _Mon. Cret. Lamell. England_, Vol. II., 1904, p. 31, Pl. V., Figs. 16–20.]

[Footnote 201: _Mon. Aptien de l’Espagne_, 1865, p. 166, Pl. XXVI., Figs. 1, 2.]

[Footnote 202: For figures see Woods, _Mon. Cret. Lamell. England_, Vol. II., 1905, p. 64, Pl. IX., Figs. 2–4. Compare also d’Orbigny, _Pal. Franç. Terr. Crét._, Vol. III., 1846, p. 478, Pl. CCCXCII., Figs. 1–3. When describing this species I overlooked Guéranger’s statement that he had seen specimens showing ligament pits; from the presence of those pits it is evident that this species cannot belong to _Pteria_. It seems probable that _Pseudoptera_ should be regarded as a sub-genus of _Gervillia_. Guéranger, _Album Paléont. de la Sarthe_, 1867, pp. 17, 20, Pl. XXII., Figs. 9, 10; Pl. XXV., Figs. 10, 11.]

[Footnote 203: _Géol. et Pal. de Constantine_, 1862, p. 292.]

[Footnote 204: Peron, _Moll. Foss. Terr. Crét. Tunisie_, 1890, p. 238.]

[Footnote 205: “Kreidebild. des Fürbergs u. Sulzbergs,” _Palæontographica_, XXXVIII., 1891, p. 74, Pl. III., Fig. 8.]

[Footnote 206: _Ann. S. African Mus._, IV., 1906, p. 300, Pl. XXXV., Figs. 18, 19.]

[Footnote 207: _Palæont. Indica, Cret. Fauna S. India_, III., 1871, p. 256, Pl. XIV., Fig. 7.]

[Footnote 208: _Palæontographica_, XXX., 2, 1902, p. 214, Pl. XXIV., Fig. 7.]

[Footnote 209: _Ravn, Mollusk. Danmarks Kridtafl. I. Lamellibr._, 1902, p. 129, Pl. IV., Fig. 21.]

[Footnote 210: _Pal. Franç. Terr. Crét._, III., 1844, p. 37, Pl. CCXLIX, Figs. 5–9.]

[Footnote 211: Woods, _Mon. Cret. Lamell. England_, Vol. II., 1908, p. 216, Pl. XXXIV., Figs. 23–28.]

[Footnote 212: _Bull. Institut Égypt._, Ser. 4, Vol. VI., 1903, p. 270, Pl. I., Fig. 22.]

[Footnote 213: _Moll. Foss. Crét. Tunisie_, 1889, p. 47, Pl. XIX., Figs. 13, 14.]

[Footnote 214: _Cret. Fauna S. India_, Vol. II., 1867, p. 137, Pl. XI., Fig. 18.]

[Footnote 215: _Ibid._, p. 138, Pl. XI., Figs. 19, 20.]

[Footnote 216: _Mesozoic Fossils_, Vol. I., 1879, p. 119, Pl. XV., Fig. 5. Compare also Woods, _Ann. S. African Mus._, Vol. IV., 1906, p. 324, Pl. XL. Figs. 5, 6. Newton, _Trans. Roy. Soc. S. Africa_, Vol. I., 1909, p. 28, Pl. IX., Fig. 6.]

[Footnote 217: _Moll. Foss. Crét. Tunisie_, 1889, p. 27, Pl. XVIII., Figs. 5–8. Peron, _Amm. Crét. supér. Algérie_, 1896–7, p. 44, Pl. IV., Fig. 1; Pl. V., Fig. 1; Pl. XVII., Fig. 5. Pervinquière, _Paléont. Tunisienne, Ceph. secondaires_, 1907, p. 332, Pl. XXI., Fig. 1. _V. Douvillei_, Choffat, _Faune crét. Portugal_, Vol. I., 1898, p. 59, Pl. X., Fig. 6; Pl. XI., Figs. 2–5; Pl. XXI., Figs. 13–16.]

[Footnote 218: Choffat, _ibid._, p. 61, Pl. XII., Figs. 1, 2; Pl. XIII., Figs. 1, 2; Pl. XXI., Figs. 17–21.]

[Footnote 219: _Ibid._, p. 61, Pl. XII., Fig. 3; Pl. XIII., Figs. 3–6; Pl. XXI., Figs. 22–24.]

[Footnote 220: “Contrib. Paleont. Brazil,” _Archiv. Mus. Nac. Rio de Janeiro_, VII., 1887, p. 226, Pl. XIX., Figs. 1, 2; Pl. XX., Fig. 3. Hyatt, “Pseudoceratites of the Cretaceous,” _U. S. Geol. Survey, Mon._, XLIV., 1903, p. 103, Pl. XIV., Fig. 16.]

[Footnote 221: _Faune crét. Portugal_, Vol. I., 1898, p. 64, Pl. XV., Figs. 1–3; Pl. XVI., Fig. 4; Pl. XXII., Figs. 28–31.]

[Footnote 222: “Ammonites du Damergou (Sahara meridional),” _Bull. Soc. géol. de France_ (4), IX., 1909, p. 68, Pls. I., II., III.]

[Footnote 223: _Faune crét. Portugal_, Vol. I., 1898, p. 66, Pl. XVI., Figs. 9, 10; Pl. XXII., Figs. 3, 4.]

[Footnote 224: _Palæont. Indica, Ceph. Cret. S. India_, 1864, p. 101, Pl. LII., Figs. 1, 2. Kossmat, “Südindische Kreideformat,” _Beitr. Pal. Geol. Osterr-ungarns u. d. Orients_, XI., 1897, p. 20. Petrascheck, “Amm. sächsich. Kreideformat., _ibid._, XIV., 1902, p. 144. Pl. IX., Fig. 1.]

[Footnote 225: _Études Paléont. Tunisienne, I. Ceph. Second._, 1907, p. 315, Pl. XIX., Fig. 1.]

[Footnote 226: “Contrib. Paleont. Brazil,” _Archiv. Mus. Nac. Rio de Janeiro_, VII., 1887, p. 212, Pl. XXII., Figs. 1, 2.]

[Footnote 227: _Études Pal. Tunis, I, Ceph._, 1907, p. 217, Fig. 83, Pl. X., Figs. 1, 2.]

[Footnote 228: Solger, _Foss. Mungokreide in Kamerun_, 1904, p. 137, Pl. V., Figs. 8, 9.]

[Footnote 229: _Amm. Crét. supér. de l’Algérie_, 1897, p. 82, Pl. XVI., Figs. 9, 10; Pl. XVIII., Fig. 20. Pervinquière, _Études Pal. Tunis, I., Ceph._, 1907, p. 379, Pl. XXIII., Fig. 7.]

[Footnote 230: Specimens of _Hoplitoides_ have also been found at Reme, but are not sufficiently well-preserved for specific identification. An imperfect Ammonite from Kumberi resembles in the form of its shell and in the general character of the sutures _Coilopoceras lesseli_, Brüggen, _Neues Jahrb. für Min._, etc., Beil.-Band XXX., 1910, p. 734, Plate XXIX.]

INDEX

INDEX OF AUTHORS

Alexander, Boyd, 2, 13, 31, 45, 55

Allen and Thomson, 2

Ammon, A. von, 122

Andrews and Bailey, 199

Baikie, W. B., 2, 214

Bailey, _see_ Andrews

Barratt, J., 122

Barth, H., 2, 52, 58, 89, 106, 181, 186, 193

Bather, F. A., 165

Böhm, J., 279

Bornhardt, W., 18, 245

Brüggen, 286

Campbell, J. M., 209, 211

Chamberlain and Salisbury, 196

Chautard, J., 122, 205, 207, 253, 263

Chevalier, A., 122, 233

Choffat, P., 282

Chudeau, R., 109, 120, 122, 135, 140, 141, 144, 162, 165, 169, 170,
191–5, 199, 219, 220, 233, 244, 250, 251, 258–60, 262, 263, 283; _see
also_ Gautier

Clapperton, _see_ Denham

Coquand, H., 277, 279

Corstorphine, _see_ Hatch

Courtet, H., 106, 122, 193, 216

Crick, G. C., 273

Crowther, S. A., 2

Dames, 273

Denham and Clapperton, 2, 90

D’Orbigny, 278, 280

Downes, W. D., 104, 258

Dunstan, W. R., 92, 96, 265

Du Toit, _see_ Rogers

Edlinger, W., 186, 233

Esch, E., 122, 163, 191, 226, 250, 263

Evans, J. W., 269

Falconer, J. D., 257–8, 263, 273

Flamand, G. B. M., 121

Flett, J. S., 131

Forteau, _see_ Peron

Foureau, F., 135, 206

Foureau and Gentil, 135

Freydenberg, H., 135, 206, 215, 218, 220; _see also_ Gentil

Garde, G., 135, 140, 141, 216, 219, 258

Gautier, E. F., 226, 233

Gentil, L., 121, 135, 140, 258

Gentil and Freydenberg, 106, 134, 135, 140, 258

Guéranger, 279

Guillemain and Harbort, 275

Gurich, G., 174, 236

Harker, A., 264

Harbort, _see_ Guillemain

Harrison, J. B., 246

Hatch, F. H., 206

Hatch and Corstorphine, 206

Haug, E., 121

Holland, Sir T. H., 207

Horwood and Wade, 122, 143

Hubert, H., 69, 109, 121, 135, 140, 168, 170, 191, 196, 202, 204, 207,
226, 249

Hyatt, 282

Knox, A., 122

Kossmat, 284

Lacoin, L., 206, 258

Lacroix, A., 135, 138, 263

Laird and Oldfield, 2, 6

Lander, R. and J., 2

Lapparent, A. de, 162, 165, 194, 207, 229

Lenfant, Capt., 2, 8

Lenz, O., 122, 197

Longbottom, A., 13–16, 20, 22, 33–5, 87, 96, 98, 103–6, 147–51, 153,
154–7, 184–91, 227–8, 261–2, 273

Lugard, Sir F. D., 2

Maclaren, J. M., 209

Maufe, H. B., 208, 211

Mennell, F. P., 204, 209, 211

Merrill, G. P., 246

Newton, R. B., 165, 281

Oldfield, _see_ Laird

Park, Mungo, 2

Parkinson, J., 81, 112, 119, 122, 163, 191, 226, 250

Passarge, S., 2, 122, 140, 186, 191, 198, 204, 207, 224, 233, 237,
241, 245, 247, 248, 258, 259, 263

Peron, A., 279, 282, 286

Peron and Fortau, 280

Peron and Thomas, 281, 282

Pervinquière, L., 282, 284–6

Petrascheck, 284

Prior, G. T., 264

Quaas, 280

Rogers and Du Toit, 206

Rohlfs, G., 200

Salisbury, _see_ Chamberlain

Solger, F., 285

Stoliczka, 276, 280, 281, 284

Suess, E., 140, 165, 233, 247, 248, 252

Thomas, _see_ Peron

Thomson, _see_ Allen

Vandeleur, S., 7

Van Hise, C. R., 118

Vogel, H., 2

Voit, F. W., 123

Wade, _see_ Horwood

Wallace, Sir W., 2, 268

Walther, J., 199, 207

Whiteaves, 281

Whitlock, G. F. A., 32

Woods, H., 166, 273, 277–81

Woodward, A. S., 273

GENERAL INDEX

Abuja: the Rock, 27

granites and gneisses of, 99

Alpine movements in Sudan, 251

Ansongo, flints of, 170

Arofu: Cretaceous rocks of, 148

saltings of, 149, 266

silicified limestone of, 149

galena veins of, 149

Augite-syenite, 135

Awe: brine springs of, 148, 266

Cretaceous rocks of, 146

volcanic hills of, 31, 260, 262

Axes of elevation: 234

Bagele hills: 14, 34, 186

Barbur basalt plateau, 146, 257

Baro, 4, 173

Basalts, 139

of Sahara, 140

of Tertiary age, 253

nepheline basalts, 255

plateau basalts, 51, 100, 257

Bassa: scenery of, 25–6

crystalline rocks of, 82

Bauchi plateau, 3, 38–43

summit of, 40

limits of, 41

scenery of, 42

volcanic hills of, 42

drift deposits of, 43, 203

former continuity with plains of Hausaland, 203

elevation of, 237

not a horst formation, 237

Bauchi province, scenery of, 50

eastern plains of, 44

crystalline rocks of, 101

intrusive rocks of, 102, 133

Benue, watersheds of, 3

tributaries of, 10

scenery of, 11

volcanic tract of, 12

plain of, 13

sandbanks of, 15

drift of Benue valley, 223

antecedent character of the upper and middle Benue valley, 231, 243

Bida, 24

Bima, hills, 50

sandstones, 161

Borgu, scenery of, 20

crystalline rocks of, 69

drift of, 196

Bornu province, scenery of, 50–56

sandstones of, 50, 179

volcanic plateau of, 51

northern plains of, 52–3

crystalline rocks of, 106

drift of, 215

area of predominant depression, 218

dry water-courses of, 220

Bussa, 8, 9, 19, 71

Calc silicate rocks, 114

Carboniferous rocks of Sahara, 144

Cassiterite, _see_ Tinstone

Chad, lake, 2, 52

crystalline rocks near, 107

stratigraphy of rocks around, 192–3

ferruginous clay on shores of, 206

alluvial deposits of, 215

shelly marls of, 216, 218

former greater extent of, 217

not continuous with Eocene seas, 217

excavation of present floor of, 219

climatic changes in Chad area, 219, 240

depression of Chad area, 216, 217, 240

Clays,

of Giro, 168

of Kurukuru, 168

of Pali, 177

of Kirifi, 178

of Deu, 178

of Gombe, 178

Climate, changes of, in Sudan, 210

in Hausaland, 214

in Chad area, 219

favourable to formation of surface ironstones, 210

Cretaceous rocks, distribution of, 144

relation to crystallines, 146

of Muri province, 147

of Yola province, 154

of Bauchi and Bornu, 157

folding of, 147, 154, 158

classification of, 161

of French Sudan, 162

of Southern Nigeria, 163

of Kameruns, 163

palæontology of, 273 _et seq._

Crustal movements, _see_ Movements

Dala, _see_ Mt. Dala

Dallols, 61, 242, 250, 251

Desert periods in Nigeria, 214, 217

recent arid period, 210, 214, 219, 240

Devonian rocks of Sahara, 144

Diabase, 139

Diorites, of Bauchi, 136

of Kano, 136

of Kontagora, 136

diorite porphyrites, 138

Drainage system, recent rearrangement of, 198, 213, 233, 240

Drift, 195

of Hausaland and Borgu, 196, 199

ferruginous crust of, 199

origin of, 201

of Bauchi plateau, 203

of Bornu, 215

of Katagum, 221

of Gongola valley, 222

of Benue valley, 223–4

of Sahara, 226

Duguri, canyon valleys of, 48

sandstones of, 175

Dunes, ancient, 53, 58, 214

Eocene rocks of Northern Nigeria, 164

unconformable upon Cretaceous, 164, 175

of Sokoto province, 165

of the Niger valley, 169

conditions of accumulation of, 171

of Kontagora, 172

of Lokoja, 174

of Nupe, 173

of Bassa, 174

of Nassarawa, 174

of Kabba, 173, 175

of Duguri, Gombe and Kerri Kerri, 175

age of, 181

unconformity upon Cretaceous, 182–3

of Yola, 184

of Muri, 189

of Upper Niger, 191

of Kameruns, 191

Eocene rocks of Southern Nigeria, 191

basins of sedimentation, 228

probable extension over Central Africa, 193, 229

Faulting, of Cretaceous rocks, 145, 147, 154, 157, 158

of margin of Bauchi plateau, 237

on Upper Benue, 190

Ferruginous crust of drift deposits, _see_ Surface ironstones

Firki of Bornu, 52, 215

Galena, of Arofu, 149, 270

of Kudu valley, 154, 270

Gateri Hills, 46, 48, 153

grits of, 153

Gneisses, softer and harder, 69, 108

replacement of softer by harder in Niger valley, 74, 120

in Kabba and Ilorin, 80, 84

near Abuja, 99

in Bauchi, 102

relations of harder and softer, 119

of Sahara, 121

of West Africa, 122

of Transvaal, 123

meridional strike of, 109

of sedimentary origin, 110

metamorphism of, 111

Gold, in Northern Zaria, 96, 269

in Southern Muri, 269

in Bauchi, 269

Gombe, grits and clays of, 175, 178

Gongola, plain of, 14, 33, 47

valley of, 46, 50

drift of, 222

antecedent character of middle Gongola valley, 231, 244

Granites, 123

petrography of older, 123

of younger, 129

soda granites, 102, 130, 135, 140

age of younger, 140

periods of intrusion of, 142

Granulites, 116

Hausaland, provinces of, 3

scenery of, 21, 35

plains of, 21, 36, 198

drift of, 196 _et seq._

surface ironstones of, 199

origin of present aspect of, 198, 246

periods of elevation and depression of, 213

Ibi, 12

Ilo, 4

Ilorin, orographical structure of, 16

great plain of, 19

crystalline rocks of, 75

Inselberge of Kabba, 17

of Borgu, 20

of Kontagora, 22

of Nassarawa, 27

of Muri, 31

of Yola, 35

of Zaria, 36

of Bauchi, 44

of Kano, 56

of Sokoto, 60

origin of, 201, 246

Inselberg landscape, 18, 245

Intrusive rocks of Bauchi province, 102

petrography of, 123

older granites, 123

younger granites, 129

pegmatites, 129

syenites and diorites, 135

porphyries, 137

basalts, 137

Iron sands, 268

Ironstones, crystalline, 78, 81, 110, 114, 269

Cretaceous, 154, 160

Eocene, 164, 269

of Sokoto, 166

of Kontagora, 172

of Baro (Mt. Gidda), 173

of Lokoja (Mt. Patti), 174, 269

of Kantana, 177

of Panguru, 178

of Tagum hills, 179

of Kerri Kerri, 180

_See also_ Surface ironstones

Jakpara hills, 18

Jakura and Wa, limestone of, 66, 78, 110, 113

Jebba, 7 _et seq._

gorge of the Niger above, 7

Ju Ju Rock of, 8, 70

quartzites of, 70

Kabba, orographical structure of, 16

central tableland of, 16

scenery of, 17, 37

crystalline rocks of, 77 _et seq._

Kaduna, scenery of, 24, 36

tributaries of, 36

gorge at Zungeru, 35–6

in axial trough, 234

Kano, province of, 56–8

Mts. Dala and Kogon Dutsi, 58, 90, 136, 201, 247

crystalline rocks of, 89

drift of, 196

Karakai quartzites, 60, 88

Kara river, 92

Katagum, 57

drift of, 221

Kato phyllites, 95

Katsina, scenery around, 59

granites of, 89

granite surface rock, 89

sandstones of, 89

Kazaure, blue quartzite of, 58, 89–90

Kerko hills, granite massifs of, 37

Kerri Kerri, plateau of, 54

trench-like valleys of, 56

rocks of, 179

ironstones of, 181

Kilba hills, 35, 105

Kogon Dutsi, _see_ Mt. Dala

Kontagora, 21

scenery of, 22

crystalline rocks of, 91, 92

sandstones of, 170

Kurefi, 89

Kwaba hill, 33

Lake Chad, _see_ Chad

Limestone, crystalline, between Jakura and Wa, 66, 78, 110

at Igbo, 82

origin of, 110

petrography of, 113

Turonian, of Muri province, 144, 147

of Awe, 147

of Kumberi, 150

of Arofu, 149

of Yola, 155

of Gongola valley, 159

of Gongila, 169

of Reme, 160

of Sudan, 162

palæontology of, 273 _et seq._

Eocene, of Sokoto, 165

nummulitic, 167

Lokoja, 2, 6, 82, 174

crystalline rocks of, 82

sandstones and ironstones of, 174

Loko, 11

Mada hills, peaks of, 30

Magnetite schists, 78, 81, 110, 114

Manga, 238

Maradu, volcanic agglomerates of, 60, 88, 254

Mahorro, ironstones of, 22, 172, 269

Maibirro, quartzite hills of, 21, 73

Malenda river, granites and quartzites of, 21

Metamorphism, absence of contact metamorphism in Kabba, 83

variation in alternate belts, 111

of granites, 123

Mineral resources of Northern Nigeria, 265

Miocene rocks of Sudan, 194

Monazite, 270

Morrua, plains of, 29

Mts. Dala and Kogon Dutsi, 58, 90, 91, 201, 205, 212, 225, 247

Mt. Patti, 6, 11, 174, 269

Mt. Purdy, 6

Movements, crustal, post-Cretaceous, 164, 227

Tertiary, 212, 227 _et seq._

alternate periods of elevation and depression, 213, 230

flexuring of crust, 234, 241

elevation of Bauchi plateau, 237

Alpine movements in Nigeria, 252

Mumuye-Manna plateau, 32, 104

Murchison hills, 2, 12, 31, 103, 231

Muri, great plain of, 12, 30

sandstones, 153

crystalline rocks of, 30, 103

Cretaceous rocks of, 145, 147

volcanic hills of, 31, 262

Muri sandstones, 153

Nassarawa, province of, 26

scenery of, 27–30

central plain of, 28

northern tableland of, 29, 39

crystalline rocks of, 100

Nepheline basalt, 255

syenite, 259

Nigeria, Northern, area of, 1

boundaries of, 1

provinces of, 2

headquarters of, 2

physical features of, 2

hydrographical systems of, 3

hydrographical centre of, 3, 40

recent origin of river system of, 240–243

crystalline rocks of, 63

Cretaceous rocks of, 144

Eocene rocks of, 164

superficial accumulations of, 194

mineral resources of, 265

Niger, the, 4 _et seq._

watersheds of, 3, 4, 19, 36

tributaries of, 5

gorge above Lokoja, 7

sandstone plateaux of, 7

gorge between Jebba and Yelwa, 8

rapids of, 9

establishment of present course of, 241

relation of scenery to character of rocks, 242

recent origin of Niger valley, 243

Ningi hills, 44

Ningi massif, 102

Nodules, phosphatic, in Turonian limestones, 156

in Eocene limestones, 166

Nupe, scenery of, 23

crystalline rocks of, 98

Odouape, granite and gneisses, 80

Olle, 114

Okoro, 77

Okuruku granite, 126

quartz magnetite rock of, 81, 115

Okwa river, 28

Orissa hills, 19, 76

Petrography, of gneisses and schists, 108

of intrusive rocks, 119

of early Tertiary lavas, 254

of later Tertiary lavas, 262

petrographical provinces, 263

Phonolites of Northern Nigeria, 256

Phyllites, of Bussa, 71

of Ngashki, 73

of Sokoto, 86–8

of Zungeru belt, 93–5

petrography of, 112

Porphyries, 137

Porphyrites, 138–9

Quartzites, of Jebba, 70

of Maibirro, 73

of Lukke, 78

of Kazaure, 89

of Zungeru, 93

petrography of, 113

River system of Northern Nigeria recent origin of, 233, 241

Salt, 265

in western Muri, 148

in eastern Muri, 151

between Putu and Tangalto, 158

vegetable salt of Bornu 267

Shappa hills, 19, 76

Shebshi hills, 30, 32

Silurian rocks of Sahara, 121

Sokoto, province of, 60

dallols of, 61, 242, 250

crystalline rocks of, 86

Eocene rocks of, 165

Superficial accumulations of Nigeria, 194

of West Africa, 226

Surface ironstones of Borgu, 20, 199

of Bauchi and Zaria, 199

platforms of, 200

occurring upon drifted alluvium, 205

mode of formation, 205–211

period of formation, 211

absence in Bornu, Katagum and Gongola valley, 215

vesicular character of, 199

lustrous surface of, 199

irregular distribution of, 209

Syenites of Bauchi, 135

Syenite porphyries, 138

Tabachi, 73

Tagum hills, 52, 179

Tangale hills, 47, 48

Peak, 49

Tinstone, in eastern Ilorin, 77, 131

in eastern Zaria, 98

in Bauchi, 103

in pegmatites, 131

in alkaline granites, 134

in plateau drift, 203

economic development of, 270

Tongolan, 176

Tourmaline, in quartzites, 70

in quartz veins, 72, 73

in pegmatites, 76, 82, 99

in granites, 85, 99, 130

in slaty schists, 88

associated with younger granites, 129

schorl rocks, 131

Trachytes of Bussa, 72, 115

Traverses, typical, 64

Ture Peak, 49

Upper Benue sandstones, 155, 184

relation to crystalline rocks, 184

unconformable upon Cretaceous, 188

cross-bedding in, 187

mode of formation, 187, 190

Valleys, canyon, of Bauchi, 46, 244

flat-bottomed valleys of Sokoto, 61, 242

shallow valleys of Borgu, 20

of Hausaland, 22, 57

canyon, of Kontagora, 23, 242

canyon of Duguri, 48, 244

trench-like, of Kerri Kerri, 56

interlacing valleys of Kerri Kerri, 56, 245

Vere hills, 14, 34, 105, 247

Volcanic hills of Muri, 12, 31, 260

of Yola, 13, 35, 260

Barbur volcanic plateau, 51, 257

volcanic agglomerate of Maradu, 60, 88, 254

Morrua volcanic plateau, 100, 203

absence of pre-Tertiary volcanic rocks, 253

character of Tertiary volcanic eruptions, 254

early Tertiary volcanic period, 254

later Tertiary volcanic period, 259

Wase river, 39, 45

Wase rock, 31

phonolite of, 256

Watersheds, primary, 3, 36, 40

character of, 36, 40, 241

Weathering: absence of weathered crust upon rocks of Sudan, 195

dry weathering not a potent factor in denudation, 199

former sheet of weathered rock in Nigeria, 201

Wuru, Great Rapid of, 8, 9

Wurkum hills, 30

Yo river, 4, 234

Yola, eastern, 230

scenery of, 32–5

southern plateau of, 32, 104, 227

volcanic hills of, 13, 35, 260

crystalline rocks of, 103

Cretaceous rocks of, 154

Eocene rocks of, 184

Zaria, province of, 35

scenery of, 37

hills of, 36

crystalline rocks of, 93–98

plains of, 38

vesicular ironstone of, 200

drift of, 197

Zungeru, 2, 35

quartzites and schists of, 93

* * * * *

ERRATUM.

p. 203, line 13, for “larvas” _read_ “lavas.”

RICHARD CLAY AND SONS, LIMITED, BREAD STREET HILL, E.C., AND BUNGAY,
SUFFOLK.

Compiled by Dr. J. D. FALCONER.

London. Macmillan & Co., Ltd.]

Transcriber's note:

The change in the ERRATUM has been made.

Page 6, Changed: "down on either si de, a n from" to: "side, and"

Page 45, One ref. to footnote missing. Ref. "2" treated as ref. to
ftn. 13, and a ref. to ftn. 14 placed after "the plains of Yergum."

Page 49, Changed: "those which form the the western boundary" to:
"form the western"

Page 115, Changed: "may be recognised all the familar stages" to:
"familiar"

Page 122, Changed: "comparision which M. Chudeau" to: "comparison"

Page 123, Changed: "the epidorites, amphibolites, and granulites" to:
"epidiorites"

Page 151, Changed: "Gateri but the the associated rocks" to: "but the
associated"

Page 154, Changed: "corrugation ofthea whole series of gently" to: "of
the whole"

Page 154, Changed: "limestones of the Kudu vlley" to: "valley"

Page 167, Changed: "limestones, however, no here form thick" to:
"nowhere"

Page 207, footnote 121, Changed: "De Lapparent, _Traité des Geologie_"
to: "_Traité de Géologie_"

Page 232, Changed: "that lacustrune conditions prevailed" to:
"lacustrine"

Page 233, footnote 150, Changed: "Passarge, _Adamana_, 1895, p. 385."
to: "_Adamaua_"

Page 290, Changed: "Stroliczka" to: "Stoliczka"

Minor changes in punctuation have been done silently.