The bottom portion of the bed is from 6 to 12 inches thick, and containing much titaniferous iron, has the most free gold, and it is this portion alone that is worked by the native Fantis. They sink vertically a small round shaft, or rather chimney (locally termed tobon), about 21⁄2 feet in diameter, to the richest part of the seam. The shafts are nowhere deeper than 100 feet, as the natives cannot cope with the water below that depth. Having cut the seam, they work it away in a very irregular manner. After driving horizontally a few feet, they sink a little on the dip, working the seam away for several yards on either side as they go down; they may then drive again for a short distance along the bed, sink a few yards deeper, and so on. The above was the method which had been adopted in some old workings examined by the writer. In places the workings are so narrow that one has to wriggle up and down the slope of the seam on all fours. The exertion is terrible, and when, as sometimes happens, one comes in contact with a run of driver ants, the situation is anything but a pleasant one. It can be readily understood that in workings measuring only 14 inches wide there is no room to swing a pick; the natives work out the seam with hammer and chisel, carrying the mineral to the surface in earthen pots or calabaslies up a bamboo ladder about 5 inches wide. In sinking they use, according to Skertchly,* a small iron hoe 2 inches broad and from 4 to 6 inches long, with which they scrape the sandy earth into a calabash; but McCarthy says a method of "fire-setting" is also employed. It was the custom to allow the natives thus to work out portions of the seam on tribute, the company providing the tools and allowing the natives half the ore raised to bank. This method was merely an imitation of the old native custom of paying half the ore gotten to the kings or chiefs,† but, as it gives free scope to extensive fraud, it has recently been abandoned. The whole bulk of the seam-the best portion being from 2 to 24 feet thick-is sent to the stamps, and a partial hand-picking takes place there. The ore yields at the mill from 5 to 7 dwts. of gold to the ton. It is easy to crush, and the gold, being entirely free, is readily caught on the plates; some, however, in very fine powder ("flour gold"), is only partially caught on the lower amalgamated plates and on the blanketing.

It will be seen from the section (Plate X.) that another and upper seam has been explored, but the main seam is the only one now being worked. The upper seam, from 2 to 3 feet thick, is of similar structure, but it contains less gold; and the lower portion of it said to be rich-is at present under water. A sample taken from the best part of the main seam, assayed 9 dwts. 18 grains; while one showing titaniferous iron ore in layers in sandstone gave 7 dwts. 19 grains, and one showing thick layers of titaniferous ore gave 13 dwts. 16 grains of gold to the ton of 20 cwts. (Dr. George Tate); hence the assays confirm the panning results, that where there is most black sand there is most gold; the former is in this district an almost certain indication of the latter.

* Mungo Park describes in his book of Travels the method of digging deep pits employed by the Mandingoes. They used small spades or corn-hoes for this purpose, and drew the earth up in calabashes. Strata of fine reddish sand with small black specks (? iron sand) were usually found to be auriferous.

This custom is alluded to in an anonymous work published in 1665, and quoted below. This little book contains an interesting and fairly accurate account of the native customs, of the weights used in the sale of gold, of the traffic with the Hollanders, and of early voyages to the Gold Coast.

The old shaft should be sunk to the main seam, which will be met with at a depth of from 60 to 70 feet vertical. By this means a further 200 feet of the main and about 150 feet of the upper seam will be laid open on the dip, and very much better results may be expected than hitherto.

ABOSSO MINE.

This is six miles north of Taquah village, and is one of the most promising mines on the Gold Coast.

Plate XI. is a plan, and Plate XII. a section of the present workings in this mine, from surveys by the writer. The seam runs N. 53° E. (magn. 1890), or N. 38° 40′ E. (true), with an average dip of 35° to the N.W., and has been proved for about 700 feet in length. The main hill here trends N. 40° E. (true), and may be regarded as a continuation of the Taquah range; hence the seam is practically parallel with the average run of the main hill, the top of which is 310 feet above sea-level, and along the western slope of which it crops out. This is undoubtedly a banket deposit, although here and there portions of the seam show a structure similar to that of the Taquah deposit. The strike and dip are very uniform, the roof or hanging-wall is extremely well-defined, but the thickness varies considerably. At the south-west end the seam consists of a single layer of rich conglomerate 2 feet in width. Further north, or 80 yards from this point, the thickness is 18 feet; the upper portion, however, is very poor in gold. At one place where the seam is very rich the section shown, commencing at the roof, was as follows:-24 feet of pale sandstone containing black streaks (titaniferous), poor in gold, 6 inches of auriferous conglomerate, 9 inches of sandstone and layers of titaniferous iron with gold, 9 inches of rich conglomerate, 12 inches of sandstone rich in titaniferous iron ore and free gold forming the bottom layer; total thickness 5 feet. The true roof of the seam is a hard quartzose rock (grit) 25 feet thick, above which is a thick bed of talcose sandstone similar to that at Taquah, and upon this again lies a red marly rock (coloured by oxide of iron) proved for many yards in thickness. In crosscutting through the latter, which is soft, one meets with streaks which give a good colour of gold in the bowl. Immediately below the seam there is usually a layer of soft clay, but talcose sandstone forms the true floor or footwall. A sample of the lowermost layer of conglomerate (light in colour) assayed 4 ozs. 7 dwts., while darker conglomerate gave 5 ozs. 4 dwts. 11 grains, and conglomerate showing visible gold gave 15 ozs. 12 dwts. to the ton (Dr. George Tate). With only ten small and leaky heads the yield last April amounted to 244 ounces of gold, the ore milling nearly 13 dwts. to the ton. From 12 to 15 dwts. is said to be the average of the Main Reef Line of Witwatersrand.* The gold varies from the size of a pin's head to impalpable powder, and is waterworn. The conglomerate is composed of rounded

=

* See Official Handbook, Transvaal Republic, Mining and Metallurgical Exhibition, compiled by W. Y. Campbell, pp. 4 and 11. The averages for April, May, and June, 1890, were very constant, being 141 dwts., 144 dwts., and 14} dwts. of gold per ton respectively; latterly they have fallen off about 1 dwt, per ton.

quartz pebbles of various sizes, but seldom larger than a hen's egg, with occasional pebbles of hard quartzitic rock, set in a quartzose matrix often containing black titaniferous ore. It has not the reddish colour of the Witwatersrand banket found above the water-level, but resembles rather the greenish-grey pyritic conglomerate found below that level, although in the Gold Coast conglomerate no pyrites has as yet been met with. The gold occurs generally in the cement, and is sometimes seen collected round the quartz pebbles. Mr. Alford, speaking of the Witwatersrand banket, says :- "It is usually found that gold occurs much more freely in the matrix than in the pebbles of the conglomerates, and more so in that part of the matrix immediately adjacent to the quartz pebbles ;" and Mr. Furlonge, referring to the De Kaap conglomerates, remarks that the gold is "entirely confined to the cementing material, which is to a large extent very porous." On the other hand, a German writer distinctly says the gold is found both in the pebbles (Geschieben) and in the cement (Bindemittel);† and as gold has been found in a quartz pebble from a Carboniferous conglomerate,‡ and has been seen by Dr. C. Le Neve Foster in a pebble from a South African banket,§ it may be pretty safely concluded that gold also occasionally occurs in the pebbles of the West African bankets, although, commercially speaking, the quantity is probably of little or no account.

The workings at present are shallow, but they tend to show that the deposit becomes richer at a greater depth, which is also said to be a characteristic of some • of the Witwatersrand bankets. A shaft is now being sunk to the dip in order to open up the seam below the present adit level. By continuing this shaft until a vertical depth of 250 feet is reached, and cross-cutting from near the bottom of it to the seam, the latter will then be opened up for a total depth of 500 feet on the dip, and for this district quite a respectable depth reached.

The writer thinks that the deposits will eventually be found to consist of sediments laid down in basins scooped out in schist; an outcrop of chloritic schist is seen a little south of Taquah.

A seam 2 feet thick, with a roof of loose red clay or marl, has been proved northeast of the present workings on the slope of the hill, and about 100 feet above the old tunnel. This would appear to be a parallel seam, running about 130 yards south-east of the main seam. The best part consists of 15 inches of conglomerate, separated from the soft roof by 4 inches of pale sandstone containing layers of titaniferous iron. This seam will be cut by continuing the cross-cut of the old tunnel in a south-east direction. The native shaft, which is just large enough to allow one to descend hanging on to a rope, has struck the seam at a depth of 39 feet. The general strike is N. 31.° E. (true), and the dip from 50° to 55° N.W.

* See also Mr. Alford, Mining Journal, April 27th, 1889:-The conglomerates are composed of imperfectly rounded waterworn pebbles of white and grey amorphous quartz in a matrix of ferruginous sand, all very solidly cemented together; small pieces of felsite, talc, mica, and other rocks are also occasional constituents of the mass. The gold appears to lie in the matrix, or rather to have agglomerated round the quartz pebbles on their gradual dissolution; sometimes on removing a quartz pebble from the conglomerate the cavity is seen to be completely lined with crystalline gold."

↑ Neues Jahrbuch (1889), vol. i. (Referate), p. 113.

A. Liversidge, The Minerals of New South Wales, 1888, p. 24.

See discussion of Mr. Sawyer's paper, cited above.

ADJAH BIPPOH MINE.

About one mile north-east of Abosso there is a seam of conglomerate now being worked very similar to that of Abosso, but having a much greater dip; in fact in this respect it has the appearance of a lode. The bed strikes about N.E.; at the south end the dip is 60° N.W. (thickness 7 feet), along the centre it is practically vertical, while at the north end the dip is 75° S.E. (thickness 1 foot 9 inches). One portion of the seam is crossed by a joint running 10° S. of W. and dipping 75° N., which heaves it 10 feet to the west. The seam, 170 feet from surface was, in 1888, 3 feet thick, and gave an average of about 10 dwts. of gold to the ton. The cement of this banket is composed of blue quartz, and is much darker than that of Abosso.

CINNAMON BIPPOH MINE.

This mine lies about two miles north-east of Adjah Bippoh, and the bed is found on the western slope of a steep hill which is a continuation of the Taquah and Abosso range. The seam is a most pronounced banket deposit, striking N.E. and dipping 45° N.W. The thickness varies from 2 to 3 feet. The hanging-wall consists of sandstone rock containing thin streaks of titaniferous iron ore, poor in gold. Soft and light-coloured conglomerate occurs here very similar to that of Abosso, but the hard conglomerate is characterised by having a cement of blue quartz of even darker hue than that of Adjah Bippoh. The Cinnamon Bippoh Company's mine adjoins this, and the workings are in the same seam.

CROCKERVILLE MINE.

A little east of Abosso village two seams were worked some years ago-" Sam's Reef" to the north and "Crocker's Reef" to the south-west, but the writer is unable to give any particulars of their structure.

ABBONTUYAKOON MINE.

Three miles north-east of Taquah village, and on the road to Abosso, is a deposit, judging from specimens on the roadside, of the same nature as the Taquah main seam. The mine is now abandoned. A pile of old machinery on one side of the path, and the remains of a stone-breaker and a portion of the stamps-shed on the other, all overgrown with tropical vegetation, are sad relics of unsuccessful mining on the Gold Coast.

EFFUENTA MINE.

One mile south of the Taquah mine is a seam, striking with the hill or N. 6° E. (true) (Cameron), which appears to be strongly conglomeratic in places, for Mr. Thomas Cornish speaks of it as "6 to 8 feet of conglomerate and quartzite deposits, interspersed with boulders or blocks of quartz and ironstone." This mine is abandoned.

TEBERIBI MINE.

Two-thirds of the way from Bonsa to Taquah village is a deposit, not now being worked, very similar to the main Taquah reef, and which is conglomeratic in places (Cameron). At 100 feet from surface this seam yielded 6 dwts. of gold to the ton. The vein is said to dip 45°, and to be of a soft, friable nature.*

* Reports on Gold Mines, 1889 (Papers relating to H.M. Colonial Possessions, No. 66). Sir W. B. Griffith to Lord Knutsford, p. 9.

GEOLOGICAL NOTES.

The district at present explored stretches for about 14 miles in a north-east direction, while the average width is small, being greatest at Abosso, where it measures about 3 miles. Commander Cameron speaks of gneiss being the country rock at Teberibi, Taquah, Effuenta, Adjah Bippoh, etc., and Mr. E. McCarthy also says the sandstones and conglomerates "are often so metamorphosed as to pass into gneiss." The writer has seen no true gneiss in the district, but sandstones, when veined with titaniferous iron ore, often assume an appearance closely resembling that rock.

The band of grit forming the roof of the Abosso banket appears to be of local character; the red marl, too, is not seen at all the mines; but it must be remembered that, with the exception of the latter, which contains a large proportion of clay, all these rocks are chemically the same, being composed in the main of rounded grains of quartz, and may be described as sandstones, conglomeratic sandstones, conglomerates or quartzites, according to the texture and the cohesion between the particles; at the one extreme is a rock which falls to pieces on the slightest touch, and at the other is a very hard quartzite, through which the natives were unable to pierce.

The beds have evidently been quietly deposited by water. Specimens from Taquah clearly show this, while even the pebbles of the conglomerates appear to be arranged roughly in layers-their longer axes being generally parallel to the roof and floor of the seam.* The gold, waterworn as a rule, is undoubtedly contemporaneous with the rocks in which it occurs, differing in this respect from the Witwatersrand and De Kaap banket reefs, the gold of which is said to be of more recent date than its matrix.† The main reasons for inferring this are (1) the crystallized nature of the gold, and (2) its presence in pyrites below the water-level.

The bankets of West Africa are alluvial deposits, but whether the sandstones and conglomerates have been deposited in the sea, or in an inland lake or lagoon, which latter seems probable, or on the bottom of a wide river, cannot yet be satisfactorily determined a very careful geological examination of the whole district must be made to settle this question as well as that of the age of the deposits. If these deposits were built up on the bottom of a lagoon, the latter must have been of large extent with several rivers and streams emptying themselves into it. Near the mouths of such rivers we should expect to find the coarser materials deposited, while farther from the banks of the lagoon the fine matter would settle; and, again, the material deposited would differ from time to time according as the rivers were in a flooded or dry state. Along the shore at Axim and Winnebah the deposition of sand and titaniferous iron ore is seen going on at the present day; a little inland the native holes show titaniferous sand resting on a clay bottom-the fact of a thin band of clay occurring on the floor of the bankets at Abosso and Adjah Bippoh has * A distinct bedded arrangement is also seen in a specimen of pyritic conglomerate from Witwatersrand, possessed by the writer. See J. S. Curtis (op. cit.); Mr. Furlonge (op. cit.), speaking of the De Kaap conglomerates says:"The auriferous pyrites, and consequently the 'free gold,' is evidently of later date than the beds themselves."