[From Lamplugh, Geology of IoM, 1903]

NOTES ON OTHER VEIN-PRODUCTS.

Gold.

From the general character of the Manx Slates and some of its veins, it is not inherently improbable that a little gold should be found in the Isle of Man; but the evidence for its presence is, as yet, scarcely satisfactory. In 1867 D. Forbes in describing the occurrence of polytelite in the Foxdale Mine mentioned that the Foxdale granite is identical in composition with some auriferous granites, and that traces of gold were reported to have been found in the gullies and in quartz-veins contiguous to it.³ Capt. J. Kitto, late of the Foxdale Mines, informed me that he also had heard that specimens of gold had been found, some time ago, in this district, but had not himself seen them.

Among Cumming’s geological specimens preserved in King William’s College at Castletown, are two water-worn fragments of slate showing specks of free gold, in the onti ~ocimen on a smooth cleavage face, and in the other in a crusiiea vein-streak. An almost illegible label on one of the specimens appears to read "Langness," and the rock is of the kind which occurs in that locality. The reported presence of gold in a vein mined on the northern side of Douglas Bay has been mentioned on p. 548~.

The metal is not included in Sir W. W. Smyth’s published list of Manx Minerals.’

Since the above was written a small trial has been made near the Cluggid in Sulby Glen on a vein reported to contain gold; and another trial at Maughold. Both are however now suspended. (Aug., 1902’)

1 From information and plan furnished by Mr. W. H. Rowe.

2 MSS. in Woods and Forests Office.

3 "Researches in British Mineralogy." Phil. Mag., 4th ser., vol. xxxiv., p. 354.

4 A note of this supposed discovery appeared in "Nature" of Jan. 24th 1895, vol. ii., p. 299..

Molybdenite.

This mineral occurs as a thin incrustation on joint-faces of the Dhoon Granite in the quarry on the west side of the highroad, half a. mile north of Dhoon Glen, where, according to Smyth, it was mistaken for lead ore.² It has not been observed elsewhere in the Island.

Plumbago.

The presence of graphitic slate at two or three localities in the Manx Slate Series has been noted in a previous chapter (p. 94 and p. 134). No workable deposit of the mineral has yet been found in the Island. In Sir W. W. Smnyth’s "List of Manx Minerals" (,op. cit., p. 143) graphite is recorded as occurring "impure in the Snaefell Lode 100 and 130-fathom levels "; and in some handbooks of Mineralogy (e.g., that of Greg & Let Lsom, 1858, p. 2), " Beary in the Isle of Man" is given as a locality for the mineral. Documents in the Woods and Forests Office throw light upon the last-mentioned reference. From these it appears that in 1852 leave was granted to the Rev. J. G. Cumming and Dr. T. Underwood to search for manganese and other minerals in the parish of German, east of the Neb and north of the Peel and Douglas highroad, and that "in the course of their searches they have discovered some plumbago, which they wish to have included in their licence," which was accordingly done. In February 1854, the resident Crown Agent reported that a day-level had been driven about 25 feet in this sett, with a side-cut to meet the opposite cheek of the vein; and that about 40 tons of raw stuff had been raised, but the samples were not sufficiently good in quality to command the attention of plumbago merchants and no sale had been effected; strings of copper had also been observed in the district. The site of this working appears to have been on the slope of Beary Mountain, but the exact locality has not been identified; Cumming no doubt refers to it in his "Guide to the Isle of Man" (1861, p. 27), where he states, "Plumbago has been discovered in Glen Helen."

The discovery of a piece of plumbago of good quality on the foreshore at Douglas, derived from a neighbouring lode, has already been mentioned (p. 548).

In connection with this subject the occurrence, under circumstances previously discussed, of a singular string of anthracite in the Laxey mines should not he forgotten (p. 520).

1 Op. cit., p. 146. 2 ibid.