Mr. W, Smyth on the Iron Ores of Exmoor. 237 



In several places, as at Cornham Ford, the Roman lode, and the 

 little Woolcombe lode, hsematite has been found at or near the 

 surface, containing 98-4 per cent, of peroxide of iron, in masses 

 which present the structure of sparry iron or carbonate. Most of 

 the lodes, however, especially those of the Deer-park on Exmoor, 

 and Raleigh's Cross, consist of brown or hydrous peroxide, generally 

 occurring in large cavernous masses, with the interior of the cells often 

 lined with brilliant but minute crystals of Goethite (pure hydrous 

 peroxide), yet exhibiting the rhombohedral structure of sparry ore. 

 Analysis shows this ore, especially from certain of the Exmoor 

 veins, to contain 7r3 per cent, of peroxide of iron,'together with 

 a considerable per-centage of oxide of manganese. 



Lastly, several of the veins prove in depth to consist of sparry 

 ore (siderite or carbonate of iron), containing a notable per-centage 

 of carbonate of manganese. This has especially been shown at 

 Goosemoor, Huel Eliza, Hangley Cleave, and on Kentisbury Down. 

 The width of these veins varies from a few inches to above 20 feet, 

 and at the greatest depth hitherto reached, 140 feet, there is no de- 

 terioration in size. Quartz- veinstone and fragments of slate occa- 

 sionally fill part of the lodes ; and this fact, coupled with the in- 

 terruptions of "slides" and " heaves," has led to some misplaced 

 disappointment on the part of those who made their calculations 

 without taking into account the capricious nature of true veins. 



Hence it appears, — 1st, that the vein-fissures have been formed 

 in this district almost solely in planes conformable to those of 

 stratification, and that, after having been filled with carbonate of iron, 

 quartz, &c., they have been more or less disturbed. 



2ndly. That the sparry ore has been converted, often to a great 

 depth, into Goethite or pure hydrous peroxide, the consequent de- 

 crease of bulk giving rise to the cellular cavities lined with crystals. 

 3rdly. That some smaller portions have been converted into 

 haematite, having probably passed through the intermediate stage 

 of brown peroxide. 



4thly. The pebbles of haematite at the base of the New Red in 

 the adjoining district appear to be derived from these lodes, and 

 would indicate their having been filled with ore prior to the great 

 spread of deposits of red and brown iron-ore which took place in 

 S.W. England and South Wales soon after the deposition of the 

 coal-measures. 



The interest attaclied to these pseudomorphous changes, and to 

 the scale on which they have taken place, is heightened by com- 

 parison with the ores of Siegen, of Sommorostro near Bilboa, and 

 those brouglit by Dr. Livingstone from Central Africa. 



4. " On Native Copper in the Llandudno Mine, near Great Orme's 

 Head, North Wales." By Capt. W. Vivian, of the Llandudno 

 Mine. 



The author described some microscopic arborescent crystallizations 

 of native copper occurring with ruby copper in small cavities in a 

 brown limestone, which contains yellow bisulphuret of copper. 

 Harder sulphurous ore occurs in the bed below, and carbonates and 

 oxides of copper in the bed above. The arborescent copper is pro- 



