CHEMICAL CHANGES IN LODES. 
119 
493. Brown Iron Ore, in 
rhomboliedral crystals, pseudo- 
morplious after Carbonate of Iron. 
liestormel Royal Iron Mine, near 
Lostwithiel, Cornwall. 
494. Brown Iron Ore, and 
Quartz, proving by the fonn iji 
which they have been deposited, 
the former presence of rhoinbohe- 
dral carbonates. 
Taylor's level, liestormel Mine, 
near Lostwithiel. 
Wall-case 35. 
Shelf I. 
495. Cavernous Quartz. An 
example of what often appears on 
a considerable scale where pseudo- 
morphous action has been rife. 
496. Quartz, with pseiido- 
morphous impressions. 
Little North Lode, Dolcoath Mine, 
near Camborne, Cornwall. 
497. Aukiferous Quartz, with 
pseudomorphous impressions. 
498. Cellular Auriferous 
Quartz. 
Cwm Risen or Cwm Heisian Lead 
Mine, Merionethshire. 
Presented by James Harvey. 
499 and 500. Cellular Quartz, 
with pseudomorphous impressions. 
From the back of the Lead Lode, 
Pen-y-clyn, near Llanidloes, 
Montgomery sh ire. 
Presented by W. W. Smytb, F.R.S. 
Illustrations of Anogenic Alterations in Lodes, or changes 
originating in the Upper Part. Sulphides converted into 
Oxides and Metallic Salts. 
Shelf II. 
501. Cavernous part of a Lode, 
containing crystallized Sulphide 
of Copper and Black Oxide of 
Copper. 
Great Work, Breague, Cornwall. 
Presented by John Sjlvester. 
502. Cavernous portion of a 
Coppt:R and Lead Lode, illustrat¬ 
ing the foimation in the vein of 
carbonates by the decomposition 
of Copper Pyrites, 8cc. 
“ The Lime pits,” Ecton, Stafford¬ 
shire. 
503. Galena, with Brown Ox¬ 
ide of Iron, the cleavage fissures 
of the galena filled with white and 
green lead ore. 
Mines of Beresow, Uralian 
Mountains, Russia. 
Presented by the Imperial Mining 
Institute of Russia. 
504. Argentiferous Galena, 
mingled with White Lead Ore, or 
Carbonate of Lead. 
Eaglebrook Mine, Cardiganshire. 
Presented by W. Spooner. 
505. Galena, with Phosphate 
of Lead. 
Brassington, Derbyshire. 
506. Galena and Phosphate 
of Lead. 
Golden Valley, Bonsai, Derby¬ 
shire. 
507. Galena, with Auglesite, or 
Sulphate of Lead. 
Golden Valley, Boiisal. 
508. Galena, with Cerussite, 
or Carbonate of Lead. 
Golden Valley, Bonsai. 
Nos. 505 to 508 presented by Sir 
H. T. De la Beche. 
509. Cerussite, or Carbonate 
of Lead, crystallized on Quartz. 
Cumberland. 
510. Galena, with Carbonate 
of Lead, or Cerussite, clearly de¬ 
rived from the decomposition of 
the galena. 
Brassington, Derbyshire. 
511 and 512. Crystallized Ce- 
RUSSITE. 
From shallow woikings at Bras¬ 
sington, Derbyshire. 
