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VIII. On some Cornish Tin-Stones and Tin-Capels

Published online by Cambridge University Press:  14 March 2018

Extract

In my former paper (Min. Mag., vol. IV, page 1) the different modes of occurrence of oxide of tin in Cornwall were briefly described, and the characters both macroscopic and microscopic of the ordinary tin-stones and tin-capels were illustrated in considerable detail. I have now to describe the peculiar varieties of “wood-tin” or Cornish tin-ore, which are certainly characteristic of many of the Cornish deposits, although their occurrence is not limited to Cornwall as was at one time supposed.

The chemical composition of Cornish wood-tin differs very little from that of ordinary Cassiterite, as was shown long ago by Klaproth.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1880

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References

page 103 note * Among foreign localities for wood-tin the detrital deposits of the Mexican uplands may be especially referred to. In these many nodular and concretionary masses of a yellowish or reddish-brown wood-tin occur–sometimes associated with the rare mineral Durangite, These, however, unlike most of the Cornish wood-tins, generally contain very large proportion of oxide of iron.

page 104 note * Min. Mag., vol. IV, p. 6.

Some beautiful coloured figures of wood-tin are given in plate 1, of the Catalogue of the Rashleigh collection, published in 1797. A good drawing of the “needle-tin” from Glasteining mine in St. Mewan (now I believe known as St. Austell Consols) is given in pl. 4. Some of these “needles” are extremely fine, but unlike the “fibres” of wood-tin which are nearly opaque, these are very transparent.

page 104 note † Rep. Roy. Inst. Corn., 1841, p. 38

page 105 note * The Royal Geological Society of Cornwall. The specimens are preserved in the Museum at Penzance in wall-case No. 11.

page 107 note * First Paper, p. 7.

page 107 note † On analysis this wood-tin yielded 25 p.c. only of peroxide of iron.

page 108 note * Rep. Roy. Inst. Corn. 1841, p. 38.

page 108 note † Rep. Roy. Inst. Corn. 1841, p. 38.

page 108 note ‡ Quart. Jour. Geol. Soc., XXII, p. 535.

page 108 note § Trans. Roy. Geol. Soc. Corn. IX, pp. 206-9.

page 109 note * Private communication, August 12th, 1880.

page 109 note † First paper p. 7.

page 110 note * Vol. IV. p. 255, 1873.

page 111 note * Journ. Roy. Inst. Corn., XIII, 84, 1871.

page 112 note * Ibid.

page 112 note † First Paper, p. 8.

page 112 note ‡ Trans. Ray. Geol. Soc. of Corn., IV, p. 484. See also Dr. Boase, p. 291, and Mr. Hawkins, p. 140.

page 113 note * Rep. Roy. Inst. Corn., 1841, p. 39

page 113 note † Zeit. f. Kryst. u. Min. 1, plates VII and XVII

page 113 note ‡ See “On the Trelissick elvan and on a proposed classification of the Cornish Elvans.”–Trans. Roy. Geol. Soc. Corn., IX, p. 221.

page 114 note * Rep. Roy. Inst. Corn., 1845, p. 20.

page 114 note † Trans. Roy. Geol. Soc. Corn. IX p. 211.

page 115 note * Hall, T. M.; Mineralogists' Directory, p. 13l.Google Scholar

page 115 note † Pearce, R., Rep. Roy. Inst. Corn. 1861, and 1863.Google Scholar

page 115 note ‡ “On the occurrence of Achroite at Rock Hill.” Min. Mag. 1. p. 55.

page 116 note * The ap. gr. of unaltered (recent) deer's horn (fallow deer) I find to be 1·26, and the organic matter 62 p.c.

page 116 note † This plate will appear in the next number of the Mineralogical Magazine.