ON THE DETRITAL TIN-ORE OF CORNWALL. 247 
If—whilst stream-tin was deposited in the valleys, and shodes 
were scattered on more elevated parts of the surface—tin-ore was 
also swept into the sea,* it must now be—as on shore—concealed 
by more recent deposits ;f for, during the recent Hydrographical 
Survey, soundings—almost without number—failed to detect any- 
thing of the kind,t in even of a single instance. 
The granite of Cligger-head§ is traversed by narrow veins of 
quartz; and both the rock and the veins contain tin-ore. The 
action of the sea saps the base of the cliff; and large portions of 
it fall almost every winter. These are rapidly disintegrated by 
the waves ; and the ore they had contained is gleaned by a few 
poor people, who earn a scanty livelihood by preparing it for 
market. On several other parts of the coast small quantities of 
tin-ore are collected ;|| but most of it, if not the whole is sepa- 
* “Granite and tin-stone shingle occur round the Land’s-end and 
“Scilly Islands.” Austen, Quarterly Journal of the Geological Society, vi, 
p. 76. 
+ ‘‘If the mines [of Scilly] had ever been very productive of tin, 
‘some traces of diluvial tin-ore would, even in modern days, be from time 
‘‘to time found in the low-grounds, but in neither of them has any tin-ore 
“been discovered within the recollection of the oldest inhabitant, nor is 
‘‘there a record of such a fact at any former period; neither has any tin-ore 
‘“‘evyer been found pulverized amongst the sands of the sea shore, as it fre- 
“quently is in the mining parts of Cornwall which border on the sea.” 
Carne, Cornwall Geol: Trans: vii, p. 153. 
¢ Captain (now Rear Admiral) George Williams, R.N. Officer in charge 
of the Hydrographical Survey, MS. 
§ Sedgwick, Transactions of the Cambridge Philosophical Society, i, 
pp. 181—132. Boase, Cornwail Geol: Trans: iv, p. 303. Henwood, /bid, 
v, p. 94. Von Oeynhausen and Von Dechen, Phil: Mag: and Annals, v, p. 
169. Thomas, (R.), Wining Review, ii, p. 265. Dela Beche, Report, p. 162. 
|| Borlase, Natural History, p. 164. Ante, p. 197, Note 
‘Small quantities of tin-ore are frequently thrown up by the sea, on 
‘the beach below the Little Bounds engine [in Saint Just.] One or more 
‘workmen may generally be seen, on the return of the tide after high-water, 
“searching for tin-ore amongst the sand and shingle. It is probable that 
“this comes from the back of some of the tin-lodes which run under the 
“sea.” Carne, Cornwall Geol: Trans: ii, p. 342. 
‘‘ Tin-ore was found in small quantities, many years ago, a little below 
“‘high-water-mark, on the margin of the Loe-pool at the bar, close below the 
‘furnace discovered in 1860.” Rocrrs, Report of the Royal Institution of 
Cornwall, x1, (1863, p. 80). 
“From a stratum, also between high and low water, on the sea-shore at 
‘‘Gunwalloe fishing cove, tin-ore is now about to be returned, under a licence 
“from the Duchy of Cornwall. This, however is visible only on occasions 
“of unusual stripping of the shingle, from the rocks at the base of the cliff; 
“and occurs (as I am told by the holder of the licence) in little dishes or 
‘‘hollows in the face of the rock.” Mr. Roagrrs, of Penrose, MS, 
Hunt, Mineral Statistics, 1870, p. 8. 
