248 ON THE DETRITAL TIN-ORE OF CORNWALL. 
rated by the action of running water,* or of the sea, from the 
waste which escapes in neighbouring mines. 
. 
* “Tin is also found among the slime and sands of rivers and of the 
‘‘ seashore (as in some creeks of Falmouth harbour several lords of the soil 
‘“have lately experienced to their advantage) washed down probably from the 
“hills, and resting in such sheltered situations that the sea has not power 
‘to carry it off.” Boruasz, Natural History, p. 164. 
“ Besides stream-works, we have another sort...occasioned by the refuse 
‘and leavings from the stamping-mills, &c., which are carried by the rivers 
“down to the lower grounds...I have heen told that about seventy years 
‘“back, [1708] the low lands and sands under Perran Arworthall, which are 
‘‘ covered almost every tide with the sea, have, on its going off, employed 
“some hundreds of poor men, women, and children, incapable of earning 
“‘ their bread by any other means.” Pryce, Mineralogia Cornubiensis, p. 135. 
‘“« The sand on Marazion green [affords ]...sufficient tin-ore to pay in some 
“measure for its streaming, which process, on a small scale, is here in 
“operation.” Boasz, Cornwall Geol: Trans: iii, p. 178. 
‘At Polladan-cove [in Saint Just] portions of the sea-sand are often 
“ eollected and dressed for sake of the tin-ore deposited amongst it by the 
“rivulet flowing through the dressing-floors in Nancherrow-vale. Wherever 
‘‘ there is a strip of beach at the base of the cliff persons are employed to 
‘collect any stones containing tin-ore; whether these may be separated 
“from the rubbish of the mines by the action of the waves, or torn from 
‘‘ the backs of lodes beneath the sea, is difficult, if not impossible, to deter- 
“mine.” Hunwoop, Jbid, v, p. 8. 
Hunt, Mineral Statistics, 1870, p. 8. 
‘‘ Tin-ore is now being got—under licence from the Duchy—from the 
‘‘ sand brought down and deposited by the river Cober, at the head of the 
‘‘ Loe-pool during winter, when the water rises some feet above the ordinary 
‘“‘ surface.” Mr. Rocrrs, MS. 
‘© Small streams which rise amongst the hills south of Camborne, Tuck- 
‘‘ingmill, and Pool, are—in various parts of their course to the sea near 
‘“« Gwithian—used for (dressing ) washing the produce of Condurrow, Dolcoath, 
‘“‘ Oook’s-kitchen, North Roskear, Wheal Crofty, Tin-Croft, and some other 
‘‘ mines ; but from each mine they carry off, in suspension, small quantities 
‘‘ of tin-ore still adhering to its matrix. The separation which stamping 
‘©and other processes had failed to accomplish at first, is, however, gradually 
“‘ effected by the action of running water; portions of ore are therefore 
“ collected from lower parts of the stream, by appliances exactly similar to 
“those which had been inefficient to arrest them above.” THomas, (Captain 
Charles), Cornwall Geol: Trans: viii, p. 354, Notet. 
Tt has been stated that of late thirty thousand Pounds worth of tin-ore 
has been collected annually from these streams. 
“The ore which escaped from Gongo Soco [in Brazil] was treated a 
“ second time at Taboleiro, about a mile from the mine, and yielded, on an 
‘average about a (Troy) pound of gold per month.” HxEnwoop, Ibid, viii, 
p. 354, 
