66 

 TAB. CCCXXXVIII. 



X he upper figure came probably out of a large vein of 

 Tin, and is what the Cornish miners call Shoad Tin. It 

 occurs in the neighbourhood of the primitive formation 

 among alluvial deposits from it. It is much the same as 

 that in the veins, composed of more or less confused 

 masses of Crystals. These, and even the perfect Crystals, 

 are often found worn into pebbles in the streams, and are 

 termed Stream Tin, resembling common Flint Pebbles, 

 or Gravel Stones. They are of different colours, as here 

 figured, and may rjest be known in the first instance by 

 their superior and extraordinary weight in the hand. They 

 are also called Grain Tin when in grains or very small 

 portions. 



The streams are often conducted with much attention 

 over chasms and small valleys to the lower grounds, where 

 means are contrived, by washing, to collect large quan- 

 tities, separate from the mud and other matters, and equal 

 to that obtained by mining. There is moreover less trouble 

 in the separating and breaking for smelting. 



