﻿Vol. 64.] HIGH-LEVEL PLATFOKMS OF BODMIN MOOK. 387 



the bulk of the old stream-works are situated. These ore-bearing 

 deposits have evidently been submitted to the action of running 

 water, which has swept the 'head' or wash just described into the 

 valleys, washed away the finer and lighter components, and con- 

 centrated a more or less rounded gravel, amid which the tin-ore has 

 been dropped on account of its higher specific gravity, although the 

 size of its component grains is small. Generally speaking, it is 

 mainly in such assorted wash that stream-tin work has been carried 

 on at lower altitudes and farther south. But the old wash of the 

 higher levels (the unassorted wash or ' head ') retains most of the 

 fine-grained material; the tin-ore in it is less concentrated, and it 

 forms a lower-grade deposit, of which a larger quantity must be 

 turned over to obtain a return equal to that of the low-level 

 assorted wash. 



* Unassorted wash ' has been worked in many places on the 

 hill-sides, and it is a source of surprise that the stream-workers 

 should have been able to pick out the richer deposits despite 

 their isolated position. The work in such cases progressed up hill, 

 and was usually stopped at a point where one or more veins were 

 discovered, too small generally to pay for working to any depth, 

 although the soft decomposed portion close to the surface was 

 generally extracted ; these veins have been responsible for the 

 local enrichment of the wash in their immediate neighbourhood. 



Curiously enough, the very cause that led to the abandonment of 

 the workings several years ago has now brought about its revival. 

 .For, together with the tin-ore derived from the veins, there was 

 associated another mineral, wolfram, which could then only be 

 separated from the tin by hand-picking, a process which became 

 impracticable when the wolfram-fragments fell below a certain size. 

 At the present time the wolfram, formerly a costly nuisance, is 

 more valuable than the tin itself, being used in the manufacture of 

 high-speed steel and armour-plates, and separation from the tin-ore 

 can now be easily effected by the electromagnet. The history of 

 this local wolfram-working, which marks the survival of streaming, 

 is so curious that it is worth recordino;. 



The Buttern-Hill Wolfram-Deposit. 



When the great marsh of Bowithick, south of Davidstow Moor, 

 was turned over for tin many years ago, the streamers encountered 

 a large amount of wolfram ; and at the foot of Buttern Hill it was 

 so abundant that work was stopped altogether. The wolfram was 

 in such big pieces, that, much of it was picked out by hand and. 

 thrown on one side in little heaps. These heaps of glistening 

 mineral attracted the attention of a lad, who, thinking them valu- 

 able, hid some, and took specimens to the smelting- works, where 

 he found that they were worthless. Many years afterwards, when 

 the mineral had become valuable, he was reminded of his store 

 by the enquiries after wolfram, and ascertaining that it was the 



