ON THE DETRITAL TIN-ORE OF CORNWALL. 217 
them, however, many small tin-stream-works were still industriously 
' wrought, by speculative workmen, either on ancient detritus (whole- 
ground), or on matter imperfectly gleaned by their predecessors. 
The works were drained either by open-cuttings ;—by hand-pumps ; 
—or by little lifts worked by water-wheels, which seldom exceeded, 
and were often less than, six feet in diameter. Great part of the 
tract—at length exhausted of tin-ore—has been, for some time, 
successfully cultivated, and in the portion yet unenclosed a few 
inconsiderable spots only are now under treatment. 
On the northern side of the Moor three sections are still open 
to inspection. 
At Golden-stream, about half a mile south-east of Castle-an- 
Dinas, in Saint Columb-major, ancient works, which have been 
lately resumed, exhibit— 
(1). Vegetable mould ..........eeeeeeee cote ce sceneccees 6 inches ;— 
(2). Angular and subangular masses of slightly micaceous 
clay-slate, compact and thick-lamellar schorl-rock,* 
quartz, many vein-stones of the slate series, and 
here and there a stone of granite mixed with fels- 
pathic clay, and other disintegrated ingredients of 
the almost-adjoining elvan-cowrse ......seeeseeees 5 to 6 feet ;— 
Large lumps of peat are imbedded in portions of this detritus which 
had been previously moved. : 
(3). The tin-ground scarcely differs from the matter which 
~ overlies it, except that elvan is more abundant, and 
that small proportions of tin-ore—usually in a state 
of gravel or sand, but sometimes as minute unfrac- 
tured crystals—are mixed with the otheringredients 2 ,, 3 ,, 
The Shelf—at the part now under treatment—is disintegrated elvan con- 
taining, here and there, a few particles of cassiterite. 
Wet and Dry almost adjoins Golden-stream, and differs from it 
so slightly, that a repetition of the same detail seems unnecessary. 
Immediately north-west of a railway-bridge over the high-road 
between Lanivet and the Indian Queens, both the refuse of earlier 
streamers and unwrought (whole)-ground are now laid open in the 
* ‘Felspar, quartz, and shorl, either uniformly mixed and blended 
together, or arranged in alternate stripes and layers [occur at] Castle-en- 
Dinas, and the adjacent hills which bound the Tregoss Moors on the north.” 
BoaseE, Cornwall Geol: Trans: iv, p. 253. 
