68 Hull—Copper-bearing Rocks of Alderley Edge. 
was first discovered about six years ago. In the direction of 
the dip the rock is systematically mined by means of a series of 
shafts, of no great depth, worked by windlasses. The ores 
coat the outside of the particles of sand and the pebbles of 
quartz, and the metal is extracted by a chemical process in the 
same way as at Alderley, presently to be described. The 
miners are all Cornish men, and were, of course, greatly 
astonished when they found copper-ore lying in nearly hori- 
zontal beds of sandstone, instead of the nearly vertical lodes to 
which they had been all their lives accustomed. Together with 
the copper-ores, there occur here cobalt-ore, black oxide of 
manganese, and carbonate of lead. The percentage of copper- 
ore varies from 24 to 124. 
The beds which are worked for ore at Alderley Edge lie 
above the Conglomerate, and are marked 0? in the above list of 
strata. The rockis exposed ina large open work, which is tra- 
versed at the spot where the reservoir is made by a wide 
channel filled in with Boulder-clay. The open work has now 
been abandoned, and the richer portions of the rock are followed 
in underground tunnels, the trucks of stuff being drawn up to 
the works on tramways by a stationary engine. 
The sandstone is of a very soft uniform texture, and presents 
a face of about 40 feet, though fully 60 feet is metalliferous. 
It is stained in a series of rudely defined layers, variously co- 
loured green, umber, or black, according to the nature of the 
ore-dye, and, together with copper, there occur ores of cobalt 
and manganese, carbonate of lead, galena, barytes, and oxide of 
iron. ‘The following is the general arrangement of the courses 
of r 
ft. in. 
1. Yellowish sandstone . § 4 4 0 
2. Shaley clay, with a band of copper- ore at the bottom 2 6 
3. Ferruginous sandstone, with large nodules containing carbonate of lead 6220 
4. Cale bed. arnineted sandstone, containing mabe of cobalt* 4 6 
5. White compact sandstone, with carbonate of lead . 2 O 
6. Iron-stained sandstone, with cobalt, manganese, and iron 5 Ie @) 
Of the above minerals four are extracted—namely, the lead, 
cobalt, copper, and iron. The carbonate of lead is in the form 
of crystals, dissemimated thoughout the rock, and not very 
easily to be distinguished by the eye. Itis separated from the 
matrix by maceration and washing, and is then ready for 
smelting. In quantity it varies from 30 to 40 per cent. of the 
rock. The cobalt and manganese are generally associated in 
the rock, and are scarcely ‘distinguishable from one another. 
* Earthy cobalt, or ‘Asbolan,’ for an analysis of which see Bristow’s ‘ Glossary 
of Mineralogy,’ p. 120. ; 
