44 A Geological Sketch of a Part of Cumberland, &ec. | 
blende increases in quantity, and the sienite passes by almost 
imperceptible gradations into a compact greenish-black green- 
stone; and on the summit of High-pike this greenstone forms 
the basis of an elegant porphyry with crystals of green felspar 
resembling the antique porphyry. Near High-pike a strong 
east and west vein is wrought for lead; but, from the hardness 
of the rock and the difficulty of separating the numerous ores, | 
am afraid not to much advantage. The vein stones in this mine 
are quartz and sulphate of ‘barytes, often so internately mixed 
as to form a very singular stone. The ores are sulphuret of 
lead, carbonate of lead, and phosphate of lead*, blende, copper- 
pyrites, grey copper ore, green and blue copper ore, and ma- 
lachite. The galena is antimonial, and is very rich in silver, 
yielding in the refining furnace about 60 ounces in the ton. I 
traced this vein westward for about three miles to a place called 
Silver Gill, where there is a very fine section of it on the sur- 
face; it is about three fathoms wide and hades to the north at 
an angle of about 65°. There is a tradition in the county, that 
at this place a rich silver mine was wrought in the time of 
queen Elizabeth, and certain it is that there are remains of very 
extensive workings. An attempt has been made last spring to 
recover this mine, for which purpose a trench has been cut across 
the direction of the vein so as to bore the rock ; and although 
this trench is not more than 200 yards from the old works, the 
vein has not been found. The cause of failure is, that the sienite 
is here covered by grau-wacke slate, into which the vein does 
not penetrate: this is different from what has been observed in 
Cornwall, where the veins traverse both the granite and grau- 
wacke slate; and I consider it as an interesting fact, since it so 
decidedly marks the difference between these rocks. The clay- 
slate and hornblende slate on the summits of Skiddaw and Sad- 
dieback, with the granite gneiss and mica-slate, and the sienite 
of Carrick and Caldbeck Fells, must therefore belong to the pri- 
mitive class of rocks; whilst the grau-wacke and grau-wacke 
slate which entirely surrounds these mountains are transition 
rocks. Some other veins have been wrought for copper in the 
sienite, but not to any great extent; nor do they appear to be of 
much value. Near Hatfield Hall is a vein containing the oxides 
of titanium and iron (the titan-eisan of the Germans) ;—By the 
bye, Why is this fossil not described in any mineralogical work ? 
* T found one specimen which I believe to be muriate of lead; it has 
the following characters ;— Crystal, a rectangular prism; colour, grayish- 
white ; lustre, highly resplendent adamantine, much superior to carbenate of 
Jead ; hardness superior to carbonat of lead. Not wishing to injure the 
specimen, I am not able to give any other of its characters. M 
Wit. 
