32 Dr. F. H. Hatch—The World’s Copper Supplies. 
(c) Some swires, and also valleys which are now permanent water- 
courses (to which, however, the streams in them are often obviously 
not adjusted) were directly formed by streams flowing from the 
ice-margin, whose load of sediment was deposited as a Kaim. The 
Burners Hills, already noticed as occurring on the Cotherstone Moor, 
have drainage channels connected with them, and the trench now 
occupied by the How Beck is the course of the escaping glacial waters. 
Dr. Smythe has also noticed the association of Kaims with dry 
valleys in Northumberland! The glacier-streams in such cases did 
not flow directly into lakes, and hence sometimes developed wide 
and deep trench-like slacks. 
(11) One of the most striking features of the superficial deposits 
of these two counties 1s the great amount of erosion and reassortment 
of glacial material that has taken place along the main valleys of 
the Tyne, a feature which was first clearly pointed out by Lebour. 
The river terraces formed from the Drift in this valley between 
Bardon Mill and Haydon Bridge by the Glacial and Postglacial 
streams can be traced as high as the 300 feet contour-line. This is 
in distinct contrast with the apparently small denudation of the 
kaims, drumlins, and other surface features of the Drift out of the 
line of the main valleys, but this may be deceptive as these mounds 
and ridges may be much reduced in size, although their original 
contour is still preserved. 
(To be continued.) 
The World’s Copper Production. 
By F. H. Harcn, Ph.D., MInst.C.E., Past-President of the 
Institution of Mining and Metallurgy. 
HE following article originally appeared in the Times Trade 
Supplement of August 28 last. It is here reprinted with 
some small additions by the courtesy of the proprietors of that 
Journal. 
The world’s consumption of copper at the beginning of the 
nineteenth century was some 15,000 tons® per annum. By the 
end of the century it had increased to over 600,000 tons per 
annum, and it reached a million tons by the year 1912. In 1917 it 
was close on one and a half million tons. 
This era was one of continually growing engineering activity, and 
the high consumption of copper in the latter part of the period was 
chiefly due to the great demand for that metal for purposes of 
electric power generation and transmission, while during the late 
1 Glacial Geology of Northumberland, p. 102. 
2 Geology of Northumberland and Durham, p. 15, and “ Certain Surface 
Features of the Glacial Deposits of the Tyne Valley’’: Nat. Hist. Trans. 
Northumberland, etec., vol. xi, pt. i, 1893. 
3 Metric tons throughout. 
