Review of Recent Geological Literature. 381 
The report on iron ores, by John Birkinbine, occupies 28 pages, 
showing a product of 16,005,449 tons (long tons, of 2,240 pounds), a 
slight increase over 1895, and nearly ecjual to the maximum iron ore 
production, which was attained in 1892. A very valuable report on 
iron and steel and allied industries is presented by James M. Swank, 
the general manager of the American Iron and Steel Association, in 90 
pages. This includes statistics for long series of years in the United 
States and in all iron-working countries, with tables of their produc- 
tion, and of their exports and imports, of iron and steel and of coal 
and coke. A final table states the railroad mileage of all parts of the 
world at the end of the year 1895, the United States having 181,717 
miles, Europe in total, 155,284 miles, and the entire world, 433,953 miles. 
The product of gold by the United States in 1896 was the greatest 
ever attained, being valued at $53,088,000. It was an eighth more than 
in 1895, and a quarter more than in 1894. The commercial value of the 
silver prodviced was $39,655,000, .showing also a considerable increasa 
over the preceding years. 
Copper production attained the value of $49,456,603, of which 59 per 
cent, was exported. In similar manner each branch of our mining, 
quarrying, clay-working, and other industries developing the geologic 
resources of the United States is noted in much descriptive detail, 
statistics, and comparison with previous years and other countries. 
Among the contributors of these special reports are Charles Kirch- 
liof?, on copper, lead^ and zinc; R. L. Packard, on aluminum: John 
Birkinbine, on the ores of iron and manganese; Joseph Wharton, on 
nickel and cobalt; Edward W. Parker, on antimony, coal, coke, asphal- 
tum. soapstone, abrasive materials, sulphur and pyrites, gypsum, salt, 
fluor spar and cryolite, mica, asbestos, mineral paints, and barytes; F. 
H. Oliphant, on petroleum and natural gas: William C. Day, on stone; 
JefTerson Middleton, on clay-working statistics; Heinrich Ries, on the 
claj'-working industries, and on feldspar and quartz; Spencer B. New- 
berry, on Portland cement; Uriah Cummings, on rock cement; George 
F. Kunz, on precious stones: and Albert C. Peale, on mineral waters. 
The total value of the mineral products of the United States for 
the year 1896 is shown as $623,717,288, being about $1,090,000 more 
than in 1895, and two-fifths more than in 1880. 
For geologists, seeking knowledge of the mode of occurrence of 
valuable geologic formations and their origin (rather than the results 
of their working, which are of chief commercial importance), the most 
interesting paper of this report is by George F. Becker, on "The 
Witwatersrand Banket, with Notes of other Gold-bearing Pudding- 
stones," in 32 pages, with a map. The gold ores now worked on so 
vast scale in the vicinity of Johannesburg and elsewhere in the Trans- 
vaal are found to be m marine gravel and sand, stretching along the 
former southern shores of the African continent. In the more north- 
erly adjacent gold districts, extending into Mashonaland the gold 
occurs in veins, mostly in schists and granitoid rocks; and there many 
abandoned sites of former mining and smelting have been discovered. 
