12 MAY 1928, Page 45

Of the American oil-wells sunk in accordance with the advice

of geologists 85 per cent. proved productive, whereas of those sunk at random only 5 per cent. were successful. This statement, quoted on the first page of Professor J. W. Gregory's Economic Geology (Methuen, 10s.), illustrates the importande of his subject. As we should expect from the author, this is a most admirable textbook, giving in a compact form the latest theories of the origin of various mineral deposits and accurate information as to their location and extent.