Crushed limestone for furnace flux, not in cluded in the above summary, amounted to 23,603,508 tons, valued at $13,936,882, an average of 59 cents per ton.
The quarrying of limestone was carried on quite generally throughout the United States in 1916, Pennsylvania and Ohio showing the greatest activity, with values, respectively, of $8,167,639 and $5,337,085. Other States which contributed very largely to the grand total were Indiana, with a value of $4,657,813• Illinois, $3,362,751; Nev York, $3,035,786; Michigan, $2,389,763, and Missouri, $1,990,419. In addi tion to these, Kentucy, Virginia, West Vir ginia and Wisconsin each showed an output in value $1,000,000 These 11 States pro duced nearly 80 per cent of the entire 1916 limestone production.
Although 30 States shared in the total out put of granite in 1916, the bulk of the pro duction came from eight States. Vermont's value was $2,500,579; that of Massachusetts, $1,5197,150, and that of North Carolina, $1,798, 087. In addition to these, California, Maine, Minnesota, New Hampshire and Wisconsin each contributed a value of above $1,000,000.
Marble was quarried in 22 States, but nearly half of the total production was by Vermont — in value, $3,062,743. Most of the remainder came from Tennessee ($1,000,266) and Georgia ($903,343).
Exports.— The export trade of the United States in products of its quarries is well nigh world wide. In 1916 the value of such ex ports was $1,480,750, of which a value of $693, 723 (about 47 per cent) went to Canada. Great Britain appears in the record as the cus tomer of next importance, with purchases amounting to $169,672. Then follow in order
Italy, $93,843; Cuba, $84,242;" British East Indies, $62,311; Argentina, $42,194; France, $34,908; Australia, $21,753; Panama, $2086; British South Africa, $20,730, and Brazil, $17,365.
Imports for the same year amounted in value to $959,367, of which sum $723,411 repre sented marble and onyx ($34,359), of which less than 20 per cent was manufactured. Most of the marble ($640,805) came from Italy, and the remainder from Mexico and France, with a small quantity from Greece. Mexico and Greece supplied .the onyx., There exists In the stone industry thine tendency toward the concentration of capital and the formation of stock companies as in other branches of trade. This is due not altogether to the desire for combination with a view to controlling trade, but in part at least to change which has taken place in the character of the industry. The matidlatinn ,of lastly machinery and the fact that the ,quarries in many cases now contract not merely to fur nish the stone, but to furnish it cut and ready for its definite position in the structure, even if they do not contract to set it in place as well, involve a larger capitalization and supply of available funds. Consult Gillette, H, P., 'Handbook of Rock Excavation' (New York 1916) ; Greenwell, A., and Elad,en, J. V., 'Practical Stone Quarrying' (New York 1913). See BLASTING; BUILDING MATERIALS; MINES AND MINING; MINING AND MILLING.