destination of their slate. As the statistics collected by the Geological Survey are obtained from the quarrymen rather than from the dealers and jobbers the figures obtained for the distribution of the sales of slate in 1923 were not very satisfactory, although some of the largest dealers cooperated with the Survey by furnishing statements of the distribution of their sales for the year. Among the large jobbers of slate are the Vendor Slate Co., Easton, Pa., selling the roofing slate of many quarrymen in Pennsylvania and Vermont; the Natural Slate Blackboard Co., Pen Argyl, Pa., distributors of slate blackboards; the American Slate Works and the National School Slate Co., Slatington, Pa., distributors of school slates; and the Structural Slate Co., Pen Argyl, Pa., distributors of structural and sanitary slate, electrical slate, and slate for billiard-table tops. These companies act chiefly for the Pennsylvania quarries. In New York and Vermont the larger producing companies and other jobbers and dealers act as distributing agents.

The table below shows the shipments in 1923 by States of such products, as were reported. They range from three-fourths to practically all of the total sales reported. The States are grouped to follow as closely as possible the territories covered by the different freight associations.

Distribution of slate products reported to the Geological Survey in 1923, grouped by general freight districts

New England States: Maine, New Hampshire, Vermont, Massachusetts, Connecticut, and Rhode Island. Middle Atlantic States: New York, New Jersey, Pennsylvania, Delaware, Maryland, District of Columbia, Virginia, and West Virginia...

South Atlantic States: North Carolina, South Carolina, Georgia, and Florida. Northeastern Central States: Ohio, Indiana, Illinois, and Michigan... Southeastern Central States: Kentucky, Tennessee, Mississippi, and Alabama.. Northwestern Central States: Wisconsin, Minnesota, North Dakota, South Dakota, Nebraska, Iowa, Kansas, Missouri, and Colorado.

(square
feet)

vada, Arizona, and New Mexico..

Pacific Coast States: Washington, Oregon, and California..

Exports.....

442

3,394

562, 226 3, 814, 067
91, 267

Total distribution reported.
Total sales.....

a1, 596, 224 a1, 612, 133
2, 182, 6202, 182, 890

562, 2263, 905, 334
451, 160 4, 415, 710

a Small amount of structural slate included with electrical.

So far as these figures show, structural slate, although shipped throughout the United States, finds its largest market at present in

the New England and Middle Atlantic States, which are nearest to the source of the material, and the northeastern and northwestern Central States, which include the markets of Chicago, Cleveland, Cincinnati, Denver, St. Paul, Minneapolis, St. Louis, and other cities of considerable size. The largest markets for electrical slate are in the same groups of States as those for structural slate, the consumption being chiefly concentrated in the industrial centers of Schenectady, Pittsburgh, Boston, Newark, Philadelphia, Chicago, Cleveland, and other cities of the Middle West. Slate for blackboard and bulletin boards is shipped throughout the United States, but slate for school slates is mostly shipped abroad. (See p. 57.) Slate for billiard-table tops finds its chief market in the Middle Atlantic and northeastern Central States. Sales of slate for grave vaults and covers are apparently confined at present chiefly to the Middle Atlantic, New England, and northwestern Central States. In the northeastern Central States, where other slate products have found considerable market, sandstone quarried in Ohio is largely used for vaults and covers. As shown in the foregoing table the reported shipments in 1923 of slate for this purpose were larger than the production given in the table on page 55. This difference may be due to increased sales from stock or to the classification of slate by quarrymen as "structural and sanitary," although it may have been afterwards sold by the dealers for vaults and covers.

It is to be regretted that adequate figures showing the shipments of roofing-slate shingles by States were not obtained. The distributors of this slate product were not willing to furnish figures of their shipments by States. The figures for shipments that were received, however, showed a wide range of markets. Shipments of less than 30 per cent of the output showed that slate shingles were shipped to more than half of the United States. California, Washington, Utah, Montana, Louisiana, Florida, and Georgia received small portions of the output. The greater part, however, was distributed east of the Mississippi and, with the exception of Louisiana, north of South Carolina and of Ohio River. Slate granules and flour were shipped mostly to plants manufacturing prepared roofing, near Boston, New York, Philadelphia, Cincinnati, Chicago, and New Orleans. It is possible that some of the slate noted as shipped to the different States may not have been consumed in those States but may have been reshipped by dealers or distributors.

GYPSUM

By K. W. COTTRELL

PRODUCTION

In 1923 for the first time the quantity of gypsum, mined in the United States exceeded 4,000,000 short tons. The output showed an increase of 26 per cent over that of 1922.

Of the total quantity of crude gypsum sold only 3 per cent was sold for use in agriculture, a decrease of 75 per cent from the sales of 1922. Kansas, Montana, and Oregon, however, showed slight increases. Sales of agricultural gypsum decreased over 90 per cent in each of eight States, more than 50 per cent in each of three others, but less than 20 per cent each in California and Virginia.

The total quantity of gypsum sold crude to Portland cement factories in 1923 was 15 per cent greater than in 1922. New York was the only State which reported a decrease (15 per cent) in such sales; increases in other important producing States ranged from 10 per cent in Oklahoma to 67 per cent in Iowa.

Sales of Keenes cement increased 6 per cent over those of 1922, but the receipts from sales decreased. The The average value per ton dropped from $14.75 to $13.88.

Plaster board, tile, and blocks were made in 14 States at plants operated by the original producers of the gypsum used in their manufacture. Plants of firms that make these products but do not mine gypsum are not included here, the gypsum they use being already accounted for as plaster sold by the original manufacturers. The figures given for boards and blocks therefore do not include the entire production of these articles in the United States. Wall board increased 64 per cent in quantity and 58 per cent in value, but the average value per ton decreased from $37.32 to $36.16. Blocks and tile increased 23 per cent in quantity and 30 per cent in value, and average value per ton increased from $12.20 to $13.07.

the

Gypsum produced and sold in the United States, 1918-1923

1923