No. 6. DEPARTMENT OF AGRICULTURE, 531 



GRAPHITE 



During the year 1910, Pennsylvania produced G9G tons of crystal- 

 line graphite, valued at $82,194. This product was mined in Chester 

 county. Graphite was formerly mined at Boye.rtown and Mertztown 

 but these mines are, at present, not producing. 



STONE INDUSTRY 



Pennsylvania leads all other states in value of its production of 

 stone of various kinds. These include Granite, Trap Rock. Marble, 

 Sandstone and Limestcme. The value of its limestone product ex- 

 ceeded that of anv other state. The total value of the various kinds 

 of stone produced in 1910 was |8,621,937 as against $70,520,584, 

 the value of the production of the United States; Pennsylvania's 

 quota being 11.27 per cent, of the whole. 



FELDSPAR 



The production of feldspar in Pennsylvania in 1910 was 15*091 

 tons, value-d at |104,751. The mining of feldspar in Pennsylvania 

 is confined to Chester and Delaware counties, 



QUARTZ 



The quartz industry of Pennsylvania is confined to Adams and 

 Chester counties, there being in 1910 but two producers, the Colum- 

 bia Flint Company of Marietta, and H. T. A. Rhodewalt of Chester 

 county. The quality and value of the product mined are not avail- 

 able for publication, but the combined production of Peun.sylvania 

 and Maryland was 13,588 tons, valued at |71,864. 



SAND AND GRAVEL 



The sand and gravel produced in the United States in 1910 

 amounted to 69,410,4.30 tons and was valued at |21 ,037,630, Of this 

 amount, Pennsylvania produced 5,670,509 tons, valued at |2,974,221. 

 The quantity of the said was 4,253,103 tons valued at 12,007,215. Of 

 gravel, there were produced 1,423,347 tons, valued at |307,000. 



The classification of the sands is as follows: Glass-sand, Moulding. 

 Building, Fire, Engine, Furnace and other sands. More sand and 

 gravel were produced in 1910 than in any year previous to this. 



PORTLAND CEMENT 



In 1910, the total production of Portland cement in the United 

 States was 76,549,951 barrels, valued at $08,205,800. Pennsylvania 

 is again in the front rank, its production being 20,075,978 barrels, 

 valued at $19,551,208. It produced over three times as much Port- 

 land cement as its nearest competitor (Indiana). 



NATURAL CEMENT 



The output of Natural cement has rapidly declined and will prob- 

 ably continue to do so until better methods of treatment can be found 

 whereb}' the natural cement can be made equal in tensile strength to 

 that of the best grades of Portland cement. 



