ASPHALTUM AND BITUMINOUS ROCK 401 



series of agitating dmms, which separate the sohition contain- 

 ing the asphaltum from the taiUngs; the sohition flows hy 

 gravity to the stills, and the gasoline is removed and recovered 

 for repeated use. The residue in the still, consisting of as- 

 phaltum of 99 per cent purity, is cooled and harroled for 

 shipment. 



The product of the companies operating these mines is 

 chiefly a bituminous sandstone, largely utilized for paving 

 purposes on the Pacific coast, where, owmg to the simple 

 method of its preparation and the cheap water freight rates, 

 it competes successfully with other asphaltum j)aving mix- 

 tures. There is no production of asphaltic hmestone in 

 CaUfornia worthy of mention. In addition to the producers 

 of asphaltum from natural rock in this state, a large numl)er 

 of crude petroleum refineries have been established, which 

 furnish a considerable quantity of by-product asphaltum ol)- 

 tained from the crude petroleum oils of California. By- 

 product asphaltum possesses similar properties to that oi)- 

 tained from the rock deposits, and replaces it to a considerable 

 extent in paving and other uses. 



The kno^^^l asphaltum deposits in Indian Territory are 

 almost entirely within the reservation of the Chickasaw nation. 

 Development work has been started at Ravia, Dougherty, and 

 Tar Springs, and at the two former locaUties soft asphaltic 

 sands and a bituminous limestone have been mined, and at the 

 last named place asphaltic sandstone is produced. Graham- 

 ite is mined near Tar Springs, the product being hauled to 

 Comanche, 18 miles distant. Considerable prospecting by 

 drills has been accomplished in the vicinity of Tar Springs, 

 and other deposits of asphaltic sands have l)een found below 

 the surface deposit, separated therefrom by beds of red and 

 blue clay and shale. The thickness of the asphaltic sand beds 

 varies from 3 to 20 feet, while the clay and the shale strata 

 range from 5 to 40 feet in thickness. The lower limit of tiie 

 asphaltic sand has been found at a depth of 600 feet from the 

 surface. The present supply of asphaltum is ol)tained by 

 open cut working. The sandstone caj)ping is remo^•cd by 

 drilling and blasting, and the soft asphaltic sands are broken 

 up by blasting and removed by plows and scrapers to the re- 



Vol. 6—26 



