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THE NATIONAL GEOGRAPHIC MAGAZINE 



• Photograph from U. S. Geological Survey 



AN OUTCROP OP RICH OIP SHAPE IN UTAH 



The flexibility of the rock indicates its heavy oil content. The oil shales of Scotland, 

 which have been profitably worked for 70 years, yield about 25 gallons to the ton of rock. 

 The shales of the western United States run about 40 or 50 gallons to the ton and those 

 of one deposit gave 90 gallons to the ton. 



shale is so huge that the petroleum re- 

 serve becomes almost 'insignificant by 

 comparison. As a result of only a par- 

 tial investigation, it is estimated that the 

 oil in the shale ranges of Colorado alone 

 amounts to 20,000,000,000 barrels. There 

 are mountains — indeed, ranges of moun- 

 tains — which for many miles carry thick 

 beds of rock that yield 30 to 50 barrels 

 of oil to the ton. 



More recently the State geologist of 

 Colorado has reported that in northwest- 

 ern Colorado beds of commercially work- 

 able rock that average more than 20 feet 

 in thickness and that will yield at least 

 36 gallons of oil to the ton are found 

 in an area extending over 1,500 square 

 miles. These figures show a content of 

 24,000,000 barrels of oil to the square 

 mile, or a total of 36,000,000,000 barrels 

 for the area. Either twenty billion or 

 thirty-six billion is sufficiently impressive. 



The Geological Survey also estimates 

 that 300,000,000 tons of sulphate of am- 

 monia, worth, at before-the-war prices, 

 about $60 a ton, could be recovered as 

 a by-product in the extraction of the oil. 

 This by-product would be sufficient to 

 enrich most of the farms in the great 

 Mississippi Valley. 



In addition to the oil rock in Colorado, 

 that of Utah must be considered. The 

 government is now investigating these 

 deposits in detail and has already stated 

 that they are probably as extensive as 

 those in Colorado and are equally rich in 

 oil. Oil shales have been examined also 

 in Nevada, Wyoming, California, Mon- 

 tana, and other States. Tests of speci- 

 mens from Wyoming show from 30 to 

 50 gallons to the ton, and samples from 

 Nevada have produced from 40 to 100 

 gallons of oil to the ton. One 10-foot 



