PALEOZOIC TIME — DEVONIAN. 



609 



A barrel equals 42 gallons. The yield of Pennsylvania in 1859 was 2000 barrels ; in 1860, 

 600,000 barrels; in 1870, 5,260,234 barrels; in 1880, over 26,000,000 barrels. In 1892, the 

 yield was over 4,000,000 barrels less than in 1891. 



Por a report on the oil and gas regions of Pennsylvania, with maps, see Rep. I 5, of 

 the Penn. Geol. Surv., by John P. Carll, 1890 ; and for Ohio, Rep. vol. vi., on Economic 

 Geology, by E. Orton, 1888 ; and for Kentucky, Rep. by E. Orton, 1891 ; and for Statistics, 

 MineraJ Besources of the U. S., by D. T. Day, 8vo. ; U. S. G. S., volumes for 1891 and 

 1892, issued inl893. 



926-930. 

 929. 



927. 



928. 





Tig. 926, Archseopteris Halliana ; 927, A. minor ; 928, Aneimites obtusus ; 929, Sigillaria Vanuxemi ; 930, Lepi- 

 dodendron Chemungense. Figs. 926, 930, Hall ; 927, 928, Lesquereux ; 929, Vanuxem. 



Dana's manual — 39 



