38 



PALi^ONTOLOGICAL BOTANY. 



marking how mud was laid down on the plants, and bearing 

 evidences of vigorous vegetation on neighbouring land, from 

 which currents brought down the fine sediment, mingled with 

 broken pieces of plants. 



The total thickness of coal in the English coal-fields is 

 about 50 or 60 feet. In the Mid-Lothian field there are 

 108 feet of coal. Coal-beds are Avorked at 1725 feet below 

 the sea-level, and probably extend down to upwards of 

 20,000 feet. They rise to 12,000 feet above the sea-level, 

 and at Huanuco, in Peru, to 14,700.* It is said that the 

 first coal-works were opened at Belgium in 1198, and soon 

 after in England and Scotland ; it was not till the fifteenth 

 century that they were opened in France and Gennany. 



The following calculations have been made as to the extent 

 of the coal formation in difierent countries, and the amount 

 of coal raised : — "f* 



Cou:n'tries. 



Square Miles of 

 Coal Formation. 



Great Britain and Ireland 



British North America 



United States 



Belgium 



France 



Prussia and Austria 



Saxony 



Eussia 



Japan, China, Borneo, Australia, etc. 



Total Produce of the World... 



5,400 



7,530 



196,650 



518 



1,719 



30 

 100 



Annual Production 

 of Coal in Tons. \ 



65,887,900 

 1,500,000 

 5,000,000 

 8,409,330 

 7,740,317 

 4,200,000 

 1,000,000 

 3,500,000 

 2,000,000 



99,237,547 



The total quantity of coal annually raised over the globe ap- 

 pears thus to be about 100 millions of tons, of which the produce 

 of Great Britain is more than two-thirds, and would be sufficient 

 to girdle the earth at the equator with a belt of 3 feet in thick- 

 ness and nearly 5 feet in width. The coal-fields of the United 

 States are nearly forty times larger than those of Great Britain. 



* Our Coal-fields, by a Traveller under Ground. 



t See Hall's Coal-fields of Great Britain, 18G1 ; Roscoe's Lec- 

 tures on Coal, Manchester, 18G6-67 ; Hunt's Mineral Statistics of 

 Great Britain; Taylor's Statistics of Coal, 1855-56. 



