396 THICKNESS or COAL BEDS. 



terials of older rocks, and from chemical precipitates,) on 

 those lower spaces into which the detritus of ancient ele- 

 vated regions was transported by the force of water ; the 

 second raising these strata from the sub-aqueous regions in 

 which they were deposited, by forces analogous to those 

 whose effect we occasionally witness in the tremendous 

 movements of land, that form one of the phenomena of mo- 

 dern Earthquakes. 



I am relieved from the necessity of entering into details 

 respecting the history of the Coal Fields of our own country, 

 by the excellent summary of what is known upon this inte- 

 resting subject, which has recently been given in a judicious 

 and well selected anonymous publication, entitled The His- 

 tory and Descriftion of Fossil Fuel, the Collieries, and Coal 

 Trade of Great Britain. London, 1835. 



The most remarkable accumulations of this important ve- 

 getable production in England are in the Wolverhampton 

 and Dudley Coal Field, (PL 65, Fig. 1,) where there is a 

 bed of coal, ten yards in thickness. The Scotch Coal field 

 near Paisley presents ten beds, whose united thickness is one 

 hundred feet. And the South Welsh Coal Basin (PI. 65, 

 Fig. 2,) contains, near Pontypool, twenty-three beds of coal, 

 amounting together to ninety-three feet. 



In many Coal fields, the occurrence of rich beds of iron 

 ore in the strata of slaty clay, that alternate with the beds 

 of coal, has rendered the adjacent districts remarkable as 

 the site of most important Iron foundries ; and these locali- 

 ties, as we have before stated, (p. 65,) usually present far- 

 ther practical advantage, in having beneath the Coal and 

 Iron ore, a substratum of Limestone, that supplies the third 

 material required as a flux to reduce this ore to a metallic 

 state. 



Our section, PI. 65, Fig. 1, illustrates the result of these 

 geological conditions in enriching an important district in 

 the centre of England, near Birmingham, with a continuous 

 succession of Coal mines, and Iron foundries. A similar re- 

 sult has followed from the same causes, on the north-east 



