THE OLD COAL-MEASUEES. 



THE CARBONIFEROUS OR COAL SYSTEM ITS PLACE IN GEOLOGY 

 NATURE AND COMPOSITION OF ITS STRATA ITS UPPER, MIDDLE, 

 AND LOWER DIVISIONS VARIETIES OF ITS COALS APPARENT 

 CAUSES OF IGNEOUS ROCKS ASSOCIATED WITH ITS STRATA ITS 

 FOSSIL FLORA AND FAUNA EXUBERANCE OF ITS PLANT-LIFE 

 GENERAL GEOGRAPHICAL CONDITIONS OF THE PERIOD THE COAL- 

 MEASURES AS AN ECONOMIC REPOSITORY VARIETY AND VALUE OF 

 ITS PRODUCTS THEIR INFLUENCE ON HUMAN CIVILISATION AND 

 PROGRESS EXTENT AND DURATION OF PALEOZOIC COAL-FIELDS. 



THE reader who has perused the preceding sketch, will have 

 seen that coal is a product of every geological epoch, from 

 the peat now accumulating on the earth's surface down 

 through the lignites of the tertiary, the true coals of the 

 secondary, and the harder coals and anthracites of the pri- 

 mary periods. But though thus occurring in all stages of 

 the earth's history, it is in the so-called " Carboniferous Sys- 

 tem " that it appears in numerous seams, in many varieties, 

 and in great thickness and continuity over extensive areas. 

 It is from this old system that Britain, France, Belgium, 

 Eussia, China, Australia, and the United States of Ame- 

 rica obtain their main supplies ; hence the familiar terms 

 " Coal-Eormation " and " Coal-Measures," as if it were the 

 only series of coal-yielding strata in the crust of the globe. 

 In Britain it generally rests on a series of reddish sand- 

 stones, and is in turn overlaid by another series of red 

 sandstones ; the former being naturally designated the 



