Coal; its history and uses . uring the whole of the Carboniferousperiod. The subsidence went on at a slow but variablerate, and every now and then stopped altogether for atime. Our next step will be to mark out the boundaries ofthe sea in which the Carboniferous Limestone was principles which must guide us in this investigationhave been already explained, and the result of their appli-cation is the map in fig. 3. It would be wearisome to go into the details of theevidence for the position of every point on the coast-line;indeed, there are portions of that line so very conjectural 38
Coal; its history and uses . uring the whole of the Carboniferousperiod. The subsidence went on at a slow but variablerate, and every now and then stopped altogether for atime. Our next step will be to mark out the boundaries ofthe sea in which the Carboniferous Limestone was principles which must guide us in this investigationhave been already explained, and the result of their appli-cation is the map in fig. 3. It would be wearisome to go into the details of theevidence for the position of every point on the coast-line;indeed, there are portions of that line so very conjectural 38 COAL. that perlia,ps it will be only prudent to observe a judiciousreticence respecting them. One or two of the moresalient points in the method employed in the constructionof the map must however be noticed. The northern andsouthern boundaries of the sea are fixed by the following Fig. showing the general distribution of land and water during the forma-tion of the Carhoniferous Limestone of Great Britain and considerations. The Carboniferous Limestone of Derby-shire is from top to bottom a succession of beds of verypure limestone, many of which can even now be seen to bewholly made up of the hard parts of marine are occasionally thin partings or v?ayboards of clay CHAP. II. THE GEOLOGY OF COAL. 39 or shale between the limestone beds, but they are few innumber and very thin. I once measured a section whichshowed more than 1,500 feet of limestone, and if all theclay bands which occur in that section were laid one onthe top of another, they would not make a bed of morethan a few yards thick. The Carboniferous Limestonemaintains the character throughout Lancashire andYorkshire. Derbyshire, Yorkshire, and Lancashire therefore werein early Carboniferous times covered by portions of thesea, so far removed from land that no sediment found itsway out to them. When we reach Cumberland, the Carboniferous Lime-stone undergoes an important change. It still co
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlo, booksubjectcoal
