702 GEOLOGY. 



by South Wales. The abstraction of this enormous mass from the bowels of the land, 

 increasing every year with an augmented population, has created immense vacuities 

 beneath the surface soil, which not unfrequently proclaims their existence by its 

 subsidence. The south Staffordshire coal district has been aptly compared to a rabbit 

 warren, so completely has the country been bored into and burrowed under. Houses and 

 rows of buildings, swerving from the perpendicular, with large cracks in the walls, caused 

 by the sinking of the ground into old workings, form a common spectacle in that 

 locality ; and many have long remained tenantless, owing to the danger involved in 

 occupying them. There is an instance in the parish of Sedgeley of a church and 

 parsonage house, recently erected, composed of wooden frame- work, which will admit of 

 their being screwed up again into the perpendicular, when thrown out of it. 



The foreign localities of coal are far too numerous to be mentioned. It occurs in Spain, 

 Sweden, France, Belgium, and largely in various parts of Germany and Russia ; in the 

 Indian and Birman empires, in China, Australia, and around the Persian gulf; in 

 Melville island, within the polar circle ; and of the northern part of the western 

 continent, generally, Professor Hitchcock remarks, that its " coal deposits are among 

 the largest in the world. The anthracite deposit of Pottsville is sixty miles long and 

 about five broad ; that of Shamokin, commencing near Lehigh, is of the same length and 

 width ; and that of Wilkesbarre is forty miles long and two broad. In some instances a 

 single seam of coal in these strata is sixty feet thick ; and near the middle of the valley, 

 between the Sharp and Broad mountains no less than 65 seams have been counted. The 

 bituminous coal-field, embracing the western part of Pennsylvania, and a part of Ohio, 

 extends over an area of twenty-four thousand square miles ; the largest accumulation of 

 carbonaceous matter probably in the world. In fact, the bituminous coal measures can 

 perhaps be traced almost continuously from Pennsylvania to the Mississippi, and even 

 into Missouri, two hundred miles west of that river. Indeed, coal exists on the eastern 

 slope of the Rocky Mountains ; and it would not be strange if this should be found to 

 be the western outcrop of coal-bearing strata, whose eastern extremity is in Pennsylvania. 

 At any rate, it is certain that extensive seams of bituminous coal exist in Pennsylvania, 

 Virginia, Ohio, Indiana, Illinois, Michigan, Tennessee, Alabama, and Missouri." 



The vegetable origin of this important product is established by the most irrefragable 

 evidence, and is now universally admitted. Mr. Hutton states, that if any of the three 

 varieties of coal found near Newcastle be cut into very thin slices, and submitted to a 

 microscope, more or less of vegetable structure can be recognised ; and Dr. Macculloch 

 solved the problem of this substance by a series of interesting experiments, successfully 

 tracing the transition of vegetable matter from peat-wood, brown-coal, lignite, and jet, 

 to coal, anthracite, graphite, and plumbago. The imbedding of vegetable matter in the 

 earth the exclusion of the atmospheric air and the confinement of the gaseous 

 elements evolved, are the three necessary conditions of the process of change, and 

 according to the completeness in which they have co-existed, have we a perfectly formed 

 coal, which requires the microscope to detect the traces of vegetable structure, or a mass 

 only partially carbonised, the nature of which is at once proclaimed by a clear develop 

 ment of vegetable forms. In many coal-fields, the remains of vegetables are found, 

 retaining in wonderful perfection and beauty their original contour, even the most delicate 

 parts, and exhibiting little change at all excepting that of colour. Dr. Buckland 

 remarks of the Bohemian coal mines : " The most elaborate imitations of living foliage 

 upon the painted ceilings of Italian palaces, bear no comparison with the beauteous 

 profusion of extinct vegetable forms, with which the galleries of these instructive coal 

 mines are overhung. The roof is covered as with a canopy of gorgeous tapestry, 

 enriched with festoons of most graceful foliage, flung in wild, irregular profusion over 



