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capricious results of having cast iron at one time, and at another, 

 without any apparent reason, a superior quality of steel. 



THE GREAT WESTERN BITUMINOUS COAL AND SALT REGION. 



We come now to treat of that enormous area of nearly horizon- 

 tal strata which we have designated as the fifth great geological sub- 

 division of Virginia. It comprises as already shown, the large ter- 

 ritory lying between the western limits of the state and an irregular 

 line of mountain ranges as yet imperfectly determined, but nearly 

 coinciding with the eastern front ridge of the Alleghany, the Green- 

 brier mountains and the great Flat Top mountain. No section of 

 the whole state offers perhaps so much that is characteristic, either 

 in its physical geography or geological structure, and none holds 

 out richer promise of valuable practical results as soon as it shall be 

 systematically explored. By far the greatest portion, if not all, of 

 its strata, belong to a group of formations, distinguished not only 

 in America but through the world, as being the chief depositories of 

 bituminous coal. The title of the western carboniferous region 

 might therefore seem to be appropriately applicable to it, were we 

 sure that it might not convey to geologists and others a possibly 

 erroneous conception of the class of rocks which it comprehends. 

 While it is clearly referable to the general period of the bituminous 

 coal, it is by no means meant to signify that the rocks of the region 

 correspond with any exactitude, or indeed have any mineralogical 

 analogy to the strata which comprise the bituminous coal formation 

 of most geological writers. Nor, on the other hand, is it settled, 

 that the era of their production was precisely the same during 

 which the coal beds of other countries were deposited. We hold 

 it to be altogether premature, while the geologists of America are 

 yet only on the threshold of their researches, to endeavour to esta- 

 blish an identity of names between our strata and those of Europe. 

 This too frequent error, prejudges all the broader and more lofty 

 generalizations of the science. In a spirit of caution, therefore, 

 dictated by the many blunders daily committed in the nomenclature 

 of our rocks, we shall abstain from giving them a class of European 

 names, not always indeed applicable in the countries where they are 

 employed, and certainly less so in a region of widely different struc- 

 ture, separated by the great interval of the Atlantic. The little thai 



