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Trof, Milne — Across Europe and Asia. 



section, marked E, we find a series, the upper three parts of which 

 are respectively sandstone, Fnsulina-\\m.Q^ton.e, and sandstone, and 

 correspond to the West Ural section. An appearance of this sort 

 might be explained by assuming that the limestone was deposited 

 in deeper water than the sandstone. After the limestone had been 

 deposited up to the point 1 in deep water, by oscillation the sea 

 became shallower towards the east or E, and the limestone then be- 

 came covered as far as the point 1 with deposits from shallow water. 

 Next we may imagine the water to have deepened, and the lime- 

 stone, so to speak, encroached upon these deposits which were being 

 laid down in shallower water. In this way it was enabled gradually 

 to overlap the sandstone as far as the point 2, when another oscilla- 

 tion in the opposite direction set in, and the agencies producing the 

 limestone had to retreat towards deeper water before the advancing 

 heavy gritty material of the shore-line. At the point 3 the limestone 

 is indicated as again advancing towards 4, which would suppose still 

 further oscillation. If the intercalations of limestone amongst sand- 

 stone in the Ural mountains be of the nature I have here suggested 

 and described, it is possible that they were produced in the manner 

 indicated. 



One great distinction between the sections of the Coal-fields upon 

 the Western Ural and those to the south of Moscow, is that the 

 former contain many large beds of sandstone which are absent from 

 the latter. Just as we are able to infer from somewhat analogous 

 changes which are observed when travelling northwards over the 

 Coal-measures of Great Britain, that much of our early Carboniferous 

 land lay somewhere towards the north, so may we infer that much 

 of the Carboniferous land of Eussia lay somewhere towards the east 

 rather than to the west. 



Upon the eastern or Siberian side of the Urals the sections of the 

 Coal-measures present still greater differences as compared with the 

 Moscow series. So far as explorations have yet been carried, all the 

 upper stages which we have mentioned in the other sections are 

 apparently wanting, and we commence with the Productus-lmxesionQ. 

 Beneath this comes sandstone and conglomerate, amongst which 

 small quantities of coal are found. Still lower there is a second lime- 

 stone, also containing Productus gigas, which overlies sandstones and 

 conglomerates, amongst which true beds of coal with underclays occur. 



