402 
Prof. Milne — Across Europe and Asia. 
section, marked E, we find a series, the upper three parts of wliich 
are respectively sandstone, Fnsulina-limestone, 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, wliich would suppose still 
furtlier 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 somewliere towards the north, so may we infer that much 
of the Carboniferous land of Eussia lay somewliere towards the east 
ratlier 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 otlier sections are 
apparently wanting, and we commence with the Productus-limestoue. 
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. 
