CHAPTER XII. 
CRETACEOUS SYSTEM. 
I Prefatory Sketch of the Variations in Mineral Character of the Cretaceous System 
of Northern Europe in its range from West to East. — Succession in England, 
France, Germany, Poland and the Carpathians. — II. Cretaceous Rocks of Russia 
in the drainage of the Donetz and the Don. — Thinning out of the white Chalk 
in the Governments of Kharkof, Kursk, fyc. — Eastern mass of Chalk on the River 
Ural . — Cretaceous Rocks of the Lower Volga extending from Simbirsk to the 
Southern Steppes. — Peculiar mineral development of the Cretaceous system of 
Russia and its apparent Passage into the Tertiary Rocks. — Country between the 
Volga and the Don. — Conclusions. 
Devoting our chief attention to the Palaeozoic rocks of the northern and 
central districts of Russia, we had no great difficulty in mastering the relations 
of the Jurassic or next succeeding deposits, which exhibit well-defined characters 
and occupy limited spaces. A much shorter period, however, was spent by us in 
the vast region of the south, which, with the exception of the granitic steppe, a 
small patch of Paleozoic rocks and the carboniferous tract of the Donetz, is ex- 
clusively occupied by cretaceous and tertiary deposits. Under these circumstances 
it is evident, that we must be unprepared accurately to define the boundaries and 
relations of the superior systems. In the following pages, indeed, we shall give 
other cogent reasons, which prevent us from separating the Cretaceous from the 
Tertiary rocks, with the same decision as in England and France. To render this 
point more intelligible to our readers, and also to convey to them a clear view of 
the general range and features of the cretaceous deposits of Northern Europe, we 
shall commence this chapter with a sketch of the changes which they undergo, in 
passing from the British Isles on the West, to Russia on the East. 
In some parts of England the oolitic series is well known to be separated from 
the Cretaceous rocks, by a considerable estuary and freshwater formation called the 
