IV. Review of the Upper Carboniferous in other 



regions as connpared with the Carboniferous of 



North-east Greenland. 



The decisive feature of the Carboniferous deposits is the form 

 of development to which the strata in question can be referred: 

 marine or terrestrial. During the Carboniferous period, contin- 

 ental conditions have existed over extensive tracts, during the preval- 

 ence ot which the economically important productive coal forma- 

 tions were deposited. Other tracts were covered by sea in which 

 were laid down marine formations — in north-western Europe, 

 where these formations were first studied, the so-called Mountain 

 limestone. During this period, too, there occurred somewhat con- 

 siderable changes in the distribution of land and sea on the surface 

 of the globe, the extension of the sea, especially during the latter 

 part of the Carboniferous period, being considerably increased, under 

 great transgressions. Just this alternation of marine and terrestrial 

 deposits is of specially great importance for the classification of the 

 Carboniferous formations, and for a comparison of their strata from 

 various districts. 



In the following pages we shall employ a division of the Car- 

 boniferous system into two groups: the Lower and the Upper 

 Carboniferous. This is in agreement with the plan adopted, for 

 example, by Kayser (Lehrbuch der Geologie II, 4:lh Ed. 1911) and 

 Frech (Lethæa Geognostica), but not with that triple division of the 

 system into Lower, Middle and Upper Carboniferous which, in 

 general, is employed by Russian geologists. 



In North-Western Europe, the Lower Carboniferous deposits 

 are, as a rule, of marine origin, and are represented both in Eng- 

 land and in the north of France and in Belgium by Mountain lime- 

 stone, which is also found in some few places in Germany. The 

 Upper Carboniferous beds, on the other hand, have been devel- 

 oped in terrestrial facies, with coal beds. 



