88 PALEOZOIC TIME. [CHAP. VI. 



ever, is required before more than the general position of 

 this land can be indicated. Thus until recently it was 

 supposed that the Lower Carboniferous series was not 

 represented in Brittany. Dr. Ch. Barrois, 1 however, has 

 shown that certain slates and sandstones, which were 

 previously regarded as Devonian, are really of Carboni- 

 ferous age. They are based on conglomerates and volcanic 

 rocks, and are overlapped southward by the Coal-measures, 

 which rest on the Lower Devonian near Quimper. Land, 

 therefore, existed in the south of Brittany during Lower 

 Carboniferous time, but whether it was an island or a 

 promontory from a western Atlantic continent we can- 

 not yet decide. 



The sea which lay over so large a part of what are now 

 the British Isles stretched eastward through the north-east 

 of France, Belgium, Germany, Poland, and Eussia, cover- 

 ing, therefore, a large part of the present continent of 

 Europe, and thence extending toward the North, Pole by 

 way of Bear Island and Spitzbergen, but it seems to have 

 been bounded on the south by a more or less continuous 

 belt of land through France, Switzerland, Bavaria, Bohemia, 

 and Hungary. 



Thus it seems clear that the sea in which our Carboni- 

 ferous beds were deposited was not an open sea or ocean, 

 but a land-locked sea, comparable, to some extent, with the 

 Mediterranean of the present day ; it was studded with 

 islands of various sizes, its coast-line formed a series of 

 gulfs and promontories, and it communicated with other 

 seas by means of one or more narrow straits like the Straits 

 of Gibraltar. 



1 " Bull. Soc. Geol. de France," ser. iii. t. xiv. pp. 661, 665. 



