THi: ( AKIK'XIFEROUS 8YSTKM 283 



surprising if they bad not extended for some distance to the north 

 of these places. 



Passing now to the Atlantic region there is reason to think that 

 a large part of this was also occupied by land, and that a part of 

 its coast-line passed through the extreme north-west of Ireland. 

 Again, the'great thickness of shale in the south-west of Ireland and 

 the north-west of France indicates the neighbourhood of land and 

 the debouchures of large rivers which carried much sediment 

 derived from such land. We may therefore picture a continent 

 which almost encircled the British area, lying not only to the 

 north but also to the west and south-west of it; and indeed it 

 seems probable that a promontory of this land actually occupied 

 parts of Cornwall, Brittany, and the intervening channel area 

 during the Tournaisian epoch. 



Another tract of land which was probably connected with the 

 Atlantic continent seems to have stretched across Central France, 

 for in the basin of the Loire the Dinantian ( = Avonian) deposits 

 are entirely of terrigenous origin, and are probably all of Visean 

 and Namurian age, while to the southward in La Vendee even 

 these are absent, and small tracts of Westphalian Coal-measures rest 

 directly on Archaean rocks. We have seen also that when Dinantian 

 Beds come in again to the southward in Asturia, the Pyrenees, and 

 the Montagne Noire they are of quite a different facies, hence the 

 land above indicated seems to have separated a southern from a 

 northern Carboniferous Sea. 



From Central France this land may have extended across the 

 valley of the Rhone between Lyons and the Vaucluse, and thence 

 through the Western Alps and Northern Italy, where no traces of 

 Dinantian strata have yet been found. Land also existed at this 

 time over a certain area to the north of Metz and Sarrebruck, for 

 near the latter place Cpal-measures rest directly on the Lower 

 Devonian, but this may have been only a large island. 



The limestone facies of the Avonian Series must have been 

 formed in those parts of the Carboniferous Sea which were not 

 subject to the incursion of currents setting off the surrounding land. 

 It must originally have extended continuously from the west of 

 Ireland, all round an island which existed in Visean time over St. 

 George's Channel, Central Wales, and Central England an island 

 which I have elsewhere called " St. George's Land." Thence these 

 limestones probably extended broadly into the north-east of France 

 and through Belgium into Prussia, nearly as far as the Rhine. 



There is no valid reason for imagining any special contraction 

 of the sea space on the Franco- Belgian border, as suggested long ago 

 by Professor Gosselet, and still supported by some French geologists. 



