106 PALAEOZOIC TIME. [CHAP. VII. 



2. Geographical Restoration. 



In Chapter VI. the Carboniferous period was described 

 as one of quiescence, during which the forces of terrestrial 

 disturbance were in abeyance ; but, as a calm precedes a 

 storm in the atmosphere around our earth, and a great 

 stillness often forebodes an earthquake, so in the earth's 

 history a period of quiet deposition and rock-making has 

 often been followed by a period of disruption and rock- 

 destruction. Certain it is that the calm of Carboniferous 

 times was followed by an epoch of great disturbance in the 

 European and Atlantic areas, causing movements which 

 produced very great geographical changes in the northern 

 hemisphere, and resulted in the breaking up of the Car- 

 boniferous continents, and in the upheaval of the ground 

 which had been covered by the Carboniferous seas. 



At the close of the Carboniferous period there seem to 

 have been important upheavals of land on either side of 

 the great Atlantic continent. The Alleghany Mountains in 

 America date from this epoch, as do also the series of 

 domes, ridges, and faulted upheavals which make up the 

 Pennine chain or " backbone " of England. It appears 

 certain that the principal earth-throes, those which pro- 

 duced the more important disturbances of the Carboni- 

 ferous rocks in Britain, occurred during the unrepresented 

 period of time which intervened between the Coal-measures 

 and the Dyas. The stratigraphical relations of the latter 

 to the former make it clear that the disturbances, which 

 bent the Coal-measures into the basin- shaped forms they 

 now present, took place before any Dyas sic strata were 

 deposited. These movements resulted in the development 

 of a double system of anticlinal and synclinal axes, one 

 set running north and south, the other nearly east and 

 west. It is impossible to say whether this double system 

 of axes was formed simultaneously, or whether one set was 



