254 PICTURESQUE SKETCHES 



CHAPTER XL 



GENERAL CONSIDERATIONS CONCERNING THE SECONDARY EPOCH AND 

 THE CIRCUMSTANCES OP ITS TERMINATION. 



WE have now considered in succession the various 

 aspects of creation during the period that intervened 

 between the disturbances which broke up the older 

 rocks, distributing them in irregular patches and groups 

 over the earth, and the final close of the epoch by the 

 deposit of the chalk. This bed, originally perhaps 

 calcareous mud, afterwards became hardened under 

 water, and was at length laid bare over a great part 

 of Europe by the elevation of the sea-bottom. The 

 disturbance by which the whole of the Wealden dis- 

 trict of England was thus exposed, and the great 

 expanse of chalk which once covered it entirely re- 

 moved, must have been of later date ; and the mag- 

 nificent phenomena of altered chalk on the coast 

 of Antrim in Ireland and in the adjacent Western 

 Islands of Scotland, and of contemporaneous beds in 

 Germany, Switzerland, and eastern Europe, besides 

 the great disturbances of the cretaceous rocks along 

 the elevated district of central Europe, all clearly 

 show the extent of this disturbance, and the results 

 of it. The commencement of this series of dis- 

 turbances may be considered to have closed the 

 secondary epoch. 



