Summary. 6 1 9 



placed that, in a measure, we have the command 

 of a large portion of the commerce of the world, and 

 send out fleets of merchandise from every port. 



And we are happy, in my opinion, above all things 

 in this, that by an old denudation we have been dis- 

 severed from the Continent of Europe, and our bounda- 

 ries are clear. Thus it happens that, free from immediai } 

 contact with countries possibly hostile, and not too much 

 biassed by the influence of peoples of foreign blood, 

 during the long course of years in which our country 

 has never seen the foot of an invader, 1 we have been 

 enabled, with occasional disturbance of foreign wars and 

 political factions, progressively so to develop our own 

 ideas of religion, political freedom, and political morality, 

 that we stand one of the freest and most prosperous 

 countries on the face of the globe. 



I have now completed the somewhat arduous task 

 undertaken in preparing this much enlarged edition of 

 an old book. It is, after all, but a sketch of a large 

 subject, and no one can be more sensible than I am of 

 its imperfections ; but with all its faults and omissions, 

 I think that this is the first work in which an attempt 

 has been made to trace in detail the absolute connection 

 of the Physical Geology and Physical Geography of 

 old epochs in Britain with that of the present day. 

 Right or wrong in some of the questions raised, it is the 

 work of one who, through more than half a lifetime, 

 has 



' pry'd through Nature's store, 

 Whate'er she in th' ethereal round contains, 

 Whate'er she hides beneath her verdant floor, 

 The vegetable and the mineral reigns ; 



1 The small French descents of Pembrokeshire and Ireland do 

 not deserve the name of invasions. 



