BEFORE AND AFTER 71 



British Isles, or even England and Wales alone, are almost, 

 if not quite unique in the world in that, in their small 

 extent, they contain specimens of nearly every formation 

 from the most ancient times to the present day. In 

 other parts of the world we may find regions many times 

 this area, where we can only study the rocks of some one 

 period. But just at this point in the story comes a period, 

 a very important one, too, the Miocene of which we 

 have no remains in our Islands. We must hear a little 

 of what happened before we come back to the Isle of 

 Wight again in comparatively recent times. 



But, first, perhaps, I had better tell, just in outline, 

 something of the earlier history of the world, before any 

 of our Isle of Wight rocks were made. For, if I do not, 

 quite a wrong idea may be formed of the world's history. 

 The time of the Wealden river has seemed to us very 

 ancient. We cannot say how many hundreds of 

 thousands, or rather millions of years have passed since 

 that ancient Wealden age. And you may have thought 

 that we had got back then very near the world's birthday, 

 and were looking at some of the oldest rocks on the 

 globe. But no. We are not near the beginning yet. 

 Compared with the vast ages that went before, our Wealden 

 period is almost modern. We cannot tell with any 

 certainty the comparative time ; but we may compare 

 the thickness of strata formed to give us some sort of idea. 

 Now to the first strata in which fossil remains of living 

 things are found we have in all a thickness of strata some 

 12 times that of all the rocks we have been studying from 

 Wealden to Oligocene, together with the later rocks, 

 Miocene and Pliocene, not found in the Isle of Wight. 

 And before that there is, perhaps, an equal thickness of 

 sedimentary deposits ; though the fossils they, no doubt, 

 once contained have been destroyed by changes the rocks 

 have undergone. 



Now let me try to give you some idea of the world's 



