72 GEOLOGY OF THE ISLE OF WIGHT 



history up to the point where we began in the Isle of 

 Wight. If we could see back through the ages to the 

 furthest past of geological history, we should see our 

 world, before any of the stratified rocks were laid down 

 in the seas, before the seas themselves were made, a 

 hot globe, molten at least at the surface. How do we 

 know this ? Because under the rocks of all the world's 

 surface we find there is granite or some similar rock, 

 a rock which shows by its composition that it has crystal- 

 lised from a molten condition. Moreover we have seen 

 that the interior of the earth is intensely hot. And yet 

 all along the earth must be radiating off heat into the 

 cold depths of space, and cooling like any other hot body 

 surrounded by space cooler than itself. And this has 

 gone on for untold ages. Far enough back we must 

 come to a time when the earth was red hot, white hot. 

 In imagination we see it cooling, the molten mass solidi- 

 fies into Igneous rock, the clouds of steam in which the 

 globe is wrapped condense in oceans upon the surface. 

 The bands of crystalline rock that rise above the primeval 

 seas are gradually worn down by rain and rivers and 

 waves, and the first sedimentary deposits laid down in 

 the waters. And in the waters and on the land life 

 appeared for the first time, we know not how. 



A vast thickness of stratified rocks was formed, which 

 are called Archaean (" ancient "). They represent a time, 

 perhaps, as great as all that has followed. These rocks 

 have undergone great changes since their formation. 

 They have been pressed under masses of over-lying 

 strata, and have come into the neighbourhood of the 

 heated interior of the earth ; they have been burnt and 

 baked and compressed and folded, and acted on by heated 

 water and steam, and their whole structure altered by 

 heat and chemical action. Limestones, e.g., have become 

 marble, with a crystalline structure which has obliterated 

 any fossils they may have once contained. Yet it is 



