CHAPTER III 



THE WEALDEN STRATA: THE LAND OF THE 

 IGUANODON 



THE lowest strata in the Isle of Wight are the coloured 

 marls and blue-grey shales we have already observed in 

 Sandown Bay, which run through the Island to Brook 

 Bay. They are known as the Wealden Strata, because 

 the same strata cover the part of Kent and Sussex called 

 the Weald. They consist of marls and shales with bands 

 of sandstone and limestone. The marls and shales in 

 wet weather ' become very soft, and flow out on to the 

 shore, causing large slips of land.* Now, what we want 

 to find out is what the world was like ages ago, when 

 these Wealden Strata were being formed. We have 

 learnt something of how clays and sandstones and lime- 

 stones are formed : to learn more we must see what sort 

 of fossils we can find in these rocks. "_Fpssil " means 

 something dug up ; and the word is generally used for 

 remains of animals or plants which we find buried in the 

 rocks. We have seen shells in these strata. These we 

 must examine more closely. And as we walk on the shore 

 we shall find other fossils. In the marls and shales exposed 

 on the shore we are pretty sure to see pieces of wood, 

 black as coal, sometimes quite large logs, often partly 

 covered with shining iron pyrites. Perhaps you say 

 I hope you do there must have been land not far away 

 when these marls and shales were forming. Always try 



* Blue clays of various geological age, which in wet weather 

 become semi-liquid, and flow out on to the shore, are known in the 

 Island by the local name of Blue Slipper. 



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