— 181 — 



Paloeozoic, in which every trace of life has been 

 obliterated by the conversion or metamorphosis of the 

 deposits into crystalline masses. From the Cambrian 

 Era, noted above, we emerge into the Silurian, ( so 

 called from the rocks found in Shropshire S. of 

 England originally inhabited by the Silures ) in which 

 we notice a great beauty and strange diversity of 

 animal life although in its infancy ; we find that its 

 waters were thronged with zoophytes, starfishes, see- 

 urchins, shell-fish and crustaceae, the acephalans and 

 gasteropods ( in Molluscan life ) being the prepon- 

 derating forms. 



From the Silurian we pass into the Devonian Era 

 ( from the deposits or fossils being mainly found in 

 Devonshire S. W. of England ) : here a further step 

 is made in Animal Life as well as in Botanical organi- 

 sation : the first Vertebrates appear in the shape of 

 fishes which abound in various forms and in great pro- 

 fusion, reptiles also come into notice for the first time- 

 probably the most noticeable feature in the Fauna is 

 the large Crustaceae ( crab-like in tlieir carapace and 

 organs of mastication. ) 



Leaving the Devonian we come to The Carbonife- 

 rous 8f Vermian Bras ( the Carboniferous takes its 

 name from those strata which now form ouf Coal 

 mines. ) The chief chrracteristic of this Era is the 

 wonderful development of Plant Life : the considerable 

 thickness of these strata make one think that this Era 

 was perhaps the one that lasted longest in the history 



