FOSSIL CORALS. 71 



are of the opinion that this limestone is nothing more 

 than a Devonian coral-reef skirting the old land- 

 regions composed of Cambrian and Silurian rocks. 



Hunting for fossil corals in the older rocks implies 

 visits to some of the most picturesquely romantic 

 spots in Great Britain, with here and there a little 

 variation in some localities whose ancient loveliness 



Fig- 54. Vertical section of Lithostrotion PJiillipsii, showing tabulae. 



has had to give way to the deforming ugliness of 

 extensive mining or manufacturing operations. This 

 is the case with the Wren's Nest, near Dudley, formed 

 of a romantic cluster of highly inclined Upper Silurian 

 limestones rising from beneath the Coal formation 

 which extends up to their very base. These limestone 



