DEVONIAN AND OLD RED PERIOD. 



141 



the enclosing rock in the boldest relief, exhibiting to the ob- 

 server the most minute details of their organisation. As before, 



Fig. 80. — Cystiphylln77t vesiculosmn, 

 showing a succession of cups produced by 

 budding from the original coral. Of the 

 natural size. Devonian, America and 

 Europe. (Original.) 



Fig. 82. — Heliophyllum exigtnmz, view- 

 ed from in front and behind. Of the natu- 

 ral size. Devonian, Canada. (Original.) 



the principal representatives of the Corals are still referable to 

 the groups of the Rugosa and Tabidata. Amongst the Rugose 

 group we find a vast number of simple '^ cup-corals," generally- 

 known by the quarrymen as ^' horns," from their shape. Of 

 U 



