Fossil Corals, — Lower Silurian Rocks o/* Canada. 121 



" Finally, the coral becomes subservient to a still higher purpose than 



the support of polyps and nullipores. The debris, produced by the waves 



over a reef, settles into the many crevices among the dead trunks, and fills 



up the intervals, often large, between the scattered coral-patches ; and, by 



this combined action of living growth and detritus accumulations, a solid 



rocky basement is formed, and kept in constant increase. In this way the 



coral reef gradually uears the surface, and finally becomes the foundation of 



one of the lUirest of 



" The sea-girt isles, 

 That, like to rich and various gems, inlay 

 The unadorned bosom of the deep ;" 



the coral polyps now yield place to the flowers and groves of the land, which 



fulfil their end in promoting the comfort and happiness of man." 



Alter the above somewhat extended remarks and quotations, we shall 



now proceed to examine some of the fossil corals that may be collected 



more or less abundantly from those rocks in Canada which in remote ages 



were reefs at the bottom of the ocean, probably as brilliant in their floral 



hues as those of the Pacific. The first of these we shall mention belongs to 



tlie family of the CyathophyllincB - or cup shaped corals, and is somewhat 



common in certain localities of the Trenton Limestone. 



^^^W/i//ylM 





m^ 



Fig. 3. 



Fig. 4. 



Fig. 5. 



Figs. 3 and 4. — St.reptelasmacornicuhim,as it is 

 usually seen in the fossil state in the 

 Trenton Limestone. 



Fig. 5. — An ideal figure of a living strepte' 

 lasma. 



Fig. 6. — A section across one of those fossils 

 Fig. 6. 7iear the top. 



In the figure given of the dome-shaped Astrcea, (Fig. 1, page 119,) it will 

 be seen that the specimen from which the drawing was made, consisted of a 

 number of Polypi growing together in one mass, but in the species now 



* From the Greek " Ktcathos," a cup. 



