116 Fossil Corals, — Lower Silurian Rocks o/' Canada, 



falls or rapids of the Ohio River at Louisville, in Kentucky, where it muck 

 resembles a modern coral reef. A wide extent of surface is exposed in a 

 series of horizontal ledges, at all seasons when the water is not high ; and 

 the softer parts of the stone having decomposed and wasted away, the 

 harder corals stand out in relief, their erect stems sending out branches 

 precisely as when they were living. Among other species I observed large 

 masses, not less than five feet in dian-jeter of Favo&ites Gotldandica, with its 

 beautiful honey-comb structure, well displayed, and by the side of it, the Favis- 

 tella combining a similar honey-combed form with the star of the Astraa. There 

 was also the cup-shaped Cj/afAopAy/wTn, and the delicate net-work of the 

 Fenestella, and that elegant and well known European species of fossil called 

 the " chain coral," Catenipora cscharoides, w^th a profusion of others. — 

 These coralline forms were mingled with the joints, stems, and occasionally 

 the heads of lily encrinites. Although hundreds of fine specimens have been 

 detached from these rocks to enrich the museums of Europe and America ; 

 another crop is constantly working its way out under the action of the stream^ 

 and of the sun and rain in the warm season when the channel is laid dry." 



This corniferous limestone, '' the coral reef," of which Sir Charles 

 speaks, leaves the State of New York near Buffalo, and crosses into Canada 

 where it constitutes, as we have stated in our first article, * nearly all the 

 stratified rock that can be seen in the counties of Norfolk, Oxford, Perth^ 

 Elgin, Middlesex, Kent, Essex, and portions of several other counties adjoin- 

 ing these. It cannot, of course, be seen everywhere upon the surface, being 

 for the greater part concealed beneath the drift formation, or those deposits 

 of clay, sand, and gravel, which constitute the loose soil of the country ; and 

 again in some places where it can be seen, it is not composed altogether of 

 coral, while in other localities the corals being liberated by the decomposition 

 of the rock literally cover the ground. 



In order to convey an idea of the nriture of these fossil corals, we think 

 it proper to make in this place a few observations concerning the organiza- 

 tion of the humble, but interesting, and often most beautiful httle animals, 

 which in modern seas form the reefs bv their accumulated remains. In the 

 world of life there is a vast difference between the lowest and the highest of 

 animated creatures, but geology shews us that the former have in all ages 

 affected more in transforming the surface of the earth than the latter. The 

 physiological structure of the coral animal consists of little else than a digestive 

 cavity or stomach and a mouth leading into it, yet this simple apparatus 

 has the power of withdrawing from the ocean the various elements held in its 

 waters, and of converting them into rock. MjTiads of these creatures swarm- 

 ing together, cover the sides of submarine mountains with one unbroken 

 sheet of life and by constantly absorbing from the water the component parts 

 of coral rock, and converting it into stone, they cause the ground, as it were, 

 to grow beneath them. Every year a fresh layer is added to every portion 

 of the space occupied by them, and their subaqueous mountain grows higher 

 and higher until it reaches the surface, and becomes a coral island. 



♦ See page 22 of the first number. 



