THE DEVONIAN AGE. 89 



The central limestones of the Devonian may be 

 regarded as the head-quarters of the peculiar types 

 of coral characteristic of the Palaeozoic age. Here 

 they were not only vastly numerous, but present 

 some of their grandest and also their most peculiar 

 forms. Edwards and Haime, in their "Monograph 

 of British Fossil Corals/' in 1854, enumerate one 

 hundred and fifty well-ascertained species, and the 

 number has since been largely increased; I have 

 no doubt that my friend Dr. Bigsby, in his forth- 

 coming (t Thesaurus Devonicus," will more than 

 double it. In the Devonian limestones of England, 

 as for instance at Torquay, the specimens, though 

 abundant and well preserved as to their internal 

 structure, are too firmly imbedded in the rock to 

 show their external forms. In the Devonian of the 

 continent of Europe much finer specimens occur ; but, 

 perhaps, in no part of the world is there so clear an 

 exhibition of them as in the Devonian limestones of 

 the United States and Canada. Sir Charles Lyell thus 

 expresses his admiration of the exposure of these 

 corals, which he saw at the falls of the Ohio, near 

 Louisville. He says, "Although the water was not 

 at its lowest, I saw a grand display of what may be 

 termed an ancient coral-reef, formed by zoophytes 

 which flourished in a sea of earlier date than the 

 Carboniferous period. The ledges of horizontal 

 limestone, over which the water flows, belong to 

 the Devonian group, and the softer parts of the stone 

 have decomposed and wasted away, so that the 



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