190 Dr Hibbert on the Limestone of Burdiehouse 



acknowledgments which M. Agassiz pays to the French naturalist for having com- 

 mitted to his possession all the materials which the Baron had himself collected with 

 a view to similar researches, for which his important occupations in another depart- 

 ment, namely, in the extinct land, and amphibious animals of a past state of our 

 globe, had afforded him too little leisure. 



A second recommendation of M. Agassiz is, that he comes before us not only in 

 the character of a zoologist, but as one who has studied the character of fish in refer- 

 ence to their geological connections ; who has endeavoured to trace in this class of ani- 

 mals the changes of organization which have happened in correspondence with the 

 various revolutions which the earth has undergone. " Fish," as he observes, " be- 

 ing more than all other animals most intimately connected with the incidents of the 

 water, and their organization being besides very high up, they are better calculated 

 than any other class to give us clear ideas regarding the changes which have been 

 going on in such vast seas as have formerly covered over the earth. We shall be en- 

 abled to determine if a fish has lived in rivers, in lakes, or in ponds, in the high sea, 

 or upon its shores ; — if it was an inhabitant of the surface of the water or of its 

 great depths ; — which indications, more or less valuable, will aid us in determining 

 corresponding circumstances with regard to the formation of rocks." 



If I had space allotted me in this memoir, I could point out many instances of 

 the tact which M. Agassiz evinced while in Edinburgh, illustrative of the import- 

 ance of fossil ichthyology, in the assistance which it yields in determining the rela ■ 

 tive age of rocks, and which would show, at the same time, how inexcusable I should 

 have been if I had not availed myself of a judgment of such value as that which he 

 has evinced. 



SECTION VII— THE FOSSIL FISH REFERABLE TO THE LEPIDOID FAMILY. 



For motives of convenience, I shall not describe the fish which 

 I mean to notice in the exact order of classification already ex- 

 plained. 



As I have stated, the Lepidoid family is included in the 

 Ganoid order of fish. 



To this family the genera of Palaeoniscus, Eurynotus, and 

 Amblypterus are referred, of which one species or more of each 

 have been discovered in the quarry of Burdiehouse. 



The fish which the limestone entombs in far the greater 

 number is an individual which I had little difficulty in referring 

 to the genus of Palaeoniscus. ( The first specimens discovered of 

 this fish were sketched in Plate VII., figs. 1. and 3. But more 

 perfect ones having been subsequently obtained, they are introduced 



