218 Dr Hibbert on the Limestone of Burdiehouse, 



M. Agassiz remarks of this family, that it only comprehends 

 one genus of actual creation, the genus Cestracion ; the others 

 being fossil ; that the Hybodontes (Agass.) are equally fossil. 

 Then follow the Squali, the Rays, and the Cyclostomae. 



The limestone of Burdiehouse entombs thorny rays of im- 

 mense magnitude, and most beautifully configurated, which it is 

 impossible to contemplate without amazement. (See Plate XI, 

 fig. 1, A, B, and C.) The drawings of them given in Plate XI. 

 are upon a scale of one-half only of their original dimensions. 

 They are treble the size of a recent dorsal ray, obligingly shewn 

 me by Mr Clift of the Museum of the Royal College of Sur- 

 geons, which was supposed by M. Blainville to be the dorsal 

 bony ray of a large Silurus of the Ganges. 



M. Agassiz confesses that he knows of no other relics found 

 elsewhere to which they bear any resemblance ; — that, while the 

 mountain limestone, the has, the oolite, and the chalk formation, 

 afford some very striking and decided genera, none of them re- 

 semble the rays found at Burdiehouse, which he thinks ought to 

 be referred to a separate genus of the family of Cestraciontes. 

 He proposes to name the fish to which these rays belong the Gv- 



RACANTHUS FORMOSUS. 



It is most unfortunate that nothing is known of the Gyracan- 

 thus formosus more than is indicated by these relics, which give 

 the promise of a fossil monster some time or other turning up, 

 equalling, if not surpassing in interest, the Megalichthys. 



The teeth, even of the Gyracanthus, are unrecognised. " It is 

 not impossible," says M. Agassiz, " that the teeth of so remark- 

 a^ able an appearance, which have been discovered, may belong 

 ^ to this animal. But this is a mere supposition, solely found- 

 ed upon the analogy of what I have seen concerning the rays of 

 other formations." — I may here observe, that the teeth alluded 

 to were not found at Burdiehouse, but in the important fossili- 

 ferous coal-seam of Stoneyhill near Musselburgh, first brought to 

 notice by the researches of Lord Greenock. 



