364 Mr. MuRCHisoN on the Strata of the Oolitic Series, ^c. 



identified, imbedded in calcareous nodules of a subcrystalline radiating fibrous 

 structure. Better preserved specimens of these same nodular ichthyolites have 

 since been forwarded to me by Mr. Christie, through Mr. G. Anderson of 

 Inverness ; and from an examination of these, Mr. Pentland has been enabled 

 to give the following interesting description. " Among the ichthyolites of 

 Gamrie/' Mr. P. observes, "there appear to be at least two distinct species. 

 The first, an abdominal fish, with a single dorsal fin, placed over the anal ; 

 characters which belong to the genus Esox of the older zoologists : to this 

 character, which places the ichthyolite in the natural order Esocii, may be 

 added, its large pentagonal scales, and that very peculiar structure of the 

 caudal fin, in which the radii all arise beneath the vertebral prolongation ; a 

 character existing in the fossil fish of Caithness mentioned by Mr. Murchi- 

 son *, and in the Lepisosteus among Hving species. 



" The second ichthyolite is evidently also an abdominal fish, but of a very 

 different species, if not of a distinct family ; although the imperfect state of 

 the specimens do not permit me to speak positively as to the relative position 

 of the fins, or to judge how far the two species resembled each other in that 

 very peculiar structure of the caudal fin observed in the former. This second 

 species, however, possesses a combination of characters, which seems to distin- 

 guish it from all other ichthyolites I have seen ; namely, having the fins 

 covered with very fine quadrangular scales, a character employed by Cuvier 

 to distinguish the family of Squamipinnae in his Ichthyological arrangement. 

 The scales on the body are disposed obliquely, as in the ichthyolites of Thu- 

 ringia, and in those of the magnesian limestone of England ; on the other 

 hand, the bones of the head are covered with osseous papillae or mamillary 

 processes, as in certain species of Silurus, and in the fossil Dapedium of 

 the lias. The elongated form however of this Gamrie ichthyolite, the minute- 

 ness of its quadrangular scales, and the scaly coating which covers its fins, 

 offer characters sufficiently precise, even in these imperfect examples, to sepa- 

 rate it from any of the species above referred to ; and still further from any 

 of the genera of recent or fossil fish described by the older authors. There 

 appears to be also, in the same calcareous nodules, a third species of ichthyo- 

 lite, much larger than either of those above mentioned, which is charac- 

 terized by very large pentagonal scales ; but no fins are discoverable, and to 

 what family or genus it may belong, cannot be decided without more perfect 

 specimens." 



* See Geol. Trans, ante, p. 315. Baron Cuvier having now favoured me with an account of 

 these Caithness ichthyolites, a full description of them, accompanied by engravings, will appear 

 hereafter in a joint memoir by Professor Sedgwick and myself. — R. I.M. 



