BRODIE AND BUCKMAN ON THE COTTESWOLD HILLS. 225 



formation, or at least not sufficiently distinguishable from it, to 

 entitle it to rank as an independent formation ; but, inasmuch as 

 the Great oolite ver y much thins off where associated with Stones- 

 field slate, it would appear that the Stonesfield slate and its ac- 

 companying " ragstone " were deposited by the same sea which 

 formed the Great oolite itself, and that it partly owed its origin to 

 certain mixed conditions, arising from the influx of rivers into an 

 ocean interspersed with numerous scattered islands, abounding in 

 a luxuriant vegetation, and inhabited by numerous terrestrial 

 animals f and this opinion seems more probable from the quantity 

 of plants which occurs throughout the Stonesfield slate beds, and 

 also from the relics of land animals, such as the Didelphis and 

 Pterodactylus. 



We also find that the Great oolite thins outs towards the nor- 

 thern end, whilst the Inferior oolite thins out in like manner 

 towards the southern end of that long chain of hills of which the 

 Cotteswolds form a part. 



3dly. If the beds just referred to belong to the Great oolite, it 

 is just possible that the clays by which they are super-imposed in 

 this district, may be the equivalent, or a sort of representative of 

 the Bradford clay, judging at least from their position and the 

 analogous fossils which they contain. Or, supposing this to be 

 incorrect, we venture to conclude that these clays are the equiva- 

 lent of certain clay -beds containing Apiocrinites, which in Wilt- 

 shire separate the freestone from a lower stratum of freestone of 

 a coarser texture. 



2. Description of a Fossil Ray from Mount Lebanon (Cy- 

 clobatis oligodactyly). By Sir Philip Grey Egerton, Bart. 

 M.P., F.R.S., F.G.S. 



I am indebted to the liberality of Professor Edw. Forbes for 

 many valuable specimens of fossil fishes, procured by Capt. Graves 

 from the Lebanon range ; and amongst the number, for the 

 subject of the present memoir, one of the most interesting and 

 remarkable ichthyolites ever brought to light by paheontological 

 research. The cases of the discovery of fishes belonging to the 

 placoid order, in a condition at all approaching to completeness, 

 are exceedingly rare. The destructible nature of the endoskeleton, 

 and the loose attachment of its component members, attest the 

 probability that decomposition would complete its work ere these 

 records could be engrossed in imperishable characters. That this 

 order was nevertheless extensively represented from the earliest 

 fossiliferous period to the present time, is manifest from the fre- 

 quent occurrence of the palatal tritores, teeth, and defensive fin 

 bones of the Cestracionts, Hybodonts, and Squales ; and of the 

 dental apparatus, caudal weapons, and dermal tubercles of the Rays. 



