282 Reports and Proceedings — 



result has been a deposit known as " rich phosphate," containing 

 about 25 per cent, of phosphoric acid. This occurs in wide cracks 

 and holes in the ordinary phosphatic chalk. It usually occurs as 

 a fine sand-like powder, and is evidently the result of the action 

 of carbonated waters upon the phosphatic chalk, whereby the 

 amount of carbonate of lime is reduced. This is especially the case 

 where the phosphatic chalk is not protected by the tufaceous chalk 

 of Ciply, but is only covered by Tertiary or Quaternary beds. 



The author calculates that each square foot of the phosphatic 

 basin, which he estimates approximately at five miles by three, contains 

 3551bs. of tribasic phosphate of lime. Finally he estimates how 

 the phospbatization of the chalk may have been brought about. 



II.— May 12, 1886.— Prof. J. W. Judd, F.R.S., President, in the 

 Chair. — The following communications were read : — 



1. "On the Maxilla of Iguanodon." By J. W. Hulke, Esq., F.R.S., 

 F.G.S. 



Two fragments, together representing nearly the entire left maxilla 

 of a species of Iguanodon, have been found at Cuckfield, the locality 

 whence the first tooth of the genus was obtained by Dr. Mantell, about 

 1820. These fragments, measuring together 29 centimetres, and ex- 

 hibiting 19 alveoli in the dentary border, were described in the paper. 

 It was shown that the upper jaw in question probably belonged to 

 Iguanodon Mantelli. In addition to the detailed characters described, 

 the maxillae of Iguanodon and Hgpsilophodon were compared, and their 

 distinctions explained. 



2. " Notes on the Distribution of the Ostracoda of the Carboniferous 

 Formations of the British Isles." By Prof. T. Bupert Jones, F.R.S., 

 F.G.S., and J. W. Kirkby, Esq. 



Although all the Ostracoda of the Carboniferous formations are not 

 yet described, there are 170 species and notable varieties known, 

 belonging to 33 genera of 9 families. About 25 of these species, 

 not yet described, but determined by the authors, are introduced 

 into their lists as giving a fuller idea of the value of this manifold 

 Crustacean group. 



In the first place they referred to the classification of the Carbon- 

 iferous strata in Scotland and in England, according to the local dif- 

 ferences, taking in succession " Scotland West," " Scotland East," 

 "England North, with the Isle of Man," "England Central and 

 South, with South Wales," as the several districts from which they 

 have obtained good groups of Ostracoda from different members of the 

 Carboniferous series. 



In Fife, the lowest local Carboniferous strata contain Beyrichia sub- 

 arcuata ; higher up come in Carlonia fabulina, C. Ranhiniana, Bairdia 

 nitida and Leperditia Olceni ; the last, accompanied by other species, 

 occurs throughout this lowest series, in which the record is more com- 

 plete than in Midlothian and Linlithgowshire, where the same species 

 also occur. In Dumfriesshire and Ayrshire Leperditia Okeni and L. 

 subrecta have been found in beds even lower than the above mentioned, 

 and are therefore probably the oldest Carboniferous Ostracoda ; other 

 species accompany them higher up, and in Roxburghshire some localities 



