23 i Hepoi-ts and Proceedings — Geological Sociefy of London. 



2. " A Phosphatized Trachyte from Clipperton Atoll." By 

 J. J. H. Teall, Esq., M.A., F.K.S., V.P.G.S. 



Specimens from the projecting rock described in the preceding 

 communication are dark brown, white, or cream-coloured. The 

 brown specimens are trachytes, composed of glassy phenocrysts of 

 sanidine set in a groundmass of microlitic felspars with brown inter- 

 stitial matter. The light-coloured rocks are more or less altered 

 trachytes, in some of which the glassy phenocrysts of sanidine may 

 still be recognized. Analyses of several specimens show that the 

 rocks all contain varying amounts of phosphoric acid, as indicated 

 by the following table : — 



I. II. III. 



per cent. per cent. per cent. 



SiO, ... .;. ... 54-0 ... 43-7 ... 2-8 



PaOg 8-4 ... 17-0 ... 38-5 



Loss on ignition ... 3-1 ... 12-3 ... 23-0 



The last specimen cpnsists of 95 per cent, of hyd rated phosphate 

 of alumina, with some iron, having thus a composition allied to the 

 so-called redonite from Redonda in the West Indies. The progressive 

 alteration affects first tlie groundmass, then the microlitic felspars, 

 and lastly the porphyritic crystals of sanidine ; and it is probable 

 that the change has been effected by solutions of alkaline phosphate 

 and other compounds, derived from the droppings of sea-birds. 

 A somewhat similar pliosphate, shipped from Connetable Island off 

 French Guiana, is referred to on the authority of Mr. Player. 



3. " The Pliocene Deposits of the East of England. — Part I. The 

 Lenham Beds and the Coralline Crag." By F. W. Harmer, Esq,, 

 F.G.S. 



From the discussion of lists of fossils, a large number of sections, 

 and a series of borings, the author endeavours to establish the 

 following pro^DOsitions : — 



I. With regard to the Lenham Beds : 



(a) That they are older than the Coralline Crng, thirteen out of 

 sixty-seven molhisca found in them being characteristic Miocene or 

 Italian Lower Pliocene forms unknown or very rare in the latter 

 formation. 



(6) These beds had probably been upheaved, consolidated, and 

 exposed to denudation before the deposition of the Coralline Crag, 

 and may have been, as formerly suggested by Professor E. Eay 

 Lankester, the source from which the " boxstones " found at the 

 base of the Suffolk Crag have been derived. These boxstones 

 contain a fauna, not identical with, but of the same general 

 character as that of Lenham. 



(c) In the interval between the deposition of the Lenham Beds 

 and the Coralline Crag the sea retired to the north, in consequence 

 of the upheaval of the southern part of the area, as it did in 

 Belgium towards the close of the Diestien period. 



{d) The Lenham Beds are most nearly, though not exactly, 

 represented by the Zone a Terebratula grandis of Belgium, and 



