Geological Society of London. 239 



He discusses their relationship with other drifts, and arrives at 

 the following conclusions : — 



1. The glacial deposits are divisihle into Upper and Lower 

 Boulder Clay, with an Intermediate series. 



2. The Lower Clay is a continuation of the Basement Clay of 

 Holderness, and is the product of the first general glaciation of the 

 area. The Intermediate series passes laterally into the Purple Clays 

 of Holderness, and has been deposited at the edge of the ice-sheet. 

 The Upper Clay includes the Hessle Clay of Holderness, and marks 

 the latest glaciation of this region. 



3. The fossiliferous beds of 8ewerby (" Buried-cliflf Beds ") and 

 Speeton ("Estuarine shell-bed") are older than the Basement Clay, 

 and therefore than the earliest glaciation. 



4. The glaciation was elFected by land-ice of extraneous origin, 

 which moved coastwise down the North Sea, and did not overflow 

 the greater part of the Yorkshire Wolds. 



5. Neither the Boulder Clays nor the Intermediate gravels are of 

 marine origin, the shells which occur in them being derivative. 



6. The ice-sheet seems to have filled the North Sea basin in this 

 latitude from the commencement of the glaciation until its close. 

 There is no clear evidence here for a mild interglacial period, but 

 only for extensive fluctuations of the margin of the ice. 



3. "On a Phosphatic Chalk with BeJemnitella quadrata at Taplow." 

 By A. Strahan, Esq., M.A., F.G.S. (Communicated by permission 

 of the Director-Genei'al of the Geological Survey.) 



Two beds of brown chalk in an old pit near Taplow Court owe 

 their colour to a multitude of brown grains. These grains are 

 almost entirely of organic origin, Foraminifera and shell-prisms 

 forming the bulk of them. Mr. Player has analyzed specimens of 

 the brown chalk, and finds that it contains from 16 to 35 per cent, 

 of phosphate of lime. The tests as well as the contents of the Fora- 

 minifera seem to have been phosphatized, the phosphate appearing 

 as a translucent film in the former case, and as an opaque mass in 

 the latter. In the case of the prisms of molluscan shells, the whole 

 of the phosphate appears to be in the opaque form. Minute 

 coprolites also occur, together with many small chips of fish-bone. 

 in which Dr. Hinde has recognized lacuna3, while some have been 

 identified by Mr. E. T. Newton as portions of fish-teeth. 



Mr. Player observes that the phosphate occurs in such a condition 

 that it would not improbably serve as a valuable fertilizer, without 

 conversion into superphosphate. This condition is probably due to 

 the partial replacement of carbonate of lime by phosphate in the 

 organisms. The removal of the remaining carbonate leaves the 

 phosphate in a honeycombed state, peculiarly favourable for attack 

 by the acids in the soil. 



The author comments upon the resemblance of the deposit to the 

 phosphatic chalk with Belemnitella quadrata which is largely worked 

 in Northern France, and upon a less striking resemblance with that 

 of Ciply, which is at a higher horizon. 



