376 PEOCEEDIXGS OF TKE GEOLOGICAL SOCLETT. [Apiil 22, 



yellow sands overlying the Chillesford clay to a de^Dth of ten or 

 twelve feet — the light-grey sands nnder the carbonaceous snrface- 

 layer joining on to the golden-yellow sands in the bottom of the 

 section with an outline not corresponding with the stratification. 



In a Freestone quarry, Keuper Sandstone, Clive Hill, Shropshire 

 (fig. 49), the bleaching effect of organic matter is again evident. In 



Pig. 49. — Bed, huff, and hrown Keuper Sandstone, Clive Hill, 

 Shropshire. 



the top of the quarry dark-brown sandstone («), spotted with cream- 

 coloured blotches (fig. 40, Plate XT.), occurs with the following 

 composition, determined by Dr. Toelcker : — 



AaialTsi8Xo.62. ^"t,^:?"^ 

 Browii ground, a. blotches 

 *= ^ on a. 



Orsfanic matter, humic and ulniic acids 1-22 0'31 



Protoxide of iron, witli traces of sesquioxide tool ^ ..-) „ 0.7 



small tobe separately determined J 



Alumina ! 0-36 0-26 



Lime 006 006 



Sulphuric acid 0-08 0-07 



Magnesia and traces of alkalies 0-26 0'34 



Insoluble siliceous matter : — 



Alumina 2-441 I'So^ 



Oxides of iron 031! 030 1 



Lime 047I-97-60 043 |> 9864 



Magnesia and loss 0-08 j 049 | 



Sihca 94-30J 96-37J 



100-00 ir)o-oo 



The buff blotches were hard and crystalline, standing out from 

 the weathered surface of the rock, and they may be segregations of 

 silica ; the colour of the brown ground is due to the presence of the 

 organic acids. The bottom of the quarry exposes red sandstone (r), 

 joining on with an iiregnlar outline to the overlying mass of cream- 



