ECONOMIC GEOLOGY. 



255 



Upper Greensand of the Undercliff, 



Cherty flint .... 

 Blue limestone (rag) ... 

 Rubbly rock - . - - 



The Freestone Bed . - . 



" False freestone " . - - 



Sand with occasional chert 

 Light-brown or cream-coloured " malm " 

 Dark malm (passage-bed into the Gault) 

 Best Farnham Malm-rock, up to 



Analyses of Chalk. 



Chalk from the East Quarry, Ashey Dotvn* 



1. Analysis made at Tennant's Works, Manchester, 1874. 



2. Do. do. by Dr. Voelcker, 1875. 



3 and 4. Do. do. by Mr. Pattisou of Newcastle-on-Tyne. 

 The specimen No. 3 was taken moist. 



Analysis of Glauconite f^om the Lower Greensand of Compton 

 Bay (see p. 22), by Mr. J. HoRT Player, F.G.S., F.C.S. 

 April 12th, 1889. 



Loss by ignition - - . - - 9-2 



Silica - - - . - - 56-6 



Alumina - - - - - . 9'^ 



Ferric oxide . - - - - -14-6 



Ferrous oxide - - - - - 2'"] 



Lime - - - - . - --9 



Magnesia - - - - - -1-1 



Potosh - - - - - - 4*9 



99-6 



" The substance used in the above analysis when examined under 

 the microscope is seen to consist of glauconite with a ve'-j small 

 admixture of quartz. The grains of glauconite vary in size from 

 about 25 mm. to 5 mm. They are of fairly uniform dimension? 

 in the different directions, but many of them shew more or less 

 rounded protuberances. They are opaque by transmitted lifrht 

 except at the edges. Small particles produced by crushino- the 

 grains are grass-green by ordinary light and give minute aggregate 

 polarisation. Tliere is no trace of any definite structure in the 

 substance of the grains." — J. J. H. Teall. 



* Communicated by the late Mr. J. Young to Mr. Bristoir. 



