29 



ANALYSIS OE THE EED CHALK OF HUNSTANTON, 

 ON THE COAST OF NORFOLK. 



By E. Calvert Clapham, Esq. 



During one of the excursions of the late meeting of the British 

 Association at Cambridge, the red chalk of Hunstanton was exa- 

 mined, and as I am not aware of its having been previously analysed, 

 I obtained a specimen to analyse. 



The bed of red chalk is about 3| feet thick, and runs along the 

 coast, distinctly seen for some miles. It rests immediately upon the 

 G-reensand, and above lies a bed of white chalk, varying in thickness 

 from 25 feet downwards. 



Professor Phillips, of Oxford, informs me that this bed of red 

 chalk has been traced from Speeton, in Yorkshire, to Spilsby, in 

 Lincolnshire, and reappears at Hunstanton, in Norfolk. 



It contains many fossils, chiefly of the White Chalk, and also fossils 

 of the Grreensand and Gault. 



It is an interesting question to consider what is the cause of 

 colour in the red chalk. Professor Phillips thinks that it is derived 

 from decomposed glauconite or decomposed augite (both of which 

 contain protoxide of iron and magnesia). It may also be caused by 

 decomposed iron pyrites, as it will be observed it contains a trace of 

 sulphate of lime. 



At Speeton it is in some places a soft red clay, and is used to 

 colour bricks and rough pottery. 

 The following is the analysis : — 



Carbonate of lime . 

 Sulphate of lime 

 Peroxide of iron 



Magnesia .... 



Manganese . 



Red chalk. 

 . . 80-04 



. . o-io 



. . 9-60 

 . . nil. 

 . . trace. 



White chalk. 

 95-80 

 trace only 



1- 08 

 052 

 0-48 



2- 28 



o-ii 





100-44 



100-27 



Walker, Newcastle- on-Tyne, November, 1862. 



CORRESPONDENCE. 



Ages of Mineral Veins. 



Sir, — Upon reading your report upon Mr. Moore's paper on the " Pa- 

 laeontology of Mineral Veins, etc.," before the British Association, a cir- 

 cumstance bearing upon the question occurred to my recollection, which I 

 would have mentioned had 1 been presenl in the Section at the time the 

 paper was brought forward. Mr. Moore BUOWS thai had veins in the 



