342 
THE CRETACEOUS ROCKS OF BRITAIN. 
The carbonates in these samples, as calculated from the 
amounts of carbonic acid, appear to be as follows :— 
Lower 
Pink 
Band. 
Upper 
Pink 
Band. 
Yellow 
Chalk in 
Upper 
Pink 
Band. 
Hard 
Grey 
Chalk. 
Carbonate of lime - 
81 *96 
96*47 
90*68 
85*68 
Carbonate of magnesia 
1 *48 
*75 
1 *93 
1 *53 
Several analyses of the marls of the zone of Actinocamax plenus 
have been made for the Geological Survey and others. The fol¬ 
lowing are four of these : —No. 1 is from the Geology of Gam bridge 
p. 55 (Mem. Geol. Survey), erroneously referred to the Mel bourn 
Rock; the specimen was a yellowish marly chalk from the upper 
part of the zone near Harston, and was analysed by Dr. Frankland, 
F.R.S. No. 2 was a purple marl from a pit south-east of Gay ton- 
le-Wold, in Lincolnshire, analysed by Mr. M. Staniland, F.G.S. 
No. 3 is a purple marl from Louth, analysed by Mr. Grant Wilson. 
No. 4 is from the dark bluish-grey marl exposed in the railway 
cutting east of South Cave, Yorkshire, and was analysed by Mr. 
J. W. Knights for Mr. W. Hill. 
:£ ' 
\ 
1 . 
2 . 
3. 
4. 
Insoluble Portion. 
Silica ----- 
6*44 
6*62 
14*46 
Alumina and peroxide of iron - 
* 92 
2*18 
5*44 
j17 *80 
Lime and magnesia - 
— 
* 52 
1 *04 
Soluble Portion. 
Carbonate of lime 
87*66 
86*25 
61*97 
66 * 20 
Carbonate of magnesia 
3*44. 
*94 
5*48 
6*20 
Chloride of sodium - 
*36 
— 
— 
-— 
Alumina ----- 
Oxides of iron - 
} 1*51 
1 *35 
*65 
2*33 
} 1*20 
Oxide of manganese - 
— 
— 
3*20 
Water and organic matter 
— 
1*62 
5*10 
8*60 
100*35 
99*48 
99*67 
100*00 
The following analyses are three more of those made and 
communicated by Mr. R. A. Berry, and are interesting as showing 
the composition of the grey marl and white chalk which form 
the Belemnite Beds in Bedfordshire. A is of the lower marl 
band near Hitchin, B of the hard white chalk between, the marls 
near Hitchin, and C of the similar white chalk near Royston :— 
