24 
silica. The source of this peroxide of iron is rather obscure. From 
the abundance and state of preservation of the fossils it seems 
probable that the bed was not deposited in its present state, but 
that, when first formed, it contained some body capable of produc¬ 
ing the red colour by subsequent decomposition. Dr. Procter 
found no essential difference in the composition of the Ped Chalk 
of Hunstanton and Speeton. From the mean of three analyses of 
the latter the following results were obtained : — 
Carbonate of Lime . 42-80 
Peroxide of Iron. 36*70 
Alumina. 1*43 
Silica. 1-93 
Sulphate of Lime. 0-86 
Carbonate of Magnesia . 0*41 
Water. 15'50 
Loss . 0*37 
100-00 
i— ■ ■ ■ 
The darker parts contained as much as 30—36 per cent, of peroxide 
of iron; the pale red portions gave only 5—13 per cent. The 
peroxide of iron has been supposed to be derived from the decom¬ 
position of iron pyrites in the rock; but this would have given rise 
to a large quantity of sulphate of lime, of which, however, the 
amount never exceeded 2 per cent. No specimen yielded more than 
2 per cent, of silica, and this, with the small amount of alumina 
(1*43 per cent.) seems to preclude the notion that the oxide of iron 
is produced by the decomposition of glauconite or augite. Dr. 
Procter is inclined to adopt the suggestion made by Mr. Seeley, of 
Cambridge, that the peroxide of iron in the Ped Chalk is derived 
from the decomposition of particles similar to those of the green¬ 
sand, the dark green colour of which is likewise due to the presence 
of iron. 
Nov. 3 .—Me. W. S. Dallas read some “ Notes on Mr. Pengelly’s 
Pesearches upon the Lignite Beds of Bovey Tracey.” The deposit 
of Bovey Tracey occupies a valley among the hills of Eastern 
Devonshire, a little to the north of Torbay. It is traversed by the 
river Teign, and in its upper part also by the Bovey, a tributary of 
the Teign. Essentially the valley may be regarded as a lake-like 
expansion of the valley of the Teign, and a slight depression of its 
level would suffice to convert it again into a lake, as it was at the 
