20 Sidney Melmore—The St. Bees Sandstone. 
Full analyses were made of the Maryport and West Newton 
samples; the results are :— 
Ii. Vs 
SiQ2. ; , ‘ : 86-57 84-58 
Aly Os , : : : 6-50 7-21 
Fes O3 : : : , 1-92 - 2-05 
FeO. : ; ‘ none none 
Mn O2 ni ; 5 i none none 
CaO. ; : : ; 0:57 1-40 
MgO : : : : 0-083 0-098 
K,0O. 5 : : : 1-618 1-376 
Nag O : ; : j 0-574 0-392 
COQ.. : 0-078 none 
HO (combined) ; i 1-042 1:72 
Sulphuric acid {S Os) : 0-285 0-345 
99-240 99-171 
III. Sample from Maryport. 
IV. Sample from West Newton Quarries. 
The percentage of ferric oxide continues to increase from the value 
found at St. Bees till it also reaches a maximum near West Newton, 
and then decreases in value. The percentage of S O, rises slightly in 
a northerly direction, its amount, however, being practically the same 
. for both basins. The total alkalis gradually decrease in the same 
direction. 
Conctusions. 
Considering each basin separately, all the localities where samples 
of sandstone were taken lie practically along the strike of the rock. 
The percentage of constituents found in these samples are therefore 
functions of the same geological horizon, and differ among themselves 
by virtue of their representing samples taken from different points of 
this horizon. The results therefore show superficial variations, 
rather than variations in geological time. It is well known that the 
process of kaolinization is accompanied by the formation of combined 
water, and this water 1s produced quantitatively in proportion to the 
kaolin. The degree of kaolinization can therefore be estimated with 
considerable accuracy by determining the amount of combined water 
in any sample of sandstone and correcting the value found for the 
presence of such other hydrated compounds as gypsum (Mackie, 
Trans. Edin. Geol. Soc., vol. vii, p. 454, 1899). 
In the present connexion, the values of combined water plotted 
are uncorrected for combined water in CaS O,.2H,0, as the amount 
of calcium sulphate present in the seudeband is practically constant. 
Any alteration in the shape of the curve would be very slight if such 
a correction were applied. The substances whose presence is essential 
to kaolinization are water and carbon dioxide. 
In sea-water the amount of dissolved oxygen varies from about 1 to 
3 c.c. per litre, and the amount of carbon dioxide from 2 to nearly 40 c.c. 
per litre. The gaseous contents of sea-water increases with the depth 
to about 2,000 feet, below which depth the water contains scarcely 
any dissolved gases. 
Assuming kaolinization to have proceeded under these conditions 
