135 
mineral, but its occurrence in our own immediate neighbourhood in 
larger quantity than has been before noticed, is in a local sense 
most remarkable, and I trust not unworthy of the notice of our 
Society. 
Wad, a hydrated oxide of Manganese, has been found at 
Etchingham, in Sussex (about twelve miles S.E. of Tunbridge 
Wells). A specimen is shown in the British Museum (table case 
12, H). It has been suggested thatthe Manganese found in the 
Canterbury gravels may have been brought with the drift gravels 
from the interior of the Weald. I have found fragments of the 
Lower Greensandstone in these gravels, carried by the same 
translating force, but I do not think it possible that so friable a 
mineral as hydrated oxide of Manganese could have escaped the 
grinding of the gravel masses when we only find such hard 
survivors as the cherty limestone and silicious ironstone. 
I think from the amount of Manganese found in the ashes of 
plants, such as the Beech and Sweet Flag, on the authority before 
quoted, that living vegetation has played an important part in 
gathering this mineral from the surrounding land where it had 
past into solution by means of the acids generated by the decay of 
vegetable life, to be again deposited as the hydrated peroxide of 
Manganese accumulated at the bottom of shallow pools and 
covered by the gravels at the close of the glacial period. 
XXIII. 
SOME REMARKS ON THE LOWER GREENSAND, 
ATTRIBUTING THE CONTINUOUS FORMATION 
OF GLAUCONITE TO THE POTASH SET FREE 
BY DECAYING VEGETATION, 
BY 
CAPTAIN McDAKIN. 
Reap Marcu &th, 1888. 
In the Lower Greensand the fossils represent a marine state 
of existence except those that must have been borne seawards by 
the ancient river, that formed the estuarine deposits of the Weald, 
representing the wreckage of a vanished continent. 
The numerous specimens of drift wood occurring at the 
junction with the superimposed Gault have had their woody fibre 
largely replaced by phosphate of lime; in some specimens that I 
have examined only six per cent. of carbon remaining instead of 
