82 
Following the Toad Vein are again three seams which have not 
been worked, and then the White-ash steam coals come to an 
end. They are followed by Red-ash gas and house coals. 
The first of these is the Upper Five Coals, lying 131 yards above 
the Toad Vein, and 11 yards higher is the Doxall seam. The 
rich Flora of the Toad Vein has almost disappeared; the Sigillaria 
have only one representative, the other fossils, with the exception 
of Cordaites, have not as yet been found. 
The roof of the Doxall seam is a hard calcareous blue-stone, 
the richness of the colour being due to the amount of ferrous 
compounds contained ; on exposure to the air, the latter passes 
into the ferric state. Almost the only Fossil found is the cast 
of a small Calamite, the organic structure having been destroyed. 
There is, however, evidence of a rich Flora having existed; but 
the bulk of the vegetation has been in the main destroyed by 
the iron and sulphates, which the waters of that period contained 
and deposited. 
Mr. Epwarp T. Harpmay, F.G.S8.,* demonstrates this decom- 
position of organic matter by referring to the Flax Pits of the 
North of Ireland, where he says, “‘ the clay in which the pits are 
sunk contains nearly all the iron present in the ferric condition 
when not subject to the action of the plants, but in the mud from 
the bottom there are only parts compounds of iron mostly as 
Carbonate. Nor is there a trace of peroxide of iron in the 
flaxwater, but, on the contrary, plenty of ferrous iron.” 
Next follow numerous beds of fire-clay, shales and stone. 
These fire-clays are full of Stigmaria, but few vestiges of the 
Lepidodendroid or Sigillaroid plants, of which they were the 
roots, are met with, the only one I have found is Ulodendron 
majus, and two stems standing in situt with Stigmaria attached. 
This stratum is now being proved at the Kingswood Collieries 
by a branch from the Belgium Pit. Only one seam of coal up 
* The Atmosphere considered in its Geological relation. Quarterly Jovrnal of 
Science, No. 56, October, 1877, page 460. 
+ The structure was not well enough preserved to determine them with 
certainty. They were 8 inches in diameter, and the underclay was compressed to 
an inch thick. 
