18 flind: Life Zones in British Carbontferous Rocks. 
series assigned to the Millstone Grit in Scotland, though some 
of the beds contain a rich marine fauna, largely new to the 
Eastern Hemisphere. 
Mr. Kidston has shown that the change from a Lower Car- 
boniferous flora to the Upper occurs in the Millstone Grit series 
of Scotland, about the horizon of the Roslin sandstone. 
In the South, the sandstones of the Middle Culm most pro- 
bably represent the Millstone Grits, but it is doubtful if they are 
presented to any extent in the South Wales or Bristol coal re- 
fields. In Belgium, we know that the Millstone Grits are 
absent. In the West of Ireland, a fairly well developed series 
of flagstones, grits, and inter-bedded shales with marine bands 
evidently represent the Millstone Grit. 
Although in the localities mentioned above, the Carboniferous 
sequence differs enormously, as yet no apparent unconformity 
has been proved anywhere between the Carboniferous Limestone 
and the Coal Measures. Whatever beds overlie the Carboniferous 
Limestone appear to be conformable to it. 
Within the last two years an important fact has been made 
out for the Carboniferous areas of North Wales, the Pennine 
system, and the East of Ireland, that is, the upper beds contain 
everywhere a definite coral fauna, characterised by the presence 
of Cyathaxonia, Amplexizaphrentis, and Cladochonus; thus a 
definite top is obtained for the Carboniferous Limestone series, 
and in other words a definite base for the succeeding Pendleside 
series. 
It is at the top of these Cyathaxonia beds that the great change 
takes place in the Molluscan fauna, and in the Midlands in the 
Fish fauna. The Corals, Echinodermata, and Polyzoa became 
almost entirely annihilated, and a new fauna of mud-loving 
animals took their place, but land conditions remained constant, 
for the great floral change only took place at a much later period, 
as I have previously stated. The great Carboniferous faunal 
break must therefore be placed at the top of the Cyathaxonia 
beds, and it is here that the line dividing Upper and Lower 
Carboniferous must be drawn. 
The Cyathaxonia beds at Warsoe-end House, near Pendle 
Hill; Congleton Edge quarry, Cheshire; Torrs’ quarry near 
Bradbourne, Derbyshire, contain Prolecanites compressus, a 
fossil which characterises the junction of Upper and Lower 
Carboniferous rocks, and passes up into the lower part of the 
Pendleside series, but does not range far up. 
This fossil is plentiful in the Coddon Hill beds of the Culm, 
Naturalist, 
