557 
bottom was more or less under the influence of tidal and other 
currents. 
Towards the lower part of the formation the limestone 
ceases to be laid in a smooth and even deposit, the beds are 
of a darker tint, become lumpy and twisted, and have the 
appearance of having been formed under the influence of 
innumerable small eddies, and may, perhaps, correspond in 
geological age with the botryoidal limestone of the county 
of Durham. Here occur, in a quarry near Wormald Green, 
certain organic remains which have all the appearance of 
sponges. When broken they exhibit the sparry cavity so 
characteristic of this formation. And we may, perhaps, infer 
from this, that most of the smaller cavities have arisen from 
the decay of organic remains. At a quarry near Aldfield, 
and at another at Well, occurs a bed of hard blue limestone, 
containing fossils, apparently of the same age as the marl 
states of Durham. The fossils occurring at Aldfield, are 
Terebratula elongata, Spirifera undulata, Camerophoria 
schlotheimi, Streptorhyncus pelargonatus, Strophalosia mor- 
risiana, Producta horrida, P. latirostrata, Bakevellia antiqua, 
Axinus obscurus (small), A. schlotheimi, Monotis radialis, 
Acanthocladia anceps, Fenestella reteformis, septa of Nautilus 
frieslebeni and a small univalve. At Well, Producta horrida 
occurs abundantly. 
As a building stone, the Magnesian limestone is too easily 
affected by the weather to form a good material for outside 
work ; as, under the influence of frost, it breaks away in 
flakes, or crumbles into dust, leaving only the sparry veins 
standing out with deep intervening hollows. For inside 
work many of the beds are admirably fitted, from the ease 
with which they can be wrought and the beautiful colour of 
the stone. When used for mortar, it sets with extreme 
hardness. For agricultural purposes it is less valuable, as it 
is too caustic to allow a large amount to be used at once. 
