DEPOSITED IN WATER. 
71 
of Nidderdale may be analogous. The two F ell top and ironstone coals 
appear to agree with the two variable coal beds in the upper chert 
series of Swaledale and Arkendale ; the grindstone sill of Aldstone 
moor corresponds to the ‘ millstone grit’ of Teesdale and Arkendale, 
and the middle grit of Greenhow ; and the millstone grit of the country 
east of Aldstone moor to the highest pebbly grit of the Yorkshire 
series designated as Brimham grit. The diminution of the whole mill- 
stone grit series from Nidderdale to Aldstone moor is not considerable, 
the characteristic gritstones preserve nearly the same relative posi- 
tions, and the other parts of the series retain, amidst many variations, 
some common features. 
Thus there are three rocks called millstone grit, which arrive at their 
maximum of thickness and importance in different districts, but all are 
seen in connexion in Nidderdale. Coal, cherts, and thin crinoidal lime- 
stone, occur both above and below the lower millstone grit : the upper 
coal group is the most continuous and valuable. Flagstone and slate 
occur above the middle grit, and in more than one part of the group 
below it. 
CONSPECTUS OF CERTAIN BEDS IN 
Aldstone. 
Teesdale. 
Arkendale. 
' Millstone grit’ 
Grindstone sill 
Grits and plates 
Grits and plates 
Grits and plates 
‘ Grindstone sill’ 
‘ Millstone grit’ 
‘ Millstone grit’ 
Flagstone & plate 
Flagstone & plate 
Plates 
‘ Fell top lime- 
stone’ 
' Crow limestone’ 
COAL 
(coal ?) 
COAL 
‘ Ironstone’ 
Flagstone 
‘ Ironstone’ 
COAL 
COAL 
‘ White grit’ 
‘ Firestone’ 
‘Firestone’ 
Little limestone’ 
‘Little limestone’ 
‘Little limestone’ 
Coal 
COAL 
Chert 
' Main 
Limestone or 
Great limestone 
THE MILESTONE GRIT SERIES. 
Pen hill. 
Nidderdale and 
Costerdale. 
Brimham grit 
Grits and plates 
Penyghent. 
Top grit 
Flagstone & plate 
Sandgill grit 
Flagstone & plate 
COAL 
Top limestone 
COAL 
Flagstone 
COAL 
COAL 
(Trace of grit) 
Bearing grit 
Millstone grit 
Little limestone 
or Twelve 
COAL 
COAL 
Fathom 
Little lime 
Limestone’ 
