332 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ Feb. 23, 
Grimston. Between this last point and Sancton, the red-rock over- 
laps successively the different members of the Lias, and at the last- 
mentioned place, the representative of the Inferior Oolite, now re- 
duced to a very thin bed, is again uncovered. As we approach the 
Humber, the Kelloway, the Oxford, and the Kimmeridge successively 
reappear from beneath the Chalk; and crossing into Lincolnshire we 
recover the Lower (?) Neocomian at Worlaby, the Middle Neocomian 
at Clixby, and the Upper (?) Neocomian at Nettleton Hill. 
It is this circumstance of the overlap of the Upper Cretaceous 
beds, combined with that of the Neocomian strata dipping at a high 
angle, which has caused these latter to occupy so small an area in 
Yorkshire. 
At Speeton Cliff we have upwards of 500 feet of Neocomian clay 
exposed, although the upper part of the series is not here complete. 
Of the Upper Neocomian clays (above 150 feet thick) with the 
well-defined zone of the cement-beds, containing the remarkable 
fauna so exactly agreeing with that of the Atherfield clay of the 
South of England, no trace is discoverable inland, as they are com- 
pletely covered up by the great drift-deposits of the Vale of Pick- 
ering. 
The same is true of the Middle Neocomian (also 150 feet thick) 
with its well-defined fauna, marked especially by the abundance of 
the gigantic Pecten cinctus and the bands with numerous specimens 
of Ancyloceras towards its base. 
Of the Lower Neocomian (200 feet thick) we obtain, however, 
distinct traces inland. After a very imperfect reappearance in 
Reighton Gill, only a mile from the cliff section (fig. 2), the upper- 
most beds (zone of Ammonites speetonensis) are quite lost under the 
drift for a distance of fifteen miles; they are then seen again at West 
Heslerton, when on the very point of disappearing under the chalk 
in consequence of the overlap. The lowest beds of the Lower Neo- 
comian are also found at Knapton, when about to be similarly Loss 
under the Wolds. 
The Neocomian beds, which thus disappear at Knapton, are 
entirely concealed from us by the overlapping Chalk strata for a 
distance of over forty miles (see Map, Pl. XXIII. fig. 3). In this 
space they have undergone considerable changes both in thickness 
and mineralogical characters; but the several subdivisions are still 
recognizable by means of their characteristic fossils. 
We have seen that the whole series of these beds in Yorkshire 
consists entirely from top to bottom of clays, varying, it is true, in 
such merely accidental characters as colour, amount of pyrites, the 
number and nature of the enclosed septaria, and the abundance 
and state of mineralization of their fossils. When, however, the 
Neocomian beds first reappear at Worlaby, in Lincolnshire, it is in 
the form of a coarse, greenish-white sand, in places passing into a 
hard sandstone. The deficiency and bad state of preservation of 
the fossils in these beds, which occupy the base of the Wolds from 
Worlaby to Clixby, prevents us from certainly deciding as to their 
place in the series. It is possible that they represent in a very 
