THE MIDDLE LIAS OF NORTHAMPTONSHIRE. 
235 
quite incredible that the Lower Lias would vary in thickness 
by more than 80 feet at two places only about a mile apart. 
An anticline could not account for the increased thickness of 
any bed of the section at Kingsthorpe, and if it could the 
suggestion would be entirely opposed to the evidence which 
can now be obtained with regard to the superficial beds, for 
the Upper Estuarine Clay just at the edge of the hill, where 
the Kingsthorpe shaft is situated, is at the same level as the 
Great Oolite limestone a little further on the hill, and must, 
therefore, dip below it. By giving the Lower Lias a thickness 
of 546 feet, the same as at the Spinney Well, the Marlstone 
would be at a depth of 293 feet from the surface. 
To get a correct idea of the thicknesses of the beds above 
the Middle Lias it is necessary that measurements should be 
made where undenuded Upper Lias and Inferior Oolite at 
least are met with, and preferably where the Great Oolite 
forms the Upper bed. The nearest place I can appeal to as 
supplying the information is Duston, situate a little less than 
three miles from Kingsthorpe shaft. In a well made at Berry 
Wood Asylum the following beds were passed through :— 
Section of Well at Berry Wood Asylum. 
Upper Estuarine... Clay 
Sand 
FEET 
about 20'] 
50 
t , . ,, ) Sandstone (like that in the ( 
Inferior Oolite ^ qnarries New Dnston) 30 to 30 ) 
( Sunk. 
Blue greasy stone ... 
Upper Lias ... Clay 
Marlstone ... Hard bluish stone... 
3 
190 V Bored. 
3 
The spring at the base of the Inferior Oolite was used for 
some time before the boring to the Marlstone was made. 
It is known that the Upper Estuarine beds of the Great 
Oolite at Kingsthorpe are about 20 feet thick, the same as at 
Duston, because they were once worked for brickmaking, and 
if we add to these 83 feet of Inferior Oolite (Northampton 
Sand) and 190 feet of Upper Lias (the minimum of each at 
Duston) we get 293 feet as the depth of the Marlstone, the 
exact depth arrived at from a different set of data, a result 
certainly remarkable, and therefore strongly confirmatory of 
the contention that the Marlstone at the Kingsthorpe Well is 
below the present water-level there. 
Altogether, then, it appears that the wells at Kingsthorpe 
and Northampton which yielded water tapped the Marlstone 
at a lower level than that formation had at the Spinney Well. 
It is scarcely necessary for me to point out that so long 
as the bed is continuous, the presence of an anticline in the 
