THE MIDDLE LIAS OF NORTHAMPTONSHIRE. 
89 
through them, give rise to springs. Generally these springs 
are very inconsiderable,for these and possibly other reasons:— 
The intervening clay beds are more or less calcareous, and so do 
not offer as great resistance to the passage of water as the 
stiff clays of the Lias ; also, they are comparatively thin, the 
greatest thickness of clay in one bed that I have myself 
recorded being 15 feet 1 inch; further, they are succeeded 
downwards by the Inferior Oolite, the whole of which is very 
porous. 
The best springs occur near the top of the formation, at 
the junction of the Cornbrasli with the Great Oolite clay, but 
all of these are far removed from Northampton, and so need 
not detain us. 
The Inferior Oolite Springs.— Below the Great Oolite 
beds just referred to, we have another set of porous beds 
yielding a much larger supply of water. They belong to the 
lower part of the Inferior Oolite, and may be distinguished 
as below:— 
Ironstone Beds } Northampton Sands. 
The Lower Estuarine is the upper bed of the Inferior 
Oolite in that part of Northamptonshire we are concerned 
with. It is nearly pure sand and very porous ; vertical plant 
markings are plentiful, but it contains no fossils. The lower 
portion of the Northampton Sand is what is worked as an 
ironstone in the neighbourhood, but it sometimes becomes 
calcareous, and both it and the more indurated portions of the 
Lower Estuarine are at times used as building stones. They 
are both rather variable in character and in thickness, the 
maximum thickness being about eighty feet, and the lower 
one rests upon an eroded surface of Upper Lias clay. 
The accumulation of water on the surface of this Upper 
Lias clay gives rise to many free springs, particularly as the 
Northampton Sand in the neighbourhood of Northampton 
generally forms a cap to the hills, the sides of the liills 
affording a ready vent for the water. Amongst the many 
well-known springs in and around Northampton having an 
origin of this nature, I may mention “ St. Thomas a Bechet's 
Well“Scarlet Well" —now very properly closed—the “Old 
Nine Springs Well," which used to be on the Billing Load, 
opposite to what is now Victoria Koad ; the spring in Gypsy 
Lane , that on the Race Course , and “ Lumber Tubs Spring," &c. 
In addition to these freely running springs, there are 
many pumps in and around the town getting their supply of 
water from this same source, but the number is gradually 
diminishing. 
