34 
DE RANCE : UNDERGROUND WATERS IN LINCOLNSHIRE. 
Scothern Mill. In the sands occur the " Kellaway Rock." The 
shales support a small sheet of water of no sanitary importance. 
Above occur the impermeable Oxford and Kimmeridge Clays, 
which are practically impermeable, and prevent the water in the 
porous strata beneath from rising to the surface, and therefore con- 
stitute an area of artesian pressure, both North and South of Lincoln. 
The Geological sequence at Sleaford is similar to that of the 
Lincoln area, and for boring purposes, to obtain a water supply, the 
conditions are hardly as favourable as nearer Lincoln. 
Cretaceous Rocks. — The Lower Cretaceous, or Neocomian 
Rocks, consist of the following strata in the Tealby district : — 
Ft. 
Red Chalk .. ... ... ... ... 6 
Upper Sands or Carstone ... . . ... ... 25 
Tealby Clays, Limestones, and White Ironstones of Claxby 05 
Spilsby Sandstone and Lower Sands ... . 42 
The Spilsby Sandstone is an extremely hard calcareous grey 
grit, passing horizontally into soft sandstone with mud from oxide of 
iron. Narrow outcrops, and shallow thickness alike, prevent the 
above being useful for purposes of public water supply, and were the 
conditions otherwise the presence of iron would seriously affect their 
quality. 
The Carstone is a coarse grit, mixed with ferruginous clay, but 
never passes, like the softer portions of the Spilsby Sandstone, into 
a " running sand." 
The Red Chalk is shaly and impermeable, and throws off springs 
at the base of the Lower Chalk, and a spring half-a-mile south of 
Stanton-le-hole is thrown out by the Carstone. 
Upper Cretaceous 
Lower Chalk : This formation in Lincolnshire is marly, and 
cannot be relied on for a good supply of water. 
Middle Chalk : For borings see end of Appendix II. 
