426 
LOWER OOLITIC ROCKS OF ENGLAND : 
A well-boring made at Sleaford, for Messrs. Bass and Co., proved the 
following strata : 
FT. IN. 
Valley Gravel 
Kellaways Clay 
Cornbrash 
Great Oolite 
Clay. 
Great Oolite 
Limestone. 
rClay 
Lower Estuarine I Eock 
Soil 
Gravel and sand 
Clay 
Eock 
jClay 
JEock 
Series. 
Lincolnshire 
Limestone. 
T Green clay 
Dark clay 
f Eock 
i Clay 
I Eock 
- 1 
- 12 
- 1 
- 10 
- 12 
- 7 
- 2 
- 1 
- 4 
- 15 
- 2 
- 85 
- 24 
177 9 
Another well at Cross Keys Yard, Sleaford, showed 36 feet of clays 
with a rock- band (2 feet thick) that must be grouped with the Lower 
Estuarine Series. The Lincolnshire Limestone was reached at a depth 
of 70 feet, and penetrated to a further depth of only 11 ft. 6 in. 
Other well-borings in the neighbourhood proved the following strata, 
the details of which I have interpreted, though not always with absolute 
certainty as to the grouping of particular bands of clay or rock : 
Strata. 
Osboumby. 
Swaton. 
Heckington. 
Silk 
Willoughby. 
FT. IN. 
FT. 
IN. 
FT. IN. 
FT. IN. 
Soil 
1 6 
1 

10 
8 
Drift 

41 



Oxford Clay and Kella- 
ways Beds. 
Cornbrash 
17 6 
9 2 
58 
14 

10 
245 
7 
3 
Great Oolite Clay 
Great Oolite Limestone - 
21 
1.1 10 
28 
21 
6 
4 
22 
17 
20 
17 
Upper Estuarine Series - 
Lincolnshire Limestone - 
29 6 
58 4 
27 
59 


22 
77 
26 
104 
150 10 
250 
8 
400 
178 
At Aswarby a, boring was carried to a depth of 131 feet (into the Lin- 
colnshire Limestone), and the beds passed through were practically the 
same as at Osbournby. For the above details I am chiefly indebted to 
Messrs. Thomas Tilley and Sons. The record of the Silk Willoughby 
boring was communicated by Messrs. Wadsley and Son ; and this boring 
was continued to a further depth of 37 ft. 9 in., in " Lias 1 ' 20 feet, and 
41 Blue Eock " [P Marlstone] 17 ft. 9 in. (See p. 505.) 
Sleaford to Greetwell and Winterton. 
Near Blankney Hall the thickness of the Upper Estuarine 
Series was proved to a depth of 25 feet. Mr. W. H. Dalton 
remarks that in a well at Potter Hanworth Station, the lower part 
of the Series was found to consist of blue and green clay, with 
