202 
BORING- AT SHILLINGFORD. 
Sep., 1891. 
grey clay winch could only be regarded as Oxford Clay, so 
that it was considered useless to proceed any further. 
The following is a detailed description of the boring, drawn 
up partly from the information given by Messrs. Isler and Co., 
and partly from specimens seen at various times during the 
progress of the work :— 
Gault 
144ft. 
Yectiau or 
Lower 
Greensand, 
25ft. 
Kimeridge 
Clay, 
llUft. 
? Coral Rag, 
44§ft. 
Lower Calc, 
Grit, 
35£ft. 
Oxford Clay. 
Soil and made ground. 
Thickness. 
Ft. In. 
4 0 
Depth. 
Ft. In. 
4 0 
Sand and gravel. 
15 
0 
19 0 
'Grev clay. 
81 
0 
100 0 
Darker grey clay. 
63 
0 
163 0 
/Yellowish greensand with quartz 
pebbles . 
10 
0 
173 0 
Hard sand rock. 
4 
0 
177 0 
Greensand and pebbles. 
6 
0 
183 0 
Greensand, loamy . 
1 
0 
184 0 
Loose pebbly sand, with grains as 
large as peas. 
2 
9 
186 9 
'‘Fine loamy yellow sand. 
1 
3 
188 0 
'Stiff grey clay and stones (? septaria) 
20 
0 
208 0 
Black clay, with shells and stones, 
and phosphate nodules at 296ft... 
91 
6 
299 6 
/Rock . 
12 
9 
313 3 
Stony clay and shells* (yellow 
gritty loam) . 
4 
8 
317 11 
Rock, with some layers of clay 
9 11 
327 10 
Stony clay, with layers of rock 
8 10 
336 8 
l^Rock (fragments of shell at 342ft.).. 
7 
7 
344 3 
fSand and stone. 
7 
4 
351 7 
Alternations of hard grey rock and 
clav. 
10 
4 
361 11 
Clay and Shells (dark gritty clay) .. 
10 
0 
372 0 
Hard grey limestone (specimens) .. 
2 
6 
374 6 
^Sand and stone, with water .. 
5 0 
379 6 
Blue clay, soft and slightly mottled 
4 
6 
384 0 
With regard to the Gault, there is no record of anv seams 
of phosphatic nodules or of anything other than clay. To 
estimate its thickness we must know the difference between 
the level of its surface at Shillingford and that of the base of 
the Malmstone on the south side of the river; the former is 
given on the six-inch Ordnance map as 156 feet, and the level 
of the latter may be taken at about 180ft., the difference being 
24ft. ; adding this to the 144ft. of Gault in the boring, and the 
19ft. of gravel which we must consider as replacing Gault, we 
get 187ft. for the total thickness of that formation below the 
arbitrary line which is taken as the base of the Malmstone. 
* Well-sinkers often seem to use the word shell as if it were 
synonymous with shale ; and by shelly clay mean a shaly clay, not a 
clay with fragments of shell. 
