INFERIOR OOLITE: BRACKLUY. J77 
The same beds have been opened up to the south and north- 
west of Croughton. The sands were dug east of Warren Farm, 
and the stone-beds a little further north. There we find cal- 
careous and obscurely oolitic sandy limestones, some layers 
splitting up so as to form flags that might be used for tiling, like 
the " slates " of Duston. Slaty beds of this character evidently 
favoured the notion that these beds, and associated sands, 
belonged to the Stonesfield Slate. Beds of sand and slaty 
sandstone were observed by Prof. Green, above the Upper Lias, 
in the railway-cutting north-west of Brackley Station.* 
At the Brickyard north-east of Brackley, the following beds 
were exposed : 
FT. IN. 
Loamy soil - 1 6 
fPurplish loam and clay and white and 
brown sand - 8 
Lower Estuarine Greenish and dark sand and slightly 
Series and J calcareous sandstone, very hard and 
Northampton 
Sand. 
ferruginous : Aviciila braatnburiensis, 
Pecten, Ustrea, pebbles of hardened 
Upper Lias clay bored: (rusty 
springs) - - - -36 
{Blue pyritic clay with Ammonites 
fibulatus : the clay is worked for the 
manufacture of red bricks, tiles, and 
drain-pipes 8 
The junction of Great Oolite and Inferior Oolite has been 
exposed in quarries south of Helmedon, and between Brackley 
and Radston. In the latter neighbourhood the following section 
was observed by Prof. Green : 
FT. lar. 
[Upp,r EBtuarinej^^-^n^ - - 2 
Senen.] l Dar V b , ne clay - - 1 G 
[ Flaggy or slaty sandstone. 
It is often difficult, where the Upper and Lower Estuarine 
Beds come together, to fix a divisional-line between them. In 
the above section it appears most likely that the Upper Estuarine 
Beds have overlapped the Lower Beds, so as to rest unconform- 
ably on the Northampton Sand. 
Helmedon (according to Morton) was long celebrated for its 
extensive freestone-quarries : the stone, " which lies next under- 
neath a stratum of clay," having been used for the mansions of 
Stowe and Woburn ; but even in his time the stone was no longer 
worked for the purpose. The same writer gives the following 
details of a stone-pit at Eydon,t and these indicate that the beds 
belonged to the Northampton Sand : 
* See Green, Geol. Banbury, pp. 12, 19. 
t John Morton, Natural History of Northamptonshire, 1705, pp. 108, 126, &c. 
K 75928. M 
