GREAT OOLITE SERIES : WANSFORD. 409 
FT. IN. 
Upper and ? Lower 
Estuarine 
Soil and rubble of Great Oolite. 
"White clay - - - -10 
Yellow, sandy clay - 10 
Dark, laminated, carbonaceous clay 
White clay with vertical plant-mark 
\ ings ... 
ies ' I Dark, carbonaceous clay 
1 6 
9 
06 
I White clays, with vertical carbonaceous 
(_ markings and ferruginous stains 2 
} Ironstone-beds to the bottom - 8 
A little below the level of this pit, the Upper Lias Clay was 
dug; while the Great Oolite and Cornbrash were seen in the high 
ground above the pit. Prof. Judd was disposed to include all 
the beds above the Ironstone, with the Upper Estuarine Series, 
and in any case the formation has become greatly attenuated 
and is not more than 8 feet in thickness. He says, e< The North- 
ampton Sand also is evidently very poorly represented, and we 
have thus an illustration of the fact, that all the members of the 
Jurassic series partake in a greater or less degree of that ensternly 
attenuation, which, in the case of the Lincolnshire Oolite, is so 
marked in degree and so productive of complexity in the relations 
of the beds." 
He describes a section lower down the Nene valley, in the 
"wood-pit " at Stibbington, and this showed, the Upper Estuarine 
clays and sands, and shelly oolite (Lincolnshire Limestone) which 
was quarried beneath them. " Here the upper surface of the Oolitic 
limestone displays great irregularity, but this appearance is, in 
part at least, due to the percolation of surface waters, which have 
dissolved the upper surface of the limestone, and let down the 
superjacent clays into holes and ' pockets.' Under the sandy, 
whitish and bluish clays, with irregular plant-beds, we find the 
'junction-band,' a layer of nodules of more or less compact or 
earthy brown ironstone. This is underlaid in many places by a 
bed of white marl probably the product of the decomposition of 
the limestone, and containing apparently waterworn fragments of 
compact limestone, the beds below being highly oolitic. This 
would seem to indicate that a considerable amount of denudation 
of the Inferior Oolite limestone preceded, at this point, the 
deposition of the earliest beds of the Great Oolite series." 
" The strata of the Upper Estuarine Series were well exposed 
in making the Sibson tunnel on the Northampton and Peter- 
borough Railway, and sections of them may still be traced at 
either end of it in the deep cuttings. At the western end of the 
tunnel, near Wansford station, the whole series of beds, from the 
Great Oolite Limestone (here underlaid by a considerable thick- 
ness of freshwater sands and clays, with the ferruginous nodular 
junction band at their base), down to the thin representative of 
the Lincolnshire Limestone and Northampton Sand, may be 
seen."* 
* Judd Geol. Rutland, pp. 174, 193, 194. 
