A HISTORY OF NORTHAMPTONSHIRE 



Bradford Clay of south-eastern -England. In Northamptonshire it is a 

 variegated clay — blue, green, yellow, or purplish, and occasionally bitu- 

 minous (Peterborough) — containing, in irregular layers, white, green, 

 septarian, concretionary, calcareous, or ferruginous nodules. Ostrea sub- 

 rugulosa is fairly abundant, and quantitatively may be regarded as a 

 characteristic species of fossil in differentiating this from the beds im- 

 mediately above (see next section). Blisworth, Stowe-Nine-Churches, 

 Thrapstone, Oundle and Wansford are some of the places where it has 

 been well exposed. 



The Forest Marble Series 



This set of beds (named from its occurrence at Wychwood Forest in 

 Oxfordshire) is, in north-eastern Northamptonshire, inseparable from the 

 Great Oolite Clay, hence under the latter name is recorded a thickness 

 of 20 feet. South of the Nene valley, at Stowe-Nine-Churches, near 

 Pattishall, Roade, and Quinton, we have, over beds such as are described 

 in the previous section, variegated clays with thin bands of fibrous car- 

 bonate of lime, hard shales, flaggy limestones with abundant interbedded 

 plant remains, and oyster-beds. At Quinton a bed between 3 and 4 

 feet thick consists almost entirely of Ostrea sowerbyi, with a smaller 

 number of specimens of Modiola hnbricata and IJnkardium varicosum. 



Both the Great Oolite Clay and the Forest Marble series, although 

 containing only a marine fauna, by their changeable nature, interbedded 

 vegetation, and other characters suggest distinctly shallow water and 

 estuarine conditions, though there was probably a general sinking and 

 consequent levelling up going on, preparatory to the deposition of the 

 thick argillaceous deposits commencing with the Oxford Clay. 



The Cornbrash 



The Cornbrash is usually a hard, blue, fossiliferous limestone when 

 encountered under other rocks ; at the surface it weathers to a yellowish 

 or ruddy colour, and forms a rubbly or brashy rock and soil, supposed to 

 be particularly suited to corn, hence the name. Within Northampton- 

 shire it mostly occurs as isolated masses (see map), but no doubt at one 

 time covered the whole county, for it is the most persistent of all the cal- 

 careous strata of the Oolitic period, being met with right across England. 

 It has been found in Northamptonshire as far westward as Stowe-Nine- 

 Churches, let down by a ' fault. '^ The average thickness is about 5 

 feet, but in the eastern parts of the county (Peterborough, etc.) it reaches 

 to 1 5 feet. The stone is not much used, though some rough walling 

 may be done with it also road mending ; it is also occasionally burnt 

 for lime. 



* Beeby Thompson, ' The Oolitic Rocks of Stowe-Nine-Churches,' Journ. North. Nat, 

 Hist. Soc, No. 48, vol. vi. p. 295. 



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