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The Great Ouse upstream from Bedford (Fig. 240, b5 ) has a particularly sinuous
course which must have developed before it cut down into the Jurassic bedrock, in-
cising and fixing the meanders.
Southwest of Bedford is a remarkable topographic feature that I refer to here as
the 'Bedford Bite' ( b4 ), though it is also sometimes referred to as the Marston More-
taine Basin. The floor of this feature is underlain by Late Jurassic Oxford Clay that has
been extracted in large amounts for brick-making around Marston Moretaine and Ste-
wartby. The slope map shows small slopes edging some of the rectangular brick pits,
but also the much larger curved slopes that face into the Bite as a continuous edge to
the southeast, south, west and northwest. Some of the southern sector of this edge is
capped by Early Cretaceous sandstone (Lower Greensand), but the rest of it, to the east
and west, is made of slopes capped by Anglian ice-laid material, which has draped the
Early Cretaceous or Late and Middle Jurassic bedrock. The clear definition and curved
shape of the bounding edges of this Bite, along with the flatness of its floor, suggest
that the edges have retreated backwards as they slumped under the very varied climatic
conditions since the Anglian. The slumped material may then have been cleared from
the floor of this large feature by freeze-thaw processes, before finally being carried
downstream by the ancestors of the Great Ouse.
FIG 240. Slope and hillshade map of the Bedford sub-area (II) of Area 13 (located on Fig.
231), showing localities and hard Chalk layers 1, 2 and 4 (see Landscape C ).
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