A HISTORY OF BUCKINGHAMSHIRE 



Near Buckingham, at Tingewick, Radcliff and elsewhere coarse 

 boulder gravel with large blocks of Oolitic rocks and finer gravel and 

 sand occur with intercalations of Boulder Clay. 



If we believe that the main mass of Boulder Clay was formed on 

 the land, that much of it was overridden and pressed down into the 

 tough material which it usually is, and that it was left on the melting 

 back of the ice sheet, we might expect, along the borders of the 

 glaciated area, to find alternations of gravel, sand and Boulder Clay. The 

 ice during fluctuations in climatic conditions extended and receded for 

 some distance more than once before it finally retreated, and the melting 

 of the basal portions gave rise to such diverse sedimentary accumula- 

 tions, largely torrential, as in fact we find near Buckingham. 1 



It may be therefore that over the Chalk tracts which were not 

 glaciated the brickearths and gravels of the plateaus belong to the 

 marginal area of the ice sheet, whence more or less mixed deposits 

 were spread out by the flood waters. 



VALLEY GRAVEL AND BRICKEARTH 



In the higher courses of the Chalk valleys, where no streams now 

 flow at the surface, or only occasionally in times of excessive rain, we 

 find accumulations which have been termed ' Dry Valley Gravel ' 

 largely made up of loam with unworn and broken flints, a waste from 

 the clay-with-flints and brickearth and occasional gravel beds of the 

 bordering hills. These merge in the lower courses into the ordinary 

 valley gravel, as between Wendover and Great Missenden. 



The gravels of the Thames valley extend over broad tracts near 

 Great Marlow, Burnham, Dorney, Eton, Wraysbury and Colnbrook, 

 thence merging into the gravels of the Colne valley by Denham. 

 They consist of angular, subangular and rounded flints, with pebbles 

 of quartz and quartzite, and are exposed in pits to a depth of 1 2 or 15 

 feet or more. Over considerable areas there are sheets of brickearth 

 which at Slough and Langley have been worked for brickmaking. 



We have thus in these lower lands the same kinds of deposit as 

 occur on the Chalk and Tertiary plateaus, but the valley deposits yield 

 the mammalia characteristic of the Pleistocene deposits, and palaeolithic 

 implements. They are distinctly river deposits, although in composition 

 the gravels naturally do not differ from the higher beds from which they 

 were mainly derived ; and near Great Marlow it is difficult in places to 

 separate the higher terraces of river gravel from the plateau Drifts. 2 



In the Ouse valley we find gravels at Buckingham, Stony Stratford, 

 Stanton, Lathbury, Tyrington and Filgrave, Emberton, Olney and Cold 

 Brayfield ; and in the Ouzel valley there is gravel at Linslade, Fenny 

 Stratford, Woughton-on-the-Green and Newport Pagnell. Along the 

 borders of this valley there are extensive tracts of grazing land. 



Although the main features of the country appear to have been 



1 H. B. Woodward, Geol. Mag. pp. 485, 496 (1897). 

 * See also H. J. O. White, Prof. Geol. Aim. xv. 158. 



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