A HISTORY OF BEDFORDSHIRE 
England owing to the absence of the latest Cretaceous and earliest 
Eocene strata. 
There are great contrasts between the Upper Chalk and the Read- 
ing Beds, which, when present in this area, lie in contact with it. 
Palzontologically the contrast is between the fauna of a deep sea and 
that of an estuary; stratigraphically between a nearly pure limestone 
of organic origin slowly and evenly deposited, and bright-coloured clays, 
sands, and pebbles accumulated rapidly and distributed irregularly. The 
arm of the sea in which these beds were deposited extended from the 
district which is now the south midlands, to Hampshire or beyond, in- 
cluding the areas known as the London and Hampshire Tertiary Basins. 
The northern margin of the London Basin runs through the south or 
Hertfordshire, and beyond and not far from it there is a series of Eocene 
outliers of considerable extent followed by another of much smaller 
ones; and far away to the north, in South Beds, a few very small ones 
have escaped the complete denudation which has removed the inter- 
vening mass, testifying to its former extension. These are in the parishes 
of Caddington, Kensworth, and Studham, the largest being near Ringsall. 
In the superficial deposits of the valley of the Lea, within our 
county, there are frequently found large masses of conglomerate or ‘ pud- 
ding stone,’ which are probably of the same origin as the Hertfordshire 
conglomerate. As they are but slightly waterworn they may have been 
dropped into their present position owing to the dissolution of the 
softer strata of the Reading Beds of which they formed a part. One 
that was met with in a shallow excavation just south of Luton measured 
6 feet long, 3 feet wide, and 2 feet thick. The pebbles of the Reading 
Beds, which are thus locally consolidated into a conglomerate with a 
siliceous matrix, are almost invariably chalk-flints, indicating that the 
higher Cretaceous strata were subjected to an enormous amount of 
erosion at the beginning of the Eocene epoch. 
PLEISTOCENE 
The greatest change of climate which is definitely known to have 
taken place in this area and western Europe generally, occurred between 
the Eocene and Pleistocene epochs, tropical conditions giving place to 
arctic. The tropical fauna and flora of the London Clay became sub- 
tropical in later Eocene times, and continued so during the Oligocene 
and Miocene periods. Early in the Pliocene period temperate conditions 
set in, and before its close the climate had become boreal or arctic. This 
change or climate was accompanied by considerable alterations in the 
distribution of land and sea, the whole of south-eastern England from 
the Severn to the Humber being at first submerged, then rising so far 
above the waters that Britain became joined to the continent, neither 
German Ocean nor English Channel existing, and finally again becoming 
submerged. It was probably about this time, that is towards the close 
of the Pliocene period and before the last great submergence, that our 
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