Page:VCH Bedfordshire 1.djvu/66

 A HISTORY OF BEDFORDSHIRE type, are found here and there in the brick-earth, having been washed down from the higher land with the material by which the Palaeolithic floor was covered up. But little of this higher land now exists, Cadding- ton, the site of which then was near the bottom of the valley, being now nearly at the top of the hill. A flint from this brown drift has been found with apparent ice-scratchings, one of which stops suddenly at an artificially-flaked surface, showing that the scratches were made before the flint was chipped ; and neither here nor elsewhere has a o-lacial scratch or groove been seen on an artificially-worked surface. Nowhere can evidence be found of a pre-Glacial flint-chipping animal ; but man may have existed for ages before he acquired the art of chipping flints to a fine edge and so first left evidence of his presence. The ochreous implements found in the brick-earth of the Cadding- ton hillside are probably of the same geological age as the older imple- ments of the valley-gravels. Both date back to an earlier period than that of the deposition of the beds in which they occur, having been washed into these beds from a pre-existing land surface ; but the lustrous implements were fashioned during intervals of non-deposition of the brick-earth, the men who made them being contemporary with that formation. While the brick-earth is mostly if not altogether water-laid, the clay-with-flints which caps the hills of Upper Chalk has a very different origin. It is the residue of the Chalk left after its dissolution by water holding carbonic acid in solution, and also of Tertiary and more recent clays which formerly covered the Chalk. Its formation has doubtless been going on during the whole of the time that the Chalk has been above the level of the sea, and it is still proceeding, but it may generally be considered as of (post-Glacial) Pleistocene and Recent age. It is a stiff" brown and red clay containing unworn flints, which are often much broken up by frost and by the plough, and its presence may be recognized in ploughed fields by the soil appearing to consist of little else than broken flints. The surface of the Chalk, except when covered by an impervious stratum, is exceedingly uneven, owing to its unequal dissolu- tion, and the clay-with-flints upon it may be of any thickness, from less than a foot when its surface is fairly even, to many feet when a ' pipe ' is formed which the clay-with-flints fills up. A layer of flints in the Chalk may sometimes be seen extending across a pipe, let down a little where embedded in the clay. In an old chalk-pit on Farley Hill, now closed, a line of Chalk Rock nodules occupied a similar position in a broad but shallow pipe of brown clay. RECENT The Recent accumulations of Bedfordshire are unimportant, except in connection with the Neolithic flint implements which they contain. They consist almost entirely of the alluvium of existing rivers, which is ,'"j?re of great extent. There are far wider stretches of alluvium in from this, ley of the Colne than there are in Bedfordshire in that of the n. I 3 °