Page:Early Man in Britain and His Place in the Tertiary Period.djvu/198

170 38.—Section through Valley of the Ouse.

a. Alluvium. b. Gravel with implements and mammals. c. Boulder clay. d. Oxford clay. e. Oolite.

as is shown by Prestwich, Lyell, Evans, and others. In illustration of this, the observations made near Bedford by Mr. Wyatt may be quoted (Fig. 38). There flint implements occur in a series of fluviatile gravels in the valley of the Ouse, largely composed of materials derived from the destruction of the boulder-clay. This is the upper chalky boulder clay of Mr. Searles Wood, and out of this, as may be seen in the figure, the valley has been partly hollowed. Consequently the deposits within the valley, including the fluviatile gravels, are later than the boulder clay of the district. The same conclusion is indicated by the section at Hoxne, where fluviatile deposits with Palæolithic implements (Fig. 39) rest in a hollow of the clay, as pointed out by Prestwich and Lyell. In the Thames valley, also, and in the area to