Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/132

94 94 S. V. WOOD, JT7N., AND P. W. HARMER ON THE It is impossible to determine whether the clay with chalk debris (8?) resting in patches in this valley on the shingle of the Pebbly Sands (5) is the Upper Glacial clay of the high ground, or the bed occurring in the Yare valley under the Middle Glacial {a in section V.) ; but there are several occurrences of it in the bottom of the Ket valley resting on the Pebbly Sands. These show, however, at least that the Ket valley was excavated subsequently to the Lower Glacial, and before or during the Upper Glacial deposits. Having passed in review all the river-valleys of Eastern Norfolk, we now come to the Waveney, the principal river of Norfolk and Suffolk, the valley of which has, since the description by Mr. Prestwich of the Hoxne brick-earth deposit containing evidence of Palaeolithic man, possessed a special interest, and in connexion with which deposit, and the inferences drawn from it as to the excavation of the Waveney val- ley since the accumulation of that brick-earth, much controversy has taken place*. The late Mr. J. W. Flower maintained f, and, as it seems to us, with much reason, that the width of this valley at the source of its river, its confluence there with the valley of the Little Ouse flowing in the opposite direction, and the absence of any very high land near its source forbade the possibility of the river Waveney having been the agent producing the excavation of the valley through which it flows. Whatever be the case, however, as to this, it seems to us clear that the Waveney valley, like those which we have been describing, was produced by the denudation which has so largely destroyed the Contorted Drift, and which took place between the formation of that deposit and the Middle Glacial. It may be worth observing that if the view expressed at the con- clusion of this paper of the area beyond the limit of the Middle Glacial in Norfolk and Suffolk having been during its accumulation occupied by the branch of the land ice which flowed over Lincoln- shire be well founded, it may serve to explain the difficulties suggested by Mr. Mower, and in this way : viz. such a glacier must have greatly denuded and lowered the area on which it rested, and thus the great level of the Fenland must have been produced by it ; now if we suppose the interglacial valley of the Waveney to have been merely the eastern extremity of a far longer valley of which that of the Little Ouse formed the next portion westward, and whose head was yet further west, or north, it is not difficult to see that the slope of the Little-Ouse portion might have been reversed by the de- grading action of this ice, which was of a magnitude to be indepen- dent of such small valleys, and derived its motion from the contour of the country lying between it and its source in the mountain- districts of the north of England. The abrupt termination of the Middle Glacial and of the Contorted Drift a few miles west of the confluent source of the Little Ouse and Waveney, seems to find an show that the Hoxne brick- earth is not, as hitherto supposed, newer than the Upper Glacial clay, but Preglacial. t Quart. Joum. Geol. Soc. vol. xxiii. p. 55.
 * Mr. Belt has lately (Quart.. Joum. Science, July, 1876) endeavoured to