Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/130

92 92 S. V. WOOD, JUN., AND F. W. HAEMEE ON THE denudation, exhibits its interglacial origin very distinctly ; and the following line of section (No. XIII.) is taken across it near North Walsham, where actual open sections afford the means of verification. Fig, 13. — Section XIII., across the Ant Valley. (Length 2-| miles. Yertical scale 17| times the horizontal.) s.w. One mile south ofBT. Walsham. Sand- pits. Brick- Kiver pit. Ant. Eoad- cutting and pit. Brick-pit on Edingthorpe Heath. N.E. 5'. The Cromer Till (probably). The other references as in fig. 11. Into this valley, as into that of the Glaven, the Middle Glacial plunges boldly down ; and the natural section afforded by the coast of the country traversed by them, being not far distant, serves to check the accuracy of the above representation. The Tese is an affluent of the Yare ; and its valley in a course of about twelve miles (without reckoning the windings) is cut down in its upper extremity to the Middle Glacial only, and in its lower to the Lower Glacial pebbly sands, the Crag, and the Chalk. So great has been the interglacial denudation of this valley, that we have been able to find excavations in remnants of the Contorted Drift at three x^laces only along its course. One of these is half a mile N.E. of Shottesham-St.-Mary church, the second 6 furlongs N. by E. of Stratford-St. -Michael church, and the third one mile N. by E. of Newton-Flotman church. Assuming, as we think we are entitled to do from the presence of these remnants and from the occurrence of the Contorted Drift north, south, east, and west of this valley, that this drift once extended in full force over it, the interglacial denudation of the Tese valley was almost complete. The line of section XIY. is drawn across the principal valley, and a small one tributary to it, at the point where one of these remnants of the Con- torted Drift occurs. This deposit here yielded us Tellina balthica, Mactra ovalis, and Cardium edule. Just north of the above line of section, a bed of clay with chalk debris occurs in the valley-bottom, resting on glaciated chalk. There are similar occurrences at several places along this valley ; and some, if not all, of these, we think, must belong to the same bed as that marked a underlying the middle Glacial in the Yare valley in section Y. In the case of this valley, as in that of the Yare, it is very pro- bable that the interglacial excavation was deeper than the present one, and may be continued down into the Chalk below the level of the river, where we have represented valley -gravel (10) as present.