SESSION 1896-07. Ixv 



clay reposing- on a layer of flint-pebbles, in which layer sharks' 

 teeth (Lamna) Avere fo:ind. 



From Tyler's Hill the party crossed the valley of the Chess to 

 Aldridge's Dell, where there is a clialk-pit in which the Chalk 

 Kock is exposed, and a iew fossils were found in it. 



On returning to Chesham tea was partaken of at the Chess Yale 

 Hotel. 



In the 'Proceedings of the Geologists' Association,' vol. xv, 

 p. 89, will be found a list of fossils obtained from the Basement 

 13cd of the London Clay at Tyler's Hill, and from the Chalk Kock 

 at Aldridge's Dell. 



Field Meeting, 24Tn April, 1897. 

 THE VALLEY OF THE BOURNE, B0X3I00R. 



For fourteen years no water had flowed over the surface of the 

 ground do^Ti the Valley of the Bourne, but that the very wet 

 winter of 1896-97 would cause the Bourne to flow this year there 

 could not be the slightest doubt, and, to see if it were flowing, 

 the present writer twice visited the valley in March before any 

 water actually appeared above the surface. On the second occasion 

 it was ascertained that the cellar of an inn at the lower end of 

 the valley, which had been dry for years, was flooded. With 

 much labour the water had been taken out, but the next day it 

 was as full as before, showing that the cause of the flooding was 

 the raising of the plane of saturation of the chalk which occurs 

 preparatory to the outburst of the Bourne. 



Most of the members taking part in this meeting walked from 

 Boxmoor Station, which was left at a quarter to three, to Bourne 

 End, where tea was ordered at the White Hart Inn, to be ready 

 on the return of the party from the soiu'ce of the Bourne. 



The stream had already been seen flowing through the culvert 

 under the main road, and just after leaving the hamlet by the bye- 

 road which runs up the valley it was found that the volume of 

 water flowing down the usually dry bed of the Bourne was so great 

 as to flood this road and bar further progress. A way was, how- 

 ever, found through the meadows, and the stream was followed for 

 three miles from its junction with the Bulboume. Several times 

 it had to be crossed, and while some of the party jumped over it, 

 or into it, bridges were improvised for others out of hurdles and 

 bundles of wood ; at one spot a plank thrown across broke under 

 the weight of one of the members. The water was flowing rapidly, 

 here and there widening out into ponds, and a gravel-pit on its 

 course was full of water. At Bottom Farm there was a considerable 

 sheet of water, and not far above it the stream disappeared alto- 

 gether for a time, flowing underground only owing to the surface 

 of the ground having been raised to carry across the valley the lane 

 which leads to Harratt's End. There is a culvert under the lane, 

 but the water had not risen high enough to reach it. This raising 



