81 



when these shingle beaches are traced round the corner, into the 

 shelter of the Isle of Wight, they rapidly change their character, 

 become less pebbly, and finally are indistinguishable from 

 ordinary river gravels. Thus I cannot tell you for certain whether 

 any part of the big sheet of gravel near Bournemouth is of marine 

 origin or whether it is all fluviatile. My impression is that it 

 consists of terrace-deposits formed at different levels, corre- 

 sponding with the varying levels of the sea outside, but itself is 

 not actually of marine origin in any part. 



After the mild period the cold came on again, and we had a 

 second glacial period. During this, the sea-level seems to have 

 been a few feet lower than now ; but how much is not yet known. 

 The contours of the Solent Valley, in the part between the Needles 

 and Spithead, were probably in a general way much as we now see 

 them. But the gap opposite Bournemouth may not have yet 

 been cut, though the barrier of chalk on the south of the river 

 was getting very weak, and in places very low. It was probably 

 cut through during this second cold period. 



An observer standing at Bournemouth during this second 

 cold period would probably see a wind-swept open plain sloping 

 southward to the Solent. Beyond the Solent on the left he would 

 see the Isle of Wight; to the right would rise the Isle of Purbeck. 

 Between, these were connected by a narrow ridge of chalk, or series 

 of chalk hills, and through the gaps the sea was already 

 visible. There were probably no trees, only dwarf Arctic shrubs 

 and patches of peat-moss. The reindeer and lemming were the 

 most abundant animals, though the Arctic fox and wolf were 

 common, and the long-haired mammoth was also found. 



It was probably also during this second cold period that' the 

 gaps opposite Bournemouth became so wide that the sea was able 

 seriously to attack the soft Tertiary strata. This advance of the 

 sea, perhaps combined with a blocking of the mouth of the river 

 by ice during a flood, allowed the Solent to overflow and find a 

 new and more direct course through one of the already formed 

 gaps. Thus our big river-valley became divided into several 

 small separate catchment basins, the western alone opening into 

 the newly-formed Bournemouth Bay. Bournemouth was then 

 for the first time a sea-side place, or rather was within three or 

 four miles of the sea, and had an open view seaward. 



Concurrently, perhaps, with this shortening and lowering of 

 the bed of the River Solent there was another change. Of course 

 as this is a country of loose sands and clays, rather than of hard 

 rocks, its tributaries had their beds lowered in a corresponding 

 degree. One result of this was that the Upper Avon, which 

 before flowed into Southampton Water, was also diverted into a 

 more direct course to the sea. Exactly how and when this 

 happened is not yet clear, but I think that the diversion was 

 probably due to the lowering of the bed of the Lower Avon near 

 its head to such an extent that the water of the Upper Avon 

 soaked through the sandy strata and emerged at the head of the 



