148 Frof. T. Rupert Jones — Intermittent Streams. 



shovel and deer-honi pick were disinterred. Sir H. de la Beclie 

 tboiight these discoveries showed that a considerable change had 

 taken place in the relative levels of sea and land since man inhabited 

 Cornwall. The submerged forests show a sinking to the extent of 

 70 feet. Much information regarding the changes of level in 

 Cornwall is included in Mr. Ussher's Post-Tertiary Geology of that 

 County, 1879, and he concludes that there has been so much sub- 

 sidence since the Glacial period that only what was the watershed 

 now remains. Mr. Pigeon, in the very article I am questioning, 

 admits that there have been enormous enci'oachments of the sea in 

 Torbay since maps were published ; but how could these occur, 

 without subsidence ? Torbay is a deep indentation of the coast, of 

 a form that suggests that detritus would not be rapidly removed out 

 to sea by currents, and so fast a destruction of the coast must have 

 led to the formation of shoals were there no depression, in progress. 

 Mr. Blanford indeed pertinently questioned how smelting hearths 

 could have been situated 10 feet below high-water mark. I think I 

 have pointed to sufficient material, hastily looked up, to prove that 

 while Mr. Pigeon's facts are valuable, the conclusion he has drawn 

 from them is based on a misconception of the amount of change our 

 coasts have undergone since the human period. The difficulty is 

 not to find a coast-line that does present evidence of recent changes 

 of level, but any that does not. When we find so guarded an 

 observer as Dr. John Evans expressing the opinion that the whole of 

 Southampton Water has been excavated since the deposition of the 

 Hill Head Gravel, and stating that in the gravel at Southampton 

 Common, water- worn flint implements are met with at an elevation 

 of 180 feet above high-water mark, and at 130 feet at Bournemouth, 

 and that since Britain was inhabited by man a tract of country 

 fifteen miles long and five or six miles broad has been swept into the 

 sea, and the Isle of Wight severed from the mainland, we need 

 hardly make a difficulty in admitting that the Torbay Forest has 

 subsided even 40 feet. The late Mr. Godwin-Austen in his celebrated 

 paper proving the English Channel to be due to depression and not 

 excavation, made some such remarks as these, with which I cannot do 

 better than conclude this protest: " That the whole area of the English 

 Channel had at one time a higher level, is directly proved by the 

 numerous instances along its shores where old forest ground passes 

 beneath the present sea-bed ; these forests include elm, oak, chestnut, 

 hazel, and especially Pinus sylvestris, none of which have their usual 

 habitat along the sea-border. No wooded tracts came down to 

 the present coasts of the Channel, nor even single trees of any bulk, 

 yet in many instances the trees of these submerged lands had attained 

 considerable magnitude." 



n. — Intermittent Streams in Berkshike. 

 By Professor T. Rupert Jones, F.E.S., F.G.S., &c., &c. 



THE Lambourn river, in Berkshire, which rises from springs 

 in the Chalk hills between Up-Lambourn and Chipping- 

 Lambourn, and receives other springs lower down, has been dry for 



