320 PEOP. HULL, LL.D.j P.E.S.^ ON THE SUBMERGED TERRACES 



within the last century. In 1772 Messrs. Olassen and Povelsen 

 noted oats and rye in small portions of the island, and the great 

 outbreak of lava in 1784 destroyed the production of corn there 

 ever since, and now no grain is produced north of the Faeroes 

 because the lava set free the subterranean streams which inun- 

 dated the meadows. You cannot find butterflies in Iceland 

 because of the want of hollow trees or any shelter ; while, on the 

 other hand, certain Noctuce occur in numbers, as the caterpillars 

 of these last go underground to change, and so rest secure from 



" The dreadful pother o'er our heads " 

 of the winter storms and rain. 



The Chairman. — Before conveying your thanks to Professor Hull, 

 I would make one remark about these " deeps " to which he has 

 alluded. It is very curious to observe how portions of the beds of 

 these old channels continue deep, the remainder having entirelj'" 

 silted up. I know of several instances similar to that of the " Hurd 

 Deep." I believe they are to be accounted for by the fact that the 

 tides still continue to flow in the direction of, and in a line with 

 these deeps, as they did originally, thus keeping the channel open. 

 Whei'e the channel has silted up, the direction of the tides has 

 changed, and, running across the old channel, has filled it up. 

 This silting-up process is of course always going on, the rivers 

 bringing their sediment into these shallow seas, which is deposited 

 gradually, as the movement of the water slackens. Most of us 

 probably have noticed the change of colour of the water, as 

 soundings are reached at the entrance to the Channel, which is 

 caused by the quantity of matter held in suspension by the tidal 

 water. Professor Hull has, I am sure, taken great trouble in 

 tracing these old river beds which evidently drained the two 

 channels between Ireland and Scotland, and between England 

 and France. We are much indebted to him, and, if you will allow 

 me, I will convey to him your thanks for his interesting paper. 

 (Cheers.) 



The Hon. Secretart (Captain F. Petrie, F.G.S.). — The follow- 

 ing communication has been received from Professor T. Rupert 

 Jones, F.R.S. : — 



In praiseworthy furtherance of his researches as to the former 

 geographical conditions of what is now the North- Atlantic region. 

 Dr. E. Hull, applying the methods adopted by Dr. Spencer and 

 other American oloservers, is led by careful consideration of the 

 Admiralty charts, and with accurate reasoning on the relative depths 



