Correspondence — T. G. Bonney — J. A. Rotve. 141 



coI^I^Es:pol^^I:)'^l^^CE. 



' DEUTOZOIC 

 Sir, — I can extract no other meaning from Mr. Goodchild's 

 defence of the term ' Deutozoic' than this : that when next I am in 

 a geological difficulty — say, about the age of the earth — I should 

 refer the question to any eminent Professor of Theology, and submit 

 to his decision. T. G. Bonney. 



CEEEP-FOLDING IN VALLEY BOTTOMS. 



Sir, — "When I read in " Water," vol. vi, p. 491, an account of a 

 paper by Professor Boyd Dawkins dealing with the effect of relaxation 

 of pressure in causing folds in the rocks at the bottom of valleys 

 I thought I had come across what was no more than a reporter's 

 error, repeated in the Geological Magazine, December, 1904, 

 p. 618. Since, however, an almost identical statement appears in 

 the Proceedings of the Manchester Lit. and Phil. Soc, vol. xlix, p. 8, 

 I presume that it correctly represents Professor Dawkins's views 

 on the subject. 



The folding in the strata at the bottom of the Don and Derwent 

 Valleys is held by the author to be " analogous in every particular " 

 to ' creep ' in coal-workings ; and he goes on to say : " This may be 

 studied in any coal-pit where there is a superincumbent pressure, 

 say, of more than 1,000 feet." Now, the maximum pressure available 

 at the Howden and Derwent dams is due to no more than 900 feet ; 

 moreover, this maximum pressure is only reached at a distance 

 of 1| miles from the valley, and is increasingly reduced as the latter 

 is approached. 



It cannot be contended that the removal of " at least 9,700 feet '^ 

 of rock from above the site of the dams has had anything to do 

 with the folding in the valley bottom, and yet it is difficult to see 

 for what other purpose these figures are introduced except to lend 

 support to the theory. 



There is not the slightest evidence to show that the Derwent 

 Valley was ever deeper than it is now ; but if Professor Dawkins's 

 figures mean anything they imply a valley 9,700 feet deep loith the 

 stream on its present bed. J. Allen Howe. 



Museum of Practical Geology, 

 London. 



OBITTJJ^ia"^. 



PROFESSOR JOSEPH P. O'REILLY, C.E., M.R.I.A, 



Born July 11, 1829. Died January 6, 1905. 



By the death of Joseph P. O'Keilly, lately Professor of Mining 



and Mineralogy at the Eoyal College of Science, Dublin, yet another 



link with the older generation of Irish geologists and archaeologists 



has been severed, as also the ties of friendship which existed 



