SECTION C— GEOLOGY, 



SOME EPISODES IN THE GEOLOGICAL 

 HISTORY OF THE BRISTOL CHANNEL 



REGION. 



ADDRESS BY 



Prof. 0. T. JONES, M.A., D.Sc, F.R.S. 



PRESIDENT OF THE SECTION. 



It is manifestly impossible for me, in the time at my disposal on this 

 occasion, to deal adequately with all the events and processes which have 

 played a part in the shaping of the Bristol Channel and its bordering lands. 

 I intend, therefore, to select certain episodes or phases in the geolooical 

 record which are in themselves of interest to geologists or have a bearing 

 upon the geology and physical features of a wider region than the channel 

 and its confines. Those of you who are not acquainted with it already 

 may be reminded that a concise summary of the Evolution of the 

 Bristol Channel, by Dr. F. J. North, was recently issued by the National 

 Museum of Wales. 



The geological history of the region raises many problems that are of 

 interest both to geologists and geographers, but much work remains to be 

 done before our knowledge is fully adequate to deal with them. The sug- 

 gestions which I shall presently make are offered not as ready-made solu- 

 tions of these problems, but rather with the idea of stimulating further 

 investigations which will, I trust, lead to fuller knowledge. 



As most of you know, the Bristol Channel is bordered in the main by 

 various Palaeozoic formations, but towards the east Mesozoic rocks form 

 a large part of the coast and lands adjoining it. These strata are masked 

 in places by Alluvial Deposits, the largest area of which is that known as 

 the Bridgewater Flats. 



The episodes which appear to be the most important to consider in 

 relation to the history of the region are (i) the Triassic planation ; (ii) the 

 formation of the Mesozoic Cover ; (iii) the Miocene movements ; * (iv) the 

 late Cainozoic uplift ; and (v) the Post-Glacial movements. 



I am reluctantly compelled, however, on this occasion to confine mvself 

 to the earlier episodes concluding with the Miocene movements. ^ To 

 embark upon the more recent history of the region would entail prolonging 

 this Address to an extent that would be unwarrantable. 



I regret this the more as it was due to evidence which has come into 

 my possession within the last few years regarding one of the most recent 

 phases of the history of the region that I was led to choose the story of the 

 Bristol Channel as the subject of my Address, though it is not inappropriate 



