﻿IXSX PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [^aj I908, 



The history of the investigation of the later Palaeozoic rocks of 

 the British Isles may likewise be in no small measure gleaned from 

 the publications of our Society, where some of the most important 

 chapters of that history were for the first time recorded. Perhaps 

 no more interesting episode in the progress of geological discovery 

 can be quoted than that of the establishment of the Devonian 

 System, when, from a region of extreme stratigraphical complexity, 

 a new system was added to the geological record not only of this 

 country but of the world. We are all familiar with the details of 

 this episode, how after various errors and misconceptions, Sedgwick 

 & Murchison were guided by the genius of William Lonsdale to 

 the true solution of their problem, and how, provided with the key 

 which Lonsdale supplied to them, they were enabled to relegate to 

 its proper place in the series of fossiliferous formations a large 

 part of the old ' grauwacke ' of the South- West of England, and 

 ultimately of wide tracts on the Continent of Europe. It was one 

 of the earliest and greatest achievements gained by the comparative 

 study of organic remains, demonstrating, as had never been done 

 so strikingly before, the value of fossils in the investigation of 

 the stratigraphical succession of rocks. Well might Sedgwick and 

 Murchison declare that 'this is undoubtedly the greatest change 

 which has ever been attempted at one time in the classification of 

 British rocks.' Though these authors fully acknowledge their 

 indebtedness to Lonsdale, the share of that great palaeontological 

 master in this important reformation of geological nomenclature is 

 perhaps less generally appreciated than it should be. His modest 

 account of the successive steps by which he was led to conclude 

 that the South Devon limestones ' would prove to be of the age of 

 the Old Red Sandstone ' is a fascinating narrative in the literature 

 of geology. The Society may count as not the least of its 

 distinctions that its publications were the channel through which 

 this remarkable series of observations and generalizations was laid 

 before the world/ 



The Society has published various other communications on the 

 Devonian groups of the South- West of England. Valuable papers 

 by Grodwin- Austen appeared in the later volumes of the Transactions 



1 The paper by Sedgwick & Murchison ' On the Physical Structure of 

 Devonshire, & on the Subdivisions & Geological Eelations of the Older 

 Stratified Deposits ' is contained in the fifth volume of the second series of 

 the Transactions (1840) pp. 633-703, and Lonsdale's 'Notes on the Age of the 

 Limestones of South Devonshire ' follow on pp. 721-38. 



