1863.] 



President's Address. 



33 



foundations many important additions have been made, one of signal value 

 in 1851 — the lower palaeozoic rocks at the base of the carboniferous chain 

 between Ravenstonedale and Ribblesdale. Perhaps no district in the 

 world aifords an example of one man's researches begun so early, con- 

 tinued so long, and ending so successfully. By these persevering efforts, 

 the Geology of the Lake district came out into the light ; and there is no 

 doubt, and can be no hesitation in ascribing to them the undivided honour 

 of the first unrolling of the long series of deposits which constitute the 

 oldest groups of British Fossiliferous Rocks. 



Still more complete, however, was the success of that work which was 

 undertaken immediately afterwards on the coeval rocks of Wales ; by 

 which Professor Sedgwick and Sir Roderick Murchison, toiling in separate 

 districts, unravelled the intricate relations of those ancient rocks, and de- 

 termined the main features of the successive groups of ancient life which 

 they enclose. These labours began in 1831-32, and in 1835 the two great 

 explorers had advanced so far in their research as to present a united 

 memoir to the British Association in Dubl'n, showing the progress each 

 had made in the establishment of the Cambrian and Silurian systems, as 

 they were then called ; Professor Sedgwick taking the former, and Sir 

 Roderick Murchison the latter for his special field of study. 



In 1843 Professor Sedgwick produced two memoirs on the structure of 

 what he then termed the Protozoic rocks of North Wales. Many excel- 

 lent sections were given in detail in these memoirs ; those exhibiting the 

 structure of the westerri part of the district about Carnarvonshire being 

 principally taken from his observations in 1831-32, while the more 

 detailed sections of the eastern part were from those of 1842-43. These 

 two papers gave the complete outline or framework, as it were, of the 

 geological structure of this intricate region. In several subsequent years 

 he continued to fill up this outline with further details, observed almost 

 entirely by himself, giving numerous general and local sections, by which 

 he determined the dip and strike of the beds, normal and abnormal, and 

 all the great anticlinal and synclinal lines on which the fundamental 

 framework depends. 



Further and still minuter details were subsequently given, as was to be 

 expected, by the Government Surveyors ; but the general arrangement, 

 finally recognized on the map of the Survey, is essentially the same as 

 that previously worked out by his unaided labours. 



It was a principle always advocated by Professor Sedgwick, that the 

 geological structure of a complicated district could never be accurately 

 determined by fossils alone without a detailed examination of its stratifica- 

 tion. He always proceeded on this principle ; nor (from the paucity of 

 organic remains) would it have been possible on any other principle to 

 have determined the real geological character of those older districts which 

 he investigated so successfully. His arrangement and nomenclature of the 

 Cambrian rocks in North Wales (the Lower Silurians of Sir Roderick 



VOL. xm. D 



