STRATIGRAPHICAL GEOLOGY. 433 



to accomplish in the British area, and which was fulfilled in a 

 manner worthy of the noblest traditions of their countryman, 

 William Smith. 



In the summer of 1831 the two friends began their investi- 

 gations in Wales and the neighbouring districts. Sedgwick 

 had already studied the Transitional formations in the Lake 

 District of Cumberland and Westmoreland between 1822 and 

 1824, and had disentangled the tectonic structure and strati- 

 graphy of this very complicated district, although his sub-division 

 of the formation had been based, in the absence of fossils, merely 

 upon the lithological features and stratigraphical relations. The 

 Cambridge professor in 1831 renewed his study of the same 

 formations in North Wales, in the neighbourhood of Snowdon, 

 and elucidated the tectonic relations of the rocks with admirable 

 skill. Unfortunately the scarcity of fossils made it still impos- 

 sible for Sedgwick to establish palaeontological sub-divisions. 

 Murchison was more fortunate. While his colleague was 

 engaged in the examination of the oldest group of the 

 Transitional series, Murchison began his investigation of the 

 series in descending order from the upper members to the 

 lower. He examined the exposures of Old Red Sandstone and 

 the rocks immediately below it, which occur on the eastern and 

 southern borders of Wales. 



Murchison found fossils in abundance, and in a couple 

 of years was able to lay before the Geological Society a com- 

 plete palaeontological sequence in the upper portion of the 

 Transitional formations. At first Murchison had called these 

 higher members examined by him an " Upper fossiliferous 

 grey wacke series "; but in the year 1835, in compliance with 

 the strongly-expressed wish of Elie de Beaumont, he proposed 

 the name "Silurian System" as a special designation for the 

 upper members. And as the older members of the Transitional 

 series examined by Sedgwick in Cumberland and North Wales 

 could not be identified with any of the members in the Silurian 

 system of Murchison, the term of "Cambrian Series" was 



and he afterwards continued his researches in Devonshire, Germany, 

 Belgium, and Russia. In 1855 Murchison succeeded De la Beche as 

 Director of the Geological Survey of Great Britain. Murchison was one 

 of the founders of the British Association, twice President of the Geological 

 Society, and for many years President of the Geographical Society; he was 

 also a recipient of the Wollaston medal ; in 1866 he was created a baronet. 

 Throughout his career Murchison took a distinguished position in London 

 society. He died on the 22nd October 1871, 



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