178 J. D. Dana — Sedgwick and Murchison. 



Murchison's reply was made at the meeting of the Geolog- 

 ical Society in June.* He remarked, with regard to Sedgwick's 

 allusion to the excursion of 1834, that " if I lost my way in 



foing downward into the region of my friend, it was under 

 is own guidance ; I am answerable only for Silurian and Cam- 

 brian rocks described and drawn as such within my own 

 region." 



In his closing remarks Murchison says : 



" I am now well pleased to find that, with the exception of my 

 old friend, all my geological contemporaries in my own country 

 adhere to the unity of the Silurian System and thus sustain its 

 general adoption." 



" No one more regrets than myself that Cambrian should not 

 have proved, what it was formerly supposed to be, more ancient 

 than the Silurian region, and thus have afforded distinct fossils 

 and a separate system ; but as things which are synonymous 

 cannot have separate names, there is no doubt that, according to 

 the laws of scientific literature, the term " Silurian " must be sus- 

 tained as applied to all the fossiliferous rocks of North Wales. 



"Lastly, let me say to those who do not understand the nature 

 of the social union of the members of the Geological Society, 

 that the controversy which has prevailed between the eloquent 

 Woodwardian Professor and myself has not for a moment inter- 

 rupted our strong personal friendship; I am indeed confident we 

 shall slide down the hill of life with the same mutual regard 

 which* animated us formerly when climbing together many a 

 mountain both at home and abroad." 



Murchison was right in saying that all British geologists 

 were then with him, even in the extension of the name Si- 

 lurian to the lower fossiliferous Cambrian rocks ; and this 

 was a chief source of irritation to Sedgwick. It was also, 

 with scarcely an exception, true of geologists elsewhere. This 

 state of opinion was partly a consequence of Murchison's early 

 and wonderfully full description of the Silurian rocks and their 

 fossils, which made his work a key to the Lower Paleozoic of 

 all lands. Sedgwick's Cambrian researches and the paleon- 

 tology of the region were not published in full before the 

 years 1852-1855, when appeared his " Synopsis of the Classifi- 

 cation of the British Palaeozoic Rocks," along with M'Coy's 

 " Descriptions of British Palaeozoic Fossils." 



But this general acceptance was further due to the fact that 

 the discovered fossils of the Cambrian, from the Lingula Flags 

 downward, or the u Primordial," were few, and differed not 

 more from Silurian forms than the Silurian differed among 

 themselves ; and also, because the beds were continuous with 

 the Silurian, without a break. Geologists under the weight of 



*Q. J. Geol. Soc, viii, 173, 1852. 



