400 Sir Roderick I. Murchison^s 



its sedimentary rocks and their relations, were unknown. Still 

 less had Ireland, another region mainly palaeozoic, received any 

 striking portion of that illustration which has since appeared in 

 the excellent general map of Griffith, and which is now being 

 carried to perfection through the labours of the Geological Sur- 

 vey under my colleague Jukes. If such was our benighted state 

 as reo-arded the order and characters of the older formations at 

 our first meeting, great was the advance we had made, when at 

 our twelfth meeting we first assembled at Manchester in 1842, 

 Presiding then, as I do now, over the geological section, I showed 

 in an evening lecture how the palaeozoic rocks of Silurian, Devo- 

 nian and Carboniferous age, as well as those rocks to which I had 

 assigned the name of Permian, were spread over the vast region 

 of Russia in Europe, and the Ural Mountains. What then are 

 some of the main additions which have been made to our ac- 

 quaintance with the older rocks in the British Isles since we last 

 visited Manchester ? 



"Commencing with the oldest strata, I may now assume, from 

 the examinations of several associates on whose powers of obser- 

 vation as well as my own I rely, that what I asserted at the 

 Aberdeen meeting in 1859, as the result of several surveys, and 

 what I first put forth at the Glasgow meeting of 1855, is sub- 

 stantially true. The stratified gneiss of the north-west coast of 

 the Highlands, and of the large island of Lewis and the outer 

 Hebrides, is the fundamental rock of the British Isles, and the 

 precise equivalent of the Laureiitian system of Canada, as de- 

 scribed by Sir W. Logan. The establishment of this order, which 

 is so clearly exhibited in great natural sections on the west coast 

 of Sutherland and Ross, is of great importance in giving to 

 the science we cultivate a lower datum line than we previously 

 possessed, as first propounded by myself before the British Asso- 

 ciation in 1855.* 



*See Report of British Association for 1855 (Glasgow meeting). At 

 that time I was not aware that the same order was developed on a 

 grand scale in Canada, nor do I now know when that order was there 

 first observed by Sir W. Logan. I then (1855) simply put forward the 

 facts as exhibited on the north-west coast of Scotland — viz., the exist- 

 ence of what I termed a lower or " fundamental gneiss," lying far be- 

 neath other gneissose and crystalline strata, containing remains which 

 I even then suggested were of Lower Silurian age. Subsequently, in 

 1859, when accompanied by Professor Ramsay, I adopted, at his sug- 



