30 ADDRESS TO THE BRITISH ASSOCIATION, 1881. 



In geology the formation of our Association coin- 

 cided with the appearance of Lyell's l Principles of 

 Geology/ the first volume of which was published in 

 1830 and the second in 1832. At that time the re- 

 ceived opinion was that the phenomena of Geology could 

 only be explained by violent periodical convulsions, 

 and a high intensity of terrestrial energy culminating 

 in repeated catastrophes. Hutton and Play fair had 

 indeed maintained that such causes as those now in 

 operation, would, if only time enough were allowed, 

 account for the geological structure of the earth ; never- 

 theless the opposite view generally prevailed, until 

 Lyell, with rare sagacity and great eloquence, with a 

 wealth of illustration and most powerful reasoning, 

 convinced geologists that the forces now in action are 

 powerful enough, if only time be given, to produce 

 results quite as stupendous as those which Science 

 records. 



As regards statigraphical geology, at the time of 

 the first meeting of the British Association at York, 

 the strata between the carboniferous limestone and the 

 chalk had been mainly reduced to order and classified, 

 chiefly through the labours of William Smith. But 

 the classification of all the strata lying above the chalk 

 and below the carboniferous limestone respectively, 

 remained in. a state of the greatest confusion. The 

 year 1831 marks the period of the commencement of 

 the joint labours of Sedgwick and Murchison, which 

 resulted in the establishment of the Cambrian, Silurian, 

 and Devonian systems. Our Pre- Cambrian strata have 

 recently been divi led by Hicks into four great groups 

 of immense thickness, and implying a great lapse of 



