450 Geological Society : — Anniversary of 1839. 



in this study will be called upon to execute a more weighty and ele- 

 vated office, in framing the classifications which other observers are 

 to apply ; in drawing the great lines of division and subdivision which 

 fix the form of the subject ; in setting up the type with which ex- 

 amples are to be compared ; in constructing the language in which 

 others ai'e to narrate their facts. Steps of this kind have formed, 

 and must form, the great epoclis in the progress of all sciences of 

 classification, and especially in ours ; and I need not remind you ho>v 

 great the importance and the influence of such steps amongst you 

 have been. To pronounce at once upon the success of such steps 

 must always be in some degree hazardous; since their success is in 

 fact this, that they influence permanently and powerfully the re- 

 searches, descriptions, and speculations of future writers ; and there 

 are few of us who can pretend to tlie foresight Mhich might enable 

 us to say, in any special case, how far this will be so. Yet the great 

 works of Messrs. Murchison and Sedgwick, tending to the establish- 

 ment of a classification of the strata below the old red s,andstone 

 (works which, on all accounts, we must consider as a joint under- 

 taking), appear already to offer an augury whicli can hardly be 

 doubtful, of this influence and permanence. Mr. Murchison's ap- 

 pellation of the " Silurian System" has already been adopted by 

 MM. Elie de Beaumont and Dufresnoy, who have given it currency 

 on the continent : M. Boue and M. de Verneuil aimounce the dif- 

 fusion of " Silurian" rocks in Servia and the adjacent parts of Turkey 

 in Europe; our own members, Mr. Hamilton and Mr. Strickland, 

 have extended their range to the Thracian Bosphorus ; M. Forch- 

 hammer, of Copenhagen, visited the " Silurian region" to endeavour 

 to recognize tlie rocks of Scandinavia ; and MM. Omalius D'Halloy 

 and Dumont have just explored it, to establish a parallel between 

 its deposits and those of Belgium. It will be observed that some of 

 the districts thus mentioned are out of the limits of our geological 

 Home circuit ; and if the identification be really and permanently 

 established in these cases, will extend the limits within which the pa- 

 rallelism of geological series can be asserted : and this is, in effect, 

 what we have a right to look for, sooner or later, in tlie progress of 

 geological science. As we must be careful not to apply our domes- 

 tic types without modification to other regions, so must we take care 

 not to despair of modifying our scheme, so that it shall be far more 

 extensively applicable than it at first appeared to be. Of this pro- 

 gress of things examples are too obvious and too recent to require 

 to be pointed out. 



The labours of Professor Sedgwick refer to the " Cambrian System," 

 which lies beneath the Silurian System, occupying much of North 

 Wales, Cumberland, and a great part of Scotland ; while the Silurian 

 System spreads over a great part of South Wales and the adjoining 

 English counties. The classification of the rocks of this portion 

 of our island to which Professor Sedgwick has been led, though laid 

 before you only at a recent meeting, is the fruit of the vigorous and 

 obstinate struggles of many years, to mould into system a portion of 

 geology which appeared almost too refractory for the pliilosopher's 



