376 



The late elevations and depressions of land in the delta of the In- 

 dus are well introduced, as correlative of similar phenomena in the 

 Mediterranean and in South America, so much insisted upon in the 

 first volume : and, whatever discrepancies of opinion may still exist 

 among geologists, in reference to various questions — such as, the true 

 origin of elevation-craters — the mode of action by which sedimentary 

 deposits have been altered and crystallized, — the cause of metallic 

 veins — and other obscure problems still remaining to be solved ; 

 all inquirers agree in this fundamental opinion, that the earth's surface 

 has been mainly brought into its present condition by numerous 

 changes of relative level between the land and the sea : we must 

 therefore cordially thank Mr. Lyell for his energetic attempt to 

 elucidate the modes of action by which, in the ordinary course of 

 nature, such revolutions may have been effected. 



The last of the English works on geology, which I am called upon 

 to notice, proceeds from an eminent writer, who greatly distin- 

 guished himself by his scientific contributions to this Society during 

 its earlier years. I allude to a System of Geology recently pub- 

 lished by Dr. Macculloch. Instructed as we have all been by the 

 writings of this author, particularly by those which elucidate the 

 origin of the crystallized, igneous, and altered rocks, we have ever 

 been ready to acknowledge the full sense of our obligations to him. 



Not content, however, with that share of fame to which his ex- 

 ertions justly entitle him, Dr. Macculloch has now put forth a system, 

 written, as he states, in 1821; adding, "that he has waited ten 

 years in the hope that some better man would stand forward to re- 

 present geological science as it is ; but he grieves to say, that during 

 that long period geology has scarcely received a valuable addition, 

 and not a single fundamental one." 



This is an aspersion so groundless, that I should be unworthy of 

 the Chair with which your kindness has honoured me, were I not to 

 repel it. Gentlemen, if you wish to study geological science " as it 

 is," in the writings of your own countrymen, you will naturally 

 consult the works of Lyell and of De la Beche. But for a knowledge 

 of what "it was," I may request you to peruse these volumes of 

 Dr. Macculloch : for in truth they are chiefly made up of views pre- 

 viously expressed by himself, with the exception of certain passages, 

 I will not now fatigue you with quoting, the sense and bearing of 

 which are, however, at direct variance with the author's published 

 opinions in 1821, although they are transcripts of the opinions of 

 other observers recorded in your Transactions within the last five 

 years. This work, in short, is so far from being a new system, that 

 it can hardly be said to enter into the boundless field now opened 

 to modern geologists — the evidence derived from organic remains, 

 ,the very key-stone of our fabric, being either slightly touched upon, 

 or its value derided. It is, however, a matter of notoriety among 

 working geologists, that even within the limited field of this 

 author's personal observation, a specific acquaintance with such re- 

 mains has alone been the means, and this within the last five years, 

 of fixing the ages of the secondary deposits in the Hebrides and 



