on Mr. Lyell's "Principles of Geology." 217 



time was not yet come for a general system of geology, but 

 that all must be content for many years to be exclusively en- 

 gaged in furnishing materials for future generalizations." 



Mr. Lyell has now, however, himself given a tolerably strong 

 indication that in his opinion the present season requires a 

 bolder line of research : and as I am inclined, for the reasons 

 just stated, to coincide in that opinion, I do not hesitate to 

 throw myself by the following slender contribution, on the field 

 he has so ably opened ; although my inclination, as well as a 

 just conviction of the limits of my own powers, have hitherto 

 confined me almost entirely to the humbler and more cautious 

 path of what I may call Descriptive Geology, as opposed to 

 Theoretical Geology. 



For the present I must confine myself to a very few pre- 

 liminary observations, reserving for a future Number (if you 

 shall be willing to admit it) the detailed analysis on which 

 I propose to enter of geological phenomena, so arranged 

 as to exhibit correctly their bearing on theoretical inquiry ; 

 convinced that no real steps can be gained otherwise than 

 by proceeding in a course of induction thus regularly, minutely, 

 and patiently commenced. 



While I fairly admit that much new and important light has 

 been thrown on many particular facts by Mr. Lyell's book, 

 and that it evinces throughout both a sagacity of observation 

 and an activity of intellect, which will entitle it to the most 

 serious attention; yet as I remain after that attention alto- 

 gether unconvinced of the correctness of his general conclu- 

 sions, it were merely affecting a false humility to dissemble 

 that I record those conclusions only to show that my own in- 

 terpretation of the phenomena would lead to their direct 

 contradictories. Now whether his interpretation or mine shall 

 eventually prove to be correct, an open and manly discussion 

 can alone lead to any satisfactory result. 



The general object of Mr. Lyell's book seems to be, by a 

 constant employment of the expressions " existing causes" 

 and " the uniformity of nature" (expressions on which I shall 

 shortly have a few observations to offer), to maintain — that all 

 the geological phsenomena with which we are acquainted 

 may, and indeed must if we reason philosophically, be ac- 

 counted for by the agency not only of natural powers still 

 existing, but also by the agency of those powers, under ex- 

 actly the same modification of circumstances in every respect 

 in which they are actually placed, and with exactly the same 

 degree of general energy which still subsists; — that we are 

 authorized to predict the future occurrence of such cata- 

 strophes as the deluge of one large continent, and the elevation 



N. S. Vol. 8. No. 45. Sept. 1830. 2 F of 



