172 ^Ir AV"he\vell's Address to the 



strata and formations ; and the latter dealing with the stndy 

 of those general laws and causes of change by which we hope 

 to understand and account for the facts which Descriptive 

 Geology brings before us; — in short, the present condition 

 and the past history of the earth's crust. But as the laws of 

 permanence and change, with regard to organized beings, 

 differ very widely from the dynamics of brute matter, we may 

 conveniently make a separate study of the relations of orga- 

 nic life to which geology conducts us, and may mark it by the 

 name Paheontologi/, by which it is commonly known. I will 

 add that it still appears to me convenient, for the present, to 

 divide Descriptive Geology into two portions, — the Home cir- 

 cuit, in which the order of superposition has already been 

 established with great continuity and detail ; and the Foreign 

 region, in Avhich we are only just beginning to trace such an 

 order. I shall also, as before, take the ascending order of 

 strata. According to this arrangement of the science, I shall 

 venture to bring to yom* recollection a few of the points to 

 which our attention has mainly been called during the past 

 year. 



Descriptive Geology. 



" 1. Home {North European) Geology. — When I stated that Descrip- 

 tive Geology has for its task the reference of the rocks of some portion 

 of the earth's surface to an established classification into strata and for- 

 mations, it was implied, that the more common employment of the de- 

 scriptive geologist must be to refer the rocks which he examines to some 

 classes already fixed and recognised ; but it could hardly fail to occur to 

 you, that from time to time the leaders in this studj- will be called upon 

 to execute a more weighty and elevated office, in framing the classifica- 

 tions 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 

 llic type with which examples are to be compared; in constructing the 

 lano-uage in which others arc to narrate their facts. Steps of this kind 

 have formed, and must form, the great epochs in the progress of all 

 .science of classiflcat'on, and especially in ours ; and I need not remind 

 \o^3. how great the importance .and the influence of such steps amongst 

 vou 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 

 (ills, that they influence permanently and powerfully the researches, de- 

 scriptions, and speculations of future writers; and there are few of us 

 who can pretend to the foresight which might enable us to say, in any 



