Prof. Keilhau on (he Present State of Geology. 345 



monize with what, according to our theory^ we assume ought 

 to exist in the case under consideration. In order to be able 

 to believe, we must also be able to understand. As the objects 

 cannot here be made palpable, we are not in such a situation 

 that belief must exist under all circumstances, whether we 

 understand or not. It is even considered as a very correct 

 principle of investigation, when the question regards any geo- 

 gnostical appearance, not to recognise it as a pure fact until 

 counsel is taken from sciences to which in reality only a 

 secondary voice should be assigned in such matters. Thus it 

 has become quite usual in geology not to tolerate phenomena 

 which seem to be in discordance with the present position of the 

 sciences alluded to. These are rejected on the pretext either 

 that they are imperfectly observed, or that they constitute 

 isolated abnormal phenomena, to which no weight can be given. 

 An ample field is thus thrown open for caprice, and the science 

 is exposed to this disadvantage, that a multitude of important 

 facts are not introduced into its archives, facts belonging pre- 

 cisely to that class on which might be founded principles, that 

 are not at all, or at least not easily, to be obtained from any 

 other science but geology itself. As the key to such facts 

 cannot be found in those other sciences, these very facts are 

 thrown aside : but this is done to the irreparable detriment of 

 geology ; for, as already remarked, it may be the case that it 

 is only by the study of these facts themselves, and their analo- 

 gies, that the most important information can be obtained. I 

 hope afterwards to illustrate this more fully by distinct ex- 

 amples. 



What I have already said, is sufi&cient to shew that geology 

 is by no means in the best possible situation. However, in- 

 asmuch as the conditions for a more desirable position, such 

 as that mentioned at first, with which the actual one was 

 compared, depend on an impossibility, of what use can it be, 

 it may be asked, to think of a change of that kind ? But 

 on considering the matter more attentively, it will be found 

 that very much can be done in this respect. We have it 

 completely in our power to approach much more nearly to 

 such a position than we are at present ; it is possible in very 

 many cases at least to substitute direct observations for ideas. 



VOL. XXXVI. NO. LXXII. APRIL 1844. X 



