288 The Founders of Geology LECT. 



us by ample and painful experience, that a very large 

 mass of the geological writing of the present time is utterly 

 worthless for any of the higher purposes of the science, 

 and that it may quite safely and profitably, both as regards 

 time and temper, be left unread. If geologists, and 

 especially young geologists, could only be brought to 

 realize that the addition of another paper to the swollen 

 flood of our scientific literature involves a serious respon- 

 sibility ; that no man should publish what is not of real 

 consequence, and that his statements when published 

 should be as clear and condensed as he can make them, 

 what a blessed change would come over the faces of their 

 readers, and how greatly would they conduce to the real 

 advance of the science which they wish to serve. 



In the third and last place, it seems to me that one 

 important lesson to be learnt from a review of the early 

 history of geology is the absolute necessity of avoiding 

 dogmatism. Let us remember how often geological theory 

 has altered. The Catastrophists had it all their own way 

 until the Uniformitarians got the upper hand, only to be in 

 turn displaced by the Evolutionists. The Wernerians were 

 as certain of the origin and sequence of rocks as if they 

 had been present at the formation of the earth's crust. 

 Yet in a few years their notions and overweening con- 

 fidence became a laughing-stock. From the very nature 

 of its subject, as I have already remarked, geology does 

 not generally admit of the mathematical demonstration of 

 its conclusions. They rest upon a balance of probabilities. 

 But this balance is liable to alteration, as facts accumulate 

 or are better understood. Hence what seems to be a well- 

 established deduction in one age may be seen to be 



