THE POSITION OF GEOLOGY. 543 



mean of three hundred feet should therefore "be taken, with a cor- 

 responding shorter time-term of twelve thousand years; or are 

 we to ignore any interval of time and to look only at the beds on 

 the coast where they are consecutive ? From every point of view 

 such estimates must be worthless. 



More than this, the very leaders of the belief that the average 

 rate of motion does not exceed that above named allow that " the 

 average rate proposed is a purely arbitrary and conjectural one" 

 It is admitted also that it is not improbable that during the last 

 four hundred years there has been a still faster rate in high 

 northern latitudes. Not only, however, is the half measure 

 adopted, but the warning that higher measures exist is neglected. 

 When therefore the mean is applied to determine the length of 

 time required to effect such elevations as that of the marine shell 

 bed on Moel Tryfaen, fourteen hundred feet above sea level and 

 of late Quaternary age, uniformitarians are obliged to ask for a 

 term of fifty-six thousand if not eighty thousand years. Should 

 the case of Moel Tryfaen be objected to as uncertain, there are 

 still the unquestioned raised beaches of Norway and Sweden, 

 which are from two hundred to six hundred feet above the sea 

 level, and of still more recent date. These, on the same esti- 

 mate, would have taken for their upheaval some eight thousand 

 to twenty-four thousand years. We need not, however, pursue 

 this subject further. The very admissions of the advocates of the 

 two above-named measures of time, based upon present rates of 

 denudation and of elevation, show how untenable their conclu- 

 sions are. 



Such observations, howsoever useful and suggestive, are in 

 fact futile so far as regards their application to former rates of 

 upheaval, and needlessly play with time. If we could suppose 

 that the causes which produced those movements had always 

 acted with the same degree of energy, the reasoning would hold 

 good ; but, as that regularity depends upon the stresses to which 

 the earth's crust has been exposed at any particular time, the 

 effects must have varied in proportion as the stresses varied. 

 With a cooling globe it could not have been otherwise. What 

 those movements of the past were, and what their duration, 

 must therefore be judged of by other circumstances and on 

 surer data. 



We trust we have now said enough to show upon how insecure 

 a basis the uniformitarian measures of time and change stand. 

 They have probably done more to impede the exercise of free 

 inquiry and discussion than any of the catastrophic theories 

 which formerly prevailed. The latter found their own cure in 

 tho more accurate observation of geological phenomena and the 

 progress of the collateral sciences ; but the former hedge us in by 



