PROOFS OF SLOW CHANGES 189 



the earth's crust may have been put together in a much 

 briefer space of time than modern events might lead us 

 to suppose. Such arguments are easily adduced and 

 look sufficiently specious, but no confirmation of them 

 can be gathered from the rocks. On the contrary, 

 no one can thoughtfully study the various systems of 

 stratified formations without being impressed by the 

 fulness of their evidence that, on the whole, the 

 accumulation of sediment has been extremely slow. 

 Again and again we encounter groups of strata com- 

 posed of thin paper-like laminae of the finest silt, which 

 evidently settled down quietly and at intervals on the 

 sea bottom. We find successive layers covered with 

 ripple-marks and sun-cracks, and we recognise in them 

 memorials of ancient shores where sand and mud 

 tranquilly gathered as they do in sheltered estuaries 

 at the present day. We can see no proof whatever, 

 nor even any evidence which suggests, that on the 

 whole the rate of waste and sedimentation was more 

 rapid during Mesozoic and Palaeozoic time than it 

 is to-day. Had there been any marked difference in 

 this rate from ancient to modern times, it would be 

 incredible that no clear proof of it should have been 

 recorded in the crust of the earth. 



But in actual fact the testimony in favour of the slow 

 accumulation and high antiquity of the geological 

 record is much stronger than might be inferred from 

 the mere thickness of the stratified formations. These 

 sedimentary deposits have not been laid down in one 

 unbroken sequence, but have had their continuity 

 interrupted again and again by upheaval and depression. 

 So fragmentary are they in some regions, that we can 



