THE RIDGWAY FAULT. 67 



conversant with it : the book of Nature may be read and re-read 

 many times before we comprehend its fullest teachings. And for a 

 field day the spot is almost unique, so much lies close at hand 

 beneath us, and this is again connected with so much beyond ; 

 with problems attaching to the physical features of the whole 

 southern districts of England indirectly, indeed, to the whole 

 world. One point we may carry away with us at any rate. 

 It is this ; with all these fractures of the earth no trace exists on the 

 surface to tell us what has occurred. The edges of this great fault 

 have been smoothed down, the gaps filled up by the agency of 

 denudation. This gives us an opportunity close at hand to 

 estimate the importance of this great geological factor. To read of 

 the removal from the surface of a district of so much solid matter, 

 by the agency of running water aided by variations of temper- 

 ature, may be a matter which may strike us or not according 

 to the mood we are in at the time. But the surface of the 

 ground traversed by a fault furnishes incontrovertible evidence. 

 Here, looking across the district, where we are told of the 

 existence, and where we could, if we chose, prove the 

 existence, of a great dislocation of the strata Ixmeath us, which has 

 brought the beds on one side several hundred feet higher, possibly 

 than they would otherwise have been ; when we see not one trace 

 of the catastrophy on the surface of the country, as we look super- 

 ficially across the landscape, we must recognise the importance of 

 that ceaseless agent of geological change denudation. And then, 

 again, we may consider what was the catastrophe which produced 

 this great dislocation 1 In the recorded instances of earthquakes 

 the areas affected have been vast, the devastation resulting appalling, 

 the loss of life terrific, but the influence on the earth's crust seems 

 comparatively slight. Instances have been recorded of the elevation 

 of large tracts of land some feet relatively to the sea, as in New 

 Zealand, by Sir Charles Lyell in the Principles of Geology, 

 and by Darwin in his Voyage of the Beagle of the land round 

 the Bay of Conception in Chiloe raised two or three feet, whilst 

 at the Island of St. Maria, 30 miles distant, the elevation was 



