Eocene Strata. 349 



strata were more easily removed than the harder rocky 

 portions, and the result is that over large areas, such as 

 Marlborough Downs, great tracts of Chalk are strewn 

 with huge blocks of tabular quartz-grit, lying so close 

 together that some years ago, over miles of country, I 

 could almost leap from block to block, without touch- 

 ing the chalk on which they lie. They are, however, 

 in such great request for building and paving purposes, 

 that in the long run they will probably be all broken up 

 and carried away. 



FIG. 76. 



In the above figure, No. 1 represents the Chalk, and 2 

 the overlying Eocene clays and sands ; and the isolated 

 blocks, lying directly on the topmost beds of the Chalk, 

 represent the thickly scattered masses of stone left on 

 the ground after the removal by denudation of other 

 and softer parts of the Eocene strata. No. 2. Fre- 

 quently these masses are found scattered even on the 

 terraces of the Lower Chalk, a remarkable example of 

 which occurs at the Prehistoric town of Avebury, near 

 which, the lower terrace of Chalk (as in the diagram) 

 is strewn with c grey wethers,' as they are termed, and 

 immense masses of these, set on end by a vanished people, 

 stand in the ancient enclosure. Sometimes even on the 

 plains of Gault or Kimeridge Clay, well out to the north 

 or west of the escarpment, as for instance at Swindon, 

 and also in the Wealden area, blocks angular or half- 

 rounded lie in the meadows, marking the immense 

 waste to which the whole territory has been subjected 

 long after the close of Eocene times. They plainly 

 tell, that the Chalk: and overlying Eocene beds once 



