608 SCIENCE PROGRESS 



lieved to be of much greater age, which were possibly, though not 

 necessarily, repaired in Roman times, point as well to immuta- 

 bility of sectional outline in positions, too, where the full force 

 of the elements has been operating for a time sufficient, with 

 ordinary earthen materials, to merge to a large extent the 

 outline of rampart and fosse. This really stupendous work is 

 formed of a triple ring of sharply angular ridges and ditches 

 as much as 60 ft. deep in many places, which show no accumu- 

 lation of detritus such as one would imagine must accrue 

 from a slope of some 40 degrees, and for the greater part of its 

 two miles of circumference is extremely well preserved. The 

 grass slopes are now being patched with turf in some places, 

 but I ascertained that the bottom of the ditches, which are 

 still almost V-shaped, has remained untouched. 



