xi.] ICE ACTION. 273 



rolling two hundred miles along a sea-bottom, before 

 such a tremendous current as would have been needed 

 to carry them. 



Then rose a very clever guess. They must have 

 been carried by icebergs, as much silt and stones (we 

 know) has been carried, and have dropped, like them, 

 to the bottom, when the icebergs melted. 



There is great reason in that ; but we have cause 

 now to be certain that they did not come from Wales. 

 That they are not pieces of a rock older than the 

 chalk, but much younger; that they were very 

 probably formed close to where they now lie. 



Now how do we know that ? 



If you are not tired with all this close reasoning, I 

 will tell you. If you are, say so : but as I said at 

 first, I want to show you what steady and sharp head- 

 work this same geology requires, even in the nearest 

 gravel-pit. 



Well, then. I do not think our gravel-pit will tell 

 us what we want : but I know one which will. 



You have all heard of Lady Grenville's lovely place, 

 Dropmore, beyond Maidenhead ; where the taste of 

 that good and great man, the late Lord Grenville, con- 

 verted into a paradise of landscape-gardening art a 

 barren common, full of clay and gravel-pits. Lord 

 Grenville wanted stones for rockwork; in those pits 

 he found some blocks, of the same substance as those 

 of Stonehenge or Pirbright. And they contain the 

 answer. The upper surface of most of them is the 

 usual clear sugar- sandstone : but the under surface 

 of many has round pebbles imbedded in it, looking 

 just like plums in a pudding ; the smaller above and 

 the larger below, as if they had sunk slowly through 



so. T 



