vi.] THE SLATES ON THE ROOF 149 



should say it went to make the New Red sandstones of 

 England. 



The New Red sandstones must have come from 

 somewhere. The most likely region for them to have 

 come from is from North Wales, where, as we know, 

 vast masses of gritty rock have been ground off, such 

 as would make fine sandstones if they had the chance. 

 So that many a grain of sand in Chester walls was 

 probably once blasted out of the bowels of the earth 

 into the old Silurian sea, and after a few hundreds of 

 thousands of years' repose in a Snowdonian ash-bed, 

 was sent eastward to build the good old city and many 

 a good town more. 



And the red marl the great deposit of red marl 

 which covers a wide region of England why should 

 not it have come from the same quarter ? Why should 

 it not be simply the remains of the Snowdon Slate ? 

 Mud the slate was, and into mud it has returned. 

 Why not ? Some of the richest red marl land I know, 

 is, as I have said, actually being made now, out of the 

 black slates of Ilf racombe, wherever they are weathered 

 by rain and air. The chemical composition is the same. 

 The difference in colour between black slate and red 

 marl is caused simply by the oxidation of the iron in 

 the slate. 



And if my readers want a probable cause why the 

 sandstones lie undermost, and the red marl uppermost 

 can they not find one for themselves ? I do not say 

 that it is the cause, but it is at least a causa vera, one 

 which would fully explain the fact, though it may be 

 explicable in other ways. Think, then, or shall I think 

 for my readers ? 



Then do they not see that when the Welsh 



