jecture concerning the origin of flints in 

 general 1 ? 



Besides this bed of clay, of the existence 

 of which I was not aware before my last 

 return from town, there is another pretty 

 considerable bed of clay (for I think it is 

 not the same appearing again at another 

 place) which I have often taken notice 

 of, that shows itself in the side of the 

 hill immediately descending towards 

 Grantham, on the east side of it 2 . What 

 is the thickness of this bed I don't know, 

 but from what I have been able to learn 

 concerning it, I should suppose it is not 

 less than the other. There are also found 

 in it, in one part of the stratum, some 

 Cornua ammonis^ and in another part some 

 selenites ; but these last I pay no great 

 regard to, as they are frequently of a very 



1 [It would have been interesting to know what 

 this conjecture was. How great would have been 

 A lie he IPs astonishment could it then have been 

 revealed to him what is now known about the history 

 of the Boulder-clay which he here describes so 

 minutely.] 



1 [Probably one of the clays of the Upper Lias.] 



53 



