modern origin, being commonly found 

 in clay, where some vitriolic water oozes 

 or trickles out, provided there is a little 

 calcareous matter likewise for it to unite 

 with. There are a great many Bricks and 

 Tiles made out of this clay for the use of 

 the town of Grantham ; and I imagine, 

 what might otherwise be very well, 

 I think, supposed to be the case, that it 

 is not an accidental mass of clay in that 

 place only \ but part of a stratum of some 

 extent, for I observed some other Brick- 

 kilns, at a mile or two distance, on the 

 side of a hill, at about the same level. 

 Whether there may not be still more 

 beds of clay in some other parts of this 

 set of strata, I don't know, though from 

 these instances and general analogy, it is 

 not very unlikely there should. Almost 

 immediately to the westward on this side 

 Grantham 2 , we again have clay, which is 



1 [Like the tract of Boulder-clay above de- 

 scribed.] 



8 [The rock formations to the west of Grantham 



54 



