184 



line or two of interruption, and at length assuming the 

 colour and texture of common gray flint*. The uncoloured 

 part is sometimes less indurated^ but insoluble in acid, and 

 seems only destitute of the colouring matter. The coat 

 appears to have been formed when the process was nearly 

 complete ; as drops of coloured water, or turpentine, will, in 

 general, form a margin in the same manner on substances 

 on which they are put : the others seem formed in a similar 

 way, varying as to regularity. An approach to yellow, with 

 a border of dull crimson, is seen in the next stone, and the 

 coat is nearly black with very little variety. 



The next right hand figure was given me by a friend who 

 found it near Norwich. It is remarkable for the unifor- 

 mity of the ochraceous tint all through it, and the dark 

 coat penetrating it in the cracks, which seems to confirm 

 the idea of the margin being formed as the substance was 

 beginning to harden. The next stone is very regularly 

 formed. In this, one of the circles is of as true a yellow, 

 and nearly as bright, as I have ever found in flints. The faces 

 of broken flints sometimes become of a brighter yellow when 

 they have been exposed to the air. The upper central one is 

 more irregular, but is in the middle as bright a cinnabar, or 

 vermilion, as can perhaps be found in these sort of stories, 

 and resembles red jasper. The fragment beneath has been 



* The common ingredients are Siler - 80 

 Argil - 18 

 Liine - 2 



100 



