148 MR. F. D. LONGE ON THE FORMATION OF FLINTS IN CHALK. 
catching the cloth in straight lines, and so making stripes on the 
goods ; the cloth was always damped before being teaseled. 
The teasel is still grown in the West of England, and large 
quantities are imported from France and America. The heads of 
the cultivated plant are not so large as those of many teasels 
growing in damp ditches in Norfolk; the object of cultivation 
being to strengthen the awns and produce heads of a uniform size. 
In England the seed of the teasel is drilled in April, and the 
plants are ready to cut in July of the following year ; much care 
is needed in drying the heads. 
The teasel was formerly of such importance as to have been 
borne as a charge on coats of arms, and a Norfolk surname has 
been derived from the plant. 
Several attempts have been made to manufacture wire brushes 
which should supersede the teasel, but at present without success ; 
the metallic hooks, if meeting a strong thread, are apt to tear it 
out, and thus do serious injury to the texture of the fabric, whereas 
the horny-hooked points of teasel give where necessary. 
III. 
ON THE FORMATION OF FLINTS IN CHALK. 
L’y F. D. Longe. 
Read 27 th November, 1900. 
In September last year, 1899, I happened to see in a local journal 
a short notice of a paper read by Professor Sollas, at the meeting 
ot the British Association at Dover, on the formation of flints. 
I gathered from this notice that he considered that a chalk Hint 
was formed by the accretion of silica from the white coating with 
which Hint nodules are covered when in their chalk matrix, 
