~Fossu. SPONGE SPICULES 
FROM THE 
UPPER CHALK. 
FOUND IN THE INTERIOR OF A SINGLE FLINT-STONE FROM 
HORSTEAD, NORFOLK. 
moti ERY? 
GEORGE JENNINGS HINDE. F. G. S. 
The sponge spicules herein described were obtained from 
the material contained in the interior of a nodular flint, about 
one foot in diameter, which had been imbedded in the strata 
of the Upper Chalk Formation at Horstead, near Norwich. — 
In the Chalk pits or quarries in this neighbourhood not only 
are the nodular flints arranged in horizontal layers coinciding 
wich the stratification of the Chalk but they are also disposed 
in vertical layers, and the nodules thus arranged vertically are 
often of much larger size as well as different in form to those 
of the horizontal beds. Many of these larger flints are more 
or less cylindrical and either hollow throughout like a tube or 
with a deep cup-shaped depression at one end which has 
led them to be compared with the large horny sponges called 
Neptune's cups, though there is no evidence to show that they 
are more allied to these sponges, beyond a rude resemblance 
in outer form, than the ordinary shapeless nodules of the hort- 
zontal layers. On account of their peculiar form, these cy- 
lindrical, partly hollow masses of flint have been termed pot- 
stones or paramoudras. They have by no means a general 
distribution in the upper chalk strata, though they are of fre- 
quent occurrence at Horstead and are also met with in many 
of the Chalk pits near Norwich, and they appear as well in 
