C. dens -elephant is -2- 
ly thick and thin, without pali or transverse enlargement, four 
or five to l/lO inch* En do theca abundant and at right angles to 
the septa. The mural elevations, so far as can be judged from a 
section, are small and delicate. 
The specimen is an example of the variety of siliceous 
f ossilizat ion where the interspaces are filled with porcellanous 
and opaline silica, the aelerenchyma having lost much of its de- 
tails and being turned into homogeneous dark flint. 
From the Chert -format ion of Antigua, Coll# Geol. Soc 
