54 
THE LOWER LIAS OF KEYNSHAM. 
Interambulacral tubercles : one row of large, perforate and 
crenulate tubercles near tbe poriferous border. A second 
smaller row near the suture. The large tubercles surrounded 
by a very thin single ring of 'granules. 
Ambulacral tubercles: two rows of alternate tubercles, 
small and perforate. 
Anal gap incised. 
Spines long and thin, finely striate and granular. 
Cidaris 8p. Plates and spines of an undoubted Cidaris 
occur at the same horizon, the spines are thick and coarsely 
granular. 
Crinoids. 
Pentacydnus basaltiformis, Mill. Only fragments of the 
stem are found, but these are extremely common. 
Corals. 
Heterastrea latimeandroidea, Dune, is the only coral we 
have seen. It was not found in situ. 
