Geology. 415 
Il. GEOLOGY. 
1. On the Spongeous Origin of the Siliceous Bodies of the Chalk 
Formation ; by J. 8. Bowersank, (Proc. Brit. Assoc, August, 1856; 
Ath. No. 1505.)—The author attributes the whole of the numerous strata 
within eighteen hours, ultimately forming one sponge. e occurrence 
of the shells of Echinoderms and of bivalve shells filled with flint was 
accounted for on the same principle; and the author produced recent bi- 
valve shells, in a closed condition, completely filled with recent sponges of 
me species as the sponges of commerce. e loose specimens of 
_ fossil sponges included in the Wiltshire flints were explained on the prin- 
ciple that, although sponges of the same species readily adhere to each 
r when placed in contact, those of different species never unite, how- 
almipes roseus than to any other type of living starfish, It is to this 
; 
uite absent, there is a site re- 
iginally described by Forbes as 
ep tinbleterep erties on dort Sans had but two rows of 
large plates. The name Pa- 
