3-22 THE GEOLOGIST. 
Slowly the bright green tide is quitting the flat shore, and leaving 
again exposed the dark blue clay, dotted with black phosphatic nodes 
and glittering iridescent shells, washed clean and bright. Daily may 
you pick up hundreds of these ancient inhabitants of the sea ; 
gather the crop as clean as you will, there will be another harvest 
for you when the next tide falls. Here are Inocerami, or " fibre- 
shells." in abundance. Two species, the luocemmus sulcatus and 
Lign. 24. — Inoceramus sidvuttts, Ligll. 25. — Inoceramus conceniricus. 
Imceramus conccntricus — th6 farrowed and concentric are particularly 
characteristic of the gault. There is a third and rarer species, I. 
Coquandi, which is also found in the dark-coloured upper green-sand 
a short distance beyond, towards the old gun-brig " The Pelter," 
The individuals of these species, so remarkably abundant in the 
gault, rarely attain to the size of a few inches in length, while other 
hiffix. 'M.—Nucuhipi-ctinata. Lign. 27. — Nucula ovata. 
species of " fibre-shells" of the subsequent era of the chalk attained 
dimensions of more than a yard in diameter, with shells, however, 
singularly thin for such large molluscs living in a sea conspicuous for 
