110 Proceedings. 



chambered cells, and may often be found in the pits at 

 Nutfield. The Nautilus ought to be regarded by us with the 

 greatest veneration, for it is one of those rare instances of a 

 genus which had its beginning very far back in time, and 

 has successfully competed for existence with contemporaries 

 of all descriptions ; and after living through all the changes 

 of geography and climate which our globe has undergone, 

 and seeing race after race of beings come into existence, 

 continue for a time, and become extinct, has survived them 

 all, and now flomishes in the seas of the present day. Its 

 days, however, appear now to be numbered ; the genus has 

 dwindled to three or four species, Nautilus pompilius being 

 perhaps the best known. 



The Ammonite was not unlike a Nautilus, but stood rather 

 higher in the scale, the most obvious difference between the 

 two being that the edges of the chambers in the Ammonite 

 are crenulated — that is, they fitted into one another by a 

 most elaborate notched arrangement, very hke that seen in 

 the bones of the human skull. These joints or sections in 

 the Nautilus were plain. The siphuncle, too, or shelly tube 

 which connects the interior of the chambers together, runs 

 inside the back of the Ammonite shell, while in the Nautilus 

 it runs through the centre of the shell. 



The Belemnite belonged to another order of cephalopods. 

 Its shell was of a different kind to that of the Nautilus. The 

 greater part of it was thin and easily broken up, and the only 

 relic we find in the Lower Greensand is that portion known 

 as the guard or rostrum, which, being of hard, solid carbonate 

 of lime, has escaped the destruction which overtook the rest 

 of the animal. But, from specimens found in the clay of an 

 earlier formation than the one we are treating of, we know 

 that it was covered with this thin shell, and the presence of 

 an ink-bag showed that it bore considerable resemblance to 

 the Sepia Cuttlefish of our present seas. 



In our neighbourhood the Lower Greensand consists of 

 four members : the lowest, the Atherfield Clay, on which is 

 the Hythe division, which forms the tops of the hills ; then 

 the Sandgate Beds, to which it is probable the Fuller's-earth 



