Sheppard : The Making of East Yorkshire. 



to have become extinct, in these parts at any rate, at the close 

 of the Chalk era, whilst the Nautilus still lives on. 



G. F. Richardson has put very nicely the story of these 

 shells : — 



The Nautilus and the Ammonite 



Were launched in friendly strife, 

 Each sent to float in its tiny boat, 



On the wide, wild sea of life. 



And hand in hand, from strand to strand, 



They sailed in mirth and glee ; 

 These fairy shells, with their crystal cells. 



Twin sisters of the sea. 



The Nautilus now, in its shelly prow. 



As over the deep it strays, 

 Still seems to seek, in bay and creek, 



Its companion of other days. 



With reg-ard to the Ichthyosaurus and Plesiosaurus, huge 

 animals sometimes reaching- 30 or 40 feet in length, these 

 remind us of the (fortunately) changed conditions which now 

 prevail. In the old seas these creatures, some with short necks 

 but powerful long jaws armed with rows of teeth, others with 

 long, swan-like necks and small heads, must have had a very 

 awful effect upon their contemporaries. The gigantic flying- 

 Lizard or Pterodactyl haunted the same waters. The creeks 

 and lagoons and shallows were swarming with millions of 

 strange Squids and Cuttlefish, the hard backbones of which (the 

 only durable parts) are left to us in the form usually known as 

 ' thunderbolts ' (belemnites). Altogether the picture of the 

 Liassic sea is not a pleasant one from the point of view of 

 sailing or bathing, but at that time man had not made his 

 appearance upon the earth, and the animals would, no doubt, 

 roam about at pleasure without running the risk of being shot 

 at by bipeds with guns, called 'sportsmen.' 



Century after century, as time went on, the deposits at the 

 bottom of this sea accumulated until eventually they formed 

 a series of beds measuring several hundreds of feet in thickness. 

 If we carefully examine the slow rate at which mud deposits are 

 formed in our modern seas, and the still slower rate at which 

 beds of limestone accumulate, and then endeavour to form 

 some idea of the enormous period that it must have taken 

 for the formation of the hundreds of feet of the Liassic rocks, 

 and then remember that these Liassic rocks are a very small 



1905 April I. 



