ROCKS OF THE ESSEX DBTFT. 



363 



Mr. Whttaker saicl it was only by continual endeavours to identify 

 the rocks of the Boulder-clay that any knowledge of their original 

 derivation could be obtained. He also noticed the number of foreign 

 fragments scattered over the country artificially. The sandstone, 

 which he concurred with Mr. Eowe in regarding as Xeocomian, 

 was one of the commonest stones of the Boulder- clay in "West Nor- 

 folk, but he had tried in vain to ascertain its origin. The paucity 

 of granites was common in the Drift of the eastern counties, but the 

 occurrence of Ehsetic stone was new to him. On the Cromer coast 

 there were boulders of rocks similar to those on the table, and 

 many of the Cromer blocks were of Norwegian origin. 



Mr. Cole mentioned the numerous pebbles of igneous rocks in the 

 Bunter pebble-beds, and thought that their transference to the 

 drift might complicate the question of the origin of the materials. 



The President pointed out that 2siedermendig beds were worked 

 for mill-stones by the Eomans, and fragments occurred all over 

 Europe. The sandstone with glistening fractured surface was from 

 the Spilsby Beds of Southern Lincolnshire, as shown by a fossil it 

 contained. 



Mr. Bowe said his specimens were from large boulders, and nearly 

 all had been found in the Boulder-clay itself or could be traced to it. 



