476 PROCEEDINGS OP THE GEOLOGICAL SOCIEIT. 



of boulders from a great distance, and that, during the formation of 

 the lower Coralline Crag, movements of subsidence prevailed, suc- 

 ceeded in the upper division by an elevation of the sea-bed, which 

 brought the Coralline Crag partly above the sea-level, where it be- 

 came exposed to the action of the tides, currents, and breakers of the 

 Eed-Crag sea. In consequence of this action, a very large portion 

 of the Coralline Crag has been destroyed, and its debris incorporated 

 in the mass of the Red Crag ; and the beds of j)hosphatic nodules 

 (or the Coprolite-beds) of the Red Crag are probably derived in whole 

 or in greater part from the Coralline Crag. Floes laden with large 

 unworn flints from the neighbouring chalk coast were stranded on 

 the Sutton Coralline-Crag islets, whilst shore-ice floating off from the 

 same islets strewed the sea-bed around them with large blocks and 

 boulders of the Coralline Crag. 



The Norwich Crag, which occupies the contiguous area, and lies 

 on the same level, seems to have been divided from the more open 

 sea of the Red Crag by a barrier of CoraUine Crag, behind which were 

 sandy bays, into which flowed a river or rivers bringing down land 

 and freshwater shells, and probably mammalian remains from land 

 to the north-west and west. There is evidence of these streams 

 coming from that direction in the circumstance that in the Crag at Nor- 

 wich, Lias Ammonites, Mountain-Limestone corals, besides the many 

 fossils from the Chalk, are found. I have found also, at the base of the 

 Crag at Weyboume, a fragment of fossiliferous Kimmeridge Clay, 

 and in the Norwich Crag an encrinital column similar to some I have 

 seen in the Red Crag of Suffolk, in which latter also occur Belem- 

 nites, Ammonites, Ostrece, and Terehratulce from various Secondary 

 rocks, together with fragments of chert from the Lower Greensand, 

 while the occurrence of the fragments of red granite points to trans- 

 port from still more distant localities*. 



After a time a general subsidence of the whole area took place, 

 followed by the deposit of the ChiUesford sands over the irregular sur- 

 face of the CoraUme Crag, Red Crag, and Norwich Crag, and at the 

 same time colder currents from the north introduced new and more 

 Arctic species of Mollusca. Still notwithstanding the greater depth 

 of water and the greater cold, there is an absence of aU foreign 

 boulders, with the exception, if they may be so termed, of large blocks 

 of subangular chalk-flints. 



The sea-bed was then raised and a land surface formed in eastern 

 Norfolk, and over some adjacent part of the German Ocean. On 

 this freshwater deposits were formed, and a forest of Scotch firs, 

 Norway spruce and other trees of a temperate character grew. 

 The forest was frequented by herds of deer, whose shed antlers 

 are found in abundance (Woodward), as well as by troops of Elephas 

 antiquus. 



Another subsidence then took place submerging the whole forest, 



* For considerations on the subject of the old Crag-area, and on the causes 

 modifying the Crag-fauna, see Godwin- Austen " On the Xaiuozoic Formations of 

 Belgium ' (Quart. Journ. Geol. Soc. vol. xxii. p. 238). 



