140 F. W. HARMER OX THE KESSLNGLAND CLLFF-SECTIOX. 



Crag contains, similarly, Crag -shells*. The occurrence in it of marine 

 mollusca is hardly to be reconciled with the theory that the stone- 

 bed represents a terrestrial surfacef. 



Discussion. 



Mr. Charles worth, referring to Mr. Whitaker' s paper, stated 

 that he regarded the non-fossiliferous sands as Crag. At Felixstow 

 the London Clay is under the Crag, and without fossils ; hence he 

 argued that the fossils were not removed by chemical means, but 

 that they never were there. He could not believe that sharks' 

 teeth would be dissolved away by water charged with carbonic acid ; 

 but he had never seen sharks' teeth in the sands. With regard to 

 Mr. Harmers paper, he said that the mammalian remains in the 

 subangular beds must of necessity be rounded, but that they are not 

 therefore necessarily derivative. The Crag must have had a land- 

 fauna, the remains of which would be carried down streams by 

 floods, as in Australia. If the fossils are derivative, he asked, 

 Whence are they derived? 



Prof. Hughes, in confirmation of the view advocated by Mr. 

 Whitaker, mentioned cases which had come under his observation 

 in the Faluns and in the chalky gravel of Cambridge, where the 

 removal of the carbonate of lime from the upper part by percolating 

 acidulated water produced phenomena similar to those described by 

 Mr. Whitaker. He pointed out that other peculiarities, such as the 

 vertical arrangement of the pebbles dropped into the pipy hollows, 

 the looping of the earthy residuum, the frequent coincidence of the 

 pipes and pans with surface-features, and various other conditions 

 affecting the collecting and passage of the acidulated water, proved 

 that the explanation offered was the true one. 



Prof. Seeley maintained that the irregularities of the gravels 

 described by Mr. Whitaker were due to staining by iron and 

 solution by carbonic acid, liberated by the growth and decay of 

 vegetation and old forests. He thought that they only differed 

 from the forest stainings which cap most Postglacial gravels in 

 being of greater thickness. The fact of interglacial denudation as 

 described by Messrs. Wood and Harmer seemed to him self-evident 

 from the elevation of land after the Middle Glacial beds were 

 deposited. 



Prof. Morris remarked that the whole subject was one of extreme 

 difficulty. He thought that the occurrence of mammalian remains 

 at the base of each of the Crags needs further investigation. The 

 interglacial formation of Switzerland represents the forest-beds of 

 Norfolk. 



Prof. Hamsay said that there was a growing opinion that the 



* For one instance of this see Supplement to 'Crag Mollusca ' in Pal. Soc. 

 Publications for 1874, p. 151. 



f Mr. 8. Woodward, in his ' Geology of Norfolk ' (1823), taking the same 

 view of this stone-bed, points out that a precisely similar deposit is now form- 

 ing on the Cromer coast in places where the bed of the sea is composed of chalk. 



