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Mr, B. T. Lovvne had not the least hesitation in referring these bodies to 

 organic structures and sponges. When they knew that the bed of the Atlantic 

 was at the present time depositing chalk, and that there were sponges being en- 

 closed in these formations, he was not at all surprised at finding within flints of 

 earlier formations the remains of sponges also. 



The President inquired of Mr, Johnson if he had found any diatoms in any 

 of his flint sections ? 



Mr. .Johnson stated that he had not yet met with any specimen containing 

 diatoms, but only Foraminifera and Xanthidia; these were found in nearly all 

 specimens. 



Mr. Waller said there was much in favour of the sponge theory. He had 

 himself never found any flints which did not contain the remains of sponge. 

 The gemmules of sponge were often remarkably well seen in the flints which 

 were picked up on Blackheath ; one of these was so clearly marked that he had 

 sent the specimen to Mr Quekett. 



Mr. Johnson thought the actual origin was to be sought in the process of the 

 substitution of silicon (silicate of soda) for the carbon of the organic matter. 

 Any organic matter, under favourable conditions, would, if it contained carbon, 

 undergo the change ; its decomposition would take place by a slower process. 

 Some time ago he had made an experiment to test this. He put a number of 

 soft-bodied animals into a solution of silicate of soda, and left them there for 

 four or five days. At the end of that time he took them out, washed off' all the 

 superfluous silicate, and put them into a quantity of strong nitric acid. He 

 found that the acid had no eff'ect whatever upon them, whereas those which had 

 not been put into the silicate were disintegrated and dissolved by the acid in 

 the course of half an hour. This showed that a great change had taken place, 

 and that silicon had been substituted for carbon. Traces of nitrogen and 

 carbon were occasionally met with in flints. 



Mr. Lowne thought that Mr. Johnson's last remarks were of very great im- 

 portance, and he hoped they would be followed up so as to make certain as to 

 this substitution. Why not put something containing carbon into the solution, 

 and afterwards incinerate it, and thus ascertain how much silica had been ab- 

 sorbed ? If this substitution took place, it must of course be from a medium 

 which contained silica in solution, and they would have also to believe that 

 dead protoplasm could collect it from great distaucos. The objection which he 

 saw to foraminifera was that they naturally collected lime and not flint ; but 

 there was another class of creatures very likely to be mistaken for foraminifera 

 ■ — the Radiolarians — which were very common, and which did collect flint in large 

 quantities. Again, as regarded foraminifera, they lived on the sponges, and 

 were found everywhere else ; so that it was easily understood how they might 

 frequently get enclosed in the mass. Another fact worth naming was that the 

 mass of flint having been originally deposited as a secretion, lime and other 

 substances would become agglomerated with it. He remembered being much 

 struck the summer before last at the number of half-changed flints which he had 

 found on the downs to the north of Worthing. 



Mr. T. C. White said he had been much struck by the appearance presented 

 by apiece of chalcedony which he had rubbed down, and afterwards mounted in 

 balsam. The remarkable resemblance of the ramifications to those seen in a 

 sponge was most striking ; only in the case of the chalcedony they were all 

 hollow, or tubular. 



Mr. Johnson thought it more probable that the foraminifera were the food of 



