240 Dr MantelPs Illustrations of the Connexion 



ponding mould of the pin so laid bare. He presented them 

 to Thomas Blacker, Esq., in whose possession they now are, 

 and who has shown them to the writer of this letter." In 

 the " Gentleman's Magazine," and other periodicals, there 

 are notices of similar discoveries of keys, nails, coins, &c., in 

 flints and blocks of solid stone. 



During my early attempts to investigate the geological 

 structure of the South-East of England, I one day received 

 a note from a South-Down farmer, informing me of the 

 discovery of a large iron nail in the centre of a flint which 

 he had accidentally broken. I immediately rode a distance 

 of some twenty miles to inspect this " wonderful curiosity," 

 and was not a little surprised to find my correspondent's 

 statement apparently borne out ; for he placed in my hands 

 a large rolled stone, closely resembling externally the usual 

 flint boulders of the ploughed lands of chalk districts, and 

 which had been split down the middle ; on one side was 

 imbedded a large iron nail, and deeply impressed on the 

 opposite surface the corresponding mould. A slight inspec- 

 tion detected the nature of this specimen : it was not a flint, 

 but an aggregation of fine silicious sand that had been 

 converted into compact sandstone by a solution of iron 

 derived from the nail, which had served as a nucleus to the 

 sand that had gradually accumulated around it. The facts 

 described by Kirwan and Knight doubtless admit of the 

 same explanation ; the narrators having mistaken a sand- 

 stone of modern formation for a genuine flint nodule. When 

 residing at Brighton, I obtained many specimens of recent 

 ironstone from the fishermen, who dredged them up from the 

 British Channel. Cannon-balls, horse-shoes, nails, chains, 

 fragments of bolts, bars, anchors, &c., formed the nuclei of 

 these masses ; some of which were exceedingly interesting 

 from the variety of shells, zoophytes, aiid other marine pro- 

 ductions promiscuously impacted in the same block of stone.* 



Of the rapidity with which the aggregation and consolida- 

 tion of loose materials take place at the bottom of the sea, 



* The cement of the shell conglomerate now rapidly forming in the bed of 

 the Bea off Brighton is also ferruginous. See Medals of Creation, vol. i., p. 374. 



