266 Notices of Memoirs — Antiquity of Mining. 



Carnon. In 1829 Mr. J. W. Colenso gave the Eoyal Cornwall 

 Geological Society a description and section of the Happy Union 

 stream work at Pentuan. Here, at a considerable depth under beds 

 of gravel and silt, the result of both marine and fresh- water depo- 

 sition, there were found the remains of an ancient forest growing 

 upon and out of the stratum which contained the tin stones, the 

 trunks of many of the trees being in situ. This was thirty-four feet 

 below the level of the sea at low water springs. A piece of wood 

 shaped by man was found twelve feet above, and twenty feet 

 above that again the bones of a whale of an extinct species, and 

 human skulls. Higher up the valley, in Wheal Virgin stream- work, 

 at a point where the tin ground was still below the level of the sea, 

 it was found to have been worked. About the same time Mr. W. J. 

 Henwood, F.R.S., communicated to the same Society a paper on the 

 "Deposits of Stream Ore in Cornwall,"^ which contained sections and 

 descriptions, amongst others, of the stream-works at Carnon. The 

 sections in the two valleys, though differing, presented the same 

 general characteristics ; and whereas at Pentuan human remains were 

 found 40 feet below the surface — 34 feet below high-water — at 

 Carnon they were discovered at a depth of 58 feet — 64 below high- 

 water. And as at Pentuan traces of the " old men's workings " were 

 found below the tide level, so at Carnon, at a depth of 40 feet, there 

 were disinterred a wooden shovel and a deer-horn pick. Although 

 a mound would have been required to prevent the influx of the tide 

 in working this spot, no traces of such an erection were discovered. 

 De la Beche held that the discoveries at Pentuan and Carnon proved 

 that a considerable change had taken place in the relative levels 

 of sea and land since man inhabited Cornwall. The mere fact of 

 the occurrence of traces of human existence and industry at a cer- 

 tain depth in valley deposits did not of necessity imply any great 

 antiquity. The special industries of Cornwall had caused large 

 quantities of debris to wash down ; but the deposits overlying the 

 traces of ancient mining operations at Carnon and Pentuan, were, in 

 Mr. Worth's opinion, indicative of a gradual formation. They were 

 fluviatile, estuarine, marine, possibly lacustrine also ; and to the 

 geologist they indicated the lapse of considerable time, changes of 

 level, and other alterations of condition. After contending that the 

 remains to which he directed attention were clearly antecedent to 

 the deposits, Mr. Worth said that in that case they were driven to 

 one of two conclusions — either the ancient miners must have worked 

 beneath the level of the sea, or whereas the tin bed was now beneath 

 the sea-level, at the date of these operations it must have been 

 above. The first supposition did not require examination. There 

 were evidences of geologically recent and gradual changes of level 

 all along the coasts of Devon and Cornwall in the raised beaches 

 which \vere found 30 feet or so above the beaches now existing, and 

 in the submerged forests so frequently discovered, which showed 

 that since they flourished the land had sunk at least 70 feet. These 



"^ See Geol. Mag. April, 1874, p. 177. Also, Journ. Royal Inst, of Cornwall, 

 Truro, No. xv. 1873. 



