Prof. J. Prestwich on Artesian Wells. 235 



when 62 feet of it had been passed through, the boring entered into 

 mottled red, purple, and greenish shales, dipping at 35° in an 

 unascertained direction. These beds continued through a depth of 

 80 feet, when, their nature being clearly ascertained, the boring was 

 stopped. The fossils of these coloured beds, which included Spiri- 

 fera disjuncta, Bhynchonella cuboides, and species of Edmondia, 

 Chonetes, and Orthis, show them to be of Devonian age. Thus the 

 existence of Palaeozoic rocks at an accessible depth under London, 

 and the absence of the Jurassic series, as maintained long since by 

 Mr. Godwin- Austen, are experimentally demonstrated. 



These facts are of interest in connexion with the question of the 

 possible extension of the Coal-measures under the Cretaceous and 

 Tertiary strata of the south-east of England. The beds found at 

 the bottom of Messrs. Meux's boring are of the same character as 

 the Devonian strata which everywhere accompany the Coal-mea- 

 sures in Belgium and the north of France, being brought into juxta- 

 position with them by great faults and flexures. The author refers 

 especially to a remarkable section at Auchy-au-Bois, in the western 

 extremity of the Yalenciennes coal-field, which is particularly inter- 

 esting from its furnishing evidence that the Hardinghen coal-field, 

 between Calais and Boulogne, is a prolongation of that of Valen- 

 ciennes, and because the same strike and a prolongation of the same 

 great fault observed at Auchy-au-Bois through Hardinghen would 

 carry the southern boundary of any coal-field in the south-east of 

 England just south of Maidstone, thence passing a little north of 

 London. Hence it is in the district north of London that there is 

 most probability of the discovery of the Carboniferous strata. The 

 extent of country in which shafts could be sunk to the Palaeozoic 

 strata, however, will be limited by the presence of the water-bearing 

 Lower Greensand, which probably reaches close to London in the 

 south, reappears in Buckinghamshire and Bedfordshire 30 or 40 

 miles north of London, and probably extends some distance towards 

 the city under the Chalk hills of those counties and Hertfordshire. 



The nature of the representative of the Lower Greensand in the 

 boring, and the characters of the fossils contained in it, lead the 

 author to the conclusion that in it we have a deposit produced near 

 the shore of the Neocomian sea, here probably consisting of cliffs of 

 Devonian (or Carboniferous) rock. Prom these cliffs the calcareous 

 material which here replaces the usual loose sands of the Lower 

 Greensand was perhaps derived by the agency of springs ; and the 

 shore-line itself must be situated between the south end of Totten- 

 ham Court Poad and the Kentish Town boring. The sandy beds of 

 the Lower Greensand will probably be found to set in at no great 

 distance to the southward, presenting the conditions necessary for 

 storing and transmitting underground waters. A test boring made 

 by Mr. H. Bingham Mildmay at Shoreham Place, about 5 miles from 

 Sevenoaks, and in which the Lower Greensand was met with at 

 about the estimated depth (450 feet) and furnished a supply of 

 water, seems to confirm these views. 



