90-A J. PRESTWICH ON THE RANGE OF THE LOWER 



and with a dip of 35°*. These, with lenticular seams or thin 

 beds of hard grey and red sandstone or qnartzite, and with beds 

 of red marl, continued through a depth of 80 feet, when all doubt 

 being removed as to the geological age of the strata, the work was 

 stopped. * 



A good many fossils were met with from time to time in the 

 shales, among which Mr. Etheridge recognized the following : — 



Spirifer disjuncta. 

 Rhynchonella cuboides. 

 Edmondia. 



Orthis. 



Chonetes. 



The first two are Upper Devonian species, while the Edmondia is 

 a characteristic Devonian genus f . 



Further, in lithological characters, the rock-specimens obtained from 

 this boring agree perfectly with those I had an opportunity of seeing, 

 in company with Mr. Warington Smyth and Dr. J. Evans, last year 

 in the neighbourhood of Pernes, near Bethune, where the Upper 

 Devonian strata crop out from beneath the Chalk, with a dip 28° 

 S.W., and are in close relation with the adjacent Coal-measures at 

 Maries and Auchy-au-BoisJ. 



Eor particulars of the section, which I have given at the end of this 

 paper (p. 912), I am indebted to Major Beaumont, the Managing Di- 

 rector of the Diamond-boring Company, and to Mr. Etheridge, aided 

 by specimens in my own possession and in the Oxford University 

 Museum, which has been liberally furnished with a very fine series 

 of cores by Messrs. Meux & Co. 



Thus the great problem of the existence of Palaeozoic rocks at an 

 accessible depth under London, and of the absence of the Jurassic 

 series, as suggested upon sound theoretical grounds by Mr. Godwin- 

 Austen, has been solved in the affirmative. This geologically im- 

 portant work further shows that while the range of the Lower 

 Greensand is interrupted by the underground Palaeozoic ridge, the 

 limits of that interruption do not extend at this point south of a 

 line passing through the centre of London. 



The value of the first determination consists in the fact that in 

 the range of the Carboniferous series through Belgium and the north 

 of Prance they are everywhere accompanied, on the same strike, by 

 Devonian strata, and the latter strata are constantly brought by 

 great faults and flexures into juxtaposition with the Coal-measures. 



* The cores gave so perfect a vertical section that the angle of the planes of 

 bedding to a horizontal surface were clearly visible and easily measured. The 

 direction of the strike was not, however, ascertained. 



t Another specimen in my possession bears a close resemblance to Bhyn- 

 chonella boloniensis, characteristic of the Upper Devonian of the north of 

 France and Belgium. 



\ M. Breton's description of the Devonian strata met with in the boring 

 given in fig. 2, p. 906, might pass for that of the Tottenham-Court-Boad speci- 

 mens. He says, " Ce sont d'abord des schistes rouges, puis des gres schis- 

 teux un peu micasses, bruns melanges de vert, puis des marnes effervescentes 

 vertes et rouges. . . . ensuite des schistes rouges, avec taches verdatres, 

 sableuses, fossiliferes, contenant des plaque ttes quartzites micasseestres-dures,"&c. 

 (' Etude stratigraphique du Terrain houiller d'Aucby-au-Bois,' p. 39.) 



