508 



MESSES. WH1TAKER AND JUKES-BROWNE ON [Aug. 1 894, 



V. The Cheshunt Boring. 

 General Note. 



This boring, like that at Ware, was made for the New River 

 Company. Its site is on the western side of the high road between 

 Cheshunt and Wormley, where the word ' Turnford ' is engraved on 

 the old 1-inch map ; hence it is known to the officials of the New 

 River Company as the Turnford boring, but as this is only the name 

 of a hamlet and not that of a village, it seems better to speak of it 

 as the Cheshunt boring, as has already been done by one of us. 



The surface-soil at the site is gravel ; the level is about 110 feet 

 above Ordnance datum, and only a few feet above the alluvium of 

 the River Lea, which lies to the eastward. 



So far as we can learn, the boring was begun in 1878, and was 

 completed in 1879. The results were partly noticed by Mr. 

 Etheridge and by Mr. Hopkinson ' ; a more detailed section was 

 given by one of us, 2 and this was afterwards corrected and much 

 enlarged, partly from an inspection of specimens. 3 



Mr. J. Francis, the Engineer of the Company, having kindly 

 furnished us with specimens of all the samples retained at his office, 

 we are now able to add some further details and to prepare a still 

 more accurate account. Unfortunately, however, no samples from 

 the Upper or from the Middle Chalk seem to have been preserved, 

 so that we cannot fix the horizons of the Chalk Rock and of the 

 Melbourn Rock as we hoped to have done. 



Before noticing these samples we may supply a deficiency in the 

 former account of the section, and that from information also given 

 by Mr. Francis. No record of the top beds had come to hand, and we 

 were without information as to the Drift and the London Clay, and 

 with but little as to the Reading Beds and the Thanet Sand. The 

 succession of beds above the Chalk is now given as follows : — 



rT) t, -, fMalm[?loam] 



[EiverDrift.] | Gravel L J 



(Yellow clay 

 Blue clay 

 Blue sandy clay 

 Blue shelly clay [basement-bed].. 



r-r, -r. f White sand 



Reading Beds, J •.«- .., j , 



-la f 1 1 4 Mottled clay 



dOieet.j [ Grey sand with lignite 



Grey and black [Thanet] sand 



Thickness. 



Depth 



Feet. 



Feet. 



4i 



H 



10 



Hi 



1 



m 



151 



301 



12 



401 



2 



44£ 



44 



49 



4 



53 



27* 



80i 



10* 



91 



1 Pop. Sci. Eev. n. ser. vol. iii. (1879) p. 290, and Trans. Watford Nat. Hist. 

 Soc. toI. ii. pt. 7 (1880), p. 241. 



2 Trans. Herts. Nat. Hist. Soc. vol. iii. (1885) p. 176. 



3 Geol. Surv. Mem. 1889, 'The Geology of London and of Part of the 

 Thames Valley,' vol. ii. p. 50. 



