part 1] GAULT AND LOWER GREENSAND NEAR LEIGHTON. 39 



Littleworth Brickyard (Buckinghamshire). — This place 

 is barely 2 miles south-west of the Southcott section. The brick- 

 yard is situated 400 yards north of the fork at which the Little- 

 worth road leaves the main road from Leigh ton, and is worked in 

 the slopes of a small steep-sided valley (deeper than that at 

 Southcott) cut by a rivulet through thick Glacial drift. The 

 surface, at the top of the pit on the south side, is about 380 feet 

 above O.D. The yard has been in operation intermittently for 

 over 60 years, and has been recentlj reopened ; but the old sections 

 are mostly obliterated, and the present exposure (October 1920) 

 does not reveal the base of the Grault. During the original 

 Greological Survey of tlie district it was examined by A. H. Green, 

 whose observations were incorjoorated and first published by 

 A. J. Jukes-Browne in his general memoir on the Gault, from 

 which the following passages are quoted. ^ 



' The late Prof. Green saw a clear section on the southern side of the 

 excavations about 1860, and noted the succession as follows : — 



Feet. 



' Drift. Sand and pebbly sand 14 



f Pale-blue laminated clay with whity-brown phosphatic 1 ., - 



I nodules J 



* Gault. { Yellow earthy concretionary limestone, with much ochre, 1 



I pyrites, some carbonate of copper ^ and brown phos- I IJ to 2 

 l^ phatic nodules J 



' Kimeridge. Stiff bluish-black clay with large septaria 6 



'When I visited the place in 1884 this section was obscured, but a cut on 

 the north side showed Kimeridge Clay passing beneath Gault without any 

 stone-bed, and only a thin parting of brown ferruginous matter. The Gault 

 contained Ammonites interruptus, Am,, lautus, and Bel. 'Minim,us. In the 

 little stream, however, which runs through the yard I found blocks of the 

 stone described by Prof. Green, a hard calcareous ironstone full of phosphatic 

 nodules, and containing many small Terebratulse, which were identified by 

 Mr. Etheridge as Waldheim^ia tam^arindus^^ a Lower Cretaceous form which 

 however has been found occasionally in the Gault.' 



When the section was re-examined many years later by Dr. A. 

 Morley Davies, the base of the Gault was still visible in workings 

 south of the stream, and its variable character was again demon- 

 strated. The following are Dr. Davies's notes on the exposure, 

 published in his report of an excursion of the Geologists' Associa- 

 tion in 19014 ._ 



1 ' The Cretaceous Rocks of Britain — vol. i : The Gault & Upper Green- 

 sand of England ' Mem. Geol. Surv. 1900, p. 278. 



^ Films of copper-stain occur occasionally on slabs of iron-pan in the iron- 

 grit breccia of the pits around Leighton. 



'^ Some of the brachiopods from Shenley are near to this species, and it is 

 probable that, if the Littleworth specimens were still available for comparison, 

 they would be found to represent one of the Shenley forms. 



'^ Proc. Geol. Assoc, vol. xvii (1901) p. 140. In the same writer's account 

 of a later excursion (1914), ibid. vol. xxvi (1915) p. 92, when the base of the 

 Gault was no longer visible, the particulars of the section above the Gault 

 are stated : — ' Coarse morainic gravels, 8 feet ; Chalky Boulder-Clay, 2h feet ; 

 Sands and finer gravels, about 10 feet; Boulder-Clay, 30 feet ; Gault, 17 feet.' 



