LOWER GREENSAND. 375 



which are paralleled with the Faringdon Beds, and with the Sand- 

 gate and Folkestone beds. The series has a thickness of from 25 

 to 30 feet, and consists of red, yellow, and grey sands, containing, 

 according to Lonsdale, the following beds in descending order : ^ — 



Calcareous grit with sandy clay. 



Sandstone. 



Quartzose conglomerate. 



Ironstone-nodules. 



Chert (comparatively rare). 



The quartzose conglomerate yields pebbles of quartz, lydian 

 stone, slate, oolite, etc. It was regarded by Mr. Godwin-Austen as 

 true littoral shingle. The pebbles of quartz, etc., may have been 

 derived from the Corallian Beds (Lower Calcareous Grit) ; the 

 'lydian stone,' in Prof. Bonney's opinion, is for the most part chert 

 from the Carboniferous Limestone, and these and other pebbles 

 may perhaps have been derived from Triassic rocks, directly or 

 indirectly.^ (See Fig. 58, p. 352.) 



Diceras {Requienia) Lonsdalii occurs at Stock Orchard, south of 

 Calne, at Lockswell Heath, to the east of Bowden Hill, and at 

 other localities near Devizes and Seend. Among other fossils are 

 Terebratella ]\Ienardi, Terebratula depressa, Pecten interstriatus, Niiciila 

 impressa. Opts Coquandiana, Einarginula Neocomiensis, etc. At Seend, 

 where the beds rest on the Kimeridge Clay, they comprise false- 

 bedded brown ferruginous sands, sandstone, and quartzose sand. 

 Ochreous nodules occur, and veins of ironstone traverse the beds 

 vertically and horizontally, while here and there greenish sands 

 and laminated sandy clays occur.^ ]\Ir. W. Cunnington has pointed 

 out that at Seend the upper part of the Kimeridge Clay contains 

 septaria bored by Lithodotnus of the Lower Greensand.* 



The iron-ore at Seend has been largely worked ; and beds of quartzose sandstone 

 from this locality were used in ancient times for making querns. Quartzose 

 conglomerate occurs also near Swindon. Beds of sand and ironstone are developed 

 west of Devizes, at Poulshot Green, Rowde and Bromham. Pine white quartzose 

 sand has been extensively worked at Sands Farm, east of Calne. In the Vale of 

 Wardour the beds have not been clearly exposed.^ 



MIDLAND COUNTIES. 



Faringdon Beds. — To the south of Faringdon, in Oxfordshire, are 

 the celebrated ' Sponge-Gravels ' of Little Coxwell. The beds are 

 from 25 to 40 feet thick, and form a plateau based on Kimeridge 

 Clay and Corallian rocks. The gravels are capped in places 

 by dark ironsand, and their total thickness has been estimated at 

 from seventy to one hundred feet. The gravels consist of quartzose 



1 T. G. S. (2), iii. 266. 



2 Address to GeoL Sect. Brit. Assoc. 1886. 



^ T. R. Jones and C. D. Sherborn, G. Mag. 1886, p. 274. 



* Q.J. vi. 453. 



5 Fitton, T. G. S. (2), iv. 248. 



