Correspondence — Mr. George Maw. 335 



ON A SECTION OF THE GAULT AND LOWER GREENSAND, AT 

 LOWER FETTLEWORTH, SUSSEX. 



Sir, — The papers by Mr. Judd on tlie Speeton Clay, and the Eev. 

 T. Wiltshire on the Eed Chalk of Hunstanton, which have recently 

 appeared in the Quart. Journ. of the Geological Society, suggest my 

 sending for publication the accompanying sketch of a section ex- 

 posed in a cutting of the Petworth Eailway, near Lower Fettleworth, 

 Sussex, exhibiting the occurrence of a blood-red bed in association 

 with Gault, and probably on the horizon of the Eed-rock of Hun- 

 stanton and Speeton. 



The section, which is from forty to fifty feet deep, exhibits four 

 well-marked subdivisions. 



7 ' ■'" '\^f-'iVv^>- (a) a bed of ferruginous surface gravel, five 

 : _:; ;. ;-;;,-->- or six feet thick. 



ss^E (b) Gault about ten feet thick. 



Z^J!^ (c) A very hard blood-red ferruginous con- 

 ^'" ^~ (d) glomerate at the base of the Gault, 

 maintaining a uniform thickness of 

 about four inches, and resting on 



The Lower Greensand, thirty feet of 

 ■which is exposed in the cutting. The 

 colour of the Lower Greensand varies 

 from buff to orange ; its upper part, 

 (d), immediately under the band (c) 

 being stained to the depth of a few 

 inches of a bright blood-red. 



The peculiar clear red of anhydrous sesquioxide of iron is rare in 

 the British Cretaceous rocks, and notably distinct from the yellow 

 and orange tints pervading the Lower Greensand. The red band 

 c, like the red rock at Hunstanton, abounds in small quartz pebbles, 

 held together by the ferruginous matrix. 



Is it possible that it may be the southern extension of the red 

 rock of Hunstanton and Speeton, expanded to six or seven feet 

 thick at Hunstanton, and further north to thirty feet at Speeton? 

 The Gault does not seem to have any certain representative in the 

 north. The position of the Fettleworth red bed at the top of the 

 Lower Greensand agrees with that assigned by Mr. Wiltshire for 

 tlie Hunstanton red-rock overlying the " Carstone," and is not in- 

 consistent with the horizon suggested by Mr. Judd for the Eed 

 .Chalk, south of Speeton, resting miconformably on beds supposed to 

 be the equivalent of the Upper Neocomian. 



