Dr. FiTTON on the Strata below the Chalk. 313 



Lower green-sand. — This formation here consists, at the upper part, of highly ferruginous coarse 

 sand, one of the most remarkable components of which is Titaniferous oxidulated iron*. The 

 sand abounds in hard concretions of siliceous grains cemented by ferruginous matter, in the form 

 of thin flakes or bands, irregularly ramified, which, in Norfolk, are called " Carstone "; — beneath 

 which is finer sand of different shades of grey, yellowish, and white. The course of the out- 

 crop is generally parallel to that of the chalk : the chief localities and the local varieties are indi- 

 cated in Mr. Rose's memoir. 



In descending a hill on the road from Lynn to Snettisham, about a mile from the village of 

 Dersingham, is rvhite sand, under yellow slightly consolidated sand ; and near the line of the section 

 No. 25, between 38 miles and 39 from Norwich, about half a mile from Middleton, are pits of 

 yellowish and white sand, with ferruginous concretional bands, apparently belonging to the upper 

 member of the Lower green-sand ; and very like the Woburn sands. 



Organic remains must be very rare in this formation, as Mr. Rose states that he had not obtained 

 any specimens. At Ingoldsthorpe, however, in a brick-field near Mount Amelia, 1 found casts of 

 the following shells, in masses of agglutinated ferruginous sand, like those of Parham-park in 

 Western Sussex, and of the cliflf on the west of Shanklin Chine in the Isle of Wight ; Auricula 

 incrassata ; Avicula, a new species ; Corbula striatula ; Mya plicata ; Rostellaria calcarata ; 

 Turritella granulata ; Venus Faba ; and some other indistinct bivalves and univalves. 



No indications occur in the sections of this formation which I saw, nor in those mentioned by 

 Mr. Rose, of the threefold subdivision of the Kentish coast ; but in the lower part are thin 

 courses of Fuller's earth, not more than an inch in thickness. The lower beds are stated by 

 Mr. Rose generally to contain thin strata of Fuller's earth ; as in Surrey and at Woburn. 



(161.) Hunstanton, — The cliff at this place exhibits an epitome of all 

 the lower strata above described : the section is very distinct, and the dif- 

 ference in the characters and proportion of the beds from those of the south- 

 ern counties is so remarkable^ that I think it necessary to give an account of 

 them, although the place has been already described by Mr. R.C.Taylor f 

 and Mr. Rose. 



PI. X. a. No. 26, represents the cliff, on the same scale with the other 

 sections in that plate, and with Plate X. b. fig. I'H. a, which is copied 

 from a portion of the Ordnance Map of Norfolk. Fig. 12. b. is a sec- 

 tional elevation, for which I am indebted to Mr. Murchison; and fig. 12. c, 

 a sketch of part of the cliff, by Mr. Whewell, with whom and Professor 

 Sedgwick, I had the pleasure of examining the place in 1827. 



The following is Mr. Murchison's description of his section, (PI. X. b. fig. 12. b.), with some 

 additions from my own notes. The dip is, generally, to the north-east ; but it will be observed 

 that there is an angle in the coast; so that the section is strictly divisible into two portions, in 

 different planes, neither of them coincident in direction with the line of dip. 



* London and Edinburgh Phil. Mag., 3rd Ser., vol. vii. p. 179.; Phillips's Mineralogy, 3rd edit. 

 p. 223. 



t Geology of East Norfolk; and Phil. Mag. 1823, vol. Ixi. p. 81. 



2s2 



