LOWER GREENSAND. 379 



EASTERN COUNTIES. 



In Cambridgeshire the Lower Greensand consists of brown and 

 yellow false-bedded sands, with ironstone concretions and occa- 

 sional beds of loam ; its total thickness is about seventy feet.^ At 

 Ely it rests on the Kimeridge Clay, and is there only about nine 

 feet in thickness, and at Haddenham it is fifteen feet thick. 



The Lower Greensand of Norfolk consists of alternating beds of 

 red and white sand, sandstone and clay, from seventy to one 

 hundred feet in thickness. Some of the beds, as in the cliff at 

 Hunstanton, are conglomeratic, containing pebbles of quartz, 

 lydian stone, etc. (See Frontispiece.) The hard beds, locally 

 termed Carstone, (' gingerbread stone,' or Quern stone), are 

 quarried for building-purposes at Snettisham, while the white sand 

 of Snettisham and Castle Rising has been used in the manufacture 

 of glass. The occurrence of ' Carstone,' as remarked by Mr. 

 Whitaker, is a local feature, dependent on the presence beneath 

 the sand of beds of clay which have arrested the percolation of 

 ferruginous waters.^ (See Fig. 61, p. 366.) On the foreshore at 

 Hunstanton clayey beds (at one time thought to be Kimeridge Clay) 

 have been described as the Perna-bed by the Rev. T. Wiltshire, 

 containing P. MicUeti, Aticyloceras gigas, and Ammonites Deshaycsii; 

 Mr. Teall, however, considers that the bed cannot be properly 

 correlated with the Atherfield Clay, as it may represent a higher 

 subdivision of the Lower Greensand. In all probability the strata 

 here rest upon the Kimeridge Clay, as they do further south at 

 Lynn. The Lower Greensand contains one or two impersistent 

 beds of clay, worked for brick-making at Heacham, Ingoldsthorpe, 

 and Sandringham warren. At Heacham, Mr. Teall obtained Am- 

 moiiitcs Deshaycsii, Pecten orbicularis, and Trigonia, from ironstone- 

 nodules in the clay. These also contain fine specimens of iron- 

 pyrites. At Ingoldsthorpe the Lower Greensand is said to contain 

 a bed of Fuller's Earth ; here Dr. Fitton obtained some fossils.^ 



The sands form a fine and picturesque escarpment extending from Heacham 

 to Sandringham ; they were termed Sandringham Beds by Mr. F. W. Harmer.'' 

 Where the hard beds of Carstone appear on the fore-shore at Hunstanton, they 

 form a pavement which has been separated into isolated masses by the sea eroding 

 along the lines of joints. 



Tealby Series, etc. — In Lincolnshire the following beds occur 

 beneath the Red Chalk : — 



Carstone. 



Tealby Limestone ) 



Donnington Clay > Tealby Series. 



Spilsby Sandstone 



Mr. A. Strahan has lately pointed out that the Carstone in this 

 area rests on different members of the Tealby series, and presents 



^ Penning and Jukes-Browne, Geol. Cambridge, p. 11 ; see also Penning, 

 G. Mag. 1876, p. 218. - P. Geol. Assoc, viii. 139. 



3 T. G. S. (2), iv. 306, 313 ; see also J. J. H. Teall, The Potton and Wicken 

 Phosphatic Deposits, p. 17 ; Wiltshire, Q. J. xxv. 189; Judd, Q. J. xxiv. 236. 



* "Testimony of the Rocks " in Norfolk, 1877, 



