174- Mr. Rose's Sketch of the Geology of West Norfolk. 



5. Peat, with alder and hazel bushes 2 to 3 ft. 



6. Blue clay, with marine silt, containing ^ 



testaceous exuviae. }► about 30 



7. Blue clay, inclosing nodules of chalk J 



8. Oxford clay, with Septaria, &c 630 



A small portion of the upper part of stratum 7. at Denver, 



and 8. at Lynn, may possibly be the Kimmeridge clay, but 

 we found no fossils to determine that point. The bed of 

 clay (No. 7.) at Denver was very stiff and tenacious, and 

 parted into thick laminae upon drying: throughout the few 

 feet that were exposed, I could discern neither shale nor Sep- 

 taria. 



Specimens of the organic remains taken from the lower 

 beds of the clay in Mr. Allen's well were liberally presented 

 to me by that gentleman ; the following is a list of them : 

 Name. Reference. 



Ammonites decipiens Min. Conch., tab. 294?. 



excavatus ■ tab. 105. 



very small, species undetermined. 



Belemnites abbreviatus Min. Conch., tab. 590, fig. 9. 



Gryphaea bullata tab. 368. 



Serpula tricarinata, attached 1 . , i^l n n 



totheGiyphea j tab. 608, fig. 3. 



Mya depressa — — tab. 418. 



Venus ? a fine cast in iron pyrites, with the impression of a 



Pecten upon it. 



Muricated spine of an Echinus. 



Kimmeridge Clay. — This bed forms a narrow belt to the 

 escarpment of the superincumbent inferior greensand, and is 

 the intermediate stratum to that, and the Oxford clay beneath, 

 which rises to the west of it, but is hidden by the alluvial 

 strata of Marshland and the fens. Smith has laid down its 

 situation and course upon his map correctly, but has erred in 

 stating that it is " the deepest stratum in the county." 



We have had no opportunity of ascertaining the thickness 

 of this bed, for there is no natural section of it in the county ; 

 indeed, if there were, it would probably prove a difficult task 

 (the coral rag beds not intervening) to determine where the 

 Kimmeridge terminated and the Oxford clay commenced. 

 Its surface has been exposed at Southery* to a considerable 

 extent, but not pierced sufficiently to aid us in our inquiry re- 

 specting its thickness. Last summer I visited a brick-yard in 

 that parish, and was informed by the brickmaker, that upon 

 the removal of thirteen feet of brick-earth, he exposed N a floor 



* In Mr. Woodward's map this locality is erroneously coloured, the 

 inferior greensand being represented. 



