Mr. Rose's Sketch of the Geology of West No) folk. 175 



of shale two or three inches in thickness, and he traced it for 

 thirty yards or more. A specimen of the shale in my posses- 

 sion burns readily, crepitating like cannel coal : between its 

 laminae impressions of an Ammonite and a small Tellina? 

 are seen. This clay has also been opened at Gaywood near 

 Lynn, in sinking a well fifty feet in depth : the first eighteen 

 feet were sand, succeeded by fourteen inches of blue clay ; 

 then followed a laminated clay containing Septaria, which con- 

 tinued to the depth sunk : no organic remains were preserved. 

 The characteristic shell of this stratum is the Ostrea deltoidea; 

 I am not certain that it was met with in Norfolk by Mr. 

 William Smith. I possess two specimens, but they were found 

 in clay (diluvium) to the east of the outcrop of the greensand, 

 and were therefore transported specimens. The following 

 fossils are from the diluvial clay covering the Kimmeridge at 

 Stow Bardolph : alveolus of a Belemnite; Pecten cinctus of 

 Min. Conch., tab. 371 ; cast of a Trigonia in pyrites ; cast of 

 an Astarte? in pyrites; paddle-bone of a Plesiosaurus ; tooth 

 of a Ruminant; wood impregnated with brilliant yellow py- 

 rites ; bituminous shale very pyritous ; Septaria, and blocks of 

 a breccia composed of black pebbles and pyrites in a calca- 

 reous matrix : similar breccia and Septaria may be seen in 

 situ in the Kimmeridge clay at Ely in Cambridgeshire. 



Inferior Greensand. — This formation consists of alternating 

 beds of ferruginous sand, sandstone, and white sand. It is on 

 Smith's map denominated " Sand beneath the golt brick- 

 earth, in the lower part of which the Portland rock is occa- 

 sionally found." It is provincially called Carstone, and pre- 

 sents little of interest to the naturalist, being a mere mechani- 

 cal deposit, and, as far as it has at present been explored, af- 

 fording no animal remains. 



It occupies the high ground between the Kimmeridge clay 

 and the chalk range, extends from Hunstanton on the north 

 to Hilgay on the south, and in some parts of its course rises 

 into hills vying in altitude with those of the lower chalk ; 

 their western declivities are abrupt. Its course is faithfully 

 represented by Smith on his map ; but I am at a loss to un- 

 derstand where he " occasionally found" the Portland rock. 

 When he wrote, the divisions of the greensand formation had 

 not been ascertained as at the present time ; at that period 

 this member was confounded with the Hastings sand, which 

 reposes upon the rocks of the upper division of the oolites: it 

 is therefore probable he meant that when the series of strata 

 is complete, the Portland rock lies beneath the sand, and not 

 that it really occurs in Norfolk. 



This formation is an aggregate of siliceous particles of va- 



