58 MM. Reid 8f S/mrman — On the so-called " Gault" in Norfolk. 



To obtain the fossils of the Marl unmixed with derivative forms, 

 an old pit at Muzzle, about a mile W.N.W. of West Dereham, was 

 searched. This locality has been mentioned by several writers as 

 showing a typical exposure of Gault, and it is interesting to find 

 that not a single characteristic Gault form occurred, but that there 

 were several species which have not been recorded from below the 

 Lower Chalk. 



The section, which is very good, though the pit is now seldom 

 worked, shows a nearly vertical face of obscurely bedded blue marl 

 with small black phosphatic concretions. Belemnites are scattered 

 promiscuously throughout. Several years ago a trial was made in 

 this pit for the ' Coprolite Bed,' and it was reached three feet below 

 the floor; but only a few nodules were found, and the bed was too 

 thin to work. This section, therefore, is an upward continuation of the 

 one at the new Coprolite Works, but the lower three feet of Marl being 

 unworked, there is no complication from derived fossils. The 

 following species were obtained, but no doubt longer search would 

 soon add to the number : — 



Penlacrinus, 2 sp. 

 Pseudodiadema, sp. 



Serpula, sp. 



Kingena lima, Defr. 

 Terebratulina gracilis, Schlot. 

 sp. 



Plicatula, sp. 

 Inoceramus, sp. 



Ammonites (fragment). 

 Belmnites attenuatus, Sow. 



minimus? List. 



ultimus, D'Orb. 



Fish vertebra. 



Ostrea vesiculates, Lam. 



All of these occur in the Chalk or Chalk Marl, and the same three 

 Belemnites are found in the Bed Chalk of Hunstanton, which has 

 lately been shown probably to belong to the Lower Chalk. 1 Thus it 

 seems that the so-called Gault of West Dereham all really belongs to 

 the Chalk Marl, and in this part of Norfolk the Gault is only 

 represented by its derivative fossils in the basement bed of the 

 Chalk. This greatly simplifies the geology, as, instead of two 

 unconformities close together, there is only one, the Chalk Marl 

 having cut through the Gault, and having cut also a considerable 

 depth into the underlying Neocomian. 



There is a long dip-slope near West Dereham, which keeps the 

 Coprolite Bed conveniently near the surface over more than a 

 square mile. But the uncertainty of the dip renders it very difficult 

 to estimate the thickness of the Chalk Marl, which may be only 

 20 feet or over 50 feet. Unfortunately, the bed can only be traced 

 for a short distance. East of the Fenland it first rises above the 

 marsh-level at Wretton, and extends about three miles to the 

 north-west, to Crimplesham, with an outlier capping the hill 

 at Muzzle. 



At Crimplesham it is lost beneath the Boulder-clay for about 

 three miles, but reappears south of Shouldham as a bluish marly 

 Clay full of Belemnites attenuatus, B. minimus? and Plicatula. In 



1 See "Whitaker, Presidential Address to the Norwich Geol. Soc. 1882, Proc. Nor. 

 Geol. Soc. vol. i. pp. 207-236. 



