OF THE UPPER CRETACEOUS TE WEST SUFFOLK AND NORFOLK. 549 



with a basement-layer (9 inches thick) of sandy giauconitic clay 

 containing the " Coprolites." This layer rested directly on brownish 

 sand, the line of junction being undulating, as if indicating erosion. 

 Both here and at the other pits south-west of the church there was 

 only one seam of nodules, and all the nodules on the washed heaps 

 were of the gritty or pebbly phosphate, such as occurs in the zone 

 of Ammonites mamillaris at Folkestone. In the older pits near 

 West Dereham, phosphate-nodules of the darker compact kind 

 usually found in the Gault occurred in the clay overlying the 

 nodule-bed ; but in the present workings only pale grey or buff- 

 coloured phosphates occurred above the basement-bed. 



Near the farm called " Muzzle," about four miles west of "West 

 Dereham, a good section of the lower part of the Gault can be seen 

 in an old pit, where clay has been extensively dug for agricultural 

 and other purposes. The lower part of the face is now hidden by 

 a talus slope, due to weathering, but there yet remains a vertical 

 section of about from 4 to 6 feet. This exposure has been considered 

 by many writers to afford a proof of the existence of the Gault in 

 Norfolk. Messrs. Reid and Sharman, however, as previously men- 

 tioned, refer it to the Chalk-marl. They visited this pit to obtain 

 fossils "unmixed with derivative forms," and they consider the 

 assemblage so obtained to be characteristic of the Chalk-marl rather 

 than of the Gault. 



We have examined the exposure carefully. All the fossils found 

 here were met with in the face of the pit except Ammonites 

 interruptus. Ammonites of this species were obtained by digging 

 a little below the floor of the pit, and appeared common as soft-clay 

 casts ; but some of the interior whorls of at least one specimen 

 were phosphatized. With the Ammonites were associated numbers 

 of Inocerami, which appear to belong to Inoc. concentricus and allied 

 species. The whole assemblage is unquestionably a Gault one. 



The area occupied by the Gault north of West Dereham is much ob- 

 scured by spreads of Boulder-clay, &c, but deep ditches give occasional 

 facilities for following its outcrop. In one of these, to the south of 

 Shouldham, Messrs. Reid and Sharman record a bluish-white marly 

 clay, full of Belemnites minimus and B. attenuatus and Plicatula, 

 which they refer to as Chalk-marl *, From the evidence we have 

 obtained at Muzzle and West Dereham, and also further to the 

 north, at Grimston, we believe this marly clay to be true Gault. 

 Mr. Whitaker informs us that a boring at Narborough House passed 

 through 85 feet of chalk, which was hardest near the base, then 

 through 20 feet of blue clay or marl, reaching the Lower Greensand 

 at 105 feet. 



In the neighbourhood of Grimston we have been able to identify 

 the Gault, and have ascertained its thickness by boring. 



The point chosen for this operation was a pit about half a mile 

 N.N.E. of Eoydon Church, in which occurs a hard, grey, and gritty 

 chalk, with green-coated nodules at its base, described by Mr. 



* Geol. Mag. dec. iii. vol. iii. p. 55. 



