England and the " Red CItalk " of the Eastern Counties. 197 



Along the northern border of the Wolds the formation is seen 

 to change, and at Speeton there is a thin basal series of variegated 

 marls only some 3 ft. 6 in. in thickness, overlain by about 

 30 feet of red and mottled nodular marly Chalk. These red strata 

 were for long considered to be an expansion of the Hunstanton 

 Red Rock. Jukes-Browuc, who formerly adhered to this view, 

 afterwards placed 28 feet of these beds in the Lower Chalk {oarians- 

 zone). On the occasion of our visit to this locality we were 

 fortunate in seeing an exposure of the marls below this red 

 Lower Chalk. We were able to confirm in the main the 

 details given by Mr. Lamplugh in 1889.^ We saw the glauconitic 

 seam with eroded nodules resting directly on the black Aptian 

 clay. Within the lowest foot we noticed the presence of 

 Inoceramus sulcaUis Park, and a few other lamellibranchs, 

 all poorly preserved. The streak of dull reddish clay above 

 this was readily recognized. In the uppermost 2 feet of marly 

 shale were found numerous specimens of Inoceramus avglicv.s Woods 

 and impressions of hoplitid ammonites. These marls belong to the 

 Upper Gault, a fact proving that there is a non-sequence between 

 them and the Aptian clays below, representing a considerable gap 

 in time. 



This is contrary to the view put forward by Mr. Lamplugh, who 

 considered that the Speeton Clays most probably form an unbroken 

 series from the Kimmeridge Clay up to the Chalk. ^ The base of 

 the Spilsby Sandstone lies discordantly upon the Kimmeridge Clay 

 in Lincolnshire, where the whole of the Portland Beds are absent.* 

 A continuation of the same unconformity, between the Upper 

 Kimmeridge Clay and the base of the Lower Cretaceous clays, is 

 evidently marked by Bed E at Speeton, where the Portland zones are 

 likewise unrepresented. The Lower Cretaceous clays of Speeton 

 are thus limited below and above by non-sequences of some 

 magnitude. It must be recognized that the transgressive Upper 

 Gault, represented to the west of the Wolds and in Lincolnshire 

 in the form of Red Rock, has here assumed a different aspect. In 

 this connexion it may be remembered that at Holkham Hall, about 

 12 miles eastward from Hunstanton, a comparable change has been 

 recorded. A well-section showed the presence of clay, described 

 as Gault, beneath a "Red Marl ".* 



The thin bed of smooth, red marly Chalk overlying the Upper Gault 

 marls at Speeton, and forming a passage to the Lower Chalk, seems 



^ G. W. Lamplugh, " On the Sub-divisions of the Speeton Clay" : Quart. 

 Journ. Geol. Soc, vol. xiv, 1889, p. 603, fig. 8. 



2 Loc. cit. Also " On the Speeton Series in Yorkshire and Lincolnshire ' : 

 Quart. Journ. Gcol. Soc, vol. lii, 1896, p. 197. 



3 W. A. E. Ussher, A. J. Jukes-Brf)wne, and A. Strahan, " The Geology 

 of the Country around Lincoln " : Mem. Geol. SartK, 1888, p. 82. J. Pringle, 

 " Palaeontological Notes on the Donington Borehole of 1917." " Summary of 

 Progress for 1918": 3Iem. Geol. Surv., 1919, p. 51. 



* W. Whitaker, "The Well-Section at Holkham Hall, Norfolk": Proc, 

 Norwich Geol. Soc, pt. i, Session 1877-8, p. 16, Norwich, 1878. 



