544 MESSES. JUXES-BROWNE AND W. HILL ON THE LOWER PARI 



39. On the Lower Part of the Upper Cretaceous Series in West 

 Suffolk and Norfolk. By A. J. Jukes-Browne, Esq., B.A., 

 F.G.S., and W. Hill, Esq., F.G.S. (Read June 8, 1887.) 



Introduction. 



The zonal subdivisions of the Cambridgeshire Chalk were first 

 described in 1880 *, and more fully in the Memoirs of the Geological 

 Survey, in 1881 f, the outcrops of the Totternhoe Stone and the 

 Melbourn Rock having then been traced as far as Burwell and 

 Newmarket respectively ; but the survey of the Suffolk Chalk having 

 been previously completed, the lines Were not continued on the 

 Survey map. 



The section exposed in the cliffs near Hunstanton has often been 

 described, but the beds there seen are very different from those 

 which occupy a similar stratigraphical position near Newmarket ; it 

 was evident, therefore, that between these two places the beds 

 forming the lower part of the Chalk underwent a considerable 

 amount of lateral change, and that, until more was known of the 

 manner in which one facies of the Lower Chalk passed into the 

 other, no correlation of the Norfolk and Cambridge sections could be 

 more than suggestive. 



Moreover, in the absence of this information, one of us has found 

 much difficulty in correlating the subdivisions of the Lincolnshire 

 Chalk with that of the Midland counties, and he felt that when 

 once the constitution of the Norfolk Chalk was properly understood, 

 that of Lincolnshire, which bears great resemblance to it, would no 

 longer offer any difficulty. 



It being clear, therefore, that important issues depended upon an 

 investigation of the changes that take place in the Cretaceous rocks 

 as they pass from Suffolk into Norfolk, it was with the object of 

 exploring this terra incognita that we started from Newmarket 

 in June 1886, and worked rapidly northward as far as Shouldham 

 and Marham in Norfolk. By this traverse we succeeded in obtain- 

 ing some important information, which was communicated to the 

 Director of the Geological Survey, the result being that Mr. 

 Whitaker was sent into the district, and one of us accompanied him 

 in continuing the work through Norfolk to Hunstanton. During 

 this traverse the lines for the Melbourn Rock and Totternhoe Stone 

 were drawn, and that for the Melbourn rock will be engraved on 

 sheets 65 and 69 of the Geological Survey map. A third visit was 

 made in September, and two others in the spring of this year, for 

 the purpose of gaining further information on certain points, and 

 superintending the execution of three borings which were made for 

 the purpose of testing the accuracy of our conclusions at localities 

 where little natural evidence was obtainable. 



* G-eol. Mag. dec. ii. vol. vii. p. 248. 



t 4 Geology of the Neighbourhood of Cambridge,' by W. H. Penning and A. 

 J. Jukes-Browne, pp. 20 et seq. 



