192 ME. G. W. LAMPLUGH ON THE SPEETON SEKIES [May 1 896, 



conclusions being drawn respecting the correlation of these Lincoln- 

 shire deposits with the Speeton Series of the Yorkshire coast, 

 thereby clearing away certain prevalent misconceptions and pro- 

 viding a safer basis for future discussion of their age and origin. 



These beds seem to be unrepresented at the northern extremity 

 of the Lincolnshire Cretaceous escarpment, the pebbly base of the 

 Eed Chalk in the vicinity of the Humber resting, so far as is known, 

 directly on the Kimeridge Clay. 1 About 6 miles south of that 

 estuary, however, thin sands and clays intervene for a short space 

 between the Kimeridge Clay and the Chalk, but are not well 

 exposed, and are soon again altogether lost beneath the over- 

 lapping Chalk. They reappear in stronger force after a further 

 interval of about 5 miles; and thenceforward, from the neigh- 

 bourhood of Caistor, are continued southward, gaining steadily in 

 importance, up to the southern termination of the Chalk escarpment, 

 8 miles north of the Wash, where the drift and alluvium of the 

 low ground enshroud them. 



Where best developed the diverse lithological characters of this 

 series have afforded a ready and simple method of subdivision which 

 has been adopted by all its investigators. These divisions are 

 shown in the Table printed on p. 194, in which the results of previous 

 workers are stated and compared. 



In addition to the papers mentioned in the Table, Mr. H. Keeping 

 gave in 1882 a short but valuable account of the series, 2 and 

 especially of the sections on the Louth and Lincoln railway, 

 now in great part obscured, from which he had in 1872 secured a 

 large collection of fossils. His classification is essentially that of 

 Prof. Judd and the earlier observers ; but he seems to have 

 been the first to call attention to the band of phosphatic nodules at 

 the base of the Spilsby Sandstone, and his fossil lists are in many 

 respects in advance of those of his predecessors, though herein, as 

 in all the other palaeontological lists of the area yet published, 

 the confusion of Belemnites brunsvicensis with B. lateralis* and the 

 vagueness of the specific names employed for the ammonites, seriously 

 impair their value as aids to the correlation of the deposits. 



The detailed comparisons of the Speeton section with the Lincoln- 

 shire deposits previously put forward are shown in the Table facing 

 this page. 4 



1 A. Strahan, ' On the Lincolnshire Carstone,' Quart. Journ. Geol. Soc. vol. 

 xlii. (1886) p. 489. 



2 H. Keeping, ' On some Sections of Lincolnshire Neocomian,' Quart. 

 Journ. Geol. Soc. vol. xxxviii. (1882) p. 239. 



3 The same error pervades nearly all the fossil-lists given by Prof. Judd and 

 the Survey, and also affects the Continental lists in Judd's paper in Quart. 

 Journ. Geol. Soc. vol. xxvL (1870) p. 326. 



4 The correlation given in the late Mr. W. Keeping's ' Fossils, etc., of Upware 

 and Brickhill ' (Cambridge, 1883), p. xi, is omitted, being practically a repro- 

 duction of that of Prof. Judd. There is also a brief correlation by Mr. A. J. 

 Jukes-Browne in his paper ' On the Application of the term Neocomian ' 

 (Geol. Mag. 1886, p. 311), based upon Prof. Judd's account of the Speeton 

 sections. 



