AND LEICESTERSHIRE AND THEIR RELATIONS TO GEOLOGICAL STRUCTURE. 123 
correspondence between the structures in the Mesozoic rocks and those in the 
Palaeozoic rocks. The structures in the Mesozoic rocks are, as it were, a pale 
reflection of the more deeply situated structures. Since now the local south-eastern 
strike of the Mesozoic rocks has been shown to indicate the presence of an 
anticline with an approximately east—west axis, it is possible and even probable that 
this anticline, formed by post-Triassic movements, may be situated on the line of 
a stronger anticline initiated in the underlying Palmozoic rocks by pre-Permian 
movements. 
In favour of the existence of such an old-established east—-west anticlinal axis, there 
is other and independent evidence. In this connexion the isolated position of the 
pre-Cambrian rocks of Charnwood Forest has a considerable significance. Charnwood 
Forest is on the western continuation of the postulated east—west anticline and just 
where the anticline crosses the line of a more powerful north-west to south-east 
(Charnian) system of folding. Where the two lines of uplift cross there is the 
greatest elevation of the strata and the oldest rocks appear. Moreover, the 
southern part of the Charnwood anticline pitches to the south-east in the manner 
that would be expected if there were a cross-fold.* The later uplift, which resulted 
in the local denudation of the Triassic cover, may have been due in part to the newer 
folding which raised the Rhmtic Beds 200 feet at Melton Mowbray (p. 122). 
As regards the eastern continuation of the postulated anticline, it has been shown 
that the axis of the post-Cretaceous folding curves round eventually to the north¬ 
east, and passes through The Wash. It is probable that the axis of the older fold 
follows the same curving course, and it is suggestive that Rucker and ThorpeI 
obtained evidence for the existence of a magnetic ridge line running north-east 
through The Wash, that is, along the line of such a hidden anticline. 
The association of magnetic ridge-lines with axes of uplift among the older rocks is 
well established in other cases, as for example, the Pennine uplift mentioned above 
(p. 119). Conversely in one case the presence of a magnetic “ridge-line” has been 
used by Prof. Kendall | as lending support in favour of the existence of a buried 
anticline beneath the Mesozoic rocks of Lincolnshire. 
In this connexion, however, it is important to bear in mind that “ ridge-lines ” are 
sometimes, perhaps often, the resultants of two or more independent sets of magnetic 
disturbances. In such case the resulting “ ridge-line ” need not conform to an}^ 
definite geological line. The “ ridge-line ” previously mentioned (p. 119) as crossing 
the coalfield obliquely north of Nottingham is an example. Therefore, in the absence 
of geological evidence, one is not justified in correlating magnetic “ ridge-lines ” with 
* W. W. Watts, ‘ Geol. Mag.,’ Dec., IV., vol. HI. (1896), p. 485. 
t ‘Phil. Trans.,’ Ser. A, vol. 188 (1896), plate 14. 
1 “ Sub-report on the Concealed Portion of the Coalfields of Yorkshire, Derbyshire, and Nottingham¬ 
shire,” ‘ Appendix HI. to the Geol. Committee’s Report in Part IX. of the Report of the Royal Com¬ 
mission on Coal Supplies,’ 1905, pp. 20, 31, and 33. 
R 2 
