2 Bolton, Palceontology of the Manx Slates. 



Probably the paper by Profs. Harkness and Nicholson* 

 contributed most to the recognition of the Manx series as 

 equivalents of the Skiddaw slates. By these writers a 

 general resemblance of rock structure was traced between 

 the two series, and also the occurrence in both of Palcso- 

 chorda major was noted. One point upon which Profs. 

 Harkness and Nicholson laid considerable stress was the 

 apparent similarity of dip and strike in the two regions. 



Mr. Lamplugh's late researchesf would seem to show, 

 however, that this dip and strike is but a dominant 

 structure due to complex folding and cleavage, and that 

 the true dip and strike still remains to be determined. 



Mr. G. W. Lamplugh writes me — "This argument 

 requires modification if, as is probable, the Lake district 

 dips are also more or less mere ' dominant structures.' 

 The fact of this structure coinciding in the two areas is of 

 some importance in the correlation." 



The ashes and porphyries of most writers have not 

 been recognised by Mr. Lamplugh, nor has he found 

 evidence of contemporaneous volcanic activity [, except in 

 one very limited and obscure exposure, near Dalby, on 

 the western side of the island {vid. Annual Report of 

 the Geological Survey for 1897, p. 70). — G. W. L.]. 



The Rev J. Clifton Ward, who visited the island in 

 1879^ to determine the relationship between the two 

 series, was no more successful than his predecessors. He 

 was not able to recognise any volcanic series, nor could 

 he find that the slates showed any of those divisions 

 which he recognised in the Lake district. He still 

 regarded them as Skiddaw slates, but looked for a right 



* "The Lower Silurian Rocks of the Isle of Man." Quart. Journ, 

 Geol. Soc, Vol. xxii., 1866. 



t "The Crush Conglomerates of the Isle of Man." Quart. Journ. 

 Geol. Soc, Vol. li., 1895, p. 565. 



J Notes on the Geology of the Isle of Man. Geol. 



