658 ME. J. E. lIAPvE A2*rD DE. H. A. KTCHOLSON 



1876. "Llandovery Eocks in the Lake District," by H. Hicks 

 (Geol. Mag. dec. ii. vol. iii. pp. 335 and 429). 



Considers Stookdale Shales of Llandovery age. 



1876. " On the Yertical Eange of the Graptolitic types in Sweden," 

 by Gr. Linnarsson (Geol. Mag. dee. ii. vol. iii. p. 241). 



Correlates Stockdale Shales with Upper Graptolitic Schists of that 

 country. 



1876. " Llandovery Eocks in the Lake District," by C. Lapworth 

 (Geol. Mag. dec. ii. vol. iii. p. 447). 



Assigns Skelgill beds to Lower Llandovery. 



1877. " On the Strata and their Possil contents between the 

 Borrowdale Series of the North of England and the Coniston Plags," 

 by Profs. E. Harkness and H. A. jSTicholson " (Q. J. G. S. xxxiii. 

 p. 461). 



Describe " Graptolitic Mudstones " or " Skelgill Beds," and give 

 lists of Graptolites and of more highly organized fossils from these 

 beds ; correlate them with highest beds of Bala series or with lower 

 portion of Llandovery group. 



Describe " Knock Beds," and incline to regard them as base of 

 (Upper) Silurian. 



1878. "Discovery of Silurian Beds in Teesdale," by Messrs. 

 Gunn and Clough (Q. J. G. S. xxxiv. p. 27). 



Describe beds at Cronkley Pencil Mill resembling Pale Slates. 



1878. " The Moffat Series," by C. Lapworth (Q. J. G. S. xxxiv. 

 p. 240). 



Correlates Skelgill beds with Birkhill Shales, which he refers to 

 Lower Llandovery. 



1878. " On some well-defined Life-zones in the . . . Lake 

 District," by J. E. Marr (Q. J. G. S. xxxiv. p. 871). 



Eefers Skelgill beds to May Hill, and supposes unconformity 

 between them and Ashgill Shales. 



1879. " On the Geological Distribution of the Ehabdophora," by 

 C. Lapworth (Ann. & Mag. Nat. Hist. ser. 5, vol. iii.). 



Assigns a Llandovery May-Hill age to the Skelgill beds ; divides 

 them into a lower (tenuis) and upper (argenteus) zone, and gives 

 lists of fossils from each. 



Besides the above, many papers have appeared which contain in- 

 cidental references to the Stockdale Shales, or which describe fossils 

 contained therein. These will be alluded to in the body of the 

 paper. 



§ III. Desceiption op the Typical Sections op Skelgill Am) 

 Stockdale. 



The most convenient course for us to adopt in describing the suc- 

 cession of the different subdivisions of the Stockdale Shales is to 

 commence with an account of the typical sections of the two stages 

 of the series, and afterwards to supplement this by an account of 

 the resemblances and variations exhibited in the other sections. 



The typical section of the beds of the lower stage is that displayed 



