C— GEOLOGY. 101 



DETAILS CONCERNING VERTICAL SECTIONS. 



The iiiinimum of detail is introduced into the actual section. 

 Unconformities and other breaks = U . . ., a = algal layer, c = coal, 

 ch = chert, d = dolomite, m = Modiola-phase deposits, p = goniatite — 

 lamellibranch or Culm phase, ps = pseudobreccia, x == Zaphrentid or 

 Cyathaxonid phase. 



1. Bristol. — Mainly from Vaughan. Post-Avonian not to scale. 



2. Devonshire. — From table given by Evans, Proc. Geol. Ass., vol. xxxiii. 



(1922), p. 205 (not to scale). 



3. Chepstow Area. — From information supplied by Mr. W. W. Jervis. 



4. Forest of Dean. — From Sibly, Geol. Mag., 1912 and 1918, and from 

 information supplied by him. 



5. North Crop oJ South Wales Coalfield. — From the Geological Survey 

 Reports and information supplied by Mr. T. N. George. 



6. Gower. — Compiled from Dixon, Q.J.G.S., 1911, p. 505. Thickness of 

 the K beds from N.W. Gower, the remainder from E. Gower. In 

 addition to that at the levels indicated, there is some dolomite through- 

 out D, S, C and Z. Mr. Dixon informs me that the shales above D^, 

 classed as P in the Gower j^aper, are probably Lancastrian. 



7. South Pembroke. — From Dixon, Pembroke and Tenby Memoir. Post- 

 Avonian from Tenby area, not South Pembroke. In addition to the 

 levels indicated there is some dolomite at intervals throughout 

 D, S, C and Z. 



8. Anglesey (principal region). — From thicknesses given by Greenly, 

 Anglesey Memoir. 



9. Flint. — From thicknesses given by Wedd, Flint, &c., Memoir, 1924. 



10. North Derbyshire.— The Avonian from Sibly, Q.J.G.S., 1908, the 

 Lancastrian from information supplied by Mr. J. W. Jackson. S.^ 

 also entered on the authority of Sir. Jackson. 



11. Clitheroe District. — Adapted from Parkinson, Q.J.G.S., vol. Ixxxii. 



(1926), with additions from information supplied by him. 



12. Settle. — Adapted from Garwood and Goodyear, Q.J.G.S., vol. Ixxx. 



13. Yorkshire Dales (generalised). — From section drawn by Mr. R. G. S. 

 Hudson. 



14. West Cumberland (Whitehaven). — Mainly from Edmonds, Geol. Mag., 



1922. The upper beds chiefly from information supplied by Mr. 

 Dixon. 



15. East Cumberland (Alston). — Drawn up by Dr. Stanley Smith from 



Westgarth Forster's section. 



16. South Northumberland. — Drawn up by Dr. Stanley Smith from the 

 Northumberland Memoirs of the Geological Survey. 



17. North Northumberland. — Drawn up by Dr. Stanley Smith from the 

 Northumberland Memoirs of the Geological Survey. 



Note. — In sections 1, 3, 4, 6 and 7, the K beds succeed upper O.R.S. conformably; in 

 section 5 an unconformable junction is indicated between K beds and lower 

 O.R.S. 



