66 SECTIONAL ADDRESSES. 



I have decided to restrict my subject to England and Wales. 



Note. — I wish to convey my sincere thanks to the following for help and 

 information : Mr. W. S. Bisat, Mr. R. G. Carruthers, Dr. R. Crookall, 

 Prof. E. J. Garwood, JMr. T. Neville George, Dr. E. Greenly, Mr. 

 J. W. Jackson, Mr. W. W. Jervis, Mr. Cosmo Johns, Dr. D. Parkinson, 

 Mr. H. C. Sargent, Dr. T. Franklin Sibly, and Dr. A. E. Trueman. 



It has long proved convenient to divide England and Wales into 

 provinces, each characterised by its own special features of deposition 

 diuring Lower Carboniferous times. The following provinces have been 

 generally recognised :^ 



1. Devonshire, including parts of North Cornwall. 



2. Soidh-ivestern Province, including the Bristol district, the Forest of 

 Dean, South Wales, and the Clee Hills. 



3. Midland Province, including Anglesey and North Wales, the Wrekin, 

 and the midland area of Derbyshire, Staffordshire and Leicestershire. 



4. Yorkshire Province, including the Craven and Dale country and 

 the Clitheroe and Colne region of Lancashire. 



5. North-western Province, including parts of North-west Yorkshire, 

 Westmorland, North Lancashire and Cumberland. 



6. Northern Province, including Durham and Northumberland. 



Subdivisions o£ the Avonian Rocks in the South-western Province. 



Vaughan's subdivisions have been adopted by . all workers on the 

 Carboniferous Limestone in the central and south of England and by all 

 recent workers in Wales and Ireland. 



Certain modifications of his original classification have been introduced 

 from time to time and will be alluded to in stratigraphical order. 



1. In his original ' Bristol ' paper (1905) he called the lowest Carbon- 

 iferous rocks transitional from the Old Red Sandstone Modiola zone (M), 

 pointing out, however, in a footnote that the Modiola zone had better be 

 regarded as a shallow-water phase of the Cleistopora zone (K). Soon he 

 definitely adopted this arrangement, so that the Modiola zone became Km. 

 Later on^ Vaughan dropped the term Km, including these deposits in Kj. 

 The term Km is, however, used in the table of classification appended to 

 the Belgian^ paper, and is \ised in a phasal sense in the Tenby memoir. 



2. Although, as Vaughan explains, the fact that Caninia has two 

 maxima, one in the Tournaisian and one in the Visean, is a reason why he 

 did not adopt it as an index fossil, he still makes use of the term Caninia 

 zone. In his original paper he uses it as including the Syringothyris 

 zone (C), which he did not then subdivide, and the lower part of the 

 Seminnla zone (SJ. In the Winnipeg report the expression ' Syringothyris 

 and Caninia zone C ' is used. In the Gower paper (1911) the term 

 ' Syringothyris zone ' is still used, but in the Burrington paper (1911' it is 

 dropped in Vaughan's portion of the paper, the Caninia zone (Middle 

 Avonian) being taken to include y and C^ Dixey and Sibly ^ also drop 

 the term Syringothyris zone. 



1 Q.J.O.S., vol. Ixvii. (1911), p. 363. 

 a /6ti., vol. Ixxi. (1915). 

 "Ibid., vol. Ixxiii. (1918). 



