SECTIONAL TRANSACTIONS.— C. 329 



overlying the Halifax Hard Bed or Bullion coal ; while Green in his compre- 

 hensive memoir on the Yorkshire coalfield, records the presence of other marine 

 horizons. 



Dr. Gibson, formerly of the Geological Survey, first directed attention to the relative 

 importance of these bands from an economic point of view ; and the most persistent 

 of these, the Mansfield Marine Band, is now the index horizon sought for in every new 

 sinking. Assiduous coUe'cting from cores enabled Culpin, Dyson and others to extend 

 considerably our knowledge of these bands, while recent discoveries suggest that 

 there are at least ten distinct horizons at which marine fossils occur within the Coal 

 Measures of Yorkshire. Some are now known to be only local in occurrence, while 

 others are not only persistent throughout the coalfield, but are represented in the Coal 

 Measures in areas as far apart as Scotland and South Wales. The outcrop of the 

 Mansfield Marine Band has been traced in the Wakefield and Barnsley district, and 

 its relative position in the succession clearly determined. 



By means of the several marine bands, combined with a study of the non-marine 

 lamellibranoh fauna of the intervening measures, it is now possible to correlate 

 with considerable confidence details of the succession throughout the Yorkshire 

 coalfield. 



Mr. W. S. BiSAT. — The Major Subdivisions of the Carboniferous of 

 Western Europe. 



The Continental terms in use for major subdivisions of the Carboniferous, such as 

 Westphalian and Visean, have long been in use by British geologists, the only name 

 not generally used by us being Namurian. Exposures in the Namur area of equi- 

 valent age to our Lancastrian are apparently not good, but as the adoption of the name 

 Namurian would lead to uniformity with our Continental confreres, I here advocate 

 its use as the name for one of the major divisions. A symmetrical division of the Car- 

 boniferous is then possible, using Continental names for eight major divisions, the 

 secondary divisions being based on the dominant goniatite genera (except at the base 

 and summit) and the tertiary divisions based where possible on goniatite species, or 

 where these fail, on corals or non-marine forms of life. The eight major subdivisions 

 would be Stephanian, Upper and Lower Westphalian, Upper and Lower Namuiian, 

 Upper and Lower Visean, and Tournaisian. The floral break between Upper and 

 Lower Carboniferous forms then comes halfway up the series at the junction of Upper 

 and Lower Namurian, and the ten secondary divisions founded on dominant goniatite 

 genera (represented by the symbols in descending order A, G, R2, Ri, H,E2, Ei,?.,, Pj, B) 

 completely cover the major portion of the Carboniferous, thus : — 



T TI7 i V 1- i A (Anthracoceras) = Mansfieldian 



Lower Westphalian ^ (. joastroceras) = Halifaxian 



f ^2 1 fReticuloceras) = Marsdenian 



Upper Namurian i Ri J = Kinderscoutian 



I H (Homoceras) = Upper Sabdenian 

 — floral break — floral break 



T TVT • I Eo "! ,t;, , ., = Lower Sabdenian 



Lower Namunan | j,^ ^^ (Eumorphoceras) _ Qrassingtonian 



Upper Visean I ^'^ [ (Goniatites s. str.) = Swer Bollandian 



1 B (Beyrichoceras) = Cracoean 



Afternoon. 

 Excursion to Dundry and Keynsham. 



Tuesday, September 9. 



Discussion (Sections C, E, H) on The Relation between Past Pluvial and 

 Glacial Periods. (Prof. H. J. Fleure. Chairman ; Prof. J. W. 

 Gregory, F.R.S., and Dr. K. S. Sandford for Section C ; Miss G. 

 Caton-Thompson, Miss D. A. E. Garrod, Mr. L. S. B. Leakey, 

 Dr. L. WooLLEY, for Section H.) (See p. 371.) 



