SECTIONAL TRANSACTIONS.— C. 



327 



Maredsons by Father Gregoire, from the C2-S1 Beds ; another one also has been 

 collected by the late Dupont, from the Dl level ; and then we reach, with the 

 numerous Goniatites from Vise, the well-defined zone of Ooniatites s. str. of Bisat and 

 the restricted Glyphioceras Stnfe of Hermann Schmidt, which correspond to D2-3. 



The following table gives a resumed scheme of the succession of Goniatites in 

 Dinantian : — 



Dr. A. E. Trueman. — The Classification of the Upper Carboniferous. 



Any scheme of classification of the Upper Carboniferous rocks must have regard 

 to the marine and non-marine faunas and to the flora. The work of Mr. W. S. Bisat 

 has gone far towards providing a basis for classifying the lower part of the Upper 

 Carboniferous, where marine faunas are dominant, but marine bands with goniatites 

 are so infrequent in the upper portion of the Upper Carboniferous that they afford 

 little more than a check on conclusions arrived at from studies of other fossils. 



In Britain the divisions of the Upper Carboniferous put forward by the late 

 R. Kidston have for many years been widely employed. While the two uppermost 

 divisions (Radstockian and Staflordian) are well marked off from the lower ones, 

 there is no justification for retaining the classification into Lanarkian and Westphalian 

 (or Yorkian) proposed by Kidston. The Lanarkian as used in Scotland included 

 nearly all the pre-Staffordian measures, and is approximately equivalent to the 

 greater part of the so-called Westphalian (Yorkian) of England. Recent work bj' 

 Aliss E. Dix suggests that more precise correlation b}' means of fossil plants may be 

 possible when more collecting has been done at known horizons. The results 

 obtained at present accord with those based on the fauna, whereas it had previously 

 been supposed that a correlation based on floral evidence was not in agreement with 

 that determined by certain faunas. Similar results have been obtained on the 

 Continent by Bertrand, Jongmans, Renier and others. 



The non-marine shells have been used to divide the Coal Measures into zones, 

 most of which have now been recognised by various workers in almost every important 

 coalfield in Britain, the same general sequence being present in Scotland and in the 

 north of England as in South Wales. Certain types have a longer range in some 

 areas, whUe others are more abundant in some coalfields than in others. Recent 

 work indicates the possibility of subdividing certain of the zones already defined. 

 It is suggested that the zones afford at least an approximate correlation. The 

 changes between successive zones are due mainly to the disappearance of certain 

 groups and the incoming of others, which may partly result from the peculiar con- 

 ditions under which the Coal Measures were deposited, the formation of coal seams 

 leading to the repeated withdrawal of animal life and to the subsequent entry of a 

 new population. In this connection it is significant that some of the greatest faunal 



