Vol. 67.] THE PERMIAN AND TElAS OF NOTTINGHAMSHIRE. 



2. The Relationship of the Permian to the Trias in Nottingham- 

 shire. 1 By Robert Lionel Sherlock, B.Sc, A.R.C.Sc, F.G.S. 

 (Communicated by permission of the Director of the Geological 

 Survey. Read December 21st, 1910.) 



[Plate V — Geological Map.] 



Contents. 



Page 



I. Introduction 75 



II. Stratigraphy 79 



III. Palaeontology of the Upper Magnesian Limestone 105 



IV. Conclusions 110 



V. Summary 114 



VI. Bibliography 114 



I. Introduction. 



The Permian System is generally considered 2 to be represented in 

 England by two distinct divisions, corresponding to the Zechstein and 

 the Rothliegende of Germany. The English Rothliegende is further 

 regarded as of two types : that of the Midland Counties, or Salopian 

 type, and that of Collyhurst (Lancashire). The Zechstein is 

 supposed to be represented by the Magnesian Limestone Series of 

 the North-Eastern counties, together with some scanty deposits 

 near Manchester above the Collyhurst Sandstone, and in Cum- 

 berland. The red beds of Devon, which are of doubtful age, need 

 not be considered here. 



In recent years the Permian age of many of the deposits of 

 Salopian type has been called in question, and it has been shown 3 

 that, in many cases, they are united to the Carboniferous System 

 below and are unconformable to the Trias above. 



In the case of the English Zechstein the beds are magnesian 

 limestones, marls, and sands, and the limestones contain fossils which 

 have been recognized as Permian. This division is chiefly repre- 

 sented by the long belt of strata which stretches continuously 

 from the Northumberland and Durham coast, through Yorkshire, 

 as far south as Nottingham. The Permian in this region differs 

 from the English Rothliegende, not only in lithological character, 

 but in its relationship to the beds below ; for it has been known for 

 a long time that it is markedly unconformable to the Carboniferous 

 upon which it rests. 



The nature of the upper boundary of the Permian is, however, 



1 Thesis approved for the Degree of Doctor of Science in the University of 

 London. 



2 See E. Hull, 1869. [For full details of references, see the Bibliography, 

 §VI,p. 114.] 



3 T. C. Cantrill, 1895; and W. Gibson, 1901. 



