Rev. A. Irving — On the Permian and Trias. 221 



The intrusion of crystalline igneous rocks among the lower 

 members of the Permian series is repeated in many parts of 

 Germany as well as in England ; in the latter country it is found to 

 be the case in the Vale of Eden and in the S. Staffordshire country. 

 So great and widespread were the disturbances at this epoch that it 

 becomes exceedingly difficult to recognize any general limit for the 

 downward extension of the Permian or Dyas, and impossible to draw 

 anything like a horizontal line which shall be equally true for the 

 different portions of the European area. Among geologists a con- 

 viction has been gaining ground of late years that an error has been 

 committed in drawing the base line too low in the geological series. 

 A few references will suffice to show this. 



1. Mr. W. T. Aveline, F.G.S., in a letter to the Editor of this 

 Magazine for 1877, p. 156, says : " The links that bound the Per- 

 mian to the Carboniferous are now nearly all broken. The Lower 

 Eed Sandstone of Sedgwick, or Rothliegende of Murchison, lying 

 below the Magnesian Limestone, with its coal-plants and even coal- 

 beds, is now proved to be either Coal-measui'es or Millstone Grit, 

 and the Permians of Staffordshire and Warwickshire are now said to 

 be Upper Coal-measures, of a red colour." (In this generalization the 

 writer would seem to overlook the great brecciated deposits of the 

 Mid- West of England, which bear so striking an analogy to those 

 of Thiiriugen and the Harz). 



2. The same gentleman has recently re-surveyed the southern 

 part of the Notts and Derbyshire Coal-field. The red sandstones 

 and shales which lie conformably upon the Coal-measures, and were 

 formerly included under the name of '•' Lower Ked Sandstone " with 

 the Permian series, have been definitely given up by him to the 

 Coal-measure formation.^ He gives good reasons for adopting the 

 following tabulation of the Permian strata of this district : — 



4. Red Marls and Sandstone. 

 3. Magnesian Limestone. 

 2. Shales (Marl Slate). 

 1. Breccia. 



On this one remark is required hj way of explanation. The Eed 

 Marls and Sandstone (4) are not the same as those mentioned in 

 the previous part of this paper as having been grouped with the 

 Lower Bunter. Those now referred to are subordinated to the 

 Magnesian Limestone series ; they underlie the other and more 

 massive series in S. Notts unconformably ; and they pass, when 

 traced northwards, undei- the upper members of the Magnesian 

 Limestone series. Eor a fuller description of the interesting sections 

 in which the above sequence of deposits is exhibited the reader 

 must be referred to the memoir itself, also to papers descriptive of 

 them by Mr. E. Wilson, F.G.S.' The breccia (1) in the above table 

 is well described by Mr. Wilson in the papers referred to, but is of 

 a very different character from, and must not be confounded with, 



1 Vide Geologij of the Country aroimd Nottingham, 2nd edition, 1880. 



2 Vide Quart. Joui-n. Geol. Soc. for November, 1876, The Permians of the N.E. 

 of England ; also paper by the same author on the South Scarle Section. 



