MR. E. WILSON^ ON THE DURHAM SALT-DISTRICT. 



767 



referring to the Middlesborough boring, says, " The limestones, thick 

 salt-beds, and gypsum in that boring, are jprohahly referable to the 

 Permian ; the intervening beds of red sandstone, 673 feet, are 

 probably referable to the Waterstones and Lower Mottled Bunter, 

 the Upper Mottled and Pebble-beds having thinned out." 13ut in 

 the Eleventh Report * of the same Committee we find that this author 

 modifies his opinion as to the strata met with in the Middlesborough 

 and Saltholme borings to the extent that he considered it " more 

 probable that the pebbly character of the middle portion of the Bunter 

 has died away northwards, and that the Middlesborough section 

 represents Waterstones, pebbleless Middle Bunter and Lower Bunter." 



In a paper read before the Geological Section of tue British Asso- 

 ciation in 1886, on " The Stratigraphical Position of the Salt 

 Measures of South Durham " f, Professor G. A. Lebour, M.A., F.G.S., 

 gives reasons for suggesting " that much of the Salt-measures of the 

 South Durham district is probably the representative of the Upper or 

 Rauchwacke Permian of Germany." 



The following table shows the classification Professor Lebour 

 tentatively suggests for the strata met with in the Durham district, 

 with an alternative arrangement of the strata which I would myself 

 advocate. 



Classification of the Permian and Triassic Rocks of the 

 Durham district, according to 



Lebour 

 Avicula-contorta beds (proved in 

 Eston shaft and boring) Rhsetic. 



7. Red and green marls with gypsum 

 (known only South of Tees) 



6. Red sandstone 



Unconformity (?). 

 5. Red sandstones and marls 



Unconformity (?), 



4. Eed marly sandstones, marls with"] 

 lenticular beds of anhydrite, gyp- I 

 sum, and salt, and foetid limestone [ 

 in variable bands towards the base. J 



3. Main Magnesian Limestone , 



2. Marl-slate, with fish-bed 



1. Yellow sands , 



Unconformity. 

 Carboniferous rocks 



Upper 

 Trias. 



(? Lower) Trias. 



Upper 



Permian 



(Rauchwacke) 



Middle 

 Permian. 



Lower Permian, 



The Author. 

 Rhaetic. 



Upper 



Trias, 



\ viz. 



Upper 



Keuper. 



Unconformity. 



Permian 

 (Upper J). 



Unconformity. 

 Carboniferous. 



* Eep. Brit. Assoc. 188n, p. 384. 

 t Eep. Brit. Assoc. 1886, Trans, of Sections, p. 673. 



\ That is to say, Upper or Zechstein &c. division, as contrasted broadly with 

 the Lower or Rothliegende group. 



3e2 



