H. R. Howell — Red Rocks in 8.E. Durham. 9 



Unconformity ? ? 

 4. Red Marly Sandstones, Marls, with lenticular beds of J Upper 

 Anhydrite, Gypsum, and Salt, and foetid limestone in j Permian 



variable bands towards the base ) (Rauchwacke). 



3. Thick Magnesian Limestone ) Middle 



2. Marl Slate J Permian. 



1. Yellow Sands Lower Permian. 



Unconformity. 



And further on, at p. 81, Professor Lebour criticizes the scheme 

 adopted by the Geological Survey. I give the extract in full. He 

 says, " When I first entered upon the study of this question, I was 

 strongly prejudiced in favour of the view of the stratigrapbical 

 relations of these beds which is represented by the scheme according 

 to which the maps of the Geological Survey are coloured, viz. : — 



Phytic. 

 -ry m ( Red and Green Marl witli Gypsum, 6 feet. Red and White 



rir , < Sandstone with bed of Red Marl, Gypsum and Rock 



(Keuper). | gait, 5 feet. " 



Permian. — Magnesian Limestone. 



But there seems to be no good reason, in the total absence of 

 fossils, for separating what I have called No. 4, into two divisions, 

 the lower with and the upper without limestones. It is true that 

 the reason for separating No. 5 from No. 4 is scarcely stronger, 

 except that there is a distinct evidence that the former division now 

 occupies a larger area than the latter, which is proof of overlap, if 

 not of unconformity. There is also some, though less, evidence of 

 No. 6 overlapping No. 5, or being unconformable to it, and there 

 seems to be absolutely nothing in favour of the assumption that 

 (whichever classification be adopted) the Triassic Series is in South 

 Durham only represented by the Keuper." 



As I was District Surveyor in charge of the Geological Survey 

 of that district, and to some extent responsible for the classification 

 adopted and expressed in the maps of the Geological Survey, I may- 

 be permitted to explain the reasons which induced me to recommend 

 that the whole of the red rocks lying between the Rhaetics and the 

 Durham Permian Limestone should be classed as Trias, and as 

 belonging to the Upper or Keuper division of that formation. 



Now the position of the Rhastic beds on the Yorkshire side of 

 the Tees is well known, and beneath them there is something like 

 from 400 to 500 feet of Red Marls— the Keuper Marls— which 

 graduate down into Sandstones with beds of Red Marl — the Lower 

 Keuper Sandstones or Waterstones — of other districts in Britain. 

 Down to this horizon I believe all are agreed — there is no 

 difference of opinion — that these strata belong to the Keuper 

 division of the Trias. 



But in this district beneath these undoubted Keuper beds, there 

 is a great — an abnormal thickness of sandstones, sandy maids, and 

 marly sandstones, with thick deposits of gypsum and anhydrite at 

 their base, with which the bed of Rock Salt is associated, which 

 cannot be very well correlated with other districts. 



When I was engaged on the Geological Survey there, the 

 difficulty presented itself to me as to what these red rocks should 



