10 H. H. Howell — Red Rocks in S.JE. Durham. 



be called, and it was not neglected. Any one who will look at the 

 Drift editions of the Geological Survey maps will see at a glance 

 that the whole of the low-lying district bordering on the Tees 

 in S.E. Durham and North Yorkshire is covered by an almost 

 unbroken sheet of Glacial Drift and alluvial deposits which mask 

 the underlying solid rocks ; therefore sections of the red rocks 

 exposed at the surface are few and far between. They are visible 

 at Seaton Carew, and up the Tees at Coatham Stob, Dinsdale, 

 Hurworth, and Croft. I examined all these sections, and it was 

 my opinion then and it is my opinion now that the rocks have 

 a distinctly Keuper aspect. They are not in the least like the 

 Bunter — the soft upper and lower brick red sandstones with inter- 

 vening pebble beds, which I mapped in my 3'ounger days in the 

 Midland Counties, and which I was taught to regard as Bunter. 

 I have also examined the cores of these rocks brought up at several 

 bore-holes, and they tend to confirm me in this opinion. Neither 

 could I find any trace of a physical break or unconformity within 

 these red rocks — they seemed to be due to one continuous deposition. 

 In the face of this evidence it does seem to me that it would have 

 been absurd to split up the red rocks into divisions and draw 

 hypothetical lines separating Keuper Sandstones and Marls from 

 Bunter Sandstones and Marls, and Bunter Sandstones and Marls 

 from Permian marly Sandstones and Marls. Therefore, I felt 

 compelled to carry the base-line down to an horizon where the 

 lithological characters were marked and distinct, viz. to the 

 junction of the red rocks with the Durham Permian Limestone. 

 And there is also at this horizon, I think, some evidence of a 

 possible unconformity. I use the word " possible " advisedly, 

 because I am not very sure that the position of the Triassic rock 

 on the Permian Limestone may not be explained in another way. 

 But the evidence for the unconformity, such as it is, is this. At 

 the Seaton Carew bore-hole, I think it has been undoubtedly proved 

 that the red rocks with gypsum and anhydrite at their base rest 

 upon the upper division of the Durham Permian Limestone — that 

 division which comes to the surface in the cliffs at Hartlepool and 

 at other places along the Durham coast. The stratigraphical 

 position of this division is from 700 to 800 feet above the Marl Slate. 

 Then again in the flat country bordering upon the estuary of the 

 Tees numerous bore-holes have been put down through the red 

 rocks to work the salt-bed there, and some of these borings have 

 been carried down into limestones beneath the salt-bed. It has 

 been stated more than once that these limestones were not fossili- 

 ferous, and could not be identified with any beds coming to the 

 surface at the outcrop. As regards one bore-hole this is most 

 certainly a mistake. I refer to the one which was put down for the 

 Newcastle Chemical Company on reclaimed land on the north side 

 of the Tees opposite Middlesborough. I was consulted about this 

 boring from the first, therefore I am well acquainted with it. The 

 section of the red rocks passed through agreed very closely with 

 that of neighbouring bore-holes, with the exception of the absence 



