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On Sections in the Lower Permian Rocks at Ciaxheugii and 

 Down Hill, Co. Durham. 



By David Woolacott, D.Sc, F.G.S. 



The purpose of this paper is to describe two interesting areas 

 of disturbed Lower Permian strata occurring on the escarp- 

 ment of the Magnesian Limestone near Sunderland. The 

 section at Claxheugh is seen along the south side of the River 

 Wear about two miles west of Sunderland, while the exposures 

 on Down Hill, near West Boldon, occur on the hill north of 

 that river immediately opposite to Claxheugh. Both of these 

 areas are worthy of study by geologists and by members of 

 the Natural History Society \ as they present exposures of the 

 lower divisions of the Permian, of the Bryozoa Reef or Fossili- 

 ferous division of the Limestone, of disturbed rocks and 

 breccias, and give a clear indication of the nature of the dis- 

 turbances to which the Lower Permian rocks of north-east 

 Durham have been subjected. 



In a former paper in these Transactions I gave a detailed 

 description of the section at Claxheugh* and while the 

 account given is accurate, the explanation suggested is not a 

 correct onej. When I wrote that paper the exact nature 

 of the movements which had taken place in the Permian were 

 not understood, but since then it has been shown that 

 horizontal pressures acting on these rocks have produced a 

 series of thrusts in them and so caused many of the structural 

 peculiarities which form such an interesting feature of the 



* Trans, of Nat. Hist. Soc , Vol. XIV., Pt. 2, 1903. 



t It is there explained as being due to a cavern that had collapsed 

 Horizontal movement was shown to have occurred, but it was suggested 

 that the roof of the cavern had moved in this way on settling down. Howse 

 had explained the section as being an unconformable junction of the Yellow 

 Sands and Limestone series some years before. 



