8 E. E. Eowell—Red Rocks in S.E. Durham. 



The effects of this change of physical feature must obviously have 

 been manifold. The existence of a great Central Asiatic Sea would 

 greatly temper the Siberian climate, while the southern flow of its 

 rivers would affect the distribution of animal and vegetable life, and 

 offers at least a reasonable solution of the difficulties surrounding 

 the migration of birds in the Palaaarctic region, while it finally sweeps 

 away the hypothesis that the Mammoth remains of Siberia are the 

 wreckage of river portage. 



III. — Note on the Classification of the Red Rocks in South- 

 east Durham ; and on a possible unconformity between the 

 Trias and the Perbiian Limestone in the same District. 

 By H. H. Howell, F.G.S., etc, 

 Director of the Geological Survey of Scotland. 



THE several bore-holes which have been put down through the 

 Eed Rocks in the south-east part of the county Durham to 

 win the bed of Rock Salt there have directed attention to the age 

 and classification of these rocks. 



Mr. Edward Wilson in an exhaustive paper published in the 

 Quarterly Journal of the Geological Society of London, has strongly 

 supported the classification adopted and expressed on the maps of 

 the Government Geological Survey of that district. 



Mr. Howse, in the " Guide to the Collections of Local Fossils in 

 the Museum of the Natural History Society, Newcastle-on-Tyne," 

 recently issued, classes the whole of the Red Rocks down to and 

 including the Salt-bed as Trias, but does not divide them into Upper 

 and Lower divisions. He says, "It seems better to conclude that 

 the red shales and sandstones at the mouth of the Tees represent 

 a peculiar and local development of the Trias than attempt to split 

 it up into divisions that have no exact representatives either in 

 England or on the Continent." 



Professor Lebour, formerly on the staff of the Geological Survey 

 in Northumberland, in the " Handbook to the Geology and Natural 

 History of Northumberland and Durham," which appears to be in 

 part a re-issue (in the form of an "Official and Local Guide" 

 prepared by him for the meeting of the British Association at 

 Newcastle in 1889), of the second edition of his "Outlines of the 

 Geology of Northumberland and Durham," published in 18S6, 

 gives his most recent views on the classification of the rocks 

 between the Permian Magnesian Limestone and the Drift. He 

 gives the following scheme merely as representing his own opinions 

 derived from a careful examination of the evidence at present 

 available on the subject : — 



Avicula contorta Beds Bhjetic. 



(Proved in Eston shaft and boring-. ) 

 7. f Bed and Green Marls with Gypsum (known onlv south ) TT 



{ of the Tees) .. ... . £ PPER 



6. Bed Sandstone j Ikias. 



Unconformity ? ? 

 5. Bed Sandstones and Marls Lower Trias. 



