Dr. D. Woolacott—The Interglacial Problem. 21 
Here and there steep sandstones and clays of the Murree beds are 
exposed below them. 
About 200 metres farther west the steep Murree beds are again 
visibly covered by boulders and loess. At the base of the alluvial 
deposits bitumen appears. Also the strata of the Murree beds are 
in some parts impregnated with it (vide Fig. 8). 
No doubt the tar is lying in a secondary position, and in all 
probability originates in the Upper Nummulitic that is exposed at 
the foot of the limestone ridge of Kairi-Murat (comp. Section X, 
Plate I). 
The tar occurrence of Lundegar is a further proof of the great 
extension of oil and bitumen in the Upper Nummulitic. 
(To be continued.) 
The Interglacial Problem and the Glacial and Post- 
glacial Sequence in Northumberland and Durham. 
By Davip Woo tacort, D.Sc., F.G.8. 
See my papers on “ The Superficial Deposits and Preglacial 
Valleys of the Northumberland and Durham Coalfield”? and 
“The Origin and Influence of the chief Physical Features of 
Northumberland and Durham ’”’? were published, a great deal of 
detailed work has been done on the glacial phenomena in the 
two north-eastern counties by Smythe,? Merrick,*- Herdman,° 
Trechmann,° and myself.’ As I have given much attention to this 
subject it may be of interest and value if I give a brief resumé of 
my views, a general summary of the work done, and attempt to 
show the general sequence of the phenomena that have been 
described. My extensive study of the Drift in these two countries 
and elsewhere has convinced me of its complexity. I cannot, 
therefore, be dogmatic on any points, but will endeavour to show the 
general trend of my thoughts on the subject. 
The complexity of the superficial deposits is evident to all who 
have studied a typical glaciated area in detail, and the widely 
1 Quart. Journ. Geol. Soc., vol. 1xi, 1905, p. 68. 
2 Geogr. Journ., July, 1907, p. 37. 
’ “ Glacial Phenomena of the country between the Tyne and the Wansbeck ”’ = 
Trans. Nat. Hist. Soc. Northumberland, etc., 1914. “ Glacial Geology of 
Northumberland ”’: ibid., 1908. 
4 “ Glacial Deposits around Newcastle-upon-Tyne’”’: Proc. Univ. Durham 
Phil. Soc., 1909. 
5 “ Glacial Phenomena of the Vale of Derwent ’’: ibid., 1909. 
6 “The Scandinavian Drift of the Durham Coast’’: Quart. Journ. Geol. 
Soc., vol. Ixxi, 1915, pp. 58-82. ‘‘ Ona Deposit of Interglacial Loess and 
some transported Freshwater Clays on the Durham Coast’’: Quart. Journ. 
Geol. Soc., vol. Ixxv, pt. iii, 1920, pp. 173-203. 
7 “ The Preglacial Wash ’’ :. Proc. Univ. Durham Phil. Soc., 1906. “ Borings 
at Derwenthaugh and Durston”: ibid., 1909. “ Geology of N.E. Durham 
and 8.E, Northumberland’: Geol. Assoc., 1912, ete. There is also a large 
amount of carefully recorded data in the Boulders Com. Reports of the Univ. 
Durham Phil. Soc., 1905--12. 
