68 Dr, D. Woolacott—The Interglacial Problem. 
Professor Lebour informed me that several had been found near the 
surface on the Newcastle Town Moor. Chalk has a somewhat 
similar distribution,! but boulders of it (one striated) have been 
found in the boulder-clays of the Tyne valley at Walker and Heaton, 
near Newcastle, and I have found a small chalk pebble in gravels at 
Ponteland, several miles north-west of Newcastle. It is almost 
impossible to explain this widespread occurrence of these rocks on 
the generally accepted hypothesis of ice-carriage to the area. The 
distribution of Magnesian Limestone is also worthy of note, as it 
has been found at several places up the coast of Northumberland 
(Horsebridge Head, Lyne Burn, etc.) as far north as Amble, 
i.e. several miles north of its present outcrop; and boulders have also 
been proved to occur at Walker in the Tyne valley near Newcastle, 
some miles west of it. Are these fragments remnants of strata that 
once overlaid the area beyond the present outcrop of the Cretaceous 
and Permian strata ? 
If certain of the phenomena discussed in this paper have been 
correctly interpreted they appear to prove that definite changes of 
level have taken place in the north-east of England since the 
erosion of the Pre-glacial surface. The depressions in which 
some of the superficial deposits lie prove that prior to the Glacial 
period Northumberland and Durham were more elevated than at 
present ; if an Interval- or Interglacial shore-line was formed 
.during the early part of this epoch, then the area was only slightly 
above the present level when it was formed; while the Raised 
Beaches prove that the area was subsequently depressed and then 
uplifted. The latter movement was probably more pronounced 
along the coastal region of Durham. The depression since Pre- 
glacial times may have been the result of the load of ice which 
covered the country, and the uplift one of the results of its removal. 
THE GLACIAL AND POSTGLACIAL SEQUENCE IN NORTHUMBER- 
LAND AND DURHAM.? 
Formation of peat beds and submerged forests. 
Extensive erosion of the Drift along main superimposed 
valleys. Formation of river terraces and _ alluvial 
haughs. Deposition of thick beds of assorted Glacial 
material. 
Formation of lakes occupying rock basins, hollows in the 
Drift and amongst the Kaims. 
Post-glacial. < Final erosion of Postglacial gorges of Wear, Wansheck, 
Hawthorn, Castle Eden Dene, etc. 
Postglacial Tyne, Tees, and Upper Wear valleys super- 
imposed on Preglacial valleys. 
Formation of marginal sea-deposits, followed by an 
uplift—maximum 150 feet—producing the Raised 
Beaches. Deposition of much material in Tyne valley 
—leafy clays, sands, etc. 
1 Has been recorded from the Horsebridge Head gravels, Lyne Burn 
deposit, from clays in the Tyne valley, from the Raised Beach deposit at 
Cleadon. 
2 This table is only intended to show the general sequence of events: there 
must have been considerable overlapping, but the general order in which they 
took place 1s considered to be something of this nature. 
