Notes on the Geology of Corhndge. By G.A.Lebour 123 



the Eiver Pont are both filled up by Boulder Clay, sometimes to 

 a comparatively great depth. In the Pont Valley the Boulder 

 Clay is associated with many adventitious beds of sand and 

 gravel such as those before referred to, but these cannot be 

 observed in situ and are known only through the many borings 

 and sinkings about Clarewood and Fenwick, in the neighbour- 

 hood of Great Whittington and Matfen. At Grottington on 

 the west side of Watling Street near Stagshaw Bank a tilery has 

 been worked for some years in which the clay used, though be- 

 longing to the Boulder Clay in part is also in part to a certain 

 extent a re-assorted deposit. Several other tileries of a similar 

 character have at one time or another been established in the 

 neighbourhood. 



Millstone Grit : Two lines meeting at the river about two 

 and a half miles to the south east of Corbridge between Styford 

 and By well — one running with a north easterly curve to Har- 

 low Hill, and the other running due west, to the south of Hex- 

 ham near Beacon Grange — would separate the Millstone Grit 

 from the Carboniferous Limestone or Bernician Series. This 

 boundary is somewhat arbitrary, being determined simply for 

 convenience by the outcrop of the highest calcareous member of 

 the lower set of beds. I have frequently insisted, in various 

 papers published during the last ten or twelve years, on the 

 fact that in Northumberland the Millstone Grit is devoid of 

 any distinctive characteristics by which it can be differentiated 

 from the non-calcareous portion of the Bernicians. The valley 

 from Stocksfield to Hall Moor is cut through Millstone Grit, and 

 rocks of the same age furnish the greater part of the high 

 ground rising from beneath the Drift gravels and sands to the 

 south of Corbridge. Indeed most of the ground between the 

 Tyne and Derwent is here Millstone Grit. 



Carbonifeeotjs Limestone Series (Bernician Eocks) : All the 

 rest of the solid, as distinguished from the superficial, geology 

 of the region under consideration (excepting igneous rocks) be- 

 longs to the upper division of this series, that is, to that portion 

 of it which in West Yorkshire and "Westmoreland would be 

 called Yoredale Eocks, and to which, as exhibited in Durham 

 and Northumberland, I have, for reasons fully stated elsewhere,* 

 and now generally accepted as sufficient by competent authorities, 



* See Transactions of the Mining Institute ; for 1876, and also the Geo- 

 logical Magazine, Decade ii, vol. iv (1877). 



