﻿Vol. 6 I.] OF THE NORTHUMBERLAND AND DURHAM COALFIELD. 69 



accumulations of ice were melting at the end of the Glacial Period; 

 and also large portions of the Boulder-Clay must have been washed 

 down from the higher ground and redeposited in the valleys, partly 

 owing to the same cause, but also to the action of rain, etc. since 

 that period. 



Viewed broadly, there is considerable variation in the character of 

 the superficial deposits over the whole area, and except that the 

 Boulder-Clay is found in one or two localities to be of considerable 

 thickness, it seems utterly impossible to correlate the deposits in 

 different borings : this, however, was to be expected. 



The discussion of the distribution of the different 

 boulders in the clay over the great Northern Coalfield, or 

 of the various rocks found in the diverse superficial deposits, does 

 not come within the scope of this paper. Collecting, however, the 

 evidence from various sources, it may be asserted that in these 

 deposits, treated as a whole, there have been found within the 

 area of the Coalfield, or in its immediate neighbourhood, specimens 

 of Criffel and other granites from the South of Scotland ; Bor- 

 rowdale Ash and other rocks from the Lake-District ; Permian and 

 Triassic sandstone from the Eden Valley ; Shap Granite (which 

 probably does not occur very far north of the Tees Valley); Cheviot 

 Granite and Porphyry, Whin Sill, Tuedian Sandstone, Bernician 

 Limestone, flints, as well as specimens of the rocks that form the 

 surface of the country itself, namely, the Coal- Measures and the 

 Magnesian Limestone (2, 6, 1 5). (It is extremely doubtful, by the 

 way, whether any true Scandinavian rocks occur north of the Tees.) 

 I have collected specimens of most of these from time to time, but 

 there is still room for more detailed work on this subject before a 

 full knowledge of it can be attained. 



Besides these beds, which may be considered to be more or less 

 of true Glacial origin, there are the remains of a raised beach 

 resting upon the solid rock and Boulder-Clay. This formation, or 

 deposits associated with it, has been observed on Tynemouth Cliff, 

 Cleadon, Fulwell, and Tunstall Hills, and can be traced along the 

 coast from Seaham to Castle-Eden Dene. Eichard Howse recorded 

 a raised beach as having been exposed at Tynemouth, at an elevation 

 of about 100 feet (2) ; sea-caves were discovered on Cleadon Hills, in 

 1878, at 140 feet above high-water mark, and the old sea-cliff with 

 beds of gravel and sand can still be seen (5 & 6) ; while on Eulwell 

 Hills (11 & 12) there is a finely-exposed beach resting in places 

 upon a sea-worn platform of rock, and elsewhere upon Boulder-Clay, 

 and running up against an ancient cliff which is 150 feet above 

 sea-level (figs. 3 & 4, pp. 70 & 71). Farther south, along the 

 coast from Seaham to Castle-Eden Dene, a hard, strongly-cemented 

 conglomerate is traceable. At Tynemouth, Cleadon, and Eulwell 

 many more or less fragmental portions of Cyprina islandica and 

 Littorina littorea have been found. The most interesting point in 

 connection with this raised beach is that it seems to decrease in 

 height, both northward and southward, from what is probably the 



