179 



NOTE ON AN ABNORMAL DEPOSIT OF DRIFT COAL 

 IN NORTH DURHAM. 



By G. a. LEBOUR, M.A., F.G.S., 



Professor of Geology in the Dnrhani College of Science, Ne'wcastle-7tp07i-Tyne. 



A LARGE portion of North Durham and South Northumberland is 

 overspread by sands and gravels lying upon boulder clay. Like the 

 latter, though newer, they are no doubt of glacial age, but having 

 often been redistributed — and therefore, to a greater or less extent, 

 altered and remodelled — since that time, they have sometimes lost 

 many of the characteristics of glacial accumulation. In this Upper 

 Drift, discontinuous wedge-shaped current-bedded patches of rolled 

 coal-fragments are common; but in all cases hitherto observed by me, 

 or of which I have received information, the bits of coal forming such 

 deposits, as well as the deposits themselves, have been very small. 

 The coal, too, is always such as would naturally result from the 

 denudation of known Carboniferous seams cropping out in the higher 

 ground of the neighbourhood. 



Last month, however, Mr. W. Scorer Harris, of Andrew's House 

 Colliery, North Durham, called my attention to an interesting bed of 

 Drift Coal differing in many respects from any I had previously met 

 with, which I at once went to see, and of which the following is a 

 brief account. 



The working shaft of Andrew's House Colliery (of which Mr. 

 Harris is the resident engineer) stands about half-way between the 

 valleys of the Team and Derwent, near Marley Hill, at a height of 

 about 600 feet above sea-level. Close to the shaft is a small sand pit, 

 worked for the sake of a fine brown sand, which is the lowest deposit 

 visible there, but which rests (as is otherwise proved) upon 

 boulder clay. Above this brown bed lies a much false-bedded mass of 

 sand and gravel of various degrees of coarseness, with several small 

 ' scares' or insignificant patches of minute coal-fragments of the usual 

 kind. But on one side of the sand pit — as it was at the time of my 

 visit — extending from the original outcrop of the gravel beds for 

 several yards, as far as the pit had been worked, and how much farther 

 one could not tell, was a bed of rolled coal of more than two feet in 

 thickness, dipping steadily to the south-east. The regularity and 

 seam-like appearance were remarkable, and at a distance one might 

 well have mistaken the deposit for an ordinary Coal-Measure workable 

 seam. The , coal pebbles of which it was formed were, however, 

 obvious to closer inspection, and proved the most remarkable feature 

 of the case. Their size was most exceptional, many being several 

 inches in diameter, and almost all being very large when compared 



March 1885. 



