ON THE MAGNESIAN LIMESTONE OF DURHAM, 727 
quantity of water which in some cases is met with, more especially if the bed 
be thick, and much below the level of saturation. A very full account of 
the sinking of the Murton Winning is given by Mr. Potter in vol. v. of the 
«Transactions ’ of this Institute. In this case nearly 10,000 gallons of water 
er minute were pumped out of this bed by engines exceeding in the aggre- 
gate 1500 horse-power. ‘The circumstances which favour the remarkable 
accumulation of water in the Limestone, and the rapidity with which it is 
drained off into pits sunk through it, are due to several causes, some of which 
are peculiar to this formation, and perhaps to this district. They are :— 
1st. The arrangement of the beds of stratification. 
2nd. The contour of the country. 
3rd. The permeability of this formation to water. 
On examining the locality, it will be observed that the beds of strati- 
fication dip towards the sea at an angle somewhat more inclined than the 
surface of the ground, so that on this line of section the Magnesian lime- 
stone crops out with a bold escarpment about four miles inland from 
the sea, forming one of the most pleasing features in the landscape of the 
south-eastern portion of Durham. An observer standing on the escarpment 
‘and looking inland would have an extended view over the wide expanse of 
flat country which, owing to the softer character of the rocks of the Coal- 
measures, lies at its base, and frequently running up into the Limestone in 
deep bays or fiords, gives it the character of an ancient rugged coast-line, 
Seaward an entirely different aspect is presented—a series of undulating hills, 
intersected with many deeply-cut, picturesque, and beautiful ravines, which 
being low and sheltered are well wooded and clothed with luxuriant foliage. 
The boldness of the escarpment is no doubt to a certain extent due to the 
soft nature of the “ Yellow sandstone ” lying immediately at its base. This 
sandstone sometimes reaches a thickness of 50 feet, and extends over the 
flat base to a considerable extent beyond the Limestone, and being thoroughly 
pervious to water, forms a natural absorbent for all the drainage of the dis- 
trict around, which is further increased by the numerous before-mentioned 
bays running into the Limestone. In addition to this, over the country ex- 
tending from the outcrop of the Limestone to the sea, the large fissures already 
spoken of as intersecting in all directions the Limestone, form so many chan~ 
nels of communication between the surface and the bed of “ Yellow sand- 
stone,” down which the surface-drainage, and even in some instances small 
streams pass freely. It cannot, therefore, be wondered at that when this 
formation is pierced by any shaft below the level of saturation large volumes 
of water should be encountered; and although this may for the time increase 
the engineering difficulties and frequently add much to the cost of winning 
coal through the Limestone, it has at the same time its brighter points of 
view, affording as it does an inexhaustible supply of pure and agreeable 
water to the inhabitants residing on its surface. The large towns of Sun- 
derland and South Shields are entirely supplied by water pumped at exten- 
sive works at Humbledon, Fulwell, and Cleadon Hills. The town of Seaham 
Harbour is also similarly supplied. The water is hard for domestic purposes, 
but delightfully clear and refreshing. 
There is another point connected with this branch of our subject. which 
affords much scope for conjecture as to its cause, and offers a large field for 
further research. In all the deep winnings made near the sea-coast, the 
water met with below a certain depth is saline, but not to a uniform degree, 
gradually becoming more so as the depth increases, until it attains the same 
specific gravity as the water of the North Sea. It is difficult to obtain the 
