the County of Durham, beloiv the Magnesian Limestone. 413 



panying the magnesian limestone : the series of specimens 

 now before the Society, from the different localities, will show 

 most of the characters of the two beds. At the same time it 

 must be admitted, that hand specimens can give but a vague 

 idea of a formation of such extent and variety as this is. In 

 many situations on the line it might be taken by any one who 

 had not examined it thoroughly, to be a sandstone of the coal 

 measures; but a more extensive survey, with an attention to 

 all the circumstances under which it occurs, could not fail of 

 satisfactorily pointing out its true relations to the adjoining 

 strata. 



The most convincing proof of its total independence of, and 

 want of conformity to, the coal measures, is the difference of 

 depth at which the same seam of coal is found along the line 

 of its outcrop. If we take, for instance, the low main coal of 

 the Tyne, which is the Hutton seam in the collieries on the 

 Wear, we shall find its depth below the red sandstone, as 

 follows : — Fathoms. 



At the foot of the cliff below Tynemouth Castle itT ^_ # 



will be about J 



At Laygate Quarry about 140 



At Clacksheugh, at least 230 



At Houghton-le-Spring (Lord Durham's new pit) 132 



At Moorsley (Mr. Russell's pit) 95 



To the south of Moorsley, the seams of coal unfortunately 

 again change their names, and it would therefore be impos- 

 sible, without further investigation, to trace the continuity of 

 each individual seam; but it may be stated, that the sandstone 

 crosses the coal strata, at many various depths, above a coal 

 in that district, called the Five-quarter Seam, and in its range 

 southward very nearly comes in contact with the grit and 

 shale beds below the whole of the coal series. Fathoms 



At Quarrington Pit from the red sandstone to the! „_ 



Five-quarter Seam, is ••••J 



At Eldon Pit from the red sandstone to the Five- 

 quarter Seam, is 



And at Cowndon Pit from the red sandstone to the") 



Five-quarter Seam, is j ol 



The source of the brine springs, which are found in several 

 situations in this neighbourhood, has long been a matter of 



}° 



* This estimate is made upon the idea of the seam of coal seen imme- 

 diately beneath the Two-gun Battery, at the south end of Cullercoats 

 sand?, being the High Main; but as there is reason to believe, from the 

 very best authority (Mr. Buddie), that it is either the Bensham, or Yard 

 Coal, it is probable the Low Main Coal is much nearer the red sandstone 

 than above stated. 



interesting 



