the County of Durham, below the Magnesian Limestone. 353 



Pensher Hill is well known as the most conspicuous point 

 upon the edge of the magnesian limestone formation; the yel- 

 low sand appears, exhibiting all its usual characters, on the 

 northern face of the hill, about half-way down. 



Clack's Heugh presents a very bold cliff of limestone, rest- 

 ing upon the yellow sand, here forming a bed of immense 

 thickness ; the coal measures are made to abut against the 

 limestone by a fault which traverses the eastern end of the 

 cliff; and a portion of the red sandstone has also been forced 

 up, so as to form the uppermost bed. This is the only point 

 at which I have observed it on the south bank of the Wear, 

 although I am informed it exists higher up, near to Hylton 

 Ferry ; on the opposite side, however, it forms a most con- 

 spicuous object, being there of great thickness, and generally 

 of a dark reddish-purple colour, the yellow sand forming its 

 upper member. Above Burn's Quay is a quarry where it is 

 worked for fire-stone ; it is close-grained, but not very hard, 

 and of a pretty even texture. 



In the great Pallion Quatry the limestone is worked more 

 than sixty feet thick; the lower slaty beds are of a blueish- 

 gray colour, and being found to make good lime (probably 

 from the absence of magnesia), they are worked entirely away: 

 they are found to rest upon what the quarrymen call " black 

 stone;" a tough brown shale about seven feet thick; and be- 

 low this the yellow sand occurs to an unknown depth. It was 

 in the lower beds of the limestone, in this quarry, that the 

 fossil fish occurred, which is figured in the fourth volume of 

 the Geological Transactions, plate II. 



In the little dell running up from the Wear towards Hyl- 

 ton Castle, the yellow sand may be observed beneath the 

 limestone, of considerable thickness. 



At Down Hill, near West Boldon, we again have the sand ; 

 it cannot be seen in the quarry, but makes its appearance, at 

 each end of the escarpment, beneath the slaty beds of the 

 limestone; a single fossil fish has occurred in this quarry. 



In West Boldon, limestone is worked on the hill, below the 

 church; in the quarry the yellow sand is not visible, but it 

 appeared in cutting the foundations of a house below, and 

 a well not far from the gate of the rectory was begun in it; 

 this bed must here be of inconsiderable thickness, as the red 

 sandstone was immediately come upon, and was sunk into to 

 the depth of twenty-nine feet; the upper part was micaceous, 

 splitting into thin layers, but the stone became more compact 

 as the operations were carried deeper. 



In a little dell near Westoe, called the Deans, behind a 



house called Brinkburn House the red sandstone occurs, and 



N.S. Vol. 8. No. 47. Nov. 1830. 2 Z I am 



