8 Mr. N. J. Winch on the Geology of 



which the cavities of these rocks were once filled. From this cause 

 the promontory, on which Hartlepool stands, is rapidly crumbling 

 away. 



It is well ascertained that the magnesian limestone of this district, 

 as is the case with that of Derbyshire and Yorkshire, rests upon 

 the coal-measures. No coal mine however has yet been won in 

 Northumberland or Durham, by sinking a shaft through the lime- 

 stone, although the workings of some collieries situated on its 

 western boundary have been carried underneath it. It is therefore 

 a matter of great importance to those who have royalties within its 

 limits to know under what thickness of limestone the coal measures 

 are buried ; whether after passing under the limestone they continue 

 to dip at the same angle as before, and whether the quality or 

 thickness of the coal-seams is then altered. 



I have not been able to ascertain what is the total thickness of 

 the limestone ; but at Hart, near to Hartlepool, a bore-hole was 

 made in it to the depth of 52 fathoms, without penetrating through 

 it. This spirited undertaking was then frustrated from the per- 

 foration being filled with sand and water. At Pallion, a little to 

 the west of Sunderland, the limestone was only 12 fathoms thick, 

 below which the coal measures were bored through to the depth of 

 140 fathoms without finding a coal seam worth working. 



Along the coast of Durham from Shields to Hartlepool the lime- 

 stone strata dip to the south-east. At Chapted main near South 

 Shields, the coal measures, although approaching the limestone, rise 

 towards the sea, in conformity to their direction on the north side 

 of the Tyne ; but at Painshaw, New bottle, Rainton, &c. they dip 

 to the south-east, the limestone being there protruded into the 

 Coal-field beyond the prolongation of that line, from which the 

 coal measures that are without covering btgin to rise in an eastern 



