Nortbumberla?id and Durham. ) 



From one of these bore-holes, at a place called Woodhead, near 

 the Tees, a sulphuretted water issued, similar to the Harrowgate spa.* 

 It arose from a bed of blue stone lying beneath a bed of gypsum at 

 the depth of nineteen fathoms two feet six inches from the surface. 

 Another sulphuretted spring rises from similar strata at Croft on the 

 south side of the Tees, where baths have been erected for medical 

 purposes. 



There can be little doubt that the sandstone we have been de- 

 scribing is analogous to that extensive formation of the same sub- 

 stance and colour which is found in Nottinghamshire to the west of 

 the magnesian limestone, and it probably may be traced in continuity 

 from the banks of the Tees through Yorkshire into the neighbour- 

 ing county. 



II. Magnesian Limestone, 



To the north-west of the red sandstone the Magnesian or Sunder- 

 land limestone is found. In the cliffs at Cullercoats in Northumber- 

 land, a dyke well known by the name of the ninety fathom dyke, is 

 seen dislocating the coal-measures, and passing into the sea. Here" 

 is the northern extremity of the western boundary of the magnesian 

 limestone. A few masses again occur among the rocks of sandstone 

 and slate-clay, upon which Tynemouth castle stands ; but it is on 



* Mr. Peacock of Darlington published the following analysis of this water in a 

 pamphlet on the medical virtues of the spring. 



Contents in 1 quart. . Carbonate of Lime Grains 1.2 



Sulphate of Lime 25. 



Carbonic Acid Gas 2. 



Sulphuretted Hydrogene, containing 2 1 grains of Sulphur. 8.32 



Azotic Gas 1.5 



Specific gravity of the water 1.016. Temperature at the well 8° above that of the adjoin- 

 ing springs. 



a2 



