Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/13

Rh 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 describing is analogous to that extensive formation of the same substance 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 neighbouring county.

To the north-west of the red sandstone the Magnesian or Sunderland limestone is found. In the cliffs at Cullercoats in Northumberland, 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

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