xl PERMIAN FOSSILS. 
places between the Wear and the Tees. The railway cutting at Thrislmgton Gap 
exhibits, in the ascending scale, the Sandstone, Marl-slate, and Compact limestone. 
These members are exposed in the same relative position at several places north and 
south of this locality; and, by following them in the direction of their dip, they are 
seen to pass beneath the other members of the series. The shaft sunk near the quarry 
at Humbleton Hill for supplymg the New Water-works of Sunderland, shows that this 
Hill rests on a gritty limestone, with imperfect concretions, identical with that reposing 
on the flaggy beds of brown limestone at Down Hill: this gritty limestone has its 
uppermost beds exposed in the adjoining Lime-kiln Hole; and these beds, which 
contain a few fossils, such as Pleurophorus costatus, Leda Vinti, &c., are there seen to 
be surmounted by a thick magnesio-calcareous bed, which has been quarried for a 
number of years, and is clearly identical with the fossiliferous limestone (c) already 
noticed, as occurring at Hylton-North-Farm. By passing over the intervening valley 
to Tunstall Hill, the fossiliferous limestone is again met with ; but, in following the 
axis of this hill, it is soon observed to be overlaid by a non-fossiliferous calcareous 
rock, which either passes, or becomes changed, into the brecciated or pseudo- 
brecciated deposit exposed at the foot of Tunstall Hope: this is continued down to the 
coast, where it forms the bold and singular Cliffs extending from the Gorge near 
Ryhope, south to beyond Seaham harbour. Half a mile north of Ryhope Gorge, at 
the south end of the Crags, the breccia is seen to rise from beneath the highest member 
of the series,—the crystalline limestone (a), which is traced northward to Sunderland, 
where it forms the entire mass of those varied and singular beds constituting the low 
rounded eminence well known by the name of Building Hill. Numerous excavations in 
Bishopwearmouth have convinced me, that the crystalline limestone passes downwards 
into the brecciated rocks exposed in the Cliffs of the river Wear above the bridge, and at 
Galley’s Gill, precisely as at the Southwick quarries and the south end of the Crags. I only 
know of one place on the coast, south of the Wear, where any other member of the series 
appears to be exposed, which is at the north end of Black Hall Rocks ; and here occurs a 
breccia containing fossils the same as those characteristic of the fossiliferous limestone 
of Humbleton Hill and Hylton-North-Farm, and passing under the highest member of 
the series (a), which forms the remainder of these ‘‘ Rocks” to their southern termination. 
The beds at the south end of Black Hall Rocks have very much the aspect of the 
dull compact thick-bedded limestone occurring in several places on the coast between 
the Tyne and the Wear; and they contaim its characteristic fossils, namely Schizodus 
Schlotheimi, Mytilus septifer, §c. _ At Hartlepool, the southernmost coast point of the 
Permian limestone, the Cliffs consist principally of the oolitic variety of the highest 
member—a variety which also occurs between tide marks, opposite Sunderland, and 
near Roker Baths north of the Wear, associated with botryoidal, and other crystalline 
1 Permian fossiliferous limestones also occur in a few places a little south of the Tees; but I have not 
had an opportunity of examining them properly. 
