7 
ON THE MAGNESIAN LIMESTONE OF DURHAM. 729 
Eden, Murton and Eppleton, and Elemore Pits, and they can be seen crop- 
ping out below a coal-seam in the cliffs a little to the north of Cullercoats 
Haven. 
2nd. The fossil remains in the “ Red beds” are identical with those of the 
Coal-measures, as shown by Mr. Howse in his paper on the Permian Fossils 
(Tyneside Naturalists’ Field Club Transactions, vol. ii. p. 235). And yet, 
if independent beds, they are not “ the upper beds of the Coal-measures,” 
because in all sinkings, &c., they are found to underlie the Limestone and 
Yellow sandstone even when, as previously mentioned, in treating of the 
_ unconformability of this rock to the subjacent coal-formation, an enormous 
thickness of Coal-measure beds has been denuded off. Further, wherever 
any coal-seam has been worked, as at Kelloe, Cornforth, &c., nearly to 
its outcrop under the Limestone, the stone forming the roof becomes red— 
clearly proving either that these red measures are simply the reddened edges 
of the crop of the Coal-measures, or that they belong to the Permian series, 
resting unconformably with them on the Coal series. 
3rd. This red appearance of rocks has been observed in other parts of the 
Coal-measures where its origin could be distinctly traced. 
1st. The shales forming the roof of coal-seams are frequently found dis- 
coloured and reddened in the galleries of the mine where they 
have been exposed to the action of the atmosphere for some time. 
2nd. This character has been found strongly marked in the rock sur- 
rounding upcast shafts when the action of decomposition has 
been accelerated by increased temperature and probably by per- 
colation of water. 
3rd. In one special instance, viz. in the recent sinking of the Camboise 
Pit, which is situated close to the sea, and at the outset passes 
through 7 feet of recently-blown sand. ‘The bottom of this sand 
was found to be quite reddened, and in appearance strongly re- 
sembled the red rocks below the ‘‘ Yellow sandstone,” which 
latter, from its lying in hills, from its incoherent character and 
false bedding, was probably originally blown sand. 
It is not difficult to understand that the Coal-measure rocks, by lengthened 
exposure to the action of the atmosphere, as must have been the case prior to 
the deposition of the Limestone, would become reddened to the extent now 
witnessed, when it is considered that they all contain so large a quantity of 
iron, and that, under circumstances at all favourable, they readily take on 
them this character. 
The writers propose now to treat shortly of the general stratigraphical 
character of the Magnesian limestone of this district. 
Hitherto it has been usual for geologists to divide this formation into four 
distinct beds, or groups of beds; and these subdivisions have been compared 
to other series of beds extensively developed in other parts of Europe. 
. These groups of Magnesian limestone rocks have been named by the fol- 
lowing authors thus :— 
In 1850 Professor King published the following arrangement of the Mag- 
nesian limestone:— 
In ENGLAND. In GERMANY. 
1. Crystalline. Stinkstein. 
Brecciated. 
Pseudo-brecciated. { icin 
Fossiliferous. Dolomit. 
Compact. Zechstein. 
