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opinions held about it, without hoping either to reconcile 
them or say which ought to be adopted. The rock is found 
in force over the country between Rotherham, Whiston, 
Aston, South Anston, and Harthill, and patches of a sand- 
stone exactly like it in character occur at other spots. It 
was referred by Professor Sedgwick to the marls and sand- 
stones beneath the Magnesian Limestone, generally known 
as the Rothliegende division of the Permian formation. Its 
character, however, is so utterly unlike that which these 
beds bear in the neigbourhood, that I do not think this 
view can be upheld. Farey, Thorpe, and other local geolo- 
gists looked upon it as a regularly interbedded sandstone of 
the Coal-measures, of limited local extent; in fact, a bed just 
like the Woolley Edge Rock. In this case it ought to keep 
about the same distance from the Barnsley Seam ; actual 
sinkings have now proved that this is not the case ; and if 
all the patches of Red Rock that we know of are to be 
referred to the same bed, it will at one spot rest upon 
measures at least one hundred yards higher in the series 
than at Shireoaks Colliery, the shaft of which went through 
it. The notion, therefore, that it is a conformable Coal- 
measure sandstone, must, I think, be given up. Still, it 
seems to belong to the Coal-measures, for coal and shales 
exactly like those of that formation lie above it : such were 
sunk through at Shireoaks, and may be seen in the cutting 
of the Midland Railway, about two miles south of Mas- 
borough Station. If, then, we must have an opinion, the 
facts at present known seem to show that it belongs to an 
upper unconformable part of the Coal-measures, and that 
after the main mass of that formation had been deposited, 
upheaved, and denuded, the Red Rock, and the beds over- 
lying it, were laid down upon the upturned and truncated 
edges of the previously formed strata, so that these later 
rocks rest sometimes on one member, and sometimes on 
