1868. | The Iron Ores of Great Britain. 33 
A curious mass of Magnetic Iron ore occurred at Rosedale, in 
Yorkshire. The first discovery of this deposit of Iron-stone was at 
a quarry on the south-west side of the valley of Rosedale, about a 
mile south from Rosedale Abbey. When this quarry was opened 
out, it was found apparently to consist of a confused mass of iron- 
stone boulders, of an ellipsoidal structure, often three or four feet in 
diameter. ‘The interior of these boulders was generally blue, and 
comprised a solid dark oolitic iron ore, with, in many cases, sandy 
and solid crusts around it; and in receding from the centre the 
iron ore became paler, alternating with dark-brown purplish layers. 
Those variations did not occur where the iron-stone was covered by 
other strata, and the magnetic property proved to be most decided 
where the mass was the thickest. These circumstances appear to 
indicate that this mass was at one time in the state of a Carbonate 
of the Protoxide of Iron, not very unlike that which occurs in the 
Cleveland Hills, but that it had been exposed to influences —not 
necessarily calorific—by which the chemical change into Magnetite 
had been effected. This ore especially resembles the hydrated 
Magnetie Oxide of Iron, which can be obtained as a precipitate 
from an aqueous solution. Figures 1 and 2 in the Plate will ex- 
plain more fully than any words the peculiar conditions of this 
remarkable and valuable Iron ore formation. The first section is 
by the late Mr. Nicholas Wood, the second by Mr. Bewick. It 
should be noted that the latter observer, writing of this deposit, says, 
** The Iron ore of Rosedale, instead of being a large mineral field, 
as was first asserted, and still believed to be so by many, is nothing 
more than a volcanic dyke ; and the iron-stone opened out in this 
locality is not, as it is reputed to be, the main seam now being 
worked in Cleveland and Grosmont.” The Magnetic Oxide of Iron 
has been discovered in Banffshire, Aberdeenshire, the Shetland 
Islands, and the Hebrides. It cecurs also in Antrim, in Wicklow, 
and especially in the Mourne Mountains. 
fied Hematite—The deposits of this valuable ore—an an- 
hydrous Sesquioxide of Iron,—which are found in Furness near 
Ulverstone, and near Whitehaven, are deserving of the closest 
attention. At Whitehaven, this ore is found in the carboniferous 
limestone and millstone grit (locally called “ Whirlstone”) near 
the outcrop or surface edges of the slaty rocks upon which these 
formations rest. Fig. 8 shows the mode of occurrence. At 
Todholes, where this ore was worked as a quarry, the bed had a 
thickness of twenty feet, and at the Park Mines a thickness of 
seventy feet of solid Heematite occurred, 
The Ulverstone ore differs in physical condition from those of 
Whitehaven. Much of it is equally compact with the Cumberland 
ore, and this is known as“ blast ” ore; but the major portion occurs 
as a less coherent aggregate of exceedingly fine filmy scales of micas 
YOR, Y, Dd 
