36 The Tron Ores of Great Britain, [Jan., 
The Brown Hematites of the Oolites must be considered as 
Hydrous Sesquioxides of Iron; they are in nearly all respects 
peculiarly distinguished from those ores of which notice has been 
already taken. ‘The Northamptonshire and Lincolnshire Iron ore 
deposits especially represent this class; they are continued, with 
various shades of difference, through the adjoming counties. 
The first impression on examining the various beds of Iron ore, 
which we can now trace from near the Humber to within a few 
miles of Oxford, will be, that they are the result of deposit from 
water, as peroxide of Iron, in the same way as we see ferruginous 
springs depositing—as the water is exposed to the air—the Iron 
which they hold in solution. This hypothesis supposes those 
beds to be of recent formation. After, however, a careful examin- 
ation of all the evidences afforded by the fossil remains which exist 
in those beds, and in other beds above and below the ferruginous ores, 
no other conclusion can be arrived at, than that they are of very 
different ages, the result of a recurrence of the same conditions, 
but all of a marine origin. 
Spathose Iron Ores, Sparry Carbonate of Iron.—These ores 
of Iron have been long selected for the production of the celebrated 
“steel irons” of Siegen, Styria, and Carinthia, consequently of late 
years they have been sought after in this country. 
Mr. Charles Attwood, to whom we are especially indebted for a 
knowledge of the Spathose Iron ores of Weardale, notices the 
same conditions as those found in other districts. They have cer- 
tainly been all at first deposited as carbonates more or less pure, and 
have passed into the state of oxides and hydrates, by the joint effects 
of atmospheric and of aqueous action. Examples of every stage ot 
the transition present themselves in all directions, and there are also 
met with, from time to time, abundant proofs that whilst the car- 
bonates deposited are more or less rapidly passing into the hydrated 
condition, a fresh deposit of carbonates is continually going on in 
the cavernous interstices, and on the roofs and sides of ancient 
workings. Upon one occasion Mr. Attwood found protruding for 
six inches from a block of pure and large grained Sparry carbonate 
of iron, a rod of malleable tron, of about a quarter of an inch in 
diameter, of which the other end was firmly embedded to about the 
same depth in the block, which had just before been broken from a 
mass of it, incrusting the walls and roof of an ancient drift, but 
which block must have been formed within one or two centuries. 
Mr. W. W. Smyth remarks, ‘When we look to the successive 
introduction of the various minerals which have filled these in- 
teresting veins, it is evident that the carbonate of Jron has been 
one of the latest comers. Many of the specimens exhibit it, in- 
vesting, as a crystalline incrustation, the previously formed crystals 
of fluor spar and galena; and the striking manner in which it is 
