76 
THE PRINCIPAL PLOOR. 
steel. The crystallised variety called specular ore or iron glance 
is represented by some specimens from the Cleator Moor deposits, 
where it occurs in cavities in the compact ore. The delicate 
scaly crystals from Devon and Anglesey show the characters 
of the foliated variety of specular iron called micaceous iron 
ore or “ shining ore ; whilst the fine reniform and mammillated 
samples of compact haematite from Cumberland and Lancashire 
exhibit well the characteristic forms which have suggested for 
these varieties the popular designation of kidney ore. On 
account of the red colour of the powder the name hcematite , from 
the Greek haima ; (blood), is applied to this species. 
Case 49. — A mineral so abundant and so widely diffused as 
Limonite or brown iron ore naturally requires an extensive 
series for its illustration. Among the numerous localities repre- 
sented in the case before us, the Forest of Dean may be cited as 
a district in which the brown ores have long been raised. 
The botryoidal and stalactitic forms, sometimes called brown 
haematite; the fibrous varieties, termed from their structure 
wood iron ore ; and the friable earthy forms known as yellow 
and brown ochres, are so many varieties of this one species. 
The composition of these varieties is subject to variation within 
certain limits; but a crystallised hydrous peroxide of iron of 
definite composition is occasionally met with, and has been 
separated as a distinct species under the name of Gothite. The 
magnificent species of gothite from Restorm el, near Lostwithiel, 
in Cornwall, are in every way worthy of notice. 
The brown iron ores of the secondary strata, especially those 
of the lias and the overlying oolites, have acquired, in recent 
times, considerable importance. Samples of these will be found 
in the lower part of this Case. The celebrated Cleveland iron- 
stone, from the marlstone, or Middle Lias, was discovered in 
1848-49, on the north-eastern coast of Yorkshire. The main 
body of the Cleveland ore is an earthy carbonate of iron, but 
the upper part of the deposit passes into brown ore. Upwards 
of four million tons are raised annually. 
In Northamptonshire and Lincolnshire, ironstones are now 
extensively worked and smelted. The Northamptonshire iron- 
stone occurs at the base of the Inferior Oolite ; while the 
Lincolnshire ironstone is found partly in the Middle and Lower 
Lias and partly in the Neocomian series. A lias ironstone is 
also worked near Banbury in Oxfordshire, and an oolitic ore 
(corallian) at Westbury in Wiltshire. 
Case 50, &c. — Carbonate of iron is known to the mineralogist 
as Chalybite or siderite, or as spathic or spathose ore. In 
addition to the rhombohedral and lenticular crystals from 
Cornwall, specimens of spathose ore are shown from the valuable 
deposits of the Brendon Hills in Somersetshire, and of Weardale 
in Durham. 
Spathose iron ore is a mineral whose composition is subject to 
considerable variation, the carbonates of lime, magnesia, and 
protoxide of manganese frequently replacing to a greater or 
