398 Edward T. Hardman — On Hwmatite in Tyrone. 



with clay-ironstones, or with the aluminous ore of Antrim. As to 

 its extent, it may run for a considerable distance to the south-east; 

 and if the thickness and richness hold good, it may prove to be a 

 very valuable deposit. 



By the kind permission of Prof. Galloway the analysis was made 

 in the Laboratory of the Eoyal College of Science, Dublin. 



It appears to be a circumstance of some novelty to find an oi'e of 

 this kind as a bed, or part of a bed, in the Carboniferous Limestone, 

 and interstratified with the rocks of that formation. In the North of 

 England, where very extensive deposits of red and brown hematite 

 are worked in the limestone, their true mode of occurrence is very 

 doubtful, and for the most part it is believed that they either lie in 

 cavities of erosion in the limestone, or in veins and lodes."^ In the 

 Alston Moor district, however, brown iron ore occurs associated with 

 the beds of clay-ironstone lying between the '' Great " and " Little " 

 Limestones, but it is considered to have some relation to the veins 

 which traverse the country ; ^ and although at Cleator, in the White- 

 haven district, red heematite is found apparently interbedded with 

 shale and conglomerate, this seems to be thought by no means 

 proved.^ In at least one locality in England hasmatite has been 

 found unmistakably interbedded with the Carboniferous rocks. Its 

 position is given in a section of part of the Old Red Sandstone and 

 Carboniferous Eocks of Lower Purlieu, Forest of Dean, Gloucester- 

 shire, in Sir Henry De la Beche's Memoir on the Formation of Rocks 

 in South Wales and South- Western England.* The section is chiefly 

 made up of sandstones, shales, and limestones, like that at Cooks- 

 town, and, massed together, is as follows : — 



Feet. 



Sandstones and Shales 88 



Limestone '. 90 



Limestone ■with intermingled hsematite, extensiTely worked 60 



Limestone 330 



Sir H. De la Beche considers the occurrence of the ore, in beds, 

 very unusual in the Carboniferous Limestone. 



The above account, however, does not state in what form the 

 hasmatite is found, whether in nodules, or amorphous or crystalline 

 layers, and in fact in only two instances can I discover any definite 

 account of an iron ore existing in any quantity in the foi'm under 

 notice. It appears that in the Lower Greensand at Seend, near 

 Devizes, and also in Buckinghamshire, nodules of limonite, often 

 hollow, and filled with white sand, are found in thick brown sand. 

 The composition of that at Seend somewhat resembles that of the 

 Cookstown ore.^ 



A similar ore occurs associated with the clay-ironstones of the 

 Dungannon Coal-field, and in its analysis as given by Sir Robert 



1 Iron Ores of Great Britain, part i. p. 14, "W. W. Smyth (Mems. Geol. Surv. of 

 Gt. Brit.). 



2 Iron Ores of Great Britain, part i. pp. 14-17. 



3 Op cit pp. 20-23. 



* Memoirs Geol. Surv. Great Britain, vol, i. pp. 128-130. 



^ Bauerman's Metallurgy of Iron, p. 7fcj. Contains very little alumina, but much 

 silica. 



