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specimens ; and the one extreme shades into the other in such a 

 manner that it is occasionally hard to say where the altered rock 

 ends and the ore begins. 



I remember noticing, when the haematite was being worked 

 in Harcla Pastures, in 1872, that even crystals of calcite had 

 been replaced by pseudomorphs of haematite, while the charac- 

 teristic appearance of the original crystal was still retained. The 

 same deposit of haematite traversed beds of limestone wherein 

 chert nodules occur. In this case the carbonate of lime of the 

 limestone was alone replaced by the haematite, while the nodules 

 of chert remained, in some cases, to all appearance quite unaltered, 

 and appeared as flinty nodules surrounded by the ore of iron. It 

 is probably to this selective action that the conversion of the galls 

 of calcareous shale in the Carboniferous Rocks and of the fragments 

 and pebbles of a calcareous nature in the New Red Breccias into 

 a kind of haematite is in great part due. The replacement has 

 proceeded so far in a few cases as to mislead observers into 

 believing that the pseudomorphs represent veritable pebbles, and 

 that the haematite is therefore older than the deposit they occur in. 

 Much of the limestone adjoining the haematite veins is often 

 changed more or less into Dolomite, from the infiltration of 

 Magnesium Carbonate ; and this Dolomite seems to graduate 

 further into Siderite, or Iron Carbonate. Many of the drusy 

 cavities occurring along with the Haematite where it is found in 

 limestone may be due to the contraction or shrivelling up of the 

 rock consequent upon its general diminution in bulk in passing 

 from the unaltered condition to the state of Dolomite. It seems 

 possible that this partial rearrangement of the constituents of the 

 calcareous rocks adjoining the veins may, to a certain extent, have 

 favoured the deposition of the haematite. 



Traces of Haematite are found here and there through all the 

 Carboniferous Limestone tract that skirts the Lake District ; but 

 although a few hundred tons or so have been obtained near Kirkby 

 Stephen, and smaller quantities have occasionally been met with 

 here and there in other parts, it is not until we follow the outskirts 

 of the Lake District round to West Cumberland that deposits ot 



