218 Geology, Mineralogy, Scenery, &c. 
Both this ore and that at Salisbury form a striking m- 
stance of a great metallic deposit, not in veins, as most met- 
als occur, that 1s, filling fissures in rocks, which fissures are 
perpendicular to the horizon, or form an angle and usually 
a considerable one with it ; on the contrary, these ores are 
parallel or nearly so with the horizon—that is, taking the en- 
tire deposit into view—and form, what is technically as well 
as familiarly, called a bed of ore. 
With respect to the kind of ore at Kent, in a scientific ar- 
rangement it would be referred to the same species, as that 
at Salisbury—the brown iron stone of Werner or the brown 
hematite. Yet practical men assure us that the iron made 
from it is of a different, and as is asserted of an inferior 
quality, and that itis more difficult to be brought to the state 
of good iron.* 
It would require a careful chemical examination to de- 
cide in what the difference consists (and the subject is so 
important as well to merit this attention,) but if judging from 
appearances only, we were to hazard an opinion, it would be 
that the Kent ore containsa larger proportion of manganese. 
Most of these ores of iron contain some portion of manga- 
nese, and although a small proportion of that metal does not 
injure iron and (as some suppose,) even benefits it ; a large 
proportion renders it brittle. 
The impression that the Kent ore contains more manganese, 
is derived from the fact that the specimens have, generally, 
a darker colour than the Salisbury ore, and in their cavities 
there are appearances almost like those produced by pure 
oxid of manganese. .The Kent ore appears to be mid way 
between the brown and the black iron stone of Werner ;— 
the latter confessedly contains a great deal of manganese, 
and if we are not in an error, the Kent ore bed contains more 
of black ironstone—the Salisbury more of the brown. 
The Kent ore bed also abounds in fine specimens, the 
fibrous, stalactitical and mamillary varieties in particular, 
are uncommonly fine here, and a mineralogical traveller is 
strongly tempted to load his vehicle, more deeply than is 
convenient in so rough a country. 
On comparing the specimens both from Salisbury and 
Kent, with those of the same species in the splendid col- 
* A manufacturer of muskets assured me that he found it too brittle for 
gun barrels, while that of Salisbury is very tough. 
