LIMONITE AND LIMESTONES—GILPIN. 37 
merly passed up into the Carboniferous Limestones which, as I 
have already shown, once covered this locality. In it the waters, 
charged with iron, would readily deposit their burden, now pre- 
sented in the form of a cellular fibrous ore, very free from any 
mixture of clay, etc. 
These deposits extend over a considerable extent of country, 
the width of the ore ground being in places 800 yards, but as 
yet they have been tested only near the points of contact of 
the two systems, which is owing to the facility thereby given for 
detecting them without much preliminary work. 
At Whitehaven and Furness, and the Mendip Hills, in England, 
the Lower Carboniferous or Marine Limestones, are found oceu- 
pying positions precisely similar to those described above, and 
their sections will answer for those we are now considering. In 
these Limestones are immense deposits of ore, which are sup- 
posed to have been formed in the same way. They are largely 
mined and furnish an important supply of pure ore. 
At several places in Pennsylvania the Lower Silurian Calci- 
ferous formation holds large deposits of Limonite. These ores 
are, by some, considered to have been deposited in a similar 
manner. The Limonites of Artzberg and the Thuringian Forest 
are believed to have been formed in the same way. 
I have now detained you long enough with these dry details, 
but before closing, would briefly lay before you the important 
deductions which may justly be drawn from the facts I have 
been able to collect. 
This is, that there probably exists in the Lower Carboniferous 
Limestones of this country important and extended deposits of 
Spathie ore, and that a proper and systematic search will pro- 
bably show valuable deposits of Limonite in connection with 
them in other localities besides the East River Valley. 
The Spathie ores are highly prized by Iron makers, and are 
very valuable as a flux when the per-centage of Carbonate of 
Jron present is too low for them to rank as ores. 
The search is impeded by the perishable nature of both Limo- 
nite and Spathic ore, and by the heavy covering of soil which is 
met everywhere on the strata of this age. 
