No. 161.] S3 
perceptible manner, is supposed to be the cause which has produ- 
ced this decomposed form of the ore. 
If I am correct in my conjecture concerning the nature of this 
mineral, that it belongs to the series of argillaceous carbonates of 
iron, it is worthy of particular notice that one of the most striking 
geological peculiarities of the ores last mentioned, is their almost 
universal occurrence in the immediate vicinity of a stratum of 
coal. For the facts in regard to this point, I beg leave to refer to 
an able Memoir on the Argillaceous Carbonate of Iron, by Hugh 
Colquhoun, M, D.* 
Analysis of Lenticular Clay Iron Ore, from WolcoU^ Wayne Co^ 
Peroxide of iron, ... , .................. 51.50 
Carbonate of lime,. 24.50 
Carbonate of magnesia, 7.75 
Silica, G.OO 
Alumina, 7.53 
Moisture and loss^ 2 . 75 
100.00 
The above proportion of peroxide of iron is equivalent 1o 85.70 
of metallic iron. I am informed that the ore yields in the large 
way about 32 per cent of iron. 
Some other localities of specular iron ore, proba^bly less impor- 
tant than those above noticed, remain to be particularly examined. 
Thus the common variety is said to have been found in small 
quantities near Catskill; the micaceous, at Fort-Lee; the argilla- 
ceous red oxide and clay iron stone, in the counties of Columbia 
and New-York, and on Long-Island. 
LiMONiTE^ — Hydrous peroxide of zVo?i.-— This species, which here 
usually occurs in beds, is widely diffused. It is one of the most 
* Brewster's Edinburgh Journal of Science, VHI. 71, I have already remarlced, that 
the true argillaceous carbonate of iron does not occur in any quantity in this State. It is 
with s'ome hesitation that I have offered the suggestion, that our Ipnticular ore is allied to 
that mineral. After repeated experiments, I have no reason to think that in the specimen 
which I examined, any portion of the carbonic acid is combined with the oxide of iron, 
and yet this may turn out to be the case with specimens from other localities. The ave- 
rage loss of weight by calcination, after drying at a heat of 200=' or 300®, was 16.73 per 
cent. This ore is on several accounts deserving of a careful examination. 
[Assem. No. 161.] 6 
