80 
ECONOMICAL MINERALOGY. 
I. 
Carbonic acid, ... 39.33 
Lime, . 25.00 
Magnesia,. 17.83 
Silica,. 11.76 
Alumina,. 2.73 
Peroxide of iron, . 1.50 
Moisture,. 1.50 
II. 
•.. 38.65 
. 27.35 
. 16.70 
. 8.95 
. 4.90 
. 1.75 
Moisture, bituminous matter and loss, 1.70 
The composition of the calcined lime, in the state in which it is ordinarily used as a cement, 
is as follows : 
Carbonic acid and moisture,. 10.90 
Lime,.. 39.50 
Magnesia,. 22.27 
Silica, . 16.56 
Peroxide of iron and alumina,. 10.77 
The proportion of carbonic acid, however, depends entirely upon the manner in which the 
calcination is conducted, and it probably differs considerably in different specimens. 
The blue fetid limestone which is associated with the water limestone is a nearly pure 
carbonate of lime, containing 0.70 per cent, of insoluble matter, and a trace of oxide of iron 
and bitumen, to. which last is probably to be ascribed the odour which it gives out when struck 
with a hammer. It contains no magnesia. 
I have also examined a specimen of the calciferous slate of Eaton, from the hill on the east 
side of the village of Chittenango. The results are as follows : 
Carbonic acid, . 40.95 
Lime, . 29.00 
Magnesia,. 17.30 
Silica and alumina,. 11.00 
Peroxide of iron,.. 1.10 
Moisture and loss,. 0.65 
This composition, which I have reason to believe is quite constant, will satisfactorily ac¬ 
count for the occurrence of sulphate of magnesia or Epsom salt, which is so often found in 
efflorescences on this rock. It contains a sufficient amount of sulphuret of iron to furnish the 
acid for this decomposition. 
Onondaga County. An important locality of water limestone occurs about a mile and a 
half west of Manlius. The overlying rock is a blue limestone, similar to that found at Chit¬ 
tenango. Some of the strata of water limestone are clouded or striped, while others are of a 
uniform grey or drab colour. Through the upper layers there passes a thin seam of white 
calcareous spar, in which are to be found small crystals of fluor of a dark purple colour. 
