68 
[Assembly 
Of marl, calcareous tufa and agaric mineral, there are several valu- 
able localities. All these may at some future time be made useful to 
the agriculturalist. A specimen of marl from the the farm of Mr. Van 
Bergen near Coxsackie, gave w^hen perfectly dry, the following results 
in 100 grs. 
Carbonate of lime, 97.32 
Insoluble matters, principally of silica and alu- 
mina, 2.15 
Oxide of iron, with vegetable matter, 0.53 
Another specimen from the vicinity of Catskill contained 
Carbonate of lime, 91 .75 
Insoluble matters, with some oxide of iron, 
&c., 8.25 
Of course both of these are sufficiently pure to be advantageously 
employed as fertilizers. 
Some interesting crystalline forms of calcareous spar occur in the 
fissures of the limestone along the track of the Catskill and Canajoha- 
rie rail-road ; and there have also been found fine crystals of quartz in 
cavities in the slate rock, near Catskill. Among these are some modi- 
fications which will be particularly described in the final report of this 
department of the survey.* 
The following minerals have also been found in Greene county, viz: 
Sulphur — In minute quantities. 
Coal — Several unimportant localities. 
Sulphate of barytes. 
Labradorite — Occasionally found in bowlders. 
Alum and sulphate of iron — Both formed by the decomposition of 
iron pyrites, which is abundant. 
Specular iron ore — In small quantities. 
* A dark grey shell limestone found near the paper-mill, two miles N. W. of Cats- 
kill, on the Catskill and Canajoharie rail-road, has the following composition : 
Silica and alumina, 3.25 
Organic matter, 0 . 25 
Carbonate of lime, 95 . 00 
