COMPOSITION OF SIMPLE MINERALS. 
41 
Hypersthene. 
Silica,_ 51.35 
Lime,_ 1.84 
Magnesia,_ 11.09 
Protoxide of iron,- 33.92 
Water,_ 0.50 
98.70 
At the north, however, this substance existing in but a small proportion in the hyper¬ 
sthene rock, has but little influence upon the quality of the soil; besides, being mixed 
largely with labradorite, which contains both lime and alumina, the soil formed therefrom 
may be considered as good for grains and grass. Quartz or silex, too, is extremely scarce 
in this rock ; and hence there is no excess of sand in it, as there is usually in a pure 
granitic soil. Hypersthene, upon the whole, may be considered as rather a rare mineral 
in New-York. It is found in gneiss in Johnsburgli, but in such small quantities that it 
has no influence upon the soil. 
Serpentine is another primary rock, disposed to crumble into soil. It is one in which 
magnesia is the characteristic element. It consists of 
Serpentine. 
Silica,_ 40.08 42.69 
Magnesia,_ 41.40 40.00 
Water,__ 15.67 16.45 
Protoxide of iron,_ 2.70 1.00 
99.85 Shepard. 100.14 Vanuxem, 
Serpentine may be known by its softness and yellowish green color. It is easily cut by 
a knife, or easily impressed, and it is always found softer upon the outside than upon a 
fresh fracture; the color, too, is much paler on the weathered surface. 
In foreign treatises on agricultural geology, serpentine is set down with those rocks 
which make a poor soil. Thus, Johnson speaks of the soil at the Lizard in Cornwall, as 
being far from fertile, and so retentive of water as to form swamps and marshes; and 
even when drained, it rarely produces good grass, or average crops of corn. It is the 
opinion of the same distinguished writer that the barrenness is due to the small quantity 
of lime contained in the soil; serpentine, as will be seen from the above analysis, being 
destitute of this element. In New-York, and part of New-England, it would appear that 
the serpentine exists under different conditions. Thus, in St. Lawrence, Jefferson, Essex 
and Warren counties, it is intermixed with lime, and the lime disintegrates more rapidly 
than the serpentine; the soil, therefore, must contain a sufficient quantity of lime. How¬ 
ever this may be, there is always a luxuriant growth of vegetables about these beds. The 
serpentine hills of New-England are not so productive as those of New-York. I allude 
more particularly to the hills of Chester and Middlefield, along which the great Western 
[Agricultural Report.] 6 
