362 WISCONSIN STATE AGRICULTURAL SOCIETY . 
It is only over a portion of the state, however, that this class is 
exposed as the surface rock, consequently accessible only here, 
for agricultural purposes. Over a larger portion of the state, we 
find a sedimentary strata, from which the soil is formed, such as 
sandstone and limestone. These strata also furnish a large amount 
of matter adapted to the wants of the vegetable kingdom. But 
while these strata differ very much from granitic rocks in their 
origin and composition, we find, nevertheless, but very few new 
elementary substances. 
Sandstone, that is the surface rock over a large portion of the 
central part of our state, is almost chemically pure silica. It is a 
mass of small crystals of quartz, consequently composed of the 
same elementary substances as the quartz that enters into the 
formation of granite. 
The limestones that form a large portion of the surface rock in 
the southern part of the state, are of two kinds, common lime¬ 
stone, or carbonate of lime, and dolomite, or magnesian limestone. 
The elementary substances composing common limestone are the 
following : calcium, oxygen and carbon. Those composing dolo¬ 
mite or magnesian limestone, are, magnesium calcium, oxygen 
and carbon. The elementary substances, those composing these 
sedimentary strata, are silicon, oxygen, calcium, carbon and mag¬ 
nesium, five in all. Of this number, four enter into the composi¬ 
tion of our granitic rocks. In the whole mass of rocks from which 
the soil of our state is derived, we find but these ten elementary 
substances that enter into the composition to any great extent. 
What can we contemplate that is more wonderful or marvelous 
than the endless variety of minerals and mineral bodies which na¬ 
ture has formed out of these few simple or elementary substances? 
How beautifully she has varied the forms with the slightest vari¬ 
ation in the material, or the laws under which this material has 
been brought together. Indeed, this endless diversity and variety 
in the forms and qualities of matter is one of the most striking 
features of the mineral kingdom. 
But beautiful and diversified as the forms of matter mav be in 
the mineral kingdom, it is matter, nevertheless, in its first stages 
of preparation for other, higher and more beautiful forms; 
and as it rises from the bosom of the deep in all the freshness of 
