436 
WISCONSIN STATE AGRICULTURAL SOCIETY. 
times we find sand to be the insoluble debris of disintegrated 
rock; in other cases it is largely composed of comminuted 
shells, ground to that state by the action of the water. 
One peculiar feature of sandstone is, that when the cement 
by which the particles are held together is destroyed, we can 
examine the original particles or grains, and with a good mi¬ 
croscope determine, to a great extent, their origin. The sand¬ 
stone of the lead district, except where it has for a long time 
been exposed to the atmosphere, is very friable and in most 
cases can be crumbled between the fingers. 
In noticing this sandstone at first, I was much interested in 
finding some very remarkable features that I had not noticed 
in the sandstone with which I was familiar in early life. There 
was such uniformity, not only in the structure of the rock, but 
in the grains composing it, that I was led to examine it care¬ 
fully. In doing this with a small lens, I was surprised to find 
that the grains were pure quartz and very uniform in size. 
Not a pebble could I find, not a shell, nor any appearance of 
disintegrated rock; indeed, the grains of sand looked more 
like little crystals of quartz than anything else; and in submit¬ 
ting them afterwards to a closer microscopic examination I was 
more than ever satisfied that such is the case. I submitted this 
question to the Wisconsin Academy of Sciences, Arts, and 
Letters, in July, 1870, and have since called the attention of 
other scientific men to it, and thus far have found no objections. 
But few things have interested me more than my micro¬ 
scopic examination of these grains of sand, or in other words, 
crystals of quartz. I have observed among them not only al¬ 
most all the forms in which silica is known to crystallize, but 
some equal in beauty to those larger crystals which can be ex¬ 
amined without the aid of a glass. Some of them are trans¬ 
lucent, others almost transparent. They have plane faces and 
regular structure, and their lustre is often beautiful. If it is 
true—and I believe it is so considered—that these peculiarities 
are the known and established results of chemical deposition 
from solution, an important field of inquiry is opened up be¬ 
fore us. 
