1395.] Fluorine as a Test for the Fossilization of Animal Bones. 305 
to the other. These were submitted by me to Mr. Hildebrand, 
a Chemist of the United States Geological Survey, on duty at 
the National Museum, who furnishes the following result of 
his analysis. 
Two Fossirt Bonss. 
Man. Mylodon. 
Per cent. Per cent. 
eee eee GS as, 4.55 6.77 
Loss on estar coe See SIO Re 21.18 
Silica. = Oe : < 2209 3.71 
Phosphoric na e GF e vee 23.24 
Ree Sw ALOJ. 3.21 4.02 
trom protoxide . . . (FeQ) .., 5.65 4.44 
Manganese pon oi Cee OPS. 1.65 3.40 
lame na n oe (EQ) Soe 2038 30.48 
Magnesia py a ME Oye © 0.95 0.78 
98.41 97.02 
“Alkalies, carbonic acid and fluorine were not looked for, 
owing to the small amount of available material, hence the 
low summation.” 
The failure to test for fluorine is much to be regretted, and 
was the cause of a second application for a greater quantity 
with which to make another analysis. It will be reported 
further on in this paper. 
The importance of this analysis will be apparent at a glance. 
The human bone is in a higher state of fossilization than is 
that of the Mylodon. It has less lime and more silica. In 
their other chemical constituents they are without any great 
difference. Of lime the bone of the Mylodon has 30.48%, 
while that of man has but 25.88%. Of silica the Mylodon has 
3.71%, while man has 22.59%. Iam well aware of the ordi- 
nary uncertainty of this test when applied to specimens from 
different localities and subjected to different conditions; but 
in the present case no such differences exist. - The bones were 
all encased in the same stratum of blue clay, and were subjected 
