1 10 Analyses of Fossil Bones of Nebraska. 



It is to be regretted that time did not permit me to repeat 

 these analyses on different varieties of specimens, and by 

 different methods. However, I am able to furnish another 

 analysis, of a compact portion of the tibia of archseotherium, 

 carefully freed from all extraneous matter, made with great 

 care in Dr Genth's laboratory, and under his immediate 

 inspection, by Dr Francis V. Greene, which has resulted 

 very satisfactorily, and in which the fluorine was estimated 

 by precipitation. . 



Water, H = 197 ; Organic matter, = 4'09 ; Phosphoric acid, 

 P = 31-19 ; Silicic acid, Si = 0-26 ; Carbonic acid, C = 2*77 ; Sulphuric 

 acid, S = 2-19 ; Fluorine, F = 2*46 ; Chlorine, CI = 0'02 ; Lime, 

 Ca = 50*83; Magnesia (with a trace of Mn), Mg = 1*14 ; Baryta, 

 Ba = 1*10 ; Potash, K = - 28 ; Soda, Na = 1*57 ; Iron and Alumina, 

 a trace. Total, 99 -87. 



These analyses are remarkable : first, in shewing the ex- 

 istence of a notable quantity of fluorine amounting to from 

 2 to 3 per cent., sufficient to etch glass very distinctly, when 

 the bones are treated with strong sulphuric acid, and gently 

 heated : second, in proving the existence of from 2 to 4 per 

 cent, of the original organic matter, and from 31 to 37 per 

 cent, of the phosphate of lime in the bones of animals, which 

 have been entombed in these early tertiary deposits ever 

 since the Alps first began to lift their heads out of the ocean, 

 and in which they have been enclosed the almost inconceiv- 

 able length of time that has elapsed during a vast geological 

 epoch : in which that great mountain chain of Europe has 

 been gradually thrusting its peaks to ten or twelve thousand 

 feet above the ocean ; and while the Andes of South America, 

 during the same period, have attained probably even a greater 

 elevation. 



Reflecting on the origin of the fluorine discovered in these 

 Nebraska fossil bones, it becomes a question whether it is 

 an original constituent of the bones of the living animal, or 

 has been introduced into their composition after death. Since 

 the analysis of the bones of existing animals indicates but a 

 mere trace of fluorine, it seems more probable that that ele- 

 ment has been introduced as fluoride of calcium by infiltration 



