FrB.1901. OBSERVATIONS ON INDIANA CAvES—FARRINGTON. 255 
as probably the nearest correct, it can be easily calculated that g0,000 
years would have been required for the Pillar to rise to its present 
height had the flow of water during all this time been uniform over 
the constantly increasing surface. I believe it safe to regard this as 
a minimum age for the Pillar, though I am well aware that owing to 
various factors which may give rise to fluctuations of growth, geolo- 
gists are accustomed to believe that no satisfactory time values can 
be assigned to measurements of stalagmitic deposits. See Dana’s 
Manual of Geology, 4th edition, p. 1024. But may not these fluctu- 
ations be confined within limits as narrow as those affecting other 
measurements of time, such as the rate of recession of gorges or the 
rate of sedimentation, especially when we remember that variations 
in the rate of deposit almost certainly find expression in the form of 
the stalagmite? The stalagmite under discussion certainly has a 
remarkably symmetrical form. I believe, therefore, that it must have 
grown at a fairly uniform rate. 
Regarding the possibilities of arriving at any satisfactory value 
of the mean age of the Pillar, I have no very lively hope of suc- 
cess. It is hardly likely that the flow of calcareous waters over 
the entire mass of the Pillar was constant throughout the period of 
its growth. At the present time, growth is hardly taking place over 
one one-hundredth part of the surface, yet a mean value can be 
assigned to this factor only in a purely arbitrary way with nothing to 
guide the judgment that I can think of. The data for assigning an 
age value to the large stalagmite now in the Museum of Science and 
Art, Edinburgh, seem to me better founded. This stalagmite is 11 
feet long and 28 inches in diameter. It was sawed from its base ina 
cave in Bermuda in 1819. In 1863, Sir Alexander Milne in visiting 
the cave measured the amount of matter formed on the base since the 
removal of the stalagmite and found it to be five cubic inches. At that 
rate it can be easily calculated that about 600,000 years were 
required for the formation of the stalagmite.* Numerous considera- 
tions show that it would be incorrect to apply this ratio to the forma- 
tion of the 20,000,000 cubic inches of matter which make up the 
Pillar of the Constitution, and I introduce the illustration only to 
show that a much greater age should probably be assigned the 
Pillar than that which I have given as a minimum. In addition 
to the time consumed in the growth of the Pillar, a large previous 
period was required for the erosion of the chamber in which it stands. 
*My data are from the Museum label. I think the facts have been published, but I cannot 
give the reference. 
