OF OCiENCES 
Pisolitic Barite. 249 
stream brought to the surface only those few which happened 
to present their flat surface in a direction perpendicular to 
that of the upward pressure. The others, tilted, did not pre- 
sent as large an effective surface, i. e., did not sustain the same 
lifting force. 
The manner in which these pellets were tormed is probably 
a matter of conjecture. In this particular case, it is not likely 
that these bodies were carried by a subterranean stream, 
because, as Mr. Thrasher states, no such material has been 
encountered before in deep borings which have been carried 
on in neighboring localities. 
It is quite probable, therefore, that the pellets are the 
product of a confined locality, and were formed by a subter- 
ranean spring carrying barite in solution, much in the same 
manner as the pisolitic aragonite in the Sprudel of Carlsbad, 
Bohemia, is believed to be formed. The coral fragments result- 
ing from the breaking up of an underground deposit, were 
carried up by the spring, and each fragment was kept spinning 
around while layer after layer of barite was deposited around 
it, a process which continued until the pellets grew too heavy 
to be kept in suspension. 
The radiating tubuli may then be the result of the centri- 
fugal force by which the oil contents of the nucleus were con- 
stantly brought to the open pores on the surface, preventing 
deposition of barite within the pores. Each additional coating 
encroached, however, on the lumen of each tubule, causing 
them to grow narrower as their length increased. 
Whether the coral nucleus and the incrusting shells, orig- 
inally, consisted of barite, or of calcite subsequently changed 
by a metasomatic substitution of barite, is a question which it 
may. not be possible to decide as long as the original deposit 
of the material remains inaccessible. A similar substitution 
has taken place in the oolite from Centre County, Pa., where 
silica has taken the place of calcium carbonate. 
Dr. S. WALDBOTT, of the Ohio Mechanics Institute, has 
most kindly made a quantitative analysis of the materials 
herein described, and submits the following results : 
