94 J. M. Stiilman— Bernardinite. 
of the country by a resident who stated in his letter that on 
throwing a match upon the ground he was surprised to see 
leaving but a trace of an ash on combustion. No theory was 
advanced as to its origin, attention simply was called to its 
structure :—“ On fracture it presents a slightly fibrous struct: 
ure. Under the microscope it exhibits a two-fold structure,— 
a quantity of very fine, irregular fibers permeating a mass of a 
brittle, amorphous, structureless substance.” Since that paper 
was written I have endeavored to obtain more definite inform: 
_ness takes them into that region. However, from reports ob- 
tained through the agency of Mr. Redding, I feel tolerably con- 
fident that the true nature and origin of this substance has 
been cleared up. 
t seems that there grows and probably has grown for a long 
time a species of conifer which exudes large masses of a resin- 
ous secretion from abrasions or wounds. These resinous masses 
are reported to attain considerable size, and to fall off from their 
own weight. However that may be, the detached resin either from 
fallen and decayed trees, or from living trees, becomes scattered 
over the surface of the country and mixed with surface soil and 
rocks. By a long process of evaporation, action of atmosphere, 
and the leeching and bleaching agency of the snow which covers 
the ground for a large portion of the year, these resinous masses 
lose all vestiges of volatile and soluble matter and at the same 
time, a fungus growth permeates and splinters the whole mass 
into minute fragments rendered coherent by the fibers of the 
fungus. Hence the two-fold structure noted, the fungus growt 
as shown in the previous paper, amounting to less than 10 per 
cent of the mass. 
The perfect change which has taken place in the resin by 
these agencies evidence that the resin must have been exposed 
for an indefinite period to atmospheric agencies, and have at- 
tained a position of equilibrium toward its surrounding condi- 
tions. It is therefore apparently entirely a surface formation, 
which however has in process of time become so mixed in with 
surface soil and rocks as in some instances to present the ap- 
pearance of being 7n situ. 
University of California, May 13, 1880. 
