66 
He also announced the discovery of rare ores, orpiment, 
native bismuth, and pitchblende, in the Western Territories. 
The President and other members discussed these discoy- 
eries at length, Dr. Bolton dwelling especially on the very 
rich pitchblende from Georgetown, Colorado. <A_ large 
amount of this ore had been brought to New York and 
Hoboken, and had been employed by Dr. Morton of the 
Stevens Institute, and by himself, for the manufacture of 
oxide of uranium, to use in preparing the many uranic salts 
upon which they were experimenting as to fluorescence. 
The occurrence and yield of chromic iron were likewise 
discussed. The President described its mode of association 
with the serpentine which is found among the upheavals of 
the Coast Range of California and Oregon. Parts of this range, 
which is of Cretaceous and Tertiary age, are quite unaltered, 
and rich in fossils; others are much changed, sometimes even 
to a jasperoid rock, such as the gangue of the cinnabar at 
New Almaden and New Idria. The serpentine is plainly an 
altered rock, not an eruptive one; but whether it forms part 
of the late strata of the Coast and Cascade Ranges, or is 
an old core, is yet uncertain. The Golden Gate is cut 
through this ridge of serpentine, which shows conspicuously 
at its entrance. 
Pror. D. S. Martin remarked upon the striking differ- 
ences between the serpentines of what he termed the Atlantic 
belt, and those of the Blue Ridge and the Eozoic mountains, 
as shown both in their aspect and in their associated minerals. 
The serpentines of the eastern belt are massive and opaque, 
and are marked by a minute, but very constant, percentage of 
nickel and of chromium, occasionally rising to amounts that 
become of economic importance. They also abound in hy- 
drated magnesian minerals of many species, but do not con- 
tain chrysotile, are rarely associated with calcite, and mani- 
fest no traces of Hozoiin. The Blue Ridge and Adirondac 
serpentines, on the other hand, are frequently precious, or 
noble, in character, seamed with chrysotile, and associated 
with calcite so as to form ophites and Eozoén rock; while 
