DISTRIBUTION AND QUANTITATIVE OCCURRENCE OF VANADIUM AND MOLYBDENUM 
IN ROCKS OF THE UNITED STATES. 
By W. F. HlLLEBRAND. 
Aside from its well-known mineral combinations, vanadium lias long 
been known to occur in magnetites and other iron ores. Hayes in 1875 
reported its occurrence in a great variety of rocks and ores. Quoting 
from Thorpe's Dictionary of Chemistry: "It is said to be diffused 
with titanium through all primitive granite rocks (Dieulafait) and has 
been found by Deville in bauxite, rutile, and many other minerals, and 
by Bechi and others in the ashes of plants and in argillaceous lime- 
stones, schists, and sands * * * ." It is further reported to com- 
prise as V 2 5 0.02-0.07 per cent of many French clays, 0.02-0.03 per 
cent of some basalts, 0.24 per cent of a coal of unknown origin and 0.45 
per cent of one from Peru, amounting to 38.5 per cent and 38 per cent 
of the ash, and noted respectively by Mourlot and Torrico y Meca. 
Doubtless many other instances of its occurrence have been noted. 
In Table I following is shown its quantitative occurrence and distribu- 
tion in a large number and variety of igneous rocks of the United 
States arranged according to their silica contents; and in Table II the 
same data are given for a few of the component minerals separated 
from some of these rocks, while Table III shows its presence in meta- 
morphosed and secondary rocks by a few examples of roofing slates and 
schists and especially by two composite samples representing 253 sand- 
stone and 498 building limestones. These last two afford positive 
proof of its general distribution through rocks of those classes. Inci- 
dentally some information has been acquired as to molybdenum. 
Owing to lack of entire certainty as to its condition of oxidation, the 
vanadium is tabulated in terms of both V 2 5 and V 2 3 , a point which 
will be reverted to later on. With very few exceptions the amount of 
eacli sample taken for analysis was 5 grams. The reagents used were 
carefully tested and found free from vanadium and molybdenum. 
Except Nos. 38, 39, 47, 52, and 53, by Dr. H. N.Stokes, all determina- 
tions are by myself. 
Bull. 107 4 49 
