Hillebrand — Vanadium and Molybdenum in Rocks. 209 



Akt. XXI. — Distribution and Quantitative Occurrence of 

 Vanadium and Molybdenum in Rocks of the United States / 



by W. F. HlLLEBKAND. 



[Read before the Geological Society of "Washington, D. C. May 25th.] 



Aside from its well-known mineral combinations, vanadium 

 has 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 



limestones, schists, and sands " It is further reported 



to comprise as V 2 5 *02-*07 per cent of many French clays, 

 •02--03 per cent of some basalts, # 2i per cent of a coal of 

 unknown origin and "45 per cent of one from Peru, amounting 

 to 38*5 per cent and 38 per cent of the ash and noted respec- 

 tively 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 distribution 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 those rocks, 

 while Table III shows its presence in metamorphosed and 

 secondary rocks by a few examples of roofing slates and schists 

 and especially by two composite samples representing 253 

 sandstones and 498 building limestones. These last two afford 

 positive proof of its general distribution through rocks of 

 those classes. Incidentally 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 Y a 6 and V a O s , a point which will be reverted to later on. 

 With very few exceptions the amount of each sample taken 

 for analysis was five 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. K Stokes, all 

 determinations are by myself. 



Table I. Igneous Rocks. 



Si0 2 Y 2 5 = Vo0 3 Mo 



No. Name and locality of occurrence. % % % ' % 



1. Melihte-nepheline basalt, Uvalde Co., Texas 38 -054 -045 



2. Nephelinite, Uvalde Co., Texas ..40 -042 -035 



3. Saxonite, Douglas Co., Oregon 41-5 none none 



4. Diorile, Cecil Co., Maryland 44 -062 "052 none 



