212 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



Analysis of Quartz Monzonite — Dellenose 



(i) (2) 



SiO.. 67.27 68.36 



AI2O:: 13.67 13.24 



FcoOs 1.83 1.29 



FeO 2.49 3.39 



MgO 1.72 1. 15 



CaO 1.90 2.51 



Na-0 2.79 2.05 



K2O 5.80 5-34 



H2O above 100° 45 



H2O below 100° 08 / "^^ 



TiO^ 1.70 — 



P2O5 16 — 



MnO 19 .27 



100.05 100.23 



Note. — i. Quartz monzonite — Greenland, W. C. Phalen, analyst. 2. Glassy 

 andesite — Dellen, Sweden, H. Santesson, analyst. F. Suenonius, Andesite 

 from Helsingland, Sweden, Gcol. For. Forli., x, 1888, p. 273. 



Composition in Terms of Standard Minerals 



(I) (2) 



Quartz 22.32 26.80 



Orthoclase 34.47 3114 



Albite 23.58 17.29 



Anorthite 7.51 11.12 



Apatite 34 — 



Ilmenite 3.19 — 



Magnetite 2.55 1.86 



Diopside 88 1.18 



Hypersthene 4.68 7-98 



Water ^3 2.63 



100.05 100.08 



From the analysis of this quartz monzonite, it will be seen that 

 the silica is rather high. This is explained in part by the presence 

 of free quartz. Low lime indicates a small amount of basic feldspar. 

 The high content of titanic acid is worthy of mention. 



In the main, the analysis agrees fairly well with that of the type 

 rock from Sweden. Notable differences occur, however, in the 

 ■cont At of ferrous oxide, water, and titanic acid ; the differences in 

 the lirst and third substances, however, do not suffice to alter the 

 d'^ssificatory position, since in rocks of the first three classes these 

 oxides do not have the weight which they possess in similar divisions 

 of classes four and five. 



Note. — In conclusion, I wish to express my appreciation of the 

 inany courtesies extended to ine during the course of this work by 

 Dr. G. P. Merrill, Dr. Wirt Tassin, and Mr. Chas. Schuchert, of the 

 U. S. National Museum, and by Dr. David White of the United 

 States Geological Survey. 



June 9, 1903. 



