WACHOE MOUNTAmS. 477 



characters, and equally at variance with that of most of the other larger 

 granitic bodies, but more especially with those to the north and east. 

 All the normal mineral constituents of common granite are here present, 

 but not in the usual proportions. Quartz, orthoclase, plagioclase, and mica 

 are the essential ingredients ; in addition to these, as subordinate minerals, 

 maybe observed hornblende and a few dark specks, probably specular iron 

 but which it would be difficult by the unaided eye to determine, but for 

 the fact that in thin sections, under the microscope, it has been detected 

 inclosed in the larger feldspar crystals. The quartz is present in very small 

 quantities and always in fine grains, with a slightly gray tint. Both mono- 

 clinic and triclinic feldspars are present in considerable proportions; none 

 of them have a brilliant color, but are more or less dull and opaque. A few 

 of the larger crystals, which are frequently a half an inch in length, have a 

 vitreous lustre. Mica plays an important part ; it occurs in broad, shining 

 plates, with a fresh, undecomposed appearance ; there are also present some 

 flakes of a bronze color, which are more or less altered. 



Under the microscope, Zirkel has pointed out the presence of both 

 titanite and apatite, the latter in short thick prisms, and carrying numerous 

 liquid-inclusions, arranged in lines at right angles to the main axis of the 

 crystals, as shown on Plate I, Fig. 8, accompanying his report. The 

 liquid-inclusions of the quartz also carry minute crystals of chloride of 

 sodium, while the larger feldspars hold specular iron. 



The Wachoe granite was subjected to chemical analysis by Professor 

 Thomas M. Drown, of Lafayette College, Pennsylvania, with the following 



result : 



Silica ........: 55.53 



Alumina 18.65 



Ferrous oxide 6.14 



Manganous oxide 0.17 



Lime 5.62 



Magnesia 3.37 



Soda 4.84 



Potassa - 5.20 



Ignition 0.65 



100.17 



