54 ALBERT JOHANNSEN 



Syn.: Alaskite-quartz Spurr (in part)/ Feldspar-greisen 

 JoKELY (in part). 



(112) Tarantulite. Spurr^ used the term alaskite-quartz for a 



transition rock between alaskite and igneous quartz which occurs 

 in the Missouri mine, near Tarantula Spring, Nevada. As a simpler 

 term the name tarantulite is here proposed for Family 2, which 

 contains orthoclase and less albite. 



Syn.: Alaskite-quartz Spurr (in part), Feldspar-greisen 

 JoKELY (in part). 



(116) Orthoalaskite. The term alaskite was given by Spurr^ 

 to leucocratic rocks which contain alkali feldspars (orthoclase, 

 microcline, microperthite) , with or without albite. Here they are 

 divided into two groups. Those without albite are included under 

 the name orthoalaskite (see note under (in)), while those with 

 albite are normal alaskites of Family 7 (117). 



Runite Pinkerton.^ Syn.: Pegmatite HauYj^ Schrift- 

 granit, Hebraischerstein, graphic-granite, etc. 



Orthotordrillite. The extrusive equivalent of ortho- 

 alaskite is orthotordrillite. The name tordrillite was given by 

 Spurr^ to the extrusive equivalent of alaskite. In the present 

 classification only the tordrillites with no plagioclase are included 

 in this family. 



(117) Alaskite Spurr. See under orthoalaskite (116). 

 Tordrillite Spurr. See under orthotordrilhte (116) 



above. 



Syn. : Rhyalaskite.' 



^ J. E. Spurr, "Ore Deposits of the Silver Peak Quadrangle, Nevada," U.S. Geol. 

 Surv., Prof. Paper 55 (1906), p. 61. 



'Ihid. 



3 J. E. Spurr, "Classification of Igneous Rocks According to Composition," 

 Amer. Geol., XXV (1900), 229-30. 



4 J. Pinkerton, Petrology (London, 1811), II, 85. 



s Ascribed to Haiiy by Brongniart, "Essai d'une classification mineralogique des 

 roches melangees," Jour. d. Mines, XXXIV (1813), 32. 



*J. E. Spurr, "Classification of Igneous Rocks According to Composition," 

 Amer. Geol., XXV (1900), 230; also "Reconnaissance in Southwestern Alaska in 1898," 

 U.S. Geol. Surv., Ann. RepL, XX, Part VII (1900), p. 189. 



7 J. H. Farrell, Field Geology (New York, 191 2), p. 160, Table II. 



