38 



H. S. Washington — New Leucite Rock. 



Analyses of Italite and othee Leucite Eocks. 



12 3 4 5 6 



Si0 2 51-02 54-17 51-65 50-25 51-20 47-39 



ALA 22-21 10-16 21-60 21-41 21-21 14-79 



Fe 2 O s . 1-48 3-34 0-85 1-76 2-38 3-10 



FeO 0-57 0-65 3-12 1-82 3-67 5-08 



MgO 014 6-62 1-07 0-31 199 6-77 



CaO 2-31 4-19 4-29 4-48 5-42 11-61 



Na.,0 167 1-21 4-30 516 211 1-49 



K,0 17-94 11-91 11-60 11-32 10-63 6-93 



H 2 0— 0-11 0-52 ) n 9( , 0-62 0-28 0-77 



H 2 0+ 0-82 1-01 [ U '^ D 0-34 0-10 0-28 



CO, none 0-49 n. d. 0-32 none none 



Ti0 2 0-57 2-67 0-65 0-57 0-74 1-41 



Zr0 2 006 0-22 n. d. 0-02 0-03 0-04 



P 2 5 002 1-59 n. d. 0-12 0-36 0-45 



S0 3 0-76 0-16 n.d. 1-05 trace none 



CI 0-08 0-06 0-07 0-18 n. d. ■ n. d. 



(Ce,Y) 2 3 trace n.d. n.d. n.d. n.d. 0-05 



MnO 001 0-06 n. d. n. d. n. d. n. d. 



BaO 0-20 0-59 n.d. 0-13 0-33 0-15 



SrO n.d. 0-18 n. d. trace n. d. 0-04 



99-97 100-21* 100-20 99-86 100-45 100-35 



Less O -02 -17 -01 -04 



99-95 10004 100-19 99-82 

 * Includes F — 0-36, Cr 2 3 = 0-05, NiO and Li 2 traces. 



1. Italite (I. 9. 1. 1.). Near San Carlo, Eoeea Monfina. Washington 

 analyst. 



2. Orendite (III. 5. 1. 1). Leucite Hills, Wyoming. Hillebrand analyst. 

 W. Cross, this Journal, 4, 130, 1897. 



3. Leucite sanidinite (II. 7. 2. 2). Monte Somma. Pisani analyst. 

 Lacroix, C. E., 144, 1249, 1907. 



4. Tavolatite (I. 7. 1. 3). Tavolato, Alban Hills. Washington analyst. 

 Eom. Comag. Eegion, 51, 1906. 



5. Vicoite (leucite tephrite) (II. 6. 2. 2.). Monte San Anton 'o, Eocca 

 Monfina. Washington analyst. Eom. Comag. Eegion, 92, 1906. 



6. "Leucitite" (III. 7. 2. 2.). Mte Jugo, Bolsena Volcano. Washington 

 analyst. Eom. Comag. Eegion, 124, 1906. 



At the first glance this analysis is seen to be very 

 remarkable. It is composed almost entirely of silica, 

 alumina, and potash ; with small amounts of ferric oxide, 

 lime, and soda; and with very small amounts of the 

 other constituents. The percentage of silica is about 4 

 per cent below that in leucite, while the percentages of 

 alumina and potash are about those in this mineral. The 

 very high figure for K 2 is the most striking feature, 

 being higher by 50 per cent than any yet recorded. The 

 next highest (11-91) is found in orendite (2), one of the 

 peculiar rocks of the Leucite Hills, which is composed 

 in great part of leucite and orthoclase, with subordinate 



