361 



high percentage of alkalies. Owing to the fact that many of the 

 constituent minerals nepheline, leucite, nosean, sodalite, melilite, &c. 

 are decomposed by hydrochloric acid it follows that a large proportion 

 (often as much as 50 per cent.) of any rock belonging to this group is 

 soluble in this acid. The following analyses will give an idea of the com- 

 position of different members of the group. 



i. ii. in. iv. v. 



SiO, ... 54-61 ... 61-06 ... 55-76 ... 56-09 ... 47'44 



A1 2 3 ... 22-07 ... 19-06 ... 21-61 ... 22-22 ... 23-71 



Fe 2 3 ... 2-33 . 2-94 ... 1-65 ... 4-08 ... 6-88 



Fe(Mn)0 ... 2-50 ... ... 4-09 ... ... 3-58 



CaO ... 2-51 ... 1-09 ... 2-26 ... 0-69 ... 6-47 



MgO ... 0-88 ... 0-71 ... 0-74 ... tr. ... 1-95 



Na 2 ... 7-58 ... 5-35 ... 6'94 ... 9-16 ... 6-40 



K 2 ... 5-46 ... 6-83 ... 5-34 ... 7-21 ... 8-84 



H 2 ... 1-13 ... 3-54 ... 3-49 ... 1-09 ... 1-78 



Ti0 2 ... 0-09 ... 



Po(X 0-15 



99-31 100-58 101-88 100-54 101-40 



Sp. Gr. 2-638 



I. Elseolite-syenite, Caldas de Monchique, province of Algarve, S. Portugal (quoted from 



MERIAN N.J. Beilage Band III., p. 271.) 



II. Phonolite, La Tuilliere, Mont Dore (Rammelsberg) quoted from ROTH, Beitrage zur 

 Petrographie (1869). 



III. Elseolite-syenite (Foyaite). S. Vincent, Cape Verde Islands. DOELTER. Die 



Vulkane der Capverden. Graz (1882), p, 76. 



IV. Phonolite. S. Antao. Cape Verde Islands. DOELTER loc. cit.,p. 93. Contains traces of 80s. 

 V. Nepheline-tephrite. S. Antao. Analysis by KERTSCHBR. Quoted from the above- 

 mentioned work by DOELTER, p. 99. 



VI. VII. VIII. IX. X. 



Si0 2 ... 48-80 ... 48-59 ... 45-03 ... 44-35 ... 45-24 



A1 2 6 3 16-88 ... 19-58 ... 11-35 ... 10-20 ... 19-22 



Fe 2 3 ... ... 4-88 ... 13-91) 1Q .- ft j 5-21 



Fe(Mn)0 ... 6-60 ... 4-56 .. 4-89 J (5-69 



CaO ... 6-50 ... 9-12 ... 7-86 ... 11-47 ... 9-18 



MgO ... 1-24 ... 3-12 ... 4-61 ... 12-81 ... 6-71 



Na 2 ... 9-52 ... 2-15 ... 7-86 ... 3-37 ... 8-37 



K 2 ... 6-59 ... 6-27 ... 2-93 ... 4-42 ... 1-81 



H 2 ... 1-96 ... 0-12 ... 1-61 ... ... 8-78 



Ti0 2 ... 



PA 2-04 0-12 



98-04 99-93 100-07 99-62 99-71 



VI. Leucitophyre (leucitite with porphyritic crystals) Rieden. Eifel. Quoted from 

 MERIAN'S paper, p. 276. Contains also S0 3 1-70 and Cl. 0'26. 



VII. Leucitophyre. Vesuvius. Lava of March 3, 1881. Contains also 80s 0-15 and traces 

 of Cl. and Cr 2 3 . RICCIARDI. Quoted from ROTH. Beitrage zur Petrographie, 1884. 



VIII. Nephelinite, Katzenbuckel, Odenwald. H. ROSENBUSCH. Inaug. Diss. Freiburg 

 1869. p. 39. Contains also nickel and cobalt. 



IX. Leucite-basalt. Bongsberg near Pelm, Eifel. HUSSAK. Quoted from ROTH, 1879. 

 X. Nepheline -basalt. Naurode near "Weisbaden. SANDBERGER. Quoted from ROTH, 1884. 



