﻿110 



MR. Ch W. TTEEELL OX THE 



[vol. lxxii, 



A little orthoclase lias certainly been overlooked in the lugarites 

 and probably in the theralites. Also, in the lugarites the analcite 

 total contains some nepheline. From the chemical analyses it 

 appears that apatite has been considerably over-estimated in the 

 lugarites. 



Chemical Composition of Theralite and Lugarite. 



~No chemical analysis was made of the theralite proper. The 

 rock analysed proved to be nearer to picrite than to theralite, and 

 its composition is set out in Table VI, col. i (p. 114). The lugarite 

 was analysed by Dr. Scott : its chemical composition is unique, 

 reflecting the unicpie mineral composition of the rock. The che- 

 mical conrpositions, as calculated from the mineral compositions 

 recorded in Table III, are collected here for purposes of comparison, 

 and serve, as do the others already tabulated, to demonstrate the 

 efficiency of the Rosiwal method in suitable cases as an auxiliary 

 to actual chemical analysis. 



Table IV. 



Si0 2 



Ti0 2 



A1 2 0 3 



Feo0 3 



FeO 



MnO 



MgO 



CaO 



Na 2 0 



Kap 



H 2 0+ .. 

 H 2 0- .. 



P 2 0 5 



BaO(SrO) 



co 2 



F 



S 



Totals 



42-47 

 2'59 



14-20 

 3-25 

 8-73 



12-92 

 8-26 

 5-33 



0- 92 



| o-io 



1- 18 



0-06 



100-01 



II. 



42-75 



2- 68 

 15-19 



3- 50 



8- 44 



0- 05 



9- 47 

 8'83 

 6-50 



1- 37 



0-21 

 0-91 



0-04 



99-94 



III. 



44-42 

 1-63 



13-33 

 9-14 

 6-35 



5 V 74 

 10-60 

 5-60 

 1-81 



1-75 



0-35 



0-18 



100-90 



IV. 



46-29 

 2-37 



17-47 

 2-24 



7- 07 



0- 28 

 2-10 

 5-82 



8- 69 



1- 47 

 f 5-12 

 t 0-69 



0-70 

 009 

 none 

 p.n.d. 



V. 



VI. 



VII. 



45-56 



2- 53 

 15-92 



4-04 

 6-75 

 007 



3- 02 

 8-10 

 8-82 

 0-04 



47-35 

 1-46 



18-02 

 3-07 

 5-65 



o-ii 



0-82 

 7-82 

 9-76 

 0-06 



43-70 

 0-89 



19-77 

 3-35 

 3-47 

 tr. 

 3-94 



10-30 

 9-78 

 2-87 



3-53 



4-09 



0-89 



1-61 



1-78 



1-34 



0-12 



0-16 





100-11 



100-15 



100-30 









VIII. 



52-73 



20-05 

 3-43 

 0-99 



100-01 



I. Theralite, Bellow Water, Lugar. Calculated from Rosiwal analysis, Table III, 

 No. I (p. 109;. 



II. Hornblende-theralite, Bellow Water, Lugar. Calculated from Rosiwal 

 analysis, Table III, No. II. 



III. Theralite, Flurhubl, Duppau (Bohemia). F. Bauer, Tscherm. Min. u. Petr. 



Mitth. vol. xxii (1903) p. 281. 



IV. Lugarite, main mass. Glenmuir Wafer, Lugar. Chemical analysis by Dr. A. 



Scott. 



V. Lugarite, main mass, Glenmuir Water, Lugar. Calculated from Rosiwal 

 analysis, Table III, No. III. 

 VI. Lugarite, veins in picrite, Glenmuir Water, Lugar. Calculated from Rosiwal 

 analysis, Table III, No. IV. 

 VII. Ijolite,Iivaara, Kuuosamo (Finland). Anal. N. Sahlbom. Quoted from J. P. 

 Iddings, ' Igneous Rocks ' vol. ii (1913) p. 306. 

 VIII. Heronite, Heron Bay, Lake Superior. Anal. H. W. Charlton. Coleman, 

 Journ. Geol. Chicago, vol. vii (1899) p. 435. 

 IX. Analcite-tinguaite, Pickard's Point, Essex County (Mass.). Anal. H. S. 

 Washington. Amer. Journ. Sci. ser. 4, vol. vi (1898) p. 182. 



