IS2 



ME. II. II. READ OX THE 



[vol. lxxix, 



magnesia and high iron-oxides for this type of rock. However, the 

 mineralogical character of the xenoliths in the Arnage type of 

 contaminated rock does not invalidate the opinion that here also 

 there has heen a gain of magnesia hy the xenoliths. From the 

 Huntly and Insch Masses I have obtained xenoliths, of undoubted 

 sedimentary origin, composed largely of monoclinic pyroxene. 1 



Table VI. — Analyses of Xexoliths, etc. 





X. 



XI. 



XII. 



XIII. 



XIV. 



XV. 



XVI. 



Si0 2 



TiOo 



53-98 

 1-15 



2277 

 233 



7'22 

 0-18 



nt. fd. 

 0-12 

 1-97 

 3-16 

 2-97 

 2-14 



nt. fd. 



o-io 



1-87 

 0-17 



nt. fd. 



nt. fd. 

 0-04 



59-98 

 064 



13-52 

 1-13 



nt. fd. 

 3-50 

 0-22 



nt. fd. 

 0-03 

 9-11 

 6-28 

 1-50 

 0-94 



trace 

 055 

 0-67 

 0-13 

 0-18 

 1-70 



trace 



59-15 

 1-14 



14-09 

 1-04 



nt, fd. 

 7-73 

 0-24 



nt. fd. 

 0-06 

 3-43 

 7-11 

 2-44 

 110 



trace 

 0-44 

 0-97 

 013 

 0-05 

 0-90 

 0-03 



49-18 

 1-24 



16-00 

 0-02 

 0-03 

 8-02 

 0-20 



nt. fd. 



trace 



1254 

 9-47 

 0-26 

 2-04 



trace 

 0-07 

 0-41 



o-io 



0-02 

 0-37 

 0-33 



45-85 



115 



20-50 



11-91 



11-32 

 0-26 



nt. fd. 



nt. fd. 

 1-27 

 418 

 0-72 

 1-27 



nt. fd. 

 0-07 

 1-48 

 0-04 

 007 



nt. fd. 



5400 



27-50 

 4-31 



3-81 



4 V 68 

 j 2-60 



0-60 



Loss on 

 ignition 

 =2-60 



60-50 



14-50 

 2-70 



3-40 



5-04 

 8-64 



I 2-60 



0-80 



Loss on 

 ignition 

 = 1-60 



AI0O3 



Fe»0 3 



Cr 2 3 



FeO 



MnO 



(CoNi)O 



BaO 



CaO 



MgO 



KoO 



Na.,0 



Li.,0 



HoO at 105° C. 

 H 2 above 105° C. ... 

 Po0 5 



FeSo 



Fe-S 8 



C0 2 





Totals 



100-17 



100-08 



100-05 



10030 



100-09 



100-10 



99-78 















X. Andalnsite-scliist of Boyndie Bay Group, repeated from p. 450. 

 XI. Xenoliths in contaminated rock, right bank of River Deveron, 350 j'ards east 



of Castle Bridge, Huntly. Analyst, E. G. Radley. 

 XII. Contaminated rock surrounding xenoliths of Analysis XI. Analyst, E. G. 

 Radley. 



XIII. Initial magma of the Huntly Mass, Huntly norite, repeated from p. 480. 



XIV. Cordierite-spinel-hornfels, Gallowhill, Arnage, repeated from p. 477. 



XV & XVI. ' Shale '-xenoliths in norite of Potgietersrust and Mapoch's Country, 

 South Africa: A. L. Hall & C. Gardthausen, 'Note on some Remarkable 

 Xenoliths of Altered Shale from the Norite of Potgietersrust & Mapoch's 

 Country' Trans. Geol. Soc. S. Africa, vol. xiv (1912) p. 74. 

 XV. Coarse xenoliths, much cordierite and biotite, little pyroxene, very little 

 felspar. 



XVI. Finer-grained xenoliths, rich in plagioclase and rhombic pyroxene, fair biotite, 

 little cordierite. 



The chemical change undergone by the Arnage argillaceous 

 xenoliths can be compared with that suffered by the shale-xenoliths 

 (Analyses XV & XVI, Table VI) in the Bushveld norite described 

 by Hall & G-ardthausen. The order of abundance of the con- 

 stituent minerals in the South African xenoliths is cordierite, 



H. H. Read, op. cit. Chapters vii & viii. 



