EXPLANATION OF PLATE VIII. 
Fig. 1 . — Olivine-basalt (65(5) from cliff between Gap and Horseshoe Bay (p. 104). 
All the clear olivines, except the three crystals at the top, belong to oue individual : the more 
shaded crystals are augite. 
Magnification, 30 diarn., 1 inch objective. 
Fig. 2. — Gabbro-like nodule (415) in liuiburgite, from Winter Quarters (p. 108). 
The dark grains are altered olivine, the shaded grains are pale-green diopside, a rather more deeply- 
shaded grain on the left below is hornblende, the clear crystals showing twin-striations are 
felspar. 
Magnification, 30 diarn., 1 inch objective. 
Fig. 3. — Leucite-kenyte (818) from Cape Royds (p. 111). 
The large phenocryst of anorthoclase shows crossed twin-striations as seen between crossed nicols ; 
numerous small leucites with central inclusions are seen in the base ; on the left towards the 
bottom is a small phenocryst of olivine. 
Magnification, 20 diarn., 1^ inch objective. 
Fig. 4. — Phonolitic trachyte (248) from Mount Terror (p. 115). 
A rectangular phenocryst of anorthoclase is seen in a trachytic mesh of felspar-laths with dark 
grains of mgirine-augite. 
Magnification, 30 diarn., 1 inch objective. 
Fig. 5. — Phonolite (530) from Black Island (p. 11G). 
Hornblende near to riebeckite, in moss-like patches, in fine-grained trachytic felt of felspar-laths. 
Magnification, 30 diarn., 1 inch objective. 
Fig. 6. — Phonolitic hornblende-trachyte (277) from Observation Hill (p. 117). 
Prismatic crystals of basaltic hornblende in trachytic mesh of felspar-laths. 
Magnification, 30 diarn., 1 inch objective. 
