EXPLANATION OF PLATE X. 
Fig. 1. — Dolerite ((702) from Depot Nunatak (p. 13G). 
The shaded crystals are of augite ; some of the darker ones are altered and coloured brown with 
oxide of iron. The clear sections are of labradorite. On the left and in the interstices of 
the felspars and augites are seen patches of spherulitic material. 
Magnification, 20 diam., l^-inch objective. 
FiG.2. — Dolerite (696), 2 ft. from junction with sandstone, Dry Valleys (p. 138). 
The augite is mainly in long prismatic crystals, the felspars in small laths : interstitial felsitic 
material is crowded with magnetite. 
Magnification, 30 diam.. 1-inch objective. 
Fig. 3. — Dolerite (687), G in. from junction with sandstone, Inland Forts (p. 138). 
Long prismatic felspars and augites, and interstitial glass black with magnetite. 
Magnification, 30 diam., 1-inch objective. 
Fig. 4. — Dolerite (695), 2 in. from junction with sandstone, Dry Valleys (p. 138). 
Radiating sheaves of felspar-laths, and interstitial glass dense with magnetite ; a few porphyritic 
felspars. 
Magnification, 30 diam., 1-inch objective. 
Fig. 5. — Junction of dolerite and sandstone (669) at B, (p. 138). 
Brown glass, with dark, cloudy patches ; a few porphyritic felspars. 
Magnification, 20 diam., 1 (-inch objective. 
Fig. 6. — Dolerite (154) with granitic patches, Granite Harbour (p. 139). 
Dolerite of purplish augites, felspar-laths and magnetite, with coarse-grained patch of altered 
felspars and quartz. 
Magnification, 30 diam., 1-inch objective. 
