484 Transactions. 



isotropic, probably aiialcime. Basalt. From small cone within 200 yards 

 of Castle Rock, south of and below same. 



Castle Rock, 4. — Black basalt. Prominent crystals of black augite and 

 pale-green olivine. There is a sharply defined inclusion of granular augite 

 and olivine, with no trace of any transitional material, between this and 

 the basalt ; greatest dimension of inclusion as shown in specimen, 45 mm. 

 Another specimen shows an inclusion, equally well defined, which is practi- 

 cally all olivine, there being only one visible fragment of augite. A section 

 of the augite-olivinc inclusion shows coarse-grained olivine-augite rock 

 with ophitic structure. The augite pale green with a shade of pink, non- 

 pleochroic. The merest beginnings of schiller structure are visil)le in places. 

 Below Castle Rock, nearest to the rock. ■ 



Second Knoll. 



Black Vesicular Basalt. — This was one of the less-prominent landmarks, 

 and consisted of a cone of angular lumps of black vesicular basalt of vitreous 

 appearance. From this a ridge of snow extended northwards for some 200 

 or 300 yards. Whether this was a compacted drift ridge ov merely a bank 

 of basalt covered with snow it is impossible to say. 



Termination Rock. 



Termination Rock is officially known as Hutton Cliffs. The name was 

 given by Mr. Hodgson for his own convenience, as the exposure was 

 the most distant one from the ship, and therefore the last on the Ridge- 

 way. No. 1 was taken from the base of the cliff, which is some 200 ft. high, 

 and sheer. 



Termination Rock, 1 (Hutton (Jlifi's). — Compact, olive-green mottled 

 with black. Many of the black included fragments are obviously 

 amygdaloidal, the vesicles being filled with white zeolite ; spots of this 

 mineral also occur in the green part. A volcanic agglomerate. Frag- 

 ments of green, black, and brown glassy highly vesicular rocks, all of which 

 contain olivine crystals. Some of the black fragments are amygdaloidal, 

 the vesicles being filled with a dull dusty-looking substance of finely fibrous 

 structure, white by reflected light. This same substance also occurs at 

 intervals throughout the slide, between the constituent fragments. On<' 

 or two small black patches show numerous lath-shaped feldspars. Brown 

 augite is rare, and present in small forms only. The glass in this lock is 

 now represented by alteration-products. 



Apparently akin to the tuffs from "Bare Rocks" mentioned on jjage 110 

 of the official report. 



Termination Rock. 2 (summit). — Some small specimens of black vesi- 

 cular l)asalt. 



Termination Rock, 3 (summit). — A dark-grey slabby rock, with slight 

 green shade ; shows a little tabular feldsi)ar. Microlitic groundmass very 

 ill-defined feldspars, small irregular prisms and pairs of very pale-green 

 augite, sphene, magnetite. The larger constituents are feldspars, chiefly 

 in elongated forms, but at places stouter ; nearly all ill-bounded, and many 

 so crowded with microlites that it is only between crossed nicols that they 

 can be distinguished. There are a few augites slightly larger than the 

 general run, but these are rendered practically opaqu(^ by minute magnetite. 

 Trachyte. 



