330 



Sontlicni Cross. 



similar to those in thu basalts, are seen in a groundniass of I'elspar 

 laths, nia,i,'netic grains and ragged shreds of dull green ajgirine- 



augite. 



These rocks certainly have very similar characters to those of the 

 phonolitic rocks from Africa, but they also present perhaps even 

 more strikincj resemblances to rocks from a nearer locality, viz., the 

 Hunedin I )istrict. New Zealand. Phonolitic rocks from the top of 

 FIa;4Stan' Hill, Dunedin, in the Museum Collection, show phenocrysts 

 of anorthoclase, partially reabsorbed basaltic hornblende, and pale 

 green augites in a ground-mass of felspar laths and feathery tufts of 

 ;egirine-augite, as in the case of the rocks described above ; pheno- 

 crysts of olivine, suiTOunded by eegirine-augite, are also generally 

 present in small amount. These rocks which occur with basalts are 

 of early Tertiary age, and are, in fact, associated with Palseozoic 

 rocks, consisting of clay-slates and schists, as in the case of these 

 Antarctic rocks. 



A pumiceous rock, found by Mr. Bernacchi on the top of Cape 

 Adare, probably belongs to the same "kenyte" series. It consists of 

 a highly vesicular, nearly colourless glass, crowded witii gas-pores and 

 dark, dusty inclusions, and containing phenocrysts of large, much 

 corroded anorthoclase felspars, pleochroic (pale yellow to pale green) 

 diopside-like augites, and, very sparingly, olivine and basaltic 

 hornblende. 



A pale rhyolitic-looking rock, found by Lieutenant Colbeck at 

 Wood Bay, Xewnes Land, is of a somewhat similar character, but 

 less glassy. The same phenocrysts of anorthoclase, together with 

 olivine and pale green augite in very small amount, occur in a very 

 tine grained base, consisting of minute felspar laths showing flow 

 structure. 



A tuff from Protection Cove, near the junction of the basalt with 

 the slate, contains, Itesides fragments of basalt, also small fragments 

 of a glas.sy rock speckled with magnetite ; it shows in some cases 

 perlitic structure, and also rarely phenocrysts of felspar and a pale 

 greenish-yellow augite (see PL LIII., lig. (i). 



CONCLUSIONS. 



The granite rocks found a.s boulders on Cape Adare, together with 

 mica-schists and gneisses, such as were dredged by the ' Challcnfjrr," 

 ]»roVial»ly constitute the basement rocks of Victoria Land, underlying 

 tlie slate. 



