326 Southcni Cross. 



from ("ape Arlare consists of a fragmental ai,'gre<,'ate of sub-an<,Milar 

 j,Maiiis »»f ([uartz and a little felspar with shreds of muscovite and 

 green altered biotite: deep red doubly -refractive grains of rutile 

 and rounded grains of zircon are also present. 



A specimen from tleikie Land is nearly colourless, as it contains 

 very little chlorite. Besides angular grains of quartz shovi^ing undu- 

 lose extinction, it contains grains of twinned oligoclase in a paste of 

 what appears to be secondary quartz, with shreds of muscovite and a 

 little chlorite. 



The fragmental material of these grits has probably been derived 

 from granitic or gueissic rocks. 



BASALTS. 



These rocks are for the most part fine-grained, compact, glassy, 

 liornblende-basalts, similar to those from Cape Adare and Possession 

 Island in Mr. Borchgrevink's earlier collection, and in the Koss 

 collection, which have been previously described. They contain 

 small phenocrysts of basaltic hornblende, undergoing reabsor]^tion, 

 and often only represented by pseudomorphs of magnetite and augite, 

 in a deep brown glassy base of sharply-defined felspar laths, grains 

 of magnetite, minute rhombic sections of olivine, and a little augite 

 (see 1*1. LIIL, fig. 5). Only rarely is a much corroded phenocryst of 

 lelspar seen in these rocks, and small pale purple augite phenocrysts 

 accompanying the hornblende are only present in some specimens in 

 small amount. 



Ijasalts of this character come from Coulman Island and I'roni 

 the foot of Mouut Terror, as well as from Cape Atlare and I'ossession 

 Island, and all probably belong to contemporaneous and recent Hows. 



A cliemical analysis of the hornblciule-basalt from the foot of 

 Mount Terror gave the following result: — 



'J9-45 



