I.] GEOLOGICAL OBSERVATIONS 335 



coarse-grained pink granite with phenocrysts of feldspar up to a 

 quarter of an inch across. This exposure has suffered denudation, 

 and it is here that the type of hollowed crystalline rock with the 

 white incrustation occurs. Mr. Prior kindly analysed parts of 

 this incrustation for me, and tells me it consists mainly of carbonate 

 of lime. 



The hill on the east side of Descent Pass rises to a height of 

 4,900 feet, and consists mainly of granite with abundant large 

 crystals of orthoclase, and here the second type of cavity occurs. 

 On the north side of this hill, and in the Ferrar Glacier, the same 

 type of granite is found ; but in it occur basic dykes which, by 

 weathering, produce black patches visible on the hill-side at a 

 distance of at least eight miles. 



Dr. Koettlitz collected granitic and gneissic rocks from an 

 exposure more than 3,000 feet above sea level in the transverse 

 valley at the east foot of the Royal Society Range, while the author 

 obtained quite a normal grey granite from one of the neighbouring 

 isolated hillocks. 



The gneiss of Cathedral Rocks is overlain by a mass of granite 

 nearly 4,000 feet thick, which appears to build up this the northern 

 extremity of the Royal Society Range. Dykes of both grey and 

 pink granite ramify into the gneiss, but as a whole the granite has 

 nearly horizontal upper and lower surfaces, which can be traced 

 round the spurs of the range for a distance of four or five miles up 

 the south arm on the western side. At the foot of the first of the 

 three shoulders which go to form the Cathedral Rocks, a tongue of 

 granite appears to burst through the gneiss from below. This 

 tongue is mainly grey in colour, but great masses of pink feldspar 

 rock seem to have been caught up in it ; but the masses become 

 scarcer as one proceeds eastward along the foot of the cliff. The 

 connection of this granite with that of the hill on the east side of 

 Descent Pass has not been established owing to the glaciers which 

 descend from the valleys at the foot of the Camel's Hump. 



Granite has been obtained from three spots on the north side 

 of the Ferrar Glacier, or rather on the north side of the East 

 Fork. 



The mountain north-east of Cathedral Rocks rises to a fine 

 gable nearly 7,000 feet high, but does not rise much above the 

 mountains to the west, of which it is a part. The gable is about 

 5,000 feet above the ice, and of this height 4,000 feet appear to be 

 of granite, and a specimen of augen-gneiss taken from the foot is 



