326 THE VOYAGE OF THE 'DISCOVERY' [Appx. 



a basaltic dyke which was exposed at the north end. The rocks of 

 this island appear to lie horizontally as a whole, but an anticline on 

 the west side shows that they have been gently folded over an east- 

 and-west axis. 



Franklin Island has been visited three times, the first time by 

 Ross, who describes the north side as ' a line of dark precipitous 

 cliffs between 500 and 600 feet high, exposing several longitudinal 

 broad white bands, two or three being of a red ochre colour.' 

 The specimens he collected are all of basalt of the same type, and 

 in the 'Southern Cross' collection there is a specimen of limbrugite 

 remarkable for the number and large size of the olivine enstutite 

 nodules. Mr. J. D. Morrison, of the 'Morning' supplied similar 

 specimens with a note to the effect that this rock ' forms a belt 

 about 30 feet thick running horizontally along one side about 300 

 feet above sea level.' In addition he mentions a pebbly beach 

 similar to that at Cape Adare, and therefore probably due to the 

 same cause. 



Ross Island Group. 



This group of islands includes practically all the land within 

 fifty miles of the ' Discovery's ' Winter Quarters, and is by far the 

 most extensive mass not attached to the mainland. The rocks of 

 which these islands are composed are all volcanic, and point to 

 volcanic activity of the first magnitude, which dates back from the 

 present day, but does not quite bridge over the very long period 

 since the intrusion of the dolerite sheets on the mainland. 



Ross Island is practically made up by the material ejected from 

 the four volcanoes, Erebus, Terror, Bird, and Terra Nova. It is 

 roughly triangular in shape, and measures almost exactly fifty 

 miles from north to south and from east to west. 



Mount Erebus, in the year 1841, was observed to be emitting 

 flame and smoke in great profusion, but during the years 1902-1903 

 only steam was seen to be produced. The mountain rises more as 

 a dome than as a cone, and the flowing convex curves give it a 

 very massive and undenuded aspect. It appears to have been 

 built up in three stages, the activity becoming less as each stage 

 was completed. The earliest stage is marked by a girdle of rock 

 encircling the mountain at a height of about 6,000 feet above sea 

 level, which on the north side appears as a huge crag. The 

 second stage ended with the production of a crater at about 11,000 

 feet above sea-level, and the lava streams which issued from it are 



