128 A NATURALIST ON THE "CHALLENGER." 



of the coast, numerous caves are formed by the eating out by 

 waves of the softer strata underlying the hard cap of basalt. 



The caves are so numerous as to form a striking feature in 

 the appearance of the island as it is approached from seawards ; 

 such caves are not apparent at Inaccessible or Tristan da 

 Cunha Islands. 



The caves with the sloping ledges leading up to them, are 

 frequented as was said by fur seals. Four years before 1,400 seals 

 had been killed on the island by one ship's crew ; they are much 

 scarcer now, but the island is visited regularly once a year by 

 the Tristan people, as is also Inaccessible Island. The Germans 

 only killed seven seals at Inaccessible Island, but the Tristan 

 people killed forty there in December, 1872. Two seals were 

 seen by us in the water about the rocks, but none on land. 



The sloping rock ledges are covered with a thin coating of 

 dark green ulva, which, when dry, has a peculiar almost metallic 

 glance. A short scramble up the rocks brought us at once face 

 to face with the tall grass and penguins. 



The party broke up into small groups, each choosing what it 

 thought the best route for penetrating the enemy's country. I 

 made along the rocks to the point where, as I had seen from 

 the ship, the main street ended : here were hundreds of penguins 

 coming from and going to the sea in droves, or hurrying along 

 singly to catch up some drove, or lolling about on the rocks, 

 basking ; the moving ones going along hop, hop, hop, just like 

 men in a sack race. 



The hard rock was actually polished, and had its irregu- 

 larities smoothed oft' where the feet of the birds had worn it 

 down at the entrance to the street. No doubt the Diatom 

 skeletons present in the food and dung of the penguins, and 

 always in abundance in the mud of their rookeries, adhering to 

 their dirty feet, acts as polishing powder and assists the wearing 

 process. 



The street did not open by a single definite mouth towards 

 the sea, but split up into numerous channels leading down to a 

 number of easy tracks through the rocks. A little way in there 

 was a clear open track six feet wide, and in places as much 

 as eight or ten feet in width. 



