90 AUSTRALASIA. 



carrying awav headlands and excavating new inlets. All the works of man were 

 destroyed, and over forty thousand persons, overtaken during the terrible morning, 

 " blacker than the night," were overwhelmed in the deluge of waters rolling in 

 from the sea, or in the showers of mud and ashes falling from above. Within the 

 limits of the strait one man alone, a solitary lighthouse-keeper perched on his 

 watch-tower 130 feet above an isolated rock, escaped scatheless in the midst of the 

 surrounding pother. So dense was the darkness that he failed to notice the 

 mighty wave that submerged the lighthouse all but his lantern. 



Of Krakatau itself nothing remained but the southern volcano ; all the 

 northern heights, or about two-thirds of the island, some eight or ten miles in 

 circumference, had been blown to pieces, giving place to an abyss where the 

 sounding-line a thousand feet long failed to touch the bottom. From the 

 breached wall of the southern volcano rolled a continual avalanche of stones, while 

 the dust from the crumbling remains rose in clouds to the sky. But if some lands 

 had vanished, others, formed by vast heaps of pumice and ashes, were raised from 

 the bed of the sea. The island of Verlaten was more than doubled in size, and 

 heights appeared where the plummet had lately revealed depths of 230 feet. Other 

 islands, such as Sebesi, which had recently been covered with forests and human 

 habitations, now presented to the view nothing but a bare surface of whitish rock. 



To the new islands were added the floating masses of pumice, forming bars at 

 the entrance of the bays and for weeks and months blocking the passage to the 

 shipping. Gradually the action of the waves and marine currents swept the strait 

 clear of these floating islands and heaps of emerged scoria) ; but the submarine 

 crater which was opened to the north of Xrakatau had held its ground. The 

 geological studies made on the spot show that this crater had previously existed, 

 and that the northern part of Krakatau was on the contrary of recent formation. 

 What remains of the volcano and adjacent islets of Verlaten and Lang are the 

 three outer fragments — the tripod, so to say — of a mountain over 6,500 feet high, 

 which at some former time rose above the present eruptive crater. 



Rivers of Sumatra. 



Although slower than the underground forces in their geological work, the 

 Sumatran rivers have been more powerful agents in modifying the aspect of the 

 land. The territory shown by its horizontal alluvial formation to be the creation 

 of the running waters may be estimated at nearly one-half of the whole island. 

 The sedimentar}^ rocks are seen disposed like strands along the base of the 

 coralline limestone cliffs, which formed the primitive coastline on the eastern 

 slope of the Barisan uplands. Over two-thirds of the eastern seaboard is of quite 

 recent geological formation, and is still continually growing by the addition of 

 fresh deposits. 



On the west side of the island the action of the streams is far less considerable. 

 The catchment basins are not here of sufficient extent to convey seawards any 

 great quantity of sedimentary matter. Nevertheless, even on this slope the 



