BY THE REV. J- E. TENISON-^YOODS, F.G.S., &C. 719 



the face of them a stamp of probability which is fully warranted 

 by the facts of the case. 



The theoi-y receives new support from what has been recently 

 observed in connection with volcanic eruptions, and a reflection on 

 what really takes place during their continuance. It must be 

 obvious that such immense deposits of tufa can only have been 

 supplied by the transfer of enormous quantities of material from 

 below. The cavities and chasms thus caused in the course of time 

 must have been so great as to defy calculation. Just imagine the 

 amount of material scooped out from great depths to cover the 

 surface for nearly 100 miles north of Taal, and 10 to 30 miles 

 wide. It w^ould be hardly possible for so much of the lower 

 portions of the earth's crust to be taken away without subsidences 

 and failure of support in some direction. When even the much 

 more moderate subterranean excavations of our mining operations 

 cause land-slips and extensive suljsidences, how much more likely 

 is it to anticipate some failure of support from the unceasing 

 activity of a volcano. There is little doubt that it was to some 

 such cause as this that the catastrophe of Krakatoa owed its origin. 

 That island-volcano had been belching forth for months unceasingly 

 rock-material in the form of ashes and scorite, until the land for 

 more than 100 miles, and much of the intervening sea, were strewn 

 thickly with them. At last it would seem that the cavity thus 

 arising allowed full entry of the sea to the innermost depths, where 

 the subterranean fires were raging. Hence the awful explosions 

 which were heard in terrific distinctness 900 miles away ; hence 

 the concussions which disturbed the very foundations of the earth, 

 until at last the earth's crust collapsed, the island-crater toppled 

 over and fell in, and the regurgitation of the water carried dreadful 

 destruction on to the neighbouring lands in the form of tidal waves. 

 The island-crater of Krakatoa was partly submerged and dis- 

 appeared. Fragments of the crater-walls, now raised in broken 

 and precipitous faces to 1,.500 ft. and more above the waters, are 

 memorials of the way in which the volcano was torn and split 

 asunder, but where its highest wall stood is now marked by 100 

 fathoms of ocean. 



