68 THE RIDGWAY FAULT. 



greater. So, too, in the great eruption of Krakatoa, in the Straits 

 of Sumla, in August, 1883, the most appalling results were produced 

 with which we are familiar in modern times. It appears that the 

 explosion, which resulted from an inrush of sea water into the 

 crater of the volcano during a period of great activity, rent the 

 crater of Krakatoa in two parts, of which one part remained, 

 whilst the other entirely disappeared, and that the spot, where one* 5 

 was the apex of a mountain, is now covered by the sea to a depth 

 of 164 fathoms. 



In what way, then, was this great effect produced, which, 

 resulting in the upraising of the anticlinal axis of Weymouth, 

 Purbeck, and the Isle of Wight and parallel to it the axis of the 

 Weald comprised the fractures of the solid crust, of which the 

 Ridgway Fault is amongst the chief ? 



In February last I made a visit to the Ridgway cutting, 

 accompanied by Mr. H. J. Moule. We walked from Upwey 

 station to the tunnel, and in this way approached it from the south. 

 The bold face of the chalk escarpment seen from this side is very 

 striking, and the outlying patch of Eocene sand and gravel on the 

 top of Ridgway Hill forms a very noticeable feature in the land- 

 scape. The materials composing this survival of the Eocene beds 

 have been extensively quarried for economic purposes, and the 

 steep yellow coloured sides of the gravel pits form a strong 

 contrast to the more undulating surface of the surrounding chalk. 

 The railway crosses Ridgway Hill by means of two tunnels with a 

 cutting between them, the short tunnel to the south and nearer 

 Weymouth, passing chiefly through Purbeck beds, whilst the 

 principal tunnel, nearer Dorchester, is excavate I through the 

 chalk. The sections lying between the two tunnels are now almost 

 obliterated owing to the growth of vegetation upon them, whilst 

 the dip of the beds can scarcely be estimated since the surface soil 

 has been washed down from above to such an extent as to render 

 the identification almost impossible. Clay appears to occupy a 

 large portion of the space, but intermingled with the beds of 

 clay there occur bands of sandy character, dipping towards 



