68 THE SANDY SEA. 



some other hollow. The coarse thick grass also now 

 protects much of the outer slopes. 



As I carried my barometer to-day myself, and 

 the ponies seemed by no means so sure-footed as 

 mountain horses usually are, I walked a good part 

 of the way along the summit of the ridge, which 

 we traversed for several miles, until we had gone 

 about a third of the way round the interior " Sandy 

 sea." It then became so far degraded and 

 lowered, and the inner slope so far changed from 

 a precipice to a steep bank, that by means of a 

 zig-zag path the descent became practicable. At 

 this part of the Sandy sea, where we descended 

 into it, which I think was on the south-western 

 side, the bottom of the great crater had gradually 

 risen to a higher level than on the other, and it was 

 partially covered with grass. As we proceeded 

 however, to ride back again along the Sandy sea, at 

 the foot of the precipitous wall, of 'which we had 

 just traversed the summit, the grass disappeared, 

 and we trod a gently sloping and slightly undulating 

 plain of black volcanic sand, pretty firmly com- 

 pacted together. We could now perceive that the 

 great wall of the Ider-Ider was not absolutely built 

 of soil or clay, as thick beds of stone shewed them- 

 selves in the face of the precipice, capped, however, 

 by 60 or 70 feet of what appeared to be loose earth. 

 These beds seemed to be horizontal in the face of 

 the precipice, but no doubt dipped outwards down 

 the flanks of the mountain, of which dip occasional 



