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TK1STAN DA CUNHA. 127 



bility, and one of the surveyors started off jauntily to go to the 

 top of the Peak and make a surveying station. On closer 

 inspection, however, the real state of the case might be inferred, 

 for there was plainly visible a dark sinuous line leading from 

 the sea, right inland through the thickest of the tussock. This 

 was a great penguin road, and the whole place was one vast 

 penguin rookery, and the grass that looked like turf to walk on, 

 was higher than a man's head. 



I made out with my glass a great drove of penguins on the 

 rocks under the termination of the road, and I went below at 

 once to put on my thickest gaiters. 



We pulled on shore through beds of kelp, and landed on 

 shelving rocks leading up to caves, the haunt of the Fur Seals in 

 the proper season. We met the surveyors coming back, well 

 pecked and dead beat, having given up the Peak in despair. 



The shelving rock is composed of volcanic conglomerate, full 

 of irregular fragments and rounded lumps of hard basalt, and 

 various scoriaceous forms ; in places also of a similarly deri- 

 vative rock of a reddish colour, but devoid of larger embedded 

 fragments. In a cliff about forty feet in height, adjoining and 

 rising from the shelves, are beds of fine-grained volcanic sand- 

 stone rock, banded yellow and black, and horizontally bedded, 

 probably of submarine formation. 



These beds constitute the whole mass of two or three small 

 outlying rocks or islands lying to the N.E., and are there also 

 horizontal. These beds appear about twenty feet thick in the 

 cliff, and above them is a layer of basalt of about the same 

 thickness, which extends east and west, capping the softer beds 

 and conglomerates. This layer is evidently a lava flow of com- 

 paratively late date, as it seems to have run down the valley 

 between the two ridges, and to have come from the south ; its 

 upper surface is a little rounded, higher in the centre, and 

 thinning off at the edges, as may be seen in the section exposed 

 in the cliff. 



It is on the almost level upper surface of this flow, that the 

 great penguin rookery lies. The island has evidently, like 

 Inaccessible Island, undergone immense denudation, and there 

 is no trace of any centres of action remaining. In the low cliffs 



