Chap. i.x. 



DENUDED CRATER. 



193 



show very distinct ripple marks and lines of flow, and the rock- 

 mass is evidently a comparatively recent lava flow from a small 

 broken-down crater which stands on the shore close by. 



The remains of the crater are now in the form of three 

 fantastic irregularly conical masses, composed of very numerous 

 thin layers of scoriae, conspicuous because of their varying and 

 strongly contrasted colours and very irregular bedding. The 

 lava flow is seen in section in the low cliffs forming the coast- 

 line of the harbour. 



The present condition of Heard Island is evidently that which 

 obtained in Kerguelen's Land formerly. Glaciers once covered 



l;KOKh.N-UOVV.N CRAIKK, WHlbK.'l' liAV. Willi b.\U\V Ul'ON IT. 



Kerguelen's Land almost entirely, and dipped down into the 

 sea. It is, however, an extraordinary fact that Heard Island, 

 only 300 miles south of Kerguelen's Land, should thus still be 

 in a glacial epoch, whilst in Kerguelen's Land, a very much 

 larger tract, the glaciers should have shrunk back into the 

 interior, and have left so much of the land surface entirely 

 free of ice, the ice epoch being there already a thing of the 

 past. 



The great height of Big Ben, and consequent largeness of the 

 area where snow constantly accumulates and cannot be melted, 

 no doubt accounts to a considerable extent for the peculiar 

 conditions in Heard Island. A similar rapid descent of the 

 snow-Hne within a few degrees of latitude occurs in the Chilian 



