1S60.] Account of a visit to Barren Island. 3 



with a smooth fracture, but from the upper surface to a depth of 

 several feet it is cleft in all directions, whereby the upper part is 

 divided into rough blocks, possessing a spongy texture as well as 

 countless sharp edges and corners. 



The older lava, composing the rocks on the side of the valley and 

 also the strata of the surrounding ridge is slighty different from this. 

 The colour of its principal mass is a reddish grey, felspar and olivine 

 crystals are embedded in it in the same proportions as before, and in 

 addition small pieces of black augite of the granular kind, with con- 

 choidal fracture. From underneath the black lava, where it termin- 

 ates near the sea, issues a broad but thin sheet of hot water, mixing 

 with the sea water between the pebbles of the beach. The Ther- 

 mometer I had with me was not graduated high enough to measure 

 its temperature, its highest mark being 104° F. (40° C.) The water 

 where escaping from the rock must have been nearly at the boiling 

 point, judging from the heat felt when the hands were dipped into 

 it, or when the hot stones were touched. When bathing, we found 

 the sea water warm for many yards from the entrance of the hot 

 spring and to a depth of more than 8 feet. It is not impossible that 

 a jet of hot steam or water may emerge from the rocks below the 

 level of the sea. The hot water tasted quite fresh, and not saline as 

 might have been expected, showing that it could not have been long 

 in contact with the rocks. 



We ascended to the base of the cone, passing along the sloping 

 sides of the transverse valley through dry grass and brushwood or 

 over sandy ridges, so long as the solidified stream of lava in the mid- 

 dle left us room to do so. At last we had to ascend the rugged sur- 

 face of the black lava itself, and cross the circular vallej'", which has 

 about the same breadth as the transverse valley (not quite one-eighth 

 of a mile), until we arrived at the base about half a mile from the sea. 

 The cone rises from the lava accumulated in the circular valley, and its 

 base is about 50 feet higher than the level of the sea, at a rough esti- 

 mate. It is quite round and smooth, and the inclination of its sides is 

 40 degrees. No vegetation of any kind was visible along its surface. 

 We turned to the left and went up from the north side, where the 

 appearance of a ravine, some way up, only two or three feet deep and 

 very narrow with some tufts of grass growing along it, promised an 



b 2 



