STREAMS OF STONES. 253 



quartz insensibly passes into the sandstone, it seems 

 probable that the former owes its origin to the 

 sandstone having been heated to such a degree 

 that it became viscid, and upon cooling crystallized. 

 While in the soft state it must have been pushed 

 up through the overlying beds. 



In many parts of the island the bottoms of the 

 valleys are covered in an extraordinary manner by 

 myriads of gi-eat loose angular fragments of the 

 quartz rock, forming "streams of stones." These 

 have been mentioned with surprise by every voy- 

 ager since the time of Pernety. The blocks are 

 not water-worn, their angles being only a little 

 blunted ; they vary in size from one or two feet in 

 diameter to ten, or even more than twenty times 

 as much. They are not thrown together into ir- 

 regular piles, but are spread out into level sheets 

 or great streams. It is not possible to ascertain 

 their thickness, but the water of small streamlets 

 can be heard trickling through the stones many 

 feet below the surface. The actual depth is prob- 

 ably great, because the crevices between the lower 

 fragments must long ago have been filled up with 

 sand. The width of these sheets of stones varies 

 from a few hundred feet to a mile ; but the peaty 

 soil daily encroaches on the borders, and even forms 

 islets wherever a few fragments happen to lie close 

 together. In a valley south of Berkeley Sound, 

 which some of our party called the " great valley of 

 fragments," it was necessary to cross an uninter- 

 rupted band half a mile wide, by jumping from one 

 pointed stone to another. So large were the frag- 

 ments, that, being overtaken by a shower of rain, I 

 readily found shelter beneath one of them. 



Their little inclination is the most remarkable 

 circumstance in these "streams of stones." On 

 the hill-sides I have seen them sloping at an angle 



