98 /. G. ANDERSSON 



present an undulating land surface built up by slightly folded 

 Devonian beds and evidently subjected for a long time to subaerial 

 denudation. With the exception of some resistant quartzite ridges, 

 they, and especially the eastern island, are far advanced toward 

 the peneplain. The land is woodless over large areas, and occu- 

 pied by peat-bogs, the drier places forming grass steppes and the 

 very driest heaths covered by Eupetrum rubrum. 



This landscape, as bewildering through the monotony of its outlines 

 as deterring through its ugliness, boasts a natural phenomenon that 

 may be unparalleled in the world. The "stone-rivers," which 

 form a beloved object of the fancy of the population, were lucidly 

 described by Charles Darwin, though he could not find a satis- 

 factory explanation; but a later visitor. Sir Wyville Thomson, 

 got very near to a proper understanding of the thing. In order 

 to demonstrate the process in question, I quote the condensed des- 

 cription given by the eminent naturahst of the "Challenger:" 



In the East Island most of the valleys are occupied by pale gray glistening 

 masses, from a few hundred yards to a mile or two in width, which look at a 

 distance much like glaciers descending apparently from the adjacent ridges, 

 and gradually increasing in volume, fed by tributary streams, until they reach 

 the sea. Examined a little more closely, these are found to be vast accumula- 

 tions of blocks of quartzite, irregular in form, but having a tendency to a rude 

 diamond shape, from two to eight or ten or twenty feet long and perhaps half 

 as much in width, and of a thickness corresponding with that of the quartzite 

 bands in the ridges above. The blocks are angular like the fragments in a 

 breccia, and they rest irregularly one upon the other, supported in all positions 

 by the angles and edges of those beneath.' 



There can be no doubt that the blocks of quartzite in the valleys are derived 

 from the bands of quartzite in the ridges above, for they correspond with 

 them in every respect; the difficulty is to account for their flowing down the 

 valley, for the slope from the ridge to the valley is often not more than six to 

 eight degrees, and the slope of the valley itself only two or three, in either case 

 much too low to cause blocks of that form either to slide or to roll down. 



The process appears to be this: The beds of quartzite are of very different 

 hardness; some are soft, passing into a crumbling sandstone; while others are 

 so hard as to yield but little to ordinary weathering. The softer bands are 

 worn away in process of time, and the compact quartzites are left as long pro- 

 jecting ridges along the crests and flanks of the hill ranges. When the process 

 of the disintegration of the softer beds has gone on for some time, the support 



^Thomson, The Atlantic, p. 245. 



