VI THE GORGE OF THE AAR AND ITS TEACHINGS 133 



quently overhang and then recede again, so that it is only 

 here and there that they are sufficiently vertical to enable 

 us to catch a glimpse of the sky, and wherever we do so 

 we see that the upper edges of the chasm are little, if any, 

 farther apart than are the rock-walls between which we 

 walk. The whole surface of the rock — a hard crystalline 

 limestone — is evidently water- worn, never presenting sur- 

 faces due to fracture except perhaps where a lateral stream 

 enters by a picturesque cascade falling over a vertical 

 rock, and where the gorge opens out so that daylight and 

 sunlight freely enter it. The artificial causeway tinishes 

 where a dry lateral gorge, with a steeply rising floor of 

 earth and vegetable debris, affords an exit to the plateau 

 and the road from Meiringen. This short lateral gorge is 

 of especial interest, because it reproduces in almost every 

 detail the features of the main gorge, being about the 

 same average width, having similar walls of hollow cur- 

 vilinear form, and being equally narrow to the very top. 

 This lateral gorge is, however, quite dry, and even in the 

 wettest seasons can hardly have more than a trickle of 

 water because it has no catchment basin, opening out as it 

 does on the top of the bossy limestone rocks of the narrow 

 ridge of the Kirchet. Hence we reach the important 

 conclusion that this gorge could not have been formed by 

 water derived from ordinary streams, unless at a period so 

 remote that the whole surface contours of the district were 

 very different from what they are now. The only explana- 

 tion that seems to accord with the facts is, that we have 

 here the result of the action of sub glacial torrents acting 

 throughout the whole period during which the area was 

 buried in ice. Thus only are we able to explain the 

 fact of the almost uniform narrowness of the gorge from 

 bottom to top, since during the process of its formation 

 the rock-walls would be preserved from ordinary denuding 

 agencies, probably by a plug of ice, and be kept at a nearly 

 uniform temperature. Hence we have the actual surface 

 as it was left by the glacial waters, and its extreme narrow- 

 ness together with the luxuriant vegetation which covers 

 the plateau and fringes the edge of the chasm, aided also 

 by the comparatively mild climate of the lower valley, 



