Canon Bonne// — Moraines and Mud-streams in the Alps. 9 



of shale and friable rock, when there is a certain admixture of boulders 

 from a distance (formerly perched blocks), its origin is not so readily 

 determined. The enormous mass of debris on the north bank of the 

 Eheinthal, between Chur and Ilanz — a mass which extends from 

 Digg, through Flims, to rather beyond Laax, consisting of earthy 

 stuff, probably mainly smashed shale or slate, and of boulders, 

 apparently limestone — is regarded as bergfall by the Swiss geologists, 

 and yet any section in it might readily be taken for moraine. Even 

 more moraine-like in general aspect are the singular mounds of debris 

 in the valley of the Khone near Sierre. These consist of a clayey 

 material full of small rock fragments, angular and subangular, 

 which are generally less than an inch in diameter, and seldom 

 exceed four or five inches, though now and then a large boulder 

 occurs. Of these fragments the majority are dark limestone, some- 

 times slaty ; a small proportion, generally more water- worn, being 

 gneiss or schist. These mounds are regarded as the relics of 

 a great bergfall, but were it not for the paucity of crystalline 

 rock, especially among the boulders, they might well be passed as 

 moraines, for their relation to the slope down which the material 

 has descended is not obvious at a glance. 



The debris deposited by flooded torrents often closely resembles 

 moraine. I may quote a few instances from my own experience. 

 At Zinal in July, 1895, we heard, late one evening, an extraordinary 

 roaring noise, which proved to be caused by the descent of a mass 

 of grit and boulders mingled with water, which had issued from 

 a glen on the eastern flank of the valley.^ This formed a great fan 

 of debris (not very unlike moraine, except perhaps subangular 

 fragments were commoner), which had flowed down to the river. 

 I once actually watched a similar occurrence, the result of a violent 

 rainstorm, at Les Ouches, near Chamonix. Thousands of cubic feet 

 of black liquid mud and broken shale or slate came sweeping 

 down a gully and buried the high road for some distance. I passed 

 over another discharge of flood debris in the Zillerthal a few days 

 after it had descended. Here the valley was rather broad, the 

 carriage-road running along it near the lowest part. The discharge, 

 which had been caused by a local 'cloud-burst,' had come from the 

 mountain slopes on the left bank and had followed the path of two 

 small streams. The first had affected the larger area, having buried 

 everything — road, gardens, fields, thickets — under a mass of debris, 

 a mixture of mud and rock fragments, small and large. There 

 were hundreds, nay, thousands of blocks, in shape and size like 

 portmanteaux. A wooden chalet had been torn up and swept along 

 like an empty packing-case for about 200 yards. Here, though no 

 doubt could arise as to the nature of the deposit, the material itself 

 was not very unlike a moraine of the lowlands. Again, the road 

 and the railway in the Rhone Yalley near Monthey cut through 

 an enormous mass of material, which might easily be taken for 

 moraine, as it is a mixture of mud and rock fragments of various 



^ I was informed that the stream, some two or three thousand feet above Zinal, 

 had been dammed by a slight landslip till the ponded-back water burst the barrier. 



