518 



APPENDIX. 



[No. li 



water flowing into the Salt River gives it a very bitter taste, which it retains 

 until near its junction with the Slave River, when the addition of some fresh 

 water streams renders it only slightly brackish, A few patches of greyish 

 compact gypsum were exposed on the side of the ridge from whence the springs 

 issue, a fact which seems to point out the upper part of the new red sand- 

 stone, as the formation from whence they take their rise. A pure white gypsum 

 is said to be found at Peace Point in Peace River, which is probably a continua- 

 tion of this formation. The salt plains are much frequented by deer and buffalo. 



The banks of Slave River, below the influx of Salt River, are, as have been 

 already mentioned, entirely alluvial. A great quantity of large drift timber 

 is brought down by Peace River ; and as the trees retain their roots, which 

 are often loaded with earth or stones, they readily sink, especially when 

 water soaked, and accumulating in the eddies, form shoals which ultimately 

 augment into islands. A thicket of small willows covers the new-formed 

 island as soon as it appears above water, and their fibrous roots serve to bind 

 the whole firmly together. Sections of these islands are annually made by 

 the river, assisted by the frost ; and it is interesting to study the diversity of 

 appearances they present, according to their different ages. The trunks of 

 the trees gradually decay until they are converted into a blackish-brown sub- 

 stance resembling peat, but which still retains more or less of the fibrous 

 structure of the wood, and layers of this often alternate with layers of clay 

 and sand, the whole being penetrated to the depth of four or five yards or more 

 by the long fibrous roots of the willows. A deposition of this kind, with the aid 

 of a little infiltration of bituminous matter, would produce an excellent imitation 

 of coal with vegetable impressions of the willow root. What appeared most 

 remarkable was the horizontal slaty structure that the older alluvial banks pre- 

 sented, or the regular curve that the strata assumed from unequal subsidence. 

 It was on the rivers only that we could observe sections of these deposits, but 

 the same operation goes on in a much more magnificent scale in the lakes. A 

 shoal of many miles in extent is formed on the south side of Athabasca Lake, 

 by the drift timber and vegetable debris brought down by the Elk River ; and 

 the Slave Lake itself must in process of time be filled up by the matters daily 

 conveyed into it from Slave River. Vast quantities of drift timber are buried 

 under the sand at the mouth of the river, and enormous piles of it are accu- 

 mulated on the shores of every part of the lake. The waves, washing up much 

 disintegrated vegetable matter, fill the interstices of these entangled masses, 



